// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//
// ignore-lexer-test FIXME #15677

//! Simple getopt alternative.
//!
//! Construct a vector of options, either by using `reqopt`, `optopt`, and `optflag`
//! or by building them from components yourself, and pass them to `getopts`,
//! along with a vector of actual arguments (not including `argv[0]`). You'll
//! either get a failure code back, or a match. You'll have to verify whether
//! the amount of 'free' arguments in the match is what you expect. Use `opt_*`
//! accessors to get argument values out of the matches object.
//!
//! Single-character options are expected to appear on the command line with a
//! single preceding dash; multiple-character options are expected to be
//! proceeded by two dashes. Options that expect an argument accept their
//! argument following either a space or an equals sign. Single-character
//! options don't require the space.
//!
//! # Example
//!
//! The following example shows simple command line parsing for an application
//! that requires an input file to be specified, accepts an optional output
//! file name following `-o`, and accepts both `-h` and `--help` as optional flags.
//!
//! ```{.rust}
//! extern crate getopts;
//! use getopts::{optopt,optflag,getopts,OptGroup,usage};
//! use std::os;
//!
//! fn do_work(inp: &str, out: Option<String>) {
//!     println!("{}", inp);
//!     match out {
//!         Some(x) => println!("{}", x),
//!         None => println!("No Output"),
//!     }
//! }
//!
//! fn print_usage(program: &str, opts: &[OptGroup]) {
//!     let brief = format!("Usage: {} [options]", program);
//!     print!("{}", usage(brief, opts));
//! }
//!
//! fn main() {
//!     let args: Vec<String> = os::args();
//!
//!     let program = args[0].clone();
//!
//!     let opts = &[
//!         optopt("o", "", "set output file name", "NAME"),
//!         optflag("h", "help", "print this help menu")
//!     ];
//!     let matches = match getopts(args.tail(), opts) {
//!         Ok(m) => { m }
//!         Err(f) => { panic!(f.to_string()) }
//!     };
//!     if matches.opt_present("h") {
//!         print_usage(program, opts);
//!         return;
//!     }
//!     let output = matches.opt_str("o");
//!     let input = if !matches.free.is_empty() {
//!         matches.free[0].clone()
//!     } else {
//!         print_usage(program, opts);
//!         return;
//!     };
//!     do_work(input, output);
//! }
//! ```


// Do not remove on snapshot creation. Needed for bootstrap. (Issue #22364)
#![cfg_attr(stage0, feature(custom_attribute))]
#![crate_name = "getopts"]
#![unstable(feature = "rustc_private",
            reason = "use the crates.io `getopts` library instead")]
#![staged_api]
#![crate_type = "rlib"]
#![crate_type = "dylib"]
#![doc(html_logo_url = "http://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
       html_favicon_url = "http://www.rust-lang.org/favicon.ico",
       html_root_url = "http://doc.rust-lang.org/nightly/",
       html_playground_url = "http://play.rust-lang.org/")]

#![deny(missing_docs)]
#![feature(staged_api)]
#![feature(str_words)]
#![feature(str_char)]
#![cfg_attr(test, feature(rustc_private))]

#[cfg(test)] #[macro_use] extern crate log;

use self::Name::*;
use self::HasArg::*;
use self::Occur::*;
use self::Fail::*;
use self::Optval::*;
use self::SplitWithinState::*;
use self::Whitespace::*;
use self::LengthLimit::*;

use std::fmt;
use std::iter::repeat;
use std::result;

/// Name of an option. Either a string or a single char.
#[derive(Clone, PartialEq, Eq, Debug)]
pub enum Name {
    /// A string representing the long name of an option.
    /// For example: "help"
    Long(String),
    /// A char representing the short name of an option.
    /// For example: 'h'
    Short(char),
}

/// Describes whether an option has an argument.
#[derive(Clone, Copy, PartialEq, Eq, Debug)]
pub enum HasArg {
    /// The option requires an argument.
    Yes,
    /// The option takes no argument.
    No,
    /// The option argument is optional.
    Maybe,
}

/// Describes how often an option may occur.
#[derive(Clone, Copy, PartialEq, Eq, Debug)]
pub enum Occur {
    /// The option occurs once.
    Req,
    /// The option occurs at most once.
    Optional,
    /// The option occurs zero or more times.
    Multi,
}

/// A description of a possible option.
#[derive(Clone, PartialEq, Eq, Debug)]
pub struct Opt {
    /// Name of the option
    pub name: Name,
    /// Whether it has an argument
    pub hasarg: HasArg,
    /// How often it can occur
    pub occur: Occur,
    /// Which options it aliases
    pub aliases: Vec<Opt>,
}

/// One group of options, e.g., both `-h` and `--help`, along with
/// their shared description and properties.
#[derive(Clone, PartialEq, Eq, Debug)]
pub struct OptGroup {
    /// Short name of the option, e.g. `h` for a `-h` option
    pub short_name: String,
    /// Long name of the option, e.g. `help` for a `--help` option
    pub long_name: String,
    /// Hint for argument, e.g. `FILE` for a `-o FILE` option
    pub hint: String,
    /// Description for usage help text
    pub desc: String,
    /// Whether option has an argument
    pub hasarg: HasArg,
    /// How often it can occur
    pub occur: Occur
}

/// Describes whether an option is given at all or has a value.
#[derive(Clone, PartialEq, Eq, Debug)]
enum Optval {
    Val(String),
    Given,
}

/// The result of checking command line arguments. Contains a vector
/// of matches and a vector of free strings.
#[derive(Clone, PartialEq, Eq, Debug)]
pub struct Matches {
    /// Options that matched
    opts: Vec<Opt>,
    /// Values of the Options that matched
    vals: Vec<Vec<Optval>>,
    /// Free string fragments
    pub free: Vec<String>,
}

/// The type returned when the command line does not conform to the
/// expected format. Use the `Debug` implementation to output detailed
/// information.
#[derive(Clone, PartialEq, Eq, Debug)]
pub enum Fail {
    /// The option requires an argument but none was passed.
    ArgumentMissing(String),
    /// The passed option is not declared among the possible options.
    UnrecognizedOption(String),
    /// A required option is not present.
    OptionMissing(String),
    /// A single occurrence option is being used multiple times.
    OptionDuplicated(String),
    /// There's an argument being passed to a non-argument option.
    UnexpectedArgument(String),
}

