// Copyright (c) 2020-2024 Raúl Hernández. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
module ui

import os

pub enum KeyCode {
    null                 = 0
    tab                  = 9
    enter                = 10
    escape               = 27
    space                = 32
    backspace            = 127
    exclamation          = 33
    double_quote         = 34
    hashtag              = 35
    dollar               = 36
    percent              = 37
    ampersand            = 38
    single_quote         = 39
    left_paren           = 40
    right_paren          = 41
    asterisk             = 42
    plus                 = 43
    comma                = 44
    minus                = 45
    period               = 46
    slash                = 47
    _0                   = 48
    _1                   = 49
    _2                   = 50
    _3                   = 51
    _4                   = 52
    _5                   = 53
    _6                   = 54
    _7                   = 55
    _8                   = 56
    _9                   = 57
    colon                = 58
    semicolon            = 59
    less_than            = 60
    equal                = 61
    greater_than         = 62
    question_mark        = 63
    at                   = 64
    a                    = 97
    b                    = 98
    c                    = 99
    d                    = 100
    e                    = 101
    f                    = 102
    g                    = 103
    h                    = 104
    i                    = 105
    j                    = 106
    k                    = 107
    l                    = 108
    m                    = 109
    n                    = 110
    o                    = 111
    p                    = 112
    q                    = 113
    r                    = 114
    s                    = 115
    t                    = 116
    u                    = 117
    v                    = 118
    w                    = 119
    x                    = 120
    y                    = 121
    z                    = 122
    left_square_bracket  = 91
    backslash            = 92
    right_square_bracket = 93
    caret                = 94
    underscore           = 95
    backtick             = 96
    left_curly_bracket   = 123
    vertical_bar         = 124
    right_curly_bracket  = 125
    tilde                = 126
    insert               = 260
    delete               = 261
    up                   = 262
    down                 = 263
    right                = 264
    left                 = 265
    page_up              = 266
    page_down            = 267
    home                 = 268
    end                  = 269
    f1                   = 290
    f2                   = 291
    f3                   = 292
    f4                   = 293
    f5                   = 294
    f6                   = 295
    f7                   = 296
    f8                   = 297
    f9                   = 298
    f10                  = 299
    f11                  = 300
    f12                  = 301
    f13                  = 302
    f14                  = 303
    f15                  = 304
    f16                  = 305
    f17                  = 306
    f18                  = 307
    f19                  = 308
    f20                  = 309
    f21                  = 310
    f22                  = 311
    f23                  = 312
    f24                  = 313
}

pub enum Direction {
    unknown
    up
    down
    left
    right
}

pub enum MouseButton {
    unknown
    left
    middle
    right
}

pub enum EventType {
    unknown
    mouse_down
    mouse_up
    mouse_move
    mouse_drag
    mouse_scroll
    key_down
    key_up
    resized
}

@[flag]
pub enum Modifiers {
    ctrl
    shift
    alt
}

struct TerminalCapabilities {
    enable_ansi256            bool = true
    supports_alternate_buffer bool = true
    supports_sgr_mouse        bool = true
    supports_sync_updates     bool = true
    supports_window_title     bool = true
}

fn terminal_capabilities_for(term_name string) TerminalCapabilities {
    if term_name == 'linux' {
        return TerminalCapabilities{
            enable_ansi256:            false
            supports_alternate_buffer: false
            supports_sgr_mouse:        false
            supports_sync_updates:     false
            supports_window_title:     false
        }
    }
    return TerminalCapabilities{}
}

fn current_terminal_capabilities() TerminalCapabilities {
    return terminal_capabilities_for(os.getenv('TERM'))
}

pub struct Event {
pub:
    typ EventType
    // Mouse event info
    x         int
    y         int
    button    MouseButton
    direction Direction
    // Keyboard event info
    code      KeyCode
    modifiers Modifiers
    ascii     u8
    utf8      string
    // Resized event info
    width  int
    height int
}

pub struct Context {
    ExtraContext // contains fields specific to an implementation
pub:
    cfg Config // the initial configuration, passed to ui.init()
mut:
    print_buf                 []u8
    paused                    bool
    enable_su                 bool
    enable_rgb                bool
    enable_ansi256            bool = true
    supports_alternate_buffer bool = true
    supports_sgr_mouse        bool = true
    supports_sync_updates     bool = true
    supports_window_title     bool = true
pub mut:
    frame_count   u64
    window_width  int
    window_height int
}

pub struct Config {
pub:
    user_data  voidptr
    init_fn    ?fn (voidptr)
    frame_fn   ?fn (voidptr)
    cleanup_fn ?fn (voidptr)
    event_fn   ?fn (&Event, voidptr)
    fail_fn    ?fn (string)

    buffer_size int = 256
    frame_rate  int = 30
    use_x11     bool

    window_title         string
    hide_cursor          bool
    capture_events       bool
    mouse_enabled        bool
    use_alternate_buffer bool = true
    skip_init_checks     bool
    // All kill signals to set up exit listeners on:
    reset []os.Signal = [.hup, .int, .quit, .ill, .abrt, .bus, .fpe, .kill, .segv, .pipe, .alrm, .term,
        .stop]
}

@[inline]
fn (ctx &Context) init() {
    f := ctx.cfg.init_fn or { return }
    f(ctx.cfg.user_data)
}

@[inline]
fn (ctx &Context) frame() {
    f := ctx.cfg.frame_fn or { return }
    f(ctx.cfg.user_data)
}

@[inline]
fn (ctx &Context) cleanup() {
    f := ctx.cfg.cleanup_fn or { return }
    f(ctx.cfg.user_data)
}

@[inline]
fn (ctx &Context) fail(error string) {
    f := ctx.cfg.fail_fn or { return }
    f(error)
}

@[inline]
fn (ctx &Context) event(event &Event) {
    f := ctx.cfg.event_fn or { return }
    f(event, ctx.cfg.user_data)
}