//! The individual benchmarks (ports of `benchmark/*.zig`) and the CLI action
//! dispatch (`benchmark/cli.zig`).
use std::{hint::black_box, io::Read};

use ghostty_terminal::{
    point::{Coordinate, Point},
    render::RenderState,
    screen_set::Key as ScreenKey,
    terminal::{Options as TermOptions, Terminal},
};
use ghostty_vt::{
    osc,
    parser::Parser,
    stream::{Action, Handler, Stream},
    utf8_decoder::Utf8Decoder,
};

use crate::{
    args::{Args, data_file, read_short},
    benchmark::{Benchmark, BenchmarkFailed, Result, RunMode, RunResult, run},
};

const CHUNK: usize = 4096;

/// The available actions (benchmarks) of the CLI.
pub const ACTIONS: &[&str] = &[
    "codepoint-width",
    "grapheme-break",
    "screen-clone",
    "terminal-parser",
    "terminal-stream",
    "is-symbol",
    "osc-parser",
];

fn warn(what: &str, e: &dyn std::fmt::Display) -> BenchmarkFailed {
    log::warn!("{what} err={e}");
    BenchmarkFailed
}

/// Shared data-file handling: opened in setup, closed in teardown.
struct Data {
    path: Option<std::path::PathBuf>,
    f: Option<Box<dyn Read>>,
}

impl Data {
    fn new(path: Option<std::path::PathBuf>) -> Data {
        Data { path, f: None }
    }

    fn open(&mut self) -> Result {
        self.f =
            data_file(self.path.as_deref()).map_err(|e| warn("error opening data file", &e))?;
        Ok(())
    }

    /// Feed every 4096-byte chunk of the file to `func`.
    fn for_each_chunk(&mut self, mut func: impl FnMut(&[u8]) -> Result) -> Result {
        let Some(f) = self.f.as_mut() else {
            return Ok(());
        };
        let mut buf = [0u8; CHUNK];
        loop {
            let n = read_short(f.as_mut(), &mut buf)
                .map_err(|e| warn("error reading data file", &e))?;
            if n == 0 {
                return Ok(());
            }
            func(&buf[..n])?;
        }
    }
}

// ---------------------------------------------------------------------------
// terminal-stream

struct PrintHandler {
    t: Terminal,
}

impl Handler for PrintHandler {
    type Error = ghostty_terminal::terminal::Error;

    #[inline]
    fn vt(&mut self, action: Action<'_>) -> std::result::Result<(), Self::Error> {
        if let Action::Print(p) = action {
            self.t.print(p.cp)?;
        }
        Ok(())
    }
}

pub struct TerminalStream {
    data: Data,
    stream: Stream<PrintHandler>,
    /// Rust-only: use the full `stream_readonly` handler (applies every
    /// terminal-modifying action) instead of the print-only handler.
    full: bool,
}

impl TerminalStream {
    pub fn create(args: &mut Args) -> std::result::Result<Self, String> {
        let rows = args.take("terminal-rows", 80u16)?;
        let cols = args.take("terminal-cols", 120u16)?;
        let data = args.take_opt_path("data")?;
        let full = args.take_enum("handler", false, &[("print", false), ("full", true)])?;
        let t = Terminal::new(TermOptions::new(cols, rows)).map_err(|e| format!("{e:?}"))?;
        Ok(TerminalStream {
            data: Data::new(data),
            stream: Stream::new(PrintHandler { t }),
            full,
        })
    }

    /// Total bytes processed so far is not tracked; see `data_len`.
    pub fn terminal(&self) -> &Terminal {
        &self.stream.handler.t
    }
}

impl Benchmark for TerminalStream {
    fn setup(&mut self) -> Result {
        self.stream.handler.t.full_reset();
        self.data.open()
    }

    fn teardown(&mut self) {
        self.data.f = None;
    }

    fn step(&mut self) -> Result {
        if self.full {
            let mut s = self.stream.handler.t.vt_stream();
            return self.data.for_each_chunk(|chunk| {
                s.next_slice(chunk)
                    .map_err(|e| warn("error processing data file chunk", &format!("{e:?}")))
            });
        }
        let stream = &mut self.stream;
        self.data.for_each_chunk(|chunk| {
            stream
                .next_slice(chunk)
                .map_err(|e| warn("error processing data file chunk", &format!("{e:?}")))
        })
    }
}