/// The type of failure that occurred.
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
#[allow(missing_docs)]
pub enum FailType {
    ArgumentMissing_,
    UnrecognizedOption_,
    OptionMissing_,
    OptionDuplicated_,
    UnexpectedArgument_,
}

/// The result of parsing a command line with a set of options.
pub type Result = result::Result<Matches, Fail>;

impl Name {
    fn from_str(nm: &str) -> Name {
        if nm.len() == 1 {
            Short(nm.char_at(0))
        } else {
            Long(nm.to_string())
        }
    }

    fn to_string(&self) -> String {
        match *self {
            Short(ch) => ch.to_string(),
            Long(ref s) => s.to_string()
        }
    }
}

impl OptGroup {
    /// Translate OptGroup into Opt.
    /// (Both short and long names correspond to different Opts).
    pub fn long_to_short(&self) -> Opt {
        let OptGroup {
            short_name,
            long_name,
            hasarg,
            occur,
            ..
        } = (*self).clone();

        match (short_name.len(), long_name.len()) {
            (0,0) => panic!("this long-format option was given no name"),
            (0,_) => Opt {
                name: Long((long_name)),
                hasarg: hasarg,
                occur: occur,
                aliases: Vec::new()
            },
            (1,0) => Opt {
                name: Short(short_name.char_at(0)),
                hasarg: hasarg,
                occur: occur,
                aliases: Vec::new()
            },
            (1,_) => Opt {
                name: Long((long_name)),
                hasarg: hasarg,
                occur: occur,
                aliases: vec!(
                    Opt {
                        name: Short(short_name.char_at(0)),
                        hasarg: hasarg,
                        occur:  occur,
                        aliases: Vec::new()
                    }
                )
            },
            (_,_) => panic!("something is wrong with the long-form opt")
        }
    }
}

impl Matches {
    fn opt_vals(&self, nm: &str) -> Vec<Optval> {
        match find_opt(&self.opts[..], Name::from_str(nm)) {
            Some(id) => self.vals[id].clone(),
            None => panic!("No option '{}' defined", nm)
        }
    }

    fn opt_val(&self, nm: &str) -> Option<Optval> {
        let vals = self.opt_vals(nm);
        if vals.is_empty() {
            None
        } else {
            Some(vals[0].clone())
        }
    }

    /// Returns true if an option was matched.
    pub fn opt_present(&self, nm: &str) -> bool {
        !self.opt_vals(nm).is_empty()
    }

    /// Returns the number of times an option was matched.
    pub fn opt_count(&self, nm: &str) -> usize {
        self.opt_vals(nm).len()
    }

    /// Returns true if any of several options were matched.
    pub fn opts_present(&self, names: &[String]) -> bool {
        for nm in names {
            match find_opt(&self.opts, Name::from_str(&**nm)) {
                Some(id) if !self.vals[id].is_empty() => return true,
                _ => (),
            };
        }
        false
    }

    /// Returns the string argument supplied to one of several matching options or `None`.
    pub fn opts_str(&self, names: &[String]) -> Option<String> {
        for nm in names {
            match self.opt_val(&nm[..]) {
                Some(Val(ref s)) => return Some(s.clone()),
                _ => ()
            }
        }
        None
    }

    /// Returns a vector of the arguments provided to all matches of the given
    /// option.
    ///
    /// Used when an option accepts multiple values.
    pub fn opt_strs(&self, nm: &str) -> Vec<String> {
        let mut acc: Vec<String> = Vec::new();
        let r = self.opt_vals(nm);
        for v in &r {
            match *v {
                Val(ref s) => acc.push((*s).clone()),
                _ => ()
            }
        }
        acc
    }

    /// Returns the string argument supplied to a matching option or `None`.
    pub fn opt_str(&self, nm: &str) -> Option<String> {
        let vals = self.opt_vals(nm);
        if vals.is_empty() {
            return None::<String>;
        }
        match vals[0] {
            Val(ref s) => Some((*s).clone()),
            _ => None
        }
    }


    /// Returns the matching string, a default, or none.
    ///
    /// Returns none if the option was not present, `def` if the option was
    /// present but no argument was provided, and the argument if the option was
    /// present and an argument was provided.
    pub fn opt_default(&self, nm: &str, def: &str) -> Option<String> {
        let vals = self.opt_vals(nm);
        if vals.is_empty() {
            None
        } else {
            match vals[0] {
                Val(ref s) => Some((*s).clone()),
                _ => Some(def.to_string())
            }
        }
    }

}

fn is_arg(arg: &str) -> bool {
    arg.len() > 1 && arg.as_bytes()[0] == b'-'
}

fn find_opt(opts: &[Opt], nm: Name) -> Option<usize> {
    // Search main options.
    let pos = opts.iter().position(|opt| opt.name == nm);
    if pos.is_some() {
        return pos
    }

    // Search in aliases.
    for candidate in opts {
        if candidate.aliases.iter().position(|opt| opt.name == nm).is_some() {
            return opts.iter().position(|opt| opt.name == candidate.name);
        }
    }

    None
}

/// Create a long option that is required and takes an argument.
///
/// * `short_name` - e.g. `"h"` for a `-h` option, or `""` for none
/// * `long_name` - e.g. `"help"` for a `--help` option, or `""` for none
/// * `desc` - Description for usage help
/// * `hint` - Hint that is used in place of the argument in the usage help,
///   e.g. `"FILE"` for a `-o FILE` option
pub fn reqopt(short_name: &str, long_name: &str, desc: &str, hint: &str) -> OptGroup {
    let len = short_name.len();
    assert!(len == 1 || len == 0);
    OptGroup {
        short_name: short_name.to_string(),
        long_name: long_name.to_string(),
        hint: hint.to_string(),
        desc: desc.to_string(),
        hasarg: Yes,
        occur: Req
    }
}

/// Create a long option that is optional and takes an argument.
///
/// * `short_name` - e.g. `"h"` for a `-h` option, or `""` for none
/// * `long_name` - e.g. `"help"` for a `--help` option, or `""` for none
/// * `desc` - Description for usage help
/// * `hint` - Hint that is used in place of the argument in the usage help,
///   e.g. `"FILE"` for a `-o FILE` option
pub fn optopt(short_name: &str, long_name: &str, desc: &str, hint: &str) -> OptGroup {
    let len = short_name.len();
    assert!(len == 1 || len == 0);
    OptGroup {
        short_name: short_name.to_string(),
        long_name: long_name.to_string(),
        hint: hint.to_string(),
        desc: desc.to_string(),
        hasarg: Yes,
        occur: Optional
    }
}

