pub mod lib;

use vtcol::{Console, Fade, KbLedState, Palette, Scheme};

use anyhow::{anyhow, Result};
use std::{io::{self, BufWriter},
          sync::atomic::{AtomicBool, Ordering},
          time::Duration};

static VERBOSITY: AtomicBool = AtomicBool::new(false);

const DEFAULT_FADE_DURATION_MS: u64 = 500;
const DEFAULT_FADE_UPDATE_HZ: u8 = 25;

macro_rules! vrb {
    ( $( $e:expr ),* ) => {(
            if VERBOSITY.load(Ordering::SeqCst) { println!( $( $e ),* ) }
    )}
}

#[derive(Debug)]
enum LedJob
{
    /** Get keyboard LED state. */
    Get(bool),
    /** Set keyboard LED state; ``None`` indicates revert. */
    Set(Option<KbLedState>),
}

#[derive(Debug)]
enum ColorJob
{
    /** List available schemes. */
    List,
    /** Dump a scheme. */
    Dump(Scheme),
    /** Switch to color scheme. */
    Set(Scheme),
    /** Get currently active scheme. */
    Get(bool),
    /** Toggle between two schemes. */
    Toggle(Scheme, Scheme),
    /** Fade from current scheme to another. */
    Fade(Option<Scheme>, Scheme, Duration, u8, bool),
}

/** Subcommand and runtime parameters. */
#[derive(Debug)]
enum Job
{
    /** Console palette ops. */
    Colors(ColorJob),
    /** Keyboard LED ops. */
    Leds(LedJob),
}

impl<'a> Job
{
    pub fn from_argv() -> Result<Job>
    {
        use clap::{App, Arg, SubCommand};