// ---------------------------------------------------------------------------
// terminal-parser

pub struct TerminalParser {
    data: Data,
}

impl TerminalParser {
    pub fn create(args: &mut Args) -> std::result::Result<Self, String> {
        Ok(TerminalParser {
            data: Data::new(args.take_opt_path("data")?),
        })
    }
}

impl Benchmark for TerminalParser {
    fn setup(&mut self) -> Result {
        self.data.open()
    }

    fn teardown(&mut self) {
        self.data.f = None;
    }

    fn step(&mut self) -> Result {
        let mut p = Parser::new();
        self.data.for_each_chunk(|chunk| {
            for &c in chunk {
                p.next_with(c, drop);
            }
            Ok(())
        })
    }
}

// ---------------------------------------------------------------------------
// osc-parser

pub struct OscParser {
    data: Data,
    parser: osc::Parser,
}

impl OscParser {
    pub fn create(args: &mut Args) -> std::result::Result<Self, String> {
        Ok(OscParser {
            data: Data::new(args.take_opt_path("data")?),
            parser: osc::Parser::init(true),
        })
    }
}

impl Benchmark for OscParser {
    fn setup(&mut self) -> Result {
        self.data.open()?;
        self.parser.reset();
        Ok(())
    }

    fn teardown(&mut self) {
        self.data.f = None;
    }

    fn step(&mut self) -> Result {
        let Some(f) = self.data.f.as_mut() else {
            return Ok(());
        };
        let mut osc_buf = [0u8; 4096];
        loop {
            let mut len_buf = [0u8; 8];
            match read_short(f.as_mut(), &mut len_buf) {
                Ok(8) => {}
                Ok(_) => return Ok(()),
                Err(_) => return Err(BenchmarkFailed),
            }
            let len = usize::from_le_bytes(len_buf);
            if len > osc_buf.len() {
                return Err(BenchmarkFailed);
            }
            match read_short(f.as_mut(), &mut osc_buf[..len]) {
                Ok(n) if n == len => {}
                Ok(_) => return Ok(()),
                Err(_) => return Err(BenchmarkFailed),
            }
            self.parser.next_slice(&osc_buf[..len]);
            black_box(self.parser.end(Some(0x07)));
            self.parser.reset();
        }
    }
}

// ---------------------------------------------------------------------------
// codepoint-width

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum WidthMode {
    Noop,
    Wcwidth,
    Simd,
    Table,
}

pub struct CodepointWidth {
    data: Data,
    mode: WidthMode,
}

impl CodepointWidth {
    pub fn create(args: &mut Args) -> std::result::Result<Self, String> {
        let mode = args.take_enum(
            "mode",
            WidthMode::Noop,
            &[
                ("noop", WidthMode::Noop),
                ("wcwidth", WidthMode::Wcwidth),
                ("simd", WidthMode::Simd),
                ("table", WidthMode::Table),
            ],
        )?;
        Ok(CodepointWidth {
            data: Data::new(args.take_opt_path("data")?),
            mode,
        })
    }
}

/// Decode `chunk` and call `func` for each codepoint.
#[inline]
fn decode_each(d: &mut Utf8Decoder, chunk: &[u8], mut func: impl FnMut(u32)) {
    for &c in chunk {
        let (cp, consumed) = d.next(c);
        debug_assert!(consumed);
        if let Some(cp) = cp {
            func(cp);
        }
    }
}

/// libc `wcwidth` (`extern "c" fn wcwidth(c: u32) c_int`).
#[cfg(unix)]
#[allow(unsafe_code)]
mod libc_wcwidth {
    unsafe extern "C" {
        fn wcwidth(c: u32) -> i32;
    }

    #[allow(unsafe_code)]
    #[inline]
    pub fn call(cp: u32) -> i32 {
        // SAFETY: `wcwidth` is a pure libc function taking a plain integer
        // (wchar_t) and returning an int; no pointers or preconditions.
        unsafe { wcwidth(cp) }
    }
}

/// The `table` mode: generated two-stage lookup (`unicode.table.get(cp).width`),
/// with the same `<= 0xFF` shortcut as terminal.zig.
#[inline]
fn width_table(
    table: &ghostty_unicode::lut::Tables<'_, ghostty_unicode::Properties>,
    cp: u32,
) -> i32 {
    if cp <= 0xFF {
        1
    } else {
        i32::from(table.get(cp).width)
    }
}