/// Create a long option that is optional and does not take an argument.
///
/// * `short_name` - e.g. `"h"` for a `-h` option, or `""` for none
/// * `long_name` - e.g. `"help"` for a `--help` option, or `""` for none
/// * `desc` - Description for usage help
pub fn optflag(short_name: &str, long_name: &str, desc: &str) -> OptGroup {
    let len = short_name.len();
    assert!(len == 1 || len == 0);
    OptGroup {
        short_name: short_name.to_string(),
        long_name: long_name.to_string(),
        hint: "".to_string(),
        desc: desc.to_string(),
        hasarg: No,
        occur: Optional
    }
}

/// Create a long option that can occur more than once and does not
/// take an argument.
///
/// * `short_name` - e.g. `"h"` for a `-h` option, or `""` for none
/// * `long_name` - e.g. `"help"` for a `--help` option, or `""` for none
/// * `desc` - Description for usage help
pub fn optflagmulti(short_name: &str, long_name: &str, desc: &str) -> OptGroup {
    let len = short_name.len();
    assert!(len == 1 || len == 0);
    OptGroup {
        short_name: short_name.to_string(),
        long_name: long_name.to_string(),
        hint: "".to_string(),
        desc: desc.to_string(),
        hasarg: No,
        occur: Multi
    }
}

/// Create a long option that is optional and takes an optional argument.
///
/// * `short_name` - e.g. `"h"` for a `-h` option, or `""` for none
/// * `long_name` - e.g. `"help"` for a `--help` option, or `""` for none
/// * `desc` - Description for usage help
/// * `hint` - Hint that is used in place of the argument in the usage help,
///   e.g. `"FILE"` for a `-o FILE` option
pub fn optflagopt(short_name: &str, long_name: &str, desc: &str, hint: &str) -> OptGroup {
    let len = short_name.len();
    assert!(len == 1 || len == 0);
    OptGroup {
        short_name: short_name.to_string(),
        long_name: long_name.to_string(),
        hint: hint.to_string(),
        desc: desc.to_string(),
        hasarg: Maybe,
        occur: Optional
    }
}

/// Create a long option that is optional, takes an argument, and may occur
/// multiple times.
///
/// * `short_name` - e.g. `"h"` for a `-h` option, or `""` for none
/// * `long_name` - e.g. `"help"` for a `--help` option, or `""` for none
/// * `desc` - Description for usage help
/// * `hint` - Hint that is used in place of the argument in the usage help,
///   e.g. `"FILE"` for a `-o FILE` option
pub fn optmulti(short_name: &str, long_name: &str, desc: &str, hint: &str) -> OptGroup {
    let len = short_name.len();
    assert!(len == 1 || len == 0);
    OptGroup {
        short_name: short_name.to_string(),
        long_name: long_name.to_string(),
        hint: hint.to_string(),
        desc: desc.to_string(),
        hasarg: Yes,
        occur: Multi
    }
}

/// Create a generic option group, stating all parameters explicitly
pub fn opt(short_name: &str,
           long_name: &str,
           desc: &str,
           hint: &str,
           hasarg: HasArg,
           occur: Occur) -> OptGroup {
    let len = short_name.len();
    assert!(len == 1 || len == 0);
    OptGroup {
        short_name: short_name.to_string(),
        long_name: long_name.to_string(),
        hint: hint.to_string(),
        desc: desc.to_string(),
        hasarg: hasarg,
        occur: occur
    }
}

impl Fail {
    /// Convert a `Fail` enum into an error string.
    #[unstable(feature = "rustc_private")]
    #[deprecated(since = "1.0.0",
                 reason = "use `fmt::Display` (`{}` format specifier)")]
    pub fn to_err_msg(self) -> String {
        self.to_string()
    }
}

impl fmt::Display for Fail {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match *self {
            ArgumentMissing(ref nm) => {
                write!(f, "Argument to option '{}' missing.", *nm)
            }
            UnrecognizedOption(ref nm) => {
                write!(f, "Unrecognized option: '{}'.", *nm)
            }
            OptionMissing(ref nm) => {
                write!(f, "Required option '{}' missing.", *nm)
            }
            OptionDuplicated(ref nm) => {
                write!(f, "Option '{}' given more than once.", *nm)
            }
            UnexpectedArgument(ref nm) => {
                write!(f, "Option '{}' does not take an argument.", *nm)
            }
        }
    }
}

/// Parse command line arguments according to the provided options.
///
/// On success returns `Ok(Matches)`. Use methods such as `opt_present`
/// `opt_str`, etc. to interrogate results.
/// # Panics
///
/// Returns `Err(Fail)` on failure: use the `Debug` implementation of `Fail` to display
/// information about it.
pub fn getopts(args: &[String], optgrps: &[OptGroup]) -> Result {
    let opts: Vec<Opt> = optgrps.iter().map(|x| x.long_to_short()).collect();
    let n_opts = opts.len();

    fn f(_x: usize) -> Vec<Optval> { return Vec::new(); }

    let mut vals: Vec<_> = (0..n_opts).map(f).collect();
    let mut free: Vec<String> = Vec::new();
    let l = args.len();
    let mut i = 0;
    while i < l {
        let cur = args[i].clone();
        let curlen = cur.len();
        if !is_arg(&cur[..]) {
            free.push(cur);
        } else if cur == "--" {
            let mut j = i + 1;
            while j < l { free.push(args[j].clone()); j += 1; }
            break;
        } else {
            let mut names;
            let mut i_arg = None;
            if cur.as_bytes()[1] == b'-' {
                let tail = &cur[2..curlen];
                let tail_eq: Vec<&str> = tail.split('=').collect();
                if tail_eq.len() <= 1 {
                    names = vec!(Long(tail.to_string()));
                } else {
                    names =
                        vec!(Long(tail_eq[0].to_string()));
                    i_arg = Some(tail_eq[1].to_string());
                }
            } else {
                let mut j = 1;
                names = Vec::new();
                while j < curlen {
                    let ch = cur.char_at(j);
                    let opt = Short(ch);

