extern crate crossbeam;
extern crate clap;
#[macro_use] extern crate version;
#[macro_use] extern crate log;
extern crate walkdir;

extern crate libimagrt;
extern crate libimagerror;

use std::env;
use std::process::exit;
use std::process::Command;
use std::process::Stdio;
use std::io::ErrorKind;

use walkdir::WalkDir;
use crossbeam::*;
use clap::{Arg, AppSettings, SubCommand};

use libimagrt::runtime::Runtime;
use libimagerror::trace::trace_error;

fn help_text(cmds: Vec<String>) -> String {
    let text = format!(r#"

     _
    (_)_ __ ___   __ _  __ _
    | | '_ \` _ \/ _\`|/ _\`|
    | | | | | | | (_| | (_| |
    |_|_| |_| |_|\__,_|\__, |
                       |___/
    -------------------------

    Usage: imag [--version | --versions | -h | --help] <command> <args...>

    imag - the personal information management suite for the commandline

    imag is a PIM suite for the commandline. It consists of several commands,
    called "modules". Each module implements one PIM aspect and all of these
    modules can be used independently.

    Available commands:

    {imagbins}

    Call a command with 'imag <command> <args>'
    Each command can be called with "--help" to get the respective helptext.

    Please visit https://github.com/matthiasbeyer/imag to view the source code,
    follow the development of imag or maybe even contribute to imag.

    imag is free software. It is released under the terms of LGPLv2.1

    (c) 2016 Matthias Beyer and contributors"#, imagbins = cmds.into_iter()
        .map(|cmd| format!("\t{}\n", cmd))
        .fold(String::new(), |s, c| {
            let s = s + c.as_str();
            s
        }));
    text
}


fn get_commands() -> Vec<String> {
    let path = env::var("PATH");
    if path.is_err() {
        println!("PATH error: {:?}", path);
        exit(1);
    }
    let pathelements = path.unwrap();
    let pathelements = pathelements.split(":");

    let joinhandles : Vec<ScopedJoinHandle<Vec<String>>> = pathelements
        .map(|elem| {
            crossbeam::scope(|scope| {
                scope.spawn(|| {
                    WalkDir::new(elem)
                        .max_depth(1)
                        .into_iter()
                        .filter(|path| {
                            match path {
                                &Ok(ref p) => p.file_name()
                                    .to_str()
                                    .map_or(false, |filename| filename.starts_with("imag-")),
                                &Err(_)   => false,
                            }
                        })
                        .filter_map(|x| x.ok())
                        .filter_map(|path| {
                           path.file_name()
                               .to_str()
                               .and_then(|s| s.splitn(2, "-").nth(1).map(String::from))
                        })
                        .collect()
                })
            })
        })
        .collect();

    let mut execs = vec![];
    for joinhandle in joinhandles.into_iter() {
        let mut v = joinhandle.join();
        execs.append(&mut v);
    }

    execs
}


fn main() {
    let appname  = "imag";
    let version  = &version!();
    let about    = "imag - the PIM suite for the commandline";
    let commands = get_commands();
    let helptext = help_text(commands);
    let app      = Runtime::get_default_cli_builder(appname, version, about)
        .settings(&[AppSettings::AllowExternalSubcommands])
        .arg(Arg::with_name("version")
             .long("version")
             .takes_value(false)
             .required(false)
             .multiple(false)
             .help("Get the version of imag"))
        .arg(Arg::with_name("versions")
             .long("versions")
             .takes_value(false)
             .required(false)
             .multiple(false)
             .help("Get the versions of the imag commands"))
        .subcommand(SubCommand::with_name("help").help("Show help"))
        .help(helptext.as_str());
    let rt = Runtime::new(app)
        .unwrap_or_else(|e| {
            println!("Runtime couldn't be setup. Exiting");
            trace_error(&e);
            exit(1);
        });
    let matches = rt.cli();

    debug!("matches: {:?}", matches);

    if matches.is_present("version") {
        debug!("Showing version");
        println!("imag {}", &version!()[..]);
        exit(0);
    }

    if matches.is_present("versions") {
        debug!("Showing versions");
        let mut result = vec![];
        for command in get_commands().iter() {
            result.push(crossbeam::scope(|scope| {
                scope.spawn(|| {
                    let v = Command::new(command).arg("--version").output();
                    match v {
                        Ok(v) => match String::from_utf8(v.stdout) {
                            Ok(s) => format!("{} -> {}", command, s),
                            Err(e) => format!("Failed calling {} -> {:?}", command, e),
                        },
                        Err(e) => format!("Failed calling {} -> {:?}", command, e),
                    }
                })
            }))
        }

        for versionstring in result.into_iter().map(|handle| handle.join()) {
            println!("{}", versionstring);
        }
    }

    match matches.subcommand() {
        (subcommand, Some(scmd)) => {
            debug!("Calling with subcommand: {}", subcommand);
            let subcommand_args : Vec<&str> = match scmd.values_of("") {
                Some(values) => values.collect(),
                None => Vec::new()
            };
            debug!("Calling 'imag-{}' with args: {:?}", subcommand, subcommand_args);

            match Command::new(format!("imag-{}", subcommand))
                .stdin(Stdio::inherit())
                .stdout(Stdio::inherit())
                .stderr(Stdio::inherit())
                .args(&subcommand_args[..])
                .spawn()
                .and_then(|mut handle| handle.wait())
            {
                Ok(exit_status) => {
                    if !exit_status.success() {
                        debug!("{} exited with non-zero exit code: {:?}", subcommand, exit_status);
                        println!("{} exited with non-zero exit code", subcommand);
                        exit(exit_status.code().unwrap_or(42));
                    }
                    debug!("Successful exit!");
                },

                Err(e) => {
                    debug!("Error calling the subcommand");
                    match e.kind() {
                        ErrorKind::NotFound => {
                            println!("No such command: 'imag-{}'", subcommand);
                            println!("See 'imag --help' for available subcommands");
                            exit(2);
                        },
                        ErrorKind::PermissionDenied => {
                            println!("No permission to execute: 'imag-{}'", subcommand);
                            exit(1);
                        },
                        _ => {
                            println!("Error spawning: {:?}", e);
                            exit(1337);
                        }
                    }
                }
            }
        },
        // clap ensures we have valid input by exiting if not.
        // The above case is a catch-all for subcommands,
        // so nothing else needs to be expexted.
        _ => unreachable!(),
    }
}