/// `simd.codepointWidth` (scalar port of the highway implementation).
#[must_use]
pub fn simd_width(cp: u32) -> i32 {
    i32::from(crate::simd_width::codepoint_width(cp))
}

impl Benchmark for CodepointWidth {
    fn setup(&mut self) -> Result {
        self.data.open()
    }

    fn teardown(&mut self) {
        self.data.f = None;
    }

    fn step(&mut self) -> Result {
        match self.mode {
            WidthMode::Noop => Ok(()),
            WidthMode::Wcwidth => {
                #[cfg(unix)]
                {
                    let mut d = Utf8Decoder::new();
                    self.data.for_each_chunk(|chunk| {
                        decode_each(&mut d, chunk, |cp| {
                            black_box(libc_wcwidth::call(cp));
                        });
                        Ok(())
                    })
                }
                #[cfg(not(unix))]
                {
                    log::warn!("wcwidth is not available on this platform");
                    Ok(())
                }
            }
            WidthMode::Simd => {
                let mut d = Utf8Decoder::new();
                self.data.for_each_chunk(|chunk| {
                    decode_each(&mut d, chunk, |cp| {
                        black_box(simd_width(cp));
                    });
                    Ok(())
                })
            }
            WidthMode::Table => {
                let mut d = Utf8Decoder::new();
                let table = ghostty_unicode::table();
                self.data.for_each_chunk(|chunk| {
                    decode_each(&mut d, chunk, |cp| {
                        black_box(width_table(&table, cp));
                    });
                    Ok(())
                })
            }
        }
    }
}

// ---------------------------------------------------------------------------
// grapheme-break

pub struct GraphemeBreak {
    data: Data,
    noop: bool,
}

impl GraphemeBreak {
    pub fn create(args: &mut Args) -> std::result::Result<Self, String> {
        let noop = args.take_enum("mode", false, &[("noop", true), ("table", false)])?;
        Ok(GraphemeBreak {
            data: Data::new(args.take_opt_path("data")?),
            noop,
        })
    }
}

impl Benchmark for GraphemeBreak {
    fn setup(&mut self) -> Result {
        self.data.open()
    }

    fn teardown(&mut self) {
        self.data.f = None;
    }

    fn step(&mut self) -> Result {
        let mut d = Utf8Decoder::new();
        if self.noop {
            return self.data.for_each_chunk(|chunk| {
                for &c in chunk {
                    black_box(d.next(c));
                }
                Ok(())
            });
        }
        let mut state = ghostty_unicode::BreakState::Default;
        let mut cp1 = 0u32;
        self.data.for_each_chunk(|chunk| {
            decode_each(&mut d, chunk, |cp2| {
                black_box(ghostty_unicode::grapheme_break(cp1, cp2, &mut state));
                cp1 = cp2;
            });
            Ok(())
        })
    }
}

// ---------------------------------------------------------------------------
// is-symbol

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum SymbolMode {
    /// uucode implementation (computed from general category + block).
    Uucode,
    /// Ghostty's table-based approach.
    Table,
}

pub struct IsSymbol {
    data: Data,
    mode: SymbolMode,
}

/// Computed `is_symbol` (`computeIsSymbol` in uucode_config.zig): private
/// use (general category Co) or one of the symbol blocks, evaluated directly
/// from the ranges rather than via the generated table.
#[must_use]
pub fn is_symbol_computed(cp: u32) -> bool {
    matches!(
        cp,
        // general_category == other_private_use
        0xE000..=0xF8FF | 0xF_0000..=0xF_FFFD | 0x10_0000..=0x10_FFFD
        // arrows
        | 0x2190..=0x21FF
        // dingbats
        | 0x2700..=0x27BF
        // emoticons
        | 0x1F600..=0x1F64F
        // miscellaneous_symbols
        | 0x2600..=0x26FF
        // enclosed_alphanumerics
        | 0x2460..=0x24FF
        // enclosed_alphanumeric_supplement
        | 0x1F100..=0x1F1FF
        // miscellaneous_symbols_and_pictographs
        | 0x1F300..=0x1F5FF
        // transport_and_map_symbols
        | 0x1F680..=0x1F6FF
    )
}

impl IsSymbol {
    pub fn create(args: &mut Args) -> std::result::Result<Self, String> {
        let mode = args.take_enum(
            "mode",
            SymbolMode::Uucode,
            &[("uucode", SymbolMode::Uucode), ("table", SymbolMode::Table)],
        )?;
        Ok(IsSymbol {
            data: Data::new(args.take_opt_path("data")?),
            mode,
        })
    }
}

impl Benchmark for IsSymbol {
    fn setup(&mut self) -> Result {
        self.data.open()
    }

    fn teardown(&mut self) {
        self.data.f = None;
    }

    fn step(&mut self) -> Result {
        let mut d = Utf8Decoder::new();
        match self.mode {
            SymbolMode::Uucode => self.data.for_each_chunk(|chunk| {
                decode_each(&mut d, chunk, |cp| {
                    black_box(is_symbol_computed(cp));
                });
                Ok(())
            }),
            SymbolMode::Table => {
                let table = ghostty_unicode::symbols_table::table();
                self.data.for_each_chunk(|chunk| {
                    decode_each(&mut d, chunk, |cp| {
                        black_box(table.get(cp));
                    });
                    Ok(())
                })
            }
        }
    }
}