                    /* In a series of potential options (eg. -aheJ), if we
                       see one which takes an argument, we assume all
                       subsequent characters make up the argument. This
                       allows options such as -L/usr/local/lib/foo to be
                       interpreted correctly
                    */

                    let opt_id = match find_opt(&opts, opt.clone()) {
                      Some(id) => id,
                      None => return Err(UnrecognizedOption(opt.to_string()))
                    };

                    names.push(opt);

                    let arg_follows = match opts[opt_id].hasarg {
                        Yes | Maybe => true,
                        No => false
                    };

                    let next = j + ch.len_utf8();
                    if arg_follows && next < curlen {
                        i_arg = Some((&cur[next..curlen]).to_string());
                        break;
                    }

                    j = next;
                }
            }
            let mut name_pos = 0;
            for nm in &names {
                name_pos += 1;
                let optid = match find_opt(&opts, (*nm).clone()) {
                  Some(id) => id,
                  None => return Err(UnrecognizedOption(nm.to_string()))
                };
                match opts[optid].hasarg {
                  No => {
                    if name_pos == names.len() && !i_arg.is_none() {
                        return Err(UnexpectedArgument(nm.to_string()));
                    }
                    let v = &mut vals[optid];
                    v.push(Given);
                  }
                  Maybe => {
                    if !i_arg.is_none() {
                        let v = &mut vals[optid];
                        v.push(Val((i_arg.clone())
                            .unwrap()));
                    } else if name_pos < names.len() || i + 1 == l ||
                            is_arg(&args[i + 1][..]) {
                        let v = &mut vals[optid];
                        v.push(Given);
                    } else {
                        i += 1;
                        let v = &mut vals[optid];
                        v.push(Val(args[i].clone()));
                    }
                  }
                  Yes => {
                    if !i_arg.is_none() {
                        let v = &mut vals[optid];
                        v.push(Val(i_arg.clone().unwrap()));
                    } else if i + 1 == l {
                        return Err(ArgumentMissing(nm.to_string()));
                    } else {
                        i += 1;
                        let v = &mut vals[optid];
                        v.push(Val(args[i].clone()));
                    }
                  }
                }
            }
        }
        i += 1;
    }
    for i in 0..n_opts {
        let n = vals[i].len();
        let occ = opts[i].occur;
        if occ == Req && n == 0 {
            return Err(OptionMissing(opts[i].name.to_string()));
        }
        if occ != Multi && n > 1 {
            return Err(OptionDuplicated(opts[i].name.to_string()));
        }
    }
    Ok(Matches {
        opts: opts,
        vals: vals,
        free: free
    })
}

/// Derive a usage message from a set of long options.
pub fn usage(brief: &str, opts: &[OptGroup]) -> String {

    let desc_sep = format!("\n{}", repeat(" ").take(24).collect::<String>());

    let rows = opts.iter().map(|optref| {
        let OptGroup{short_name,
                     long_name,
                     hint,
                     desc,
                     hasarg,
                     ..} = (*optref).clone();

        let mut row = repeat(" ").take(4).collect::<String>();

        // short option
        match short_name.len() {
            0 => {}
            1 => {
                row.push('-');
                row.push_str(&short_name[..]);
                row.push(' ');
            }
            _ => panic!("the short name should only be 1 ascii char long"),
        }

        // long option
        match long_name.len() {
            0 => {}
            _ => {
                row.push_str("--");
                row.push_str(&long_name[..]);
                row.push(' ');
            }
        }

        // arg
        match hasarg {
            No => {}
            Yes => row.push_str(&hint[..]),
            Maybe => {
                row.push('[');
                row.push_str(&hint[..]);
                row.push(']');
            }
        }

        // FIXME: #5516 should be graphemes not codepoints
        // here we just need to indent the start of the description
        let rowlen = row.chars().count();
        if rowlen < 24 {
            for _ in 0..24 - rowlen {
                row.push(' ');
            }
        } else {
            row.push_str(&desc_sep[..]);
        }

        // Normalize desc to contain words separated by one space character
        let mut desc_normalized_whitespace = String::new();
        for word in desc.words() {
            desc_normalized_whitespace.push_str(word);
            desc_normalized_whitespace.push(' ');
        }

        // FIXME: #5516 should be graphemes not codepoints
        let mut desc_rows = Vec::new();
        each_split_within(&desc_normalized_whitespace[..], 54, |substr| {
            desc_rows.push(substr.to_string());
            true
        });

        // FIXME: #5516 should be graphemes not codepoints
        // wrapped description
        row.push_str(&desc_rows.connect(&desc_sep[..]));

        row
    });

    format!("{}\n\nOptions:\n{}\n", brief,
            rows.collect::<Vec<String>>().connect("\n"))
}

fn format_option(opt: &OptGroup) -> String {
    let mut line = String::new();

    if opt.occur != Req {
        line.push('[');
    }

    // Use short_name is possible, but fallback to long_name.
    if opt.short_name.len() > 0 {
        line.push('-');
        line.push_str(&opt.short_name[..]);
    } else {
        line.push_str("--");
        line.push_str(&opt.long_name[..]);
    }

    if opt.hasarg != No {
        line.push(' ');
        if opt.hasarg == Maybe {
            line.push('[');
        }
        line.push_str(&opt.hint[..]);
        if opt.hasarg == Maybe {
            line.push(']');
        }
    }

    if opt.occur != Req {
        line.push(']');
    }
    if opt.occur == Multi {
        line.push_str("..");
    }

    line
}

/// Derive a short one-line usage summary from a set of long options.
pub fn short_usage(program_name: &str, opts: &[OptGroup]) -> String {
    let mut line = format!("Usage: {} ", program_name);
    line.push_str(&opts.iter()
                       .map(format_option)
                       .collect::<Vec<String>>()
                       .connect(" ")[..]);
    line
}

#[derive(Copy, Clone)]
enum SplitWithinState {
    A,  // leading whitespace, initial state
    B,  // words
    C,  // internal and trailing whitespace
}
#[derive(Copy, Clone)]
enum Whitespace {
    Ws, // current char is whitespace
    Cr  // current char is not whitespace
}
#[derive(Copy, Clone)]
enum LengthLimit {
    UnderLim, // current char makes current substring still fit in limit
    OverLim   // current char makes current substring no longer fit in limit
}


