// Copyright 2015 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.

//! Command-line interface of the rustbuild build system.
//!
//! This module implements the command-line parsing of the build system which
//! has various flags to configure how it's run.

use std::env;
use std::fs;
use std::path::PathBuf;
use std::process;

use getopts::{Matches, Options};

use Build;
use config::Config;
use metadata;
use step;

/// Deserialized version of all flags for this compile.
pub struct Flags {
    pub verbose: bool,
    pub stage: Option<u32>,
    pub build: String,
    pub host: Vec<String>,
    pub target: Vec<String>,
    pub config: Option<PathBuf>,
    pub src: Option<PathBuf>,
    pub jobs: Option<u32>,
    pub cmd: Subcommand,
}

pub enum Subcommand {
    Build {
        paths: Vec<PathBuf>,
    },
    Doc {
        paths: Vec<PathBuf>,
    },
    Test {
        paths: Vec<PathBuf>,
        test_args: Vec<String>,
    },
    Clean,
    Dist {
        install: bool,
    },
}

impl Flags {
    pub fn parse(args: &[String]) -> Flags {
        let mut opts = Options::new();
        opts.optflag("v", "verbose", "use verbose output");
        opts.optopt("", "config", "TOML configuration file for build", "FILE");
        opts.optopt("", "build", "build target of the stage0 compiler", "BUILD");
        opts.optmulti("", "host", "host targets to build", "HOST");
        opts.optmulti("", "target", "target targets to build", "TARGET");
        opts.optopt("", "stage", "stage to build", "N");
        opts.optopt("", "src", "path to the root of the rust checkout", "DIR");
        opts.optopt("j", "jobs", "number of jobs to run in parallel", "JOBS");
        opts.optflag("h", "help", "print this help message");

        let usage = |n, opts: &Options| -> ! {
            let command = args.get(0).map(|s| &**s);
            let brief = format!("Usage: x.py {} [options] [<args>...]",
                                command.unwrap_or("<command>"));

            println!("{}", opts.usage(&brief));
            match command {
                Some("build") => {
                    println!("\
Arguments:
    This subcommand accepts a number of positional arguments of directories to
    the crates and/or artifacts to compile. For example:

        ./x.py build src/libcore
        ./x.py build src/libproc_macro
        ./x.py build src/libstd --stage 1

    If no arguments are passed then the complete artifacts for that stage are
    also compiled.

        ./x.py build
        ./x.py build --stage 1

    For a quick build with a usable compile, you can pass:

        ./x.py build --stage 1 src/libtest
");
                }

                Some("test") => {
                    println!("\
Arguments:
    This subcommand accepts a number of positional arguments of directories to
    tests that should be compiled and run. For example:

        ./x.py test src/test/run-pass
        ./x.py test src/test/run-pass/assert-*
        ./x.py test src/libstd --test-args hash_map
        ./x.py test src/libstd --stage 0

    If no arguments are passed then the complete artifacts for that stage are
    compiled and tested.

        ./x.py test
        ./x.py test --stage 1
");
                }

                Some("doc") => {
                    println!("\
Arguments:
    This subcommand accepts a number of positional arguments of directories of
    documentation to build. For example:

        ./x.py doc src/doc/book
        ./x.py doc src/doc/nomicon
        ./x.py doc src/libstd

    If no arguments are passed then everything is documented:

        ./x.py doc
        ./x.py doc --stage 1
");
                }

                _ => {}
            }

            if let Some(command) = command {
                if command == "build" ||
                   command == "dist" ||
                   command == "doc" ||
                   command == "test" ||
                   command == "clean"  {
                    println!("Available invocations:");
                    if args.iter().any(|a| a == "-v") {
                        let flags = Flags::parse(&["build".to_string()]);
                        let mut config = Config::default();
                        config.build = flags.build.clone();
                        let mut build = Build::new(flags, config);
                        metadata::build(&mut build);
                        step::build_rules(&build).print_help(command);
                    } else {
                        println!("    ... elided, run `./x.py {} -h -v` to see",
                                 command);
                    }

                    println!("");
                }
            }

println!("\
Subcommands:
    build       Compile either the compiler or libraries
    test        Build and run some test suites
    doc         Build documentation
    clean       Clean out build directories
    dist        Build and/or install distribution artifacts

To learn more about a subcommand, run `./x.py <command> -h`
");

            process::exit(n);
        };
        if args.len() == 0 {
            println!("a command must be passed");
            usage(1, &opts);
        }
        let parse = |opts: &Options| {
            let m = opts.parse(&args[1..]).unwrap_or_else(|e| {
                println!("failed to parse options: {}", e);
                usage(1, opts);
            });
            if m.opt_present("h") {
                usage(0, opts);
            }
            return m
        };

        let cwd = t!(env::current_dir());
        let remaining_as_path = |m: &Matches| {
            m.free.iter().map(|p| cwd.join(p)).collect::<Vec<_>>()
        };

        let m: Matches;
        let cmd = match &args[0][..] {
            "build" => {
                m = parse(&opts);
                Subcommand::Build { paths: remaining_as_path(&m) }
            }
            "doc" => {
                m = parse(&opts);
                Subcommand::Doc { paths: remaining_as_path(&m) }
            }
            "test" => {
                opts.optmulti("", "test-args", "extra arguments", "ARGS");
                m = parse(&opts);
                Subcommand::Test {
                    paths: remaining_as_path(&m),
                    test_args: m.opt_strs("test-args"),
                }
            }
            "clean" => {
                m = parse(&opts);
                if m.free.len() > 0 {
                    println!("clean takes no arguments");
                    usage(1, &opts);
                }
                Subcommand::Clean
            }
            "dist" => {
                opts.optflag("", "install", "run installer as well");
                m = parse(&opts);
                Subcommand::Dist {
                    install: m.opt_present("install"),
                }
            }
            cmd => {
                println!("unknown command: {}", cmd);
                usage(1, &opts);
            }
        };


        let cfg_file = m.opt_str("config").map(PathBuf::from).or_else(|| {
            if fs::metadata("config.toml").is_ok() {
                Some(PathBuf::from("config.toml"))
            } else {
                None
            }
        });

        Flags {
            verbose: m.opt_present("v"),
            stage: m.opt_str("stage").map(|j| j.parse().unwrap()),
            build: m.opt_str("build").unwrap_or_else(|| {
                env::var("BUILD").unwrap()
            }),
            host: m.opt_strs("host"),
            target: m.opt_strs("target"),
            config: cfg_file,
            src: m.opt_str("src").map(PathBuf::from),
            jobs: m.opt_str("jobs").map(|j| j.parse().unwrap()),
            cmd: cmd,
        }
    }
}

impl Subcommand {
    pub fn test_args(&self) -> Vec<&str> {
        match *self {
            Subcommand::Test { ref test_args, .. } => {
                test_args.iter().flat_map(|s| s.split_whitespace()).collect()
            }
            _ => Vec::new(),
        }
    }
}