// ---------------------------------------------------------------------------
// screen-clone

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum CloneMode {
    Noop,
    Clone,
    Render,
}

pub struct ScreenClone {
    data: Data,
    mode: CloneMode,
    terminal: Terminal,
    /// Clones are kept alive so freeing is not benchmarked.
    keep: Vec<ghostty_terminal::screen::Screen>,
}

impl ScreenClone {
    pub fn create(args: &mut Args) -> std::result::Result<Self, String> {
        let mode = args.take_enum(
            "mode",
            CloneMode::Clone,
            &[
                ("clone", CloneMode::Clone),
                ("noop", CloneMode::Noop),
                ("render", CloneMode::Render),
            ],
        )?;
        let rows = args.take("terminal-rows", 80u16)?;
        let cols = args.take("terminal-cols", 120u16)?;
        let data = args.take_opt_path("data")?;
        let terminal = Terminal::new(TermOptions::new(cols, rows)).map_err(|e| format!("{e:?}"))?;
        Ok(ScreenClone {
            data: Data::new(data),
            mode,
            terminal,
            keep: Vec::new(),
        })
    }
}

impl Benchmark for ScreenClone {
    fn setup(&mut self) -> Result {
        self.terminal.full_reset();

        // Force a style on every single row.
        let rows = self.terminal.rows;
        let mut s = self.terminal.vt_stream();
        let fail = |e: &dyn std::fmt::Debug| warn("error processing setup data", &format!("{e:?}"));
        s.next_slice(b"\x1b[48;2;20;40;60m").map_err(|e| fail(&e))?;
        for _ in 0..rows - 1 {
            s.next_slice(b"hello\r\n").map_err(|e| fail(&e))?;
        }
        s.next_slice(b"hello").map_err(|e| fail(&e))?;

        // Setup our terminal state from the data file (not benchmarked).
        self.data.open()?;
        self.data.for_each_chunk(|chunk| {
            s.next_slice(chunk)
                .map_err(|e| warn("error processing data file chunk", &format!("{e:?}")))
        })?;
        self.data.f = None;
        Ok(())
    }

    fn step(&mut self) -> Result {
        // We loop because it's so fast that a single run doesn't capture it.
        match self.mode {
            CloneMode::Noop => {
                for _ in 0..1000 {
                    black_box(self.terminal.screens.active());
                }
            }
            CloneMode::Clone => {
                for _ in 0..1000 {
                    let s = self.terminal.screens.active();
                    let copy = s
                        .clone_screen(Point::Viewport(Coordinate { x: 0, y: 0 }), None)
                        .map_err(|e| warn("error cloning screen", &format!("{e:?}")))?;
                    self.keep.push(black_box(copy));
                }
            }
            CloneMode::Render => {
                let mut state = RenderState::new();
                let fail = |e: &dyn std::fmt::Debug| {
                    warn("error updating render state", &format!("{e:?}"))
                };
                // The first run is dominated by allocation; ignore it.
                state.update(&mut self.terminal).map_err(|e| fail(&e))?;
                for _ in 0..1000 {
                    // Forces a full rebuild because it thinks our screen changed.
                    state.screen = ScreenKey::Alternate;
                    state.update(&mut self.terminal).map_err(|e| fail(&e))?;
                    black_box(&state);
                }
            }
        }
        Ok(())
    }