/// Splits a string into substrings with possibly internal whitespace,
/// each of them at most `lim` bytes long. The substrings have leading and trailing
/// whitespace removed, and are only cut at whitespace boundaries.
///
/// Note: Function was moved here from `std::str` because this module is the only place that
/// uses it, and because it was too specific for a general string function.
///
/// # Panics
///
/// Panics during iteration if the string contains a non-whitespace
/// sequence longer than the limit.
fn each_split_within<F>(ss: &str, lim: usize, mut it: F) -> bool where
    F: FnMut(&str) -> bool
{
    // Just for fun, let's write this as a state machine:

    let mut slice_start = 0;
    let mut last_start = 0;
    let mut last_end = 0;
    let mut state = A;
    let mut fake_i = ss.len();
    let mut lim = lim;

    let mut cont = true;

    // if the limit is larger than the string, lower it to save cycles
    if lim >= fake_i {
        lim = fake_i;
    }

    let mut machine = |cont: &mut bool, (i, c): (usize, char)| -> bool {
        let whitespace = if c.is_whitespace() { Ws }       else { Cr };
        let limit      = if (i - slice_start + 1) <= lim  { UnderLim } else { OverLim };

        state = match (state, whitespace, limit) {
            (A, Ws, _)        => { A }
            (A, Cr, _)        => { slice_start = i; last_start = i; B }

            (B, Cr, UnderLim) => { B }
            (B, Cr, OverLim)  if (i - last_start + 1) > lim
                            => panic!("word starting with {} longer than limit!",
                                      &ss[last_start..i + 1]),
            (B, Cr, OverLim)  => {
                *cont = it(&ss[slice_start..last_end]);
                slice_start = last_start;
                B
            }
            (B, Ws, UnderLim) => {
                last_end = i;
                C
            }
            (B, Ws, OverLim)  => {
                last_end = i;
                *cont = it(&ss[slice_start..last_end]);
                A
            }

            (C, Cr, UnderLim) => {
                last_start = i;
                B
            }
            (C, Cr, OverLim)  => {
                *cont = it(&ss[slice_start..last_end]);
                slice_start = i;
                last_start = i;
                last_end = i;
                B
            }
            (C, Ws, OverLim)  => {
                *cont = it(&ss[slice_start..last_end]);
                A
            }
            (C, Ws, UnderLim) => {
                C
            }
        };

        *cont
    };

    ss.char_indices().all(|x| machine(&mut cont, x));

    // Let the automaton 'run out' by supplying trailing whitespace
    while cont && match state { B | C => true, A => false } {
        machine(&mut cont, (fake_i, ' '));
        fake_i += 1;
    }
    return cont;
}

#[test]
fn test_split_within() {
    fn t(s: &str, i: usize, u: &[String]) {
        let mut v = Vec::new();
        each_split_within(s, i, |s| { v.push(s.to_string()); true });
        assert!(v.iter().zip(u.iter()).all(|(a,b)| a == b));
    }
    t("", 0, &[]);
    t("", 15, &[]);
    t("hello", 15, &["hello".to_string()]);
    t("\nMary had a little lamb\nLittle lamb\n", 15, &[
        "Mary had a".to_string(),
        "little lamb".to_string(),
        "Little lamb".to_string()
    ]);
    t("\nMary had a little lamb\nLittle lamb\n", ::std::usize::MAX,
        &["Mary had a little lamb\nLittle lamb".to_string()]);
}

#[cfg(test)]
mod tests {
    use super::*;
    use super::Fail::*;

    use std::result::Result::{Err, Ok};
    use std::result;

    // Tests for reqopt
    #[test]
    fn test_reqopt() {
        let long_args = vec!("--test=20".to_string());
        let opts = vec!(reqopt("t", "test", "testing", "TEST"));
        let rs = getopts(&long_args, &opts);
        match rs {
          Ok(ref m) => {
            assert!(m.opt_present("test"));
            assert_eq!(m.opt_str("test").unwrap(), "20");
            assert!(m.opt_present("t"));
            assert_eq!(m.opt_str("t").unwrap(), "20");
          }
          _ => { panic!("test_reqopt failed (long arg)"); }
        }
        let short_args = vec!("-t".to_string(), "20".to_string());
        match getopts(&short_args, &opts) {
          Ok(ref m) => {
            assert!((m.opt_present("test")));
            assert_eq!(m.opt_str("test").unwrap(), "20");
            assert!((m.opt_present("t")));
            assert_eq!(m.opt_str("t").unwrap(), "20");
          }
          _ => { panic!("test_reqopt failed (short arg)"); }
        }
    }

    #[test]
    fn test_reqopt_missing() {
        let args = vec!("blah".to_string());
        let opts = vec!(reqopt("t", "test", "testing", "TEST"));
        let rs = getopts(&args, &opts);
        match rs {
          Err(OptionMissing(_)) => {},
          _ => panic!()
        }
    }

    #[test]
    fn test_reqopt_no_arg() {
        let long_args = vec!("--test".to_string());
        let opts = vec!(reqopt("t", "test", "testing", "TEST"));
        let rs = getopts(&long_args, &opts);
        match rs {
          Err(ArgumentMissing(_)) => {},
          _ => panic!()
        }
        let short_args = vec!("-t".to_string());
        match getopts(&short_args, &opts) {
          Err(ArgumentMissing(_)) => {},
          _ => panic!()
        }
    }

    #[test]
    fn test_reqopt_multi() {
        let args = vec!("--test=20".to_string(), "-t".to_string(), "30".to_string());
        let opts = vec!(reqopt("t", "test", "testing", "TEST"));
        let rs = getopts(&args, &opts);
        match rs {
          Err(OptionDuplicated(_)) => {},
          _ => panic!()
        }
    }