        let app = App::new(clap::crate_name!())
            .version(clap::crate_version!())
            .author(clap::crate_authors!())
            .about(clap::crate_description!())
            .arg(
                Arg::with_name("verbose")
                    .short("v")
                    .long("verbose")
                    .help("enable extra diagnostics")
                    .takes_value(false),
            )
            .subcommand(
                SubCommand::with_name("colors")
                    .about("operations on the console palette")
                    .subcommand(
                        SubCommand::with_name("dump")
                            .about("dump a color scheme")
                            .arg(
                                Arg::with_name("scheme")
                                    .help("name of the scheme")
                                    .required(false)
                                    .value_name("NAME")
                                    .takes_value(true),
                            )
                            .arg(
                                Arg::with_name("base64")
                                    .short("b")
                                    .long("base64")
                                    .value_name("DATA")
                                    .help("base64 encoded binary input")
                                    .required(false)
                                    .takes_value(true),
                            ),
                    )
                    .subcommand(
                        SubCommand::with_name("list")
                            .about("list builtin schemes"),
                    )
                    .subcommand(
                        SubCommand::with_name("set")
                            .about("apply color scheme to current terminal")
                            .arg(
                                Arg::with_name("scheme")
                                    .value_name("NAME")
                                    .help("predefined color scheme")
                                    .takes_value(true)
                                    .conflicts_with("file"),
                            )
                            .arg(
                                Arg::with_name("file")
                                    .short("f")
                                    .long("file")
                                    .value_name("PATH")
                                    .help("apply scheme from file")
                                    .takes_value(true),
                            )
                            .arg(
                                Arg::with_name("base64")
                                    .short("b")
                                    .long("base64")
                                    .help("base64 encoded binary input")
                                    .value_name("DATA")
                                    .required(false)
                                    .takes_value(true),
                            ),
                    )
                    .subcommand(
                        SubCommand::with_name("get")
                            .about("get current color scheme")
                            .arg(
                                Arg::with_name("base64")
                                    .short("b")
                                    .long("base64")
                                    .help("base64 encoded binary output")
                                    .required(false)
                                    .takes_value(false),
                            ),
                    )
                    .subcommand(
                        SubCommand::with_name("toggle")
                            .about("toggle between two schemes")
                            .arg(
                                Arg::with_name("one")
                                    .value_name("NAME1")
                                    .help("predefined color scheme")
                                    .takes_value(true),
                            )
                            .arg(
                                Arg::with_name("two")
                                    .value_name("NAME2")
                                    .help("predefined color scheme")
                                    .takes_value(true),
                            ),
                    )
                    .subcommand(
                        SubCommand::with_name("fade")
                            .about("fade from one scheme to another")
                            .arg(
                                Arg::with_name("from")
                                    .short("f")
                                    .long("from")
                                    .value_name("NAME1")
                                    .help(
                                        "initial color scheme (default: \
                                         current)",
                                    )
                                    .takes_value(true),
                            )
                            .arg(
                                Arg::with_name("to")
                                    .short("t")
                                    .long("to")
                                    .value_name("NAME2")
                                    .help("final color scheme")
                                    .takes_value(true)
                                    .required(true),
                            )
                            .arg(
                                Arg::with_name("ms")
                                    .value_name("MS")
                                    .short("m")
                                    .long("ms")
                                    .help(
                                        "how long (in ms) the fade should take",
                                    )
                                    .takes_value(true),
                            )
                            .arg(
                                Arg::with_name("clear")
                                    .short("c")
                                    .long("clear")
                                    .help("clear terminal on each fade step")
                                    .takes_value(false),
                            )
                            .arg(
                                Arg::with_name("frequency")
                                    .value_name("HZ")
                                    .short("h")
                                    .long("frequency")
                                    .help(
                                        "rate (HZ/s) of intermediate scheme \
                                         changes",
                                    )
                                    .takes_value(true),
                            ),
                    ),
            )
            .subcommand(
                SubCommand::with_name("leds")
                    .about("operations regarding keyboard LEDs")
                    .subcommand(
                        SubCommand::with_name("get")
                            .about("get LED state")
                            .arg(
                                Arg::with_name("u8")
                                    .short("8")
                                    .long("u8")
                                    .help("output raw state as integer")
                                    .takes_value(false),
                            ),
                    )
                    .subcommand(
                        SubCommand::with_name("set")
                            .about("set LED state")
                            .arg(
                                Arg::with_name("u8")
                                    .short("8")
                                    .long("u8")
                                    .help("provide desired state as integer")
                                    .takes_value(true)
                                    .required_unless_one(&["revert"])
                                    .value_name("STATE"),
                            )
                            .arg(
                                Arg::with_name("revert")
                                    .short("r")
                                    .long("revert")
                                    .help("revert LED state to normal")
                                    .takes_value(false)
                                    .conflicts_with("u8"),
                            ),
                    ),
            );

        let matches = app.get_matches();

        if matches.is_present("verbose") {
            VERBOSITY.store(true, Ordering::SeqCst);
        }