    fn teardown(&mut self) {
        self.keep.clear();
    }
}

// ---------------------------------------------------------------------------
// CLI

/// Run the named action with the given (already `+action`-free) arguments.
/// When `time` is set the measured result is returned.
pub fn main_action(action: &str, mut args: Args) -> std::result::Result<RunResult, String> {
    fn go<B: Benchmark>(
        b: std::result::Result<B, String>,
        args: Args,
    ) -> std::result::Result<RunResult, String> {
        let mut b = b?;
        args.finish()?;
        run(&mut b, RunMode::Once).map_err(|e| e.to_string())
    }
    // Options are consumed by `create`; leftovers are errors.
    let a = &mut args;
    match action {
        "screen-clone" => {
            let b = ScreenClone::create(a);
            go(b, args)
        }
        "terminal-stream" => {
            let b = TerminalStream::create(a);
            go(b, args)
        }
        "codepoint-width" => {
            let b = CodepointWidth::create(a);
            go(b, args)
        }
        "grapheme-break" => {
            let b = GraphemeBreak::create(a);
            go(b, args)
        }
        "terminal-parser" => {
            let b = TerminalParser::create(a);
            go(b, args)
        }
        "is-symbol" => {
            let b = IsSymbol::create(a);
            go(b, args)
        }
        "osc-parser" => {
            let b = OscParser::create(a);
            go(b, args)
        }
        _ => Err(format!("invalid action: +{action}")),
    }
}

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

    fn run(action: &str, mode: &str, data: &std::path::Path) -> Result {
        let mut args = Args::parse([
            std::ffi::OsString::from(format!("+{action}")),
            std::ffi::OsString::from(format!("--mode={mode}")),
            {
                let mut a = std::ffi::OsString::from("--data=");
                a.push(data);
                a
            },
        ])
        .unwrap();
        match action {
            "codepoint-width" => crate::benchmark::run(
                &mut CodepointWidth::create(&mut args).unwrap(),
                crate::benchmark::RunMode::Once,
            ),
            _ => crate::benchmark::run(
                &mut IsSymbol::create(&mut args).unwrap(),
                crate::benchmark::RunMode::Once,
            ),
        }
        .map(|_| ())
    }

    fn sample_file(tag: &str) -> std::path::PathBuf {
        let p =
            std::env::temp_dir().join(format!("ghostty-bench-{tag}-{}.txt", std::process::id()));
        std::fs::write(
            &p,
            "hello \u{4e00}\u{1f600}\u{301}\u{e000} world \u{2190}\n",
        )
        .unwrap();
        p
    }

    #[test]
    fn codepoint_width_all_modes_run() {
        let p = sample_file("cw");
        for m in ["noop", "wcwidth", "simd", "table"] {
            run("codepoint-width", m, &p).unwrap();
        }
        let mut args = Args::parse(["--mode=bogus".to_owned()]).unwrap();
        assert!(CodepointWidth::create(&mut args).is_err());
        let _ = std::fs::remove_file(p);
    }

    #[test]
    fn duplicate_bad_enum_modes_fail() {
        let mk = |v: &[&str]| Args::parse(v.iter().map(|s| (*s).to_owned())).unwrap();
        for v in [
            &["--mode=bad", "--mode=noop"][..],
            &["--mode=bad", "--mode="][..],
        ] {
            assert!(CodepointWidth::create(&mut mk(v)).is_err());
            assert!(GraphemeBreak::create(&mut mk(v)).is_err());
            assert!(IsSymbol::create(&mut mk(v)).is_err());
            assert!(ScreenClone::create(&mut mk(v)).is_err());
        }
    }

    #[test]
    fn is_symbol_modes_run() {
        let p = sample_file("sym");
        for m in ["uucode", "table"] {
            run("is-symbol", m, &p).unwrap();
        }
        let _ = std::fs::remove_file(p);
    }

    #[test]
    fn is_symbol_computed_matches_table() {
        let t = ghostty_unicode::symbols_table::table();
        for cp in 0..=0x11_0000u32 {
            assert_eq!(is_symbol_computed(cp), t.get(cp), "cp={cp:x}");
        }
    }

    #[test]
    fn simd_matches_table_on_samples() {
        let t = ghostty_unicode::table();
        for cp in [
            0x61, 0x100, 0x3400, 0x2E3A, 0x1F1E6, 0x4E00, 0xF900, 0x1F600, 0x20000, 0x30000, 0x301,
            0x200B, 0x200D, 0xFE0F, 0x20DD, 0xE0100, 0xE0001, 0x1160, 0xAC00,
        ] {
            assert_eq!(simd_width(cp), width_table(&t, cp), "cp={cp:x}");
        }
    }

    #[cfg(unix)]
    #[test]
    fn wcwidth_ascii() {
        // The C locale is in effect (no setlocale, like Zig): ASCII only.
        assert_eq!(libc_wcwidth::call(u32::from(b'a')), 1);
        assert_eq!(libc_wcwidth::call(0), 0);
    }
}