    // Tests for optopt
    #[test]
    fn test_optopt() {
        let long_args = vec!("--test=20".to_string());
        let opts = vec!(optopt("t", "test", "testing", "TEST"));
        let rs = getopts(&long_args, &opts);
        match rs {
          Ok(ref m) => {
            assert!(m.opt_present("test"));
            assert_eq!(m.opt_str("test").unwrap(), "20");
            assert!((m.opt_present("t")));
            assert_eq!(m.opt_str("t").unwrap(), "20");
          }
          _ => panic!()
        }
        let short_args = vec!("-t".to_string(), "20".to_string());
        match getopts(&short_args, &opts) {
          Ok(ref m) => {
            assert!((m.opt_present("test")));
            assert_eq!(m.opt_str("test").unwrap(), "20");
            assert!((m.opt_present("t")));
            assert_eq!(m.opt_str("t").unwrap(), "20");
          }
          _ => panic!()
        }
    }

    #[test]
    fn test_optopt_missing() {
        let args = vec!("blah".to_string());
        let opts = vec!(optopt("t", "test", "testing", "TEST"));
        let rs = getopts(&args, &opts);
        match rs {
          Ok(ref m) => {
            assert!(!m.opt_present("test"));
            assert!(!m.opt_present("t"));
          }
          _ => panic!()
        }
    }

    #[test]
    fn test_optopt_no_arg() {
        let long_args = vec!("--test".to_string());
        let opts = vec!(optopt("t", "test", "testing", "TEST"));
        let rs = getopts(&long_args, &opts);
        match rs {
          Err(ArgumentMissing(_)) => {},
          _ => panic!()
        }
        let short_args = vec!("-t".to_string());
        match getopts(&short_args, &opts) {
          Err(ArgumentMissing(_)) => {},
          _ => panic!()
        }
    }

    #[test]
    fn test_optopt_multi() {
        let args = vec!("--test=20".to_string(), "-t".to_string(), "30".to_string());
        let opts = vec!(optopt("t", "test", "testing", "TEST"));
        let rs = getopts(&args, &opts);
        match rs {
          Err(OptionDuplicated(_)) => {},
          _ => panic!()
        }
    }

    // Tests for optflag
    #[test]
    fn test_optflag() {
        let long_args = vec!("--test".to_string());
        let opts = vec!(optflag("t", "test", "testing"));
        let rs = getopts(&long_args, &opts);
        match rs {
          Ok(ref m) => {
            assert!(m.opt_present("test"));
            assert!(m.opt_present("t"));
          }
          _ => panic!()
        }
        let short_args = vec!("-t".to_string());
        match getopts(&short_args, &opts) {
          Ok(ref m) => {
            assert!(m.opt_present("test"));
            assert!(m.opt_present("t"));
          }
          _ => panic!()
        }
    }

    #[test]
    fn test_optflag_missing() {
        let args = vec!("blah".to_string());
        let opts = vec!(optflag("t", "test", "testing"));
        let rs = getopts(&args, &opts);
        match rs {
          Ok(ref m) => {
            assert!(!m.opt_present("test"));
            assert!(!m.opt_present("t"));
          }
          _ => panic!()
        }
    }

    #[test]
    fn test_optflag_long_arg() {
        let args = vec!("--test=20".to_string());
        let opts = vec!(optflag("t", "test", "testing"));
        let rs = getopts(&args, &opts);
        match rs {
          Err(UnexpectedArgument(_)) => {},
          _ => panic!()
        }
    }

    #[test]
    fn test_optflag_multi() {
        let args = vec!("--test".to_string(), "-t".to_string());
        let opts = vec!(optflag("t", "test", "testing"));
        let rs = getopts(&args, &opts);
        match rs {
          Err(OptionDuplicated(_)) => {},
          _ => panic!()
        }
    }

    #[test]
    fn test_optflag_short_arg() {
        let args = vec!("-t".to_string(), "20".to_string());
        let opts = vec!(optflag("t", "test", "testing"));
        let rs = getopts(&args, &opts);
        match rs {
          Ok(ref m) => {
            // The next variable after the flag is just a free argument

            assert!(m.free[0] == "20");
          }
          _ => panic!()
        }
    }

    // Tests for optflagmulti
    #[test]
    fn test_optflagmulti_short1() {
        let args = vec!("-v".to_string());
        let opts = vec!(optflagmulti("v", "verbose", "verbosity"));
        let rs = getopts(&args, &opts);
        match rs {
          Ok(ref m) => {
            assert_eq!(m.opt_count("v"), 1);
          }
          _ => panic!()
        }
    }

    #[test]
    fn test_optflagmulti_short2a() {
        let args = vec!("-v".to_string(), "-v".to_string());
        let opts = vec!(optflagmulti("v", "verbose", "verbosity"));
        let rs = getopts(&args, &opts);
        match rs {
          Ok(ref m) => {
            assert_eq!(m.opt_count("v"), 2);
          }
          _ => panic!()
        }
    }

    #[test]
    fn test_optflagmulti_short2b() {
        let args = vec!("-vv".to_string());
        let opts = vec!(optflagmulti("v", "verbose", "verbosity"));
        let rs = getopts(&args, &opts);
        match rs {
          Ok(ref m) => {
            assert_eq!(m.opt_count("v"), 2);
          }
          _ => panic!()
        }
    }

    #[test]
    fn test_optflagmulti_long1() {
        let args = vec!("--verbose".to_string());
        let opts = vec!(optflagmulti("v", "verbose", "verbosity"));
        let rs = getopts(&args, &opts);
        match rs {
          Ok(ref m) => {
            assert_eq!(m.opt_count("verbose"), 1);
          }
          _ => panic!()
        }
    }

    #[test]
    fn test_optflagmulti_long2() {
        let args = vec!("--verbose".to_string(), "--verbose".to_string());
        let opts = vec!(optflagmulti("v", "verbose", "verbosity"));
        let rs = getopts(&args, &opts);
        match rs {
          Ok(ref m) => {
            assert_eq!(m.opt_count("verbose"), 2);
          }
          _ => panic!()
        }
    }

    #[test]
    fn test_optflagmulti_mix() {
        let args = vec!("--verbose".to_string(), "-v".to_string(),
                        "-vv".to_string(), "verbose".to_string());
        let opts = vec!(optflagmulti("v", "verbose", "verbosity"));
        let rs = getopts(&args, &opts);
        match rs {
          Ok(ref m) => {
            assert_eq!(m.opt_count("verbose"), 4);
            assert_eq!(m.opt_count("v"), 4);
          }
          _ => panic!()
        }
    }