        match matches.subcommand() {
            ("colors", Some(subm)) =>
                match subm.subcommand() {
                    ("dump", Some(subm)) => {
                        if let Some(b64) = subm.value_of("base64") {
                            let scheme = Scheme::from_base64(b64)?;
                            return Ok(Self::Colors(ColorJob::Dump(scheme)));
                        }
                        if let Some(name) = subm.value_of("scheme") {
                            let scm = Scheme::from(name);
                            return Ok(Self::Colors(ColorJob::Dump(scm)));
                        }
                        Err(anyhow!("dump requires an argument"))
                    },
                    ("list", _) => Ok(Self::Colors(ColorJob::List)),
                    ("set", Some(subm)) => {
                        if let Some(b64) = subm.value_of("base64") {
                            let scheme = Scheme::from_base64(&b64)?;
                            return Ok(Self::Colors(ColorJob::Set(scheme)));
                        }
                        let scheme = match subm.value_of("scheme") {
                            Some("-") => Self::read_scheme_from_stdin(),
                            Some(name) => {
                                vrb!("pick predefined scheme [{}]", name);
                                Scheme::from(name)
                            },
                            None =>
                                match subm.value_of("file") {
                                    None | Some("-") =>
                                        Self::read_scheme_from_stdin(),
                                    Some(fname) => {
                                        vrb!(
                                            "read custom scheme from file [{}]",
                                            fname
                                        );
                                        Scheme::from_path(fname)
                                    },
                                },
                        };
                        Ok(Self::Colors(ColorJob::Set(scheme)))
                    },
                    ("get", Some(subm)) =>
                        Ok(Self::Colors(ColorJob::Get(
                            subm.is_present("base64"),
                        ))),
                    ("toggle", Some(subm)) => {
                        match (subm.value_of("one"), subm.value_of("two")) {
                            (Some(one), Some(two)) => {
                                vrb!("toggle schemes [{}] and [{}]", one, two);
                                Ok(Self::Colors(ColorJob::Toggle(
                                    Scheme::from(one),
                                    Scheme::from(two),
                                )))
                            },
                            _ =>
                                Err(anyhow!(
                                    "please supply two schemes to toggle \
                                     between"
                                )),
                        }
                    },
                    ("fade", Some(subm)) => {
                        let dur: u64 = if let Some(ms) = subm.value_of("ms") {
                            ms.parse()?
                        } else {
                            DEFAULT_FADE_DURATION_MS
                        };
                        let hz: u8 =
                            if let Some(ms) = subm.value_of("frequency") {
                                ms.parse()?
                            } else {
                                DEFAULT_FADE_UPDATE_HZ
                            };
                        let clear = subm.is_present("clear");
                        let dur = Duration::from_millis(dur);

                        match (subm.value_of("from"), subm.value_of("to")) {
                            (_, None) =>
                                Err(anyhow!(
                                    "please supply color scheme to fade to"
                                )),
                            (from, Some(to)) =>
                                Ok(Self::Colors(ColorJob::Fade(
                                    from.map(Scheme::from),
                                    Scheme::from(to),
                                    dur,
                                    hz,
                                    clear,
                                ))),
                        }
                    },
                    (junk, _) =>
                        Err(anyhow!(
                            "invalid sub-subcommand to colors: [{}]; try ``{} \
                             colors --help``",
                            junk,
                            clap::crate_name!()
                        )),
                },

            ("leds", Some(subm)) =>
                match subm.subcommand() {
                    ("get", Some(subm)) => {
                        let raw = subm.is_present("u8");
                        Ok(Self::Leds(LedJob::Get(raw)))
                    },
                    ("set", Some(subm)) => {
                        if subm.is_present("revert") {
                            return Ok(Self::Leds(LedJob::Set(None)));
                        }
                        let st: u8 = subm.value_of("u8").unwrap().parse()?;
                        let st = KbLedState::try_from(st)?;
                        Ok(Self::Leds(LedJob::Set(Some(st))))
                    },
                    (junk, _) =>
                        Err(anyhow!(
                            "invalid sub-subcommand to leds: [{}]; try ``{} \
                             leds --help``",
                            junk,
                            clap::crate_name!()
                        )),
                },

            (junk, _) =>
                Err(anyhow!(
                    "invalid subcommand [{}]; try ``{} --help``",
                    junk,
                    clap::crate_name!()
                )),
        }
    }

    fn list_schemes()
    {
        println!("{} color schemes available:", vtcol::BUILTIN_SCHEMES.len());
        for s in vtcol::BUILTIN_SCHEMES {
            println!("      * {}", s.name());
        }
    }

    fn read_scheme_from_stdin() -> Scheme
    {
        vrb!("Go ahead, type your color scheme …");
        vrb!("vtcol>");
        Scheme::from_stdin()
    }

    fn dump(scm: Scheme) -> Result<()>
    {
        vrb!("Dumping color scheme {}", scm);
        let mut out = BufWriter::new(io::stdout());