    // Tests for optmulti
    #[test]
    fn test_optmulti() {
        let long_args = vec!("--test=20".to_string());
        let opts = vec!(optmulti("t", "test", "testing", "TEST"));
        let rs = getopts(&long_args, &opts);
        match rs {
          Ok(ref m) => {
            assert!((m.opt_present("test")));
            assert_eq!(m.opt_str("test").unwrap(), "20");
            assert!((m.opt_present("t")));
            assert_eq!(m.opt_str("t").unwrap(), "20");
          }
          _ => panic!()
        }
        let short_args = vec!("-t".to_string(), "20".to_string());
        match getopts(&short_args, &opts) {
          Ok(ref m) => {
            assert!((m.opt_present("test")));
            assert_eq!(m.opt_str("test").unwrap(), "20");
            assert!((m.opt_present("t")));
            assert_eq!(m.opt_str("t").unwrap(), "20");
          }
          _ => panic!()
        }
    }

    #[test]
    fn test_optmulti_missing() {
        let args = vec!("blah".to_string());
        let opts = vec!(optmulti("t", "test", "testing", "TEST"));
        let rs = getopts(&args, &opts);
        match rs {
          Ok(ref m) => {
            assert!(!m.opt_present("test"));
            assert!(!m.opt_present("t"));
          }
          _ => panic!()
        }
    }

    #[test]
    fn test_optmulti_no_arg() {
        let long_args = vec!("--test".to_string());
        let opts = vec!(optmulti("t", "test", "testing", "TEST"));
        let rs = getopts(&long_args, &opts);
        match rs {
          Err(ArgumentMissing(_)) => {},
          _ => panic!()
        }
        let short_args = vec!("-t".to_string());
        match getopts(&short_args, &opts) {
          Err(ArgumentMissing(_)) => {},
          _ => panic!()
        }
    }

    #[test]
    fn test_optmulti_multi() {
        let args = vec!("--test=20".to_string(), "-t".to_string(), "30".to_string());
        let opts = vec!(optmulti("t", "test", "testing", "TEST"));
        let rs = getopts(&args, &opts);
        match rs {
          Ok(ref m) => {
              assert!(m.opt_present("test"));
              assert_eq!(m.opt_str("test").unwrap(), "20");
              assert!(m.opt_present("t"));
              assert_eq!(m.opt_str("t").unwrap(), "20");
              let pair = m.opt_strs("test");
              assert!(pair[0] == "20");
              assert!(pair[1] == "30");
          }
          _ => panic!()
        }
    }

    #[test]
    fn test_unrecognized_option() {
        let long_args = vec!("--untest".to_string());
        let opts = vec!(optmulti("t", "test", "testing", "TEST"));
        let rs = getopts(&long_args, &opts);
        match rs {
          Err(UnrecognizedOption(_)) => {},
          _ => panic!()
        }
        let short_args = vec!("-u".to_string());
        match getopts(&short_args, &opts) {
          Err(UnrecognizedOption(_)) => {},
          _ => panic!()
        }
    }

    #[test]
    fn test_combined() {
        let args =
            vec!("prog".to_string(),
                 "free1".to_string(),
                 "-s".to_string(),
                 "20".to_string(),
                 "free2".to_string(),
                 "--flag".to_string(),
                 "--long=30".to_string(),
                 "-f".to_string(),
                 "-m".to_string(),
                 "40".to_string(),
                 "-m".to_string(),
                 "50".to_string(),
                 "-n".to_string(),
                 "-A B".to_string(),
                 "-n".to_string(),
                 "-60 70".to_string());
        let opts =
            vec!(optopt("s", "something", "something", "SOMETHING"),
              optflag("", "flag", "a flag"),
              reqopt("", "long", "hi", "LONG"),
              optflag("f", "", "another flag"),
              optmulti("m", "", "mmmmmm", "YUM"),
              optmulti("n", "", "nothing", "NOTHING"),
              optopt("", "notpresent", "nothing to see here", "NOPE"));
        let rs = getopts(&args, &opts);
        match rs {
          Ok(ref m) => {
            assert!(m.free[0] == "prog");
            assert!(m.free[1] == "free1");
            assert_eq!(m.opt_str("s").unwrap(), "20");
            assert!(m.free[2] == "free2");
            assert!((m.opt_present("flag")));
            assert_eq!(m.opt_str("long").unwrap(), "30");
            assert!((m.opt_present("f")));
            let pair = m.opt_strs("m");
            assert!(pair[0] == "40");
            assert!(pair[1] == "50");
            let pair = m.opt_strs("n");
            assert!(pair[0] == "-A B");
            assert!(pair[1] == "-60 70");
            assert!((!m.opt_present("notpresent")));
          }
          _ => panic!()
        }
    }

    #[test]
    fn test_multi() {
        let opts = vec!(optopt("e", "", "encrypt", "ENCRYPT"),
                     optopt("", "encrypt", "encrypt", "ENCRYPT"),
                     optopt("f", "", "flag", "FLAG"));

        let args_single = vec!("-e".to_string(), "foo".to_string());
        let matches_single = &match getopts(&args_single, &opts) {
          result::Result::Ok(m) => m,
          result::Result::Err(_) => panic!()
        };
        assert!(matches_single.opts_present(&["e".to_string()]));
        assert!(matches_single.opts_present(&["encrypt".to_string(), "e".to_string()]));
        assert!(matches_single.opts_present(&["e".to_string(), "encrypt".to_string()]));
        assert!(!matches_single.opts_present(&["encrypt".to_string()]));
        assert!(!matches_single.opts_present(&["thing".to_string()]));
        assert!(!matches_single.opts_present(&[]));

        assert_eq!(matches_single.opts_str(&["e".to_string()]).unwrap(), "foo");
        assert_eq!(matches_single.opts_str(&["e".to_string(), "encrypt".to_string()]).unwrap(),
                   "foo");
        assert_eq!(matches_single.opts_str(&["encrypt".to_string(), "e".to_string()]).unwrap(),
                   "foo");

        let args_both = vec!("-e".to_string(), "foo".to_string(), "--encrypt".to_string(),
                             "foo".to_string());
        let matches_both = &match getopts(&args_both, &opts) {
          result::Result::Ok(m) => m,
          result::Result::Err(_) => panic!()
        };
        assert!(matches_both.opts_present(&["e".to_string()]));
        assert!(matches_both.opts_present(&["encrypt".to_string()]));
        assert!(matches_both.opts_present(&["encrypt".to_string(), "e".to_string()]));
        assert!(matches_both.opts_present(&["e".to_string(), "encrypt".to_string()]));
        assert!(!matches_both.opts_present(&["f".to_string()]));
        assert!(!matches_both.opts_present(&["thing".to_string()]));
        assert!(!matches_both.opts_present(&[]));

        assert_eq!(matches_both.opts_str(&["e".to_string()]).unwrap(), "foo");
        assert_eq!(matches_both.opts_str(&["encrypt".to_string()]).unwrap(), "foo");
        assert_eq!(matches_both.opts_str(&["e".to_string(), "encrypt".to_string()]).unwrap(),
                   "foo");
        assert_eq!(matches_both.opts_str(&["encrypt".to_string(), "e".to_string()]).unwrap(),
                   "foo");
    }

    #[test]
    fn test_nospace() {
        let args = vec!("-Lfoo".to_string(), "-M.".to_string());
        let opts = vec!(optmulti("L", "", "library directory", "LIB"),
                     optmulti("M", "", "something", "MMMM"));
        let matches = &match getopts(&args, &opts) {
          result::Result::Ok(m) => m,
          result::Result::Err(_) => panic!()
        };
        assert!(matches.opts_present(&["L".to_string()]));
        assert_eq!(matches.opts_str(&["L".to_string()]).unwrap(), "foo");
        assert!(matches.opts_present(&["M".to_string()]));
        assert_eq!(matches.opts_str(&["M".to_string()]).unwrap(), ".");

    }

    #[test]
    fn test_nospace_conflict() {
        let args = vec!("-vvLverbose".to_string(), "-v".to_string() );
        let opts = vec!(optmulti("L", "", "library directory", "LIB"),
                     optflagmulti("v", "verbose", "Verbose"));
        let matches = &match getopts(&args, &opts) {
          result::Result::Ok(m) => m,
          result::Result::Err(e) => panic!( "{}", e )
        };
        assert!(matches.opts_present(&["L".to_string()]));
        assert_eq!(matches.opts_str(&["L".to_string()]).unwrap(), "verbose");
        assert!(matches.opts_present(&["v".to_string()]));
        assert_eq!(3, matches.opt_count("v"));
    }

    #[test]
    fn test_long_to_short() {
        let mut short = Opt {
            name: Name::Long("banana".to_string()),
            hasarg: HasArg::Yes,
            occur: Occur::Req,
            aliases: Vec::new(),
        };
        short.aliases = vec!(Opt { name: Name::Short('b'),
                                hasarg: HasArg::Yes,
                                occur: Occur::Req,
                                aliases: Vec::new() });
        let verbose = reqopt("b", "banana", "some bananas", "VAL");

        assert!(verbose.long_to_short() == short);
    }

    #[test]
    fn test_aliases_long_and_short() {
        let opts = vec!(
            optflagmulti("a", "apple", "Desc"));

        let args = vec!("-a".to_string(), "--apple".to_string(), "-a".to_string());

        let matches = getopts(&args, &opts).unwrap();
        assert_eq!(3, matches.opt_count("a"));
        assert_eq!(3, matches.opt_count("apple"));
    }

    #[test]
    fn test_usage() {
        let optgroups = vec!(
            reqopt("b", "banana", "Desc", "VAL"),
            optopt("a", "012345678901234567890123456789",
                             "Desc", "VAL"),
            optflag("k", "kiwi", "Desc"),
            optflagopt("p", "", "Desc", "VAL"),
            optmulti("l", "", "Desc", "VAL"));

        let expected =
"Usage: fruits

Options:
    -b --banana VAL     Desc
    -a --012345678901234567890123456789 VAL
                        Desc
    -k --kiwi           Desc
    -p [VAL]            Desc
    -l VAL              Desc
";

        let generated_usage = usage("Usage: fruits", &optgroups);

        debug!("expected: <<{}>>", expected);
        debug!("generated: <<{}>>", generated_usage);
        assert_eq!(generated_usage, expected);
    }

    #[test]
    fn test_usage_description_wrapping() {
        // indentation should be 24 spaces
        // lines wrap after 78: or rather descriptions wrap after 54

        let optgroups = vec!(
            optflag("k", "kiwi",
                "This is a long description which won't be wrapped..+.."), // 54
            optflag("a", "apple",
                "This is a long description which _will_ be wrapped..+.."));

        let expected =
"Usage: fruits

Options:
    -k --kiwi           This is a long description which won't be wrapped..+..
    -a --apple          This is a long description which _will_ be
                        wrapped..+..
";

        let usage = usage("Usage: fruits", &optgroups);

        debug!("expected: <<{}>>", expected);
        debug!("generated: <<{}>>", usage);
        assert!(usage == expected)
    }

    #[test]
    fn test_usage_description_multibyte_handling() {
        let optgroups = vec!(
            optflag("k", "k\u{2013}w\u{2013}",
                "The word kiwi is normally spelled with two i's"),
            optflag("a", "apple",
                "This \u{201C}description\u{201D} has some characters that could \
confuse the line wrapping; an apple costs 0.51€ in some parts of Europe."));

        let expected =
"Usage: fruits

Options:
    -k --k–w–           The word kiwi is normally spelled with two i's
    -a --apple          This “description” has some characters that could
                        confuse the line wrapping; an apple costs 0.51€ in
                        some parts of Europe.
";

        let usage = usage("Usage: fruits", &optgroups);

        debug!("expected: <<{}>>", expected);
        debug!("generated: <<{}>>", usage);
        assert!(usage == expected)
    }

    #[test]
    fn test_short_usage() {
        let optgroups = vec!(
            reqopt("b", "banana", "Desc", "VAL"),
            optopt("a", "012345678901234567890123456789",
                     "Desc", "VAL"),
            optflag("k", "kiwi", "Desc"),
            optflagopt("p", "", "Desc", "VAL"),
            optmulti("l", "", "Desc", "VAL"));

        let expected = "Usage: fruits -b VAL [-a VAL] [-k] [-p [VAL]] [-l VAL]..".to_string();
        let generated_usage = short_usage("fruits", &optgroups);

        debug!("expected: <<{}>>", expected);
        debug!("generated: <<{}>>", generated_usage);
        assert_eq!(generated_usage, expected);
    }
}