        match scm {
            Scheme::Builtin(bltn) =>
                Palette::from(bltn.palette()).dump(&mut out).map_err(|e| {
                    anyhow!(
                        "error loading builtin scheme {}: {}",
                        bltn.name(),
                        e
                    )
                }),
            Scheme::Custom(None) =>
                Palette::from_stdin()?.dump(&mut out).map_err(|e| {
                    anyhow!("error loading palette from stdin: {}", e)
                }),
            Scheme::Custom(Some(fname)) =>
                Palette::from_file(&fname)?.dump(&mut out).map_err(|e| {
                    anyhow!(
                        "error loading palette from file [{}]: {}",
                        fname.display(),
                        e
                    )
                }),
            Scheme::Palette(pal) =>
                pal.dump(&mut out)
                    .map_err(|e| anyhow!("error dumping palette: {}", e)),
        }
    }

    fn run(self) -> Result<()>
    {
        match self {
            Self::Colors(ColorJob::Dump(scm)) => Self::dump(scm)?,
            Self::Colors(ColorJob::List) => Self::list_schemes(),
            Self::Colors(ColorJob::Set(scm)) => Self::set_scheme(scm)?,
            Self::Colors(ColorJob::Get(b64)) => Self::get_scheme(b64)?,
            Self::Colors(ColorJob::Toggle(one, two)) =>
                Self::toggle_scheme(one, two)?,
            Self::Colors(ColorJob::Fade(from, to, ms, hz, clear)) =>
                Self::fade(from, to, ms, hz, clear)?,
            Self::Leds(LedJob::Get(raw)) => Self::get_leds(raw)?,
            Self::Leds(LedJob::Set(st)) => Self::set_leds(st)?,
        }

        Ok(())
    }

    fn set_scheme(scheme: Scheme) -> Result<()>
    {
        let con = Console::current()?;
        vrb!("console fd: {}", con);

        con.apply_scheme(&scheme)?;
        con.clear()?;

        vrb!("successfully enabled scheme {:?}", scheme);
        /* It’s fine to leak the fd, the kernel will clean up anyways. */
        Ok(())
    }

    fn get_scheme(b64: bool) -> Result<()>
    {
        let fd = Console::current()?;
        vrb!("console fd: {}", fd);

        let scm = fd.current_scheme()?;
        if b64 {
            print!("{}", scm.base64()?);
        } else {
            vrb!("active scheme:");
            println!("{}", scm);
        }

        Ok(())
    }

    /** Toggle between two schemes. Defaults to ``one`` in case neither scheme
    is active.
    */
    fn toggle_scheme(one: Scheme, two: Scheme) -> Result<()>
    {
        let fd = Console::current()?;
        vrb!("console fd: {}", fd);

        if fd.current_palette()? == Palette::try_from(&one)? {
            Self::set_scheme(two)
        } else {
            Self::set_scheme(one)
        }
    }

    /** Fade from one scheme to another.

    If ``from`` is ``None``, the current palette is used as starting point. */
    fn fade(
        from: Option<Scheme>,
        to: Scheme,
        dur: Duration,
        hz: u8,
        clear: bool,
    ) -> Result<()>
    {
        let fd = Console::current()?;
        vrb!("console fd: {}", fd);

        let from = if let Some(from) = from {
            Palette::try_from(&from)?
        } else {
            fd.current_palette()?
        };
        let to = Palette::try_from(&to)?;

        let fade = Fade::new(from, to, dur, hz, clear);

        fade.commence(&fd)?;
        Ok(())
    }

    /** Get the keyboard LED state. */
    fn get_leds(raw: bool) -> Result<()>
    {
        let fd = Console::current()?;
        vrb!("console fd: {}", fd);

        let leds = KbLedState::get(&fd)?;

        if raw {
            println!("{}", u8::from(leds));
        } else {
            println!("{}", leds);
        }

        Ok(())
    }

    /** Set the keyboard LED state. */
    fn set_leds(st: Option<KbLedState>) -> Result<()>
    {
        let fd = Console::current()?;
        vrb!("console fd: {}", fd);

        if let Some(st) = st {
            st.set(&fd)?;
            vrb!("applied");
        } else {
            KbLedState::revert(&fd)?;
            vrb!("reverted");
        }

        Ok(())
    }
} /* [impl Job] */

fn main() -> Result<()>
{
    let job = Job::from_argv()?;
    vrb!("job parms: {:?}", job);

    job.run()
}