#if OS == .WINDOWS {
    #load "windows.jai";
} else #if (OS == .LINUX) || (OS == .MACOS) {
    #load "unix.jai";
} else {
    #assert(false, "Unsupported OS.");
}

#import "String";

// https://learn.microsoft.com/en-us/windows/console/console-virtual-terminal-sequences
// https://learn.microsoft.com/en-us/windows/console/console-virtual-terminal-sequences#designate-character-set
// https://github.com/MicrosoftDocs/Console-Docs/blob/main/docs/console-virtual-terminal-sequences.md

isTUIActive := false; // TODO Rename this variable.


Drawings :: struct {
    CornerBR                :: "\x6A";
    CornerTR                :: "\x6B";
    CornerTL                :: "\x6C";
    CornerBL                :: "\x6D";
    Cross                   :: "\x6E";
    LineH                   :: "\x71";
    TeeL                    :: "\x74";
    TeeR                    :: "\x75";
    TeeB                    :: "\x76";
    TeeT                    :: "\x77";
    LineV                   :: "\x78";

    Blank                   :: "\x5F";
    Diamond                 :: "\x60";
    Checkerboard            :: "\x61";
    PlusMinus               :: "\x67";
    LessThanOrEqual         :: "\x79";
    GreaterThanOrEqual      :: "\x7A";
    Pi                      :: "\x7B";
    NotEqual                :: "\x7C";
    CenteredDot             :: "\x7E";
}

Commands :: struct {
    EnterAlternateBuffer    :: "\e[?1049h";
    EnterMainBuffer         :: "\e[?1049l";

    EnterDrawingMode        :: "\e(0";
    EnterNormalMode         :: "\e(B";
    ClearScreen             :: "\e[2J";
    ClearLine               :: "\e[2K";

    RefreshWindow           :: "\e[7t"; // TODO Not yet tested.

    SetUTF8                 :: "\e%G"; // TODO TEST ME PLEASE

    // Cursor Visibility
    ShowCursor              :: "\e[?25h";
    HideCursor              :: "\e[?25l";
    StartBlinking           :: "\e[?25h]";
    StopBlinking            :: "\e[?25l]";
    SaveCursorPosition      :: "\e7";
    RestoreCursorPosition   :: "\e8";

    // Cursor Shape
    DefaultShape            :: "\e[0 q";
    BlinkingBlockShape      :: "\e[1 q";
    SteadyBlockShape        :: "\e[2 q";
    BlinkingUnderlineShape  :: "\e[3 q";
    SteadyUnderlineShape    :: "\e[4 q";
    BlinkingBarShape        :: "\e[5 q";
    SteadyBarShape          :: "\e[6 q";

    // Input Mode
    KeypadAppMode           :: "\e=";
    KeypadNumMode           :: "\e>";
    CursorAppMode           :: "\e[?1h";
    CursorNormalMode        :: "\e[?1l";

    // Query State
    QueryCursorPosition     :: "\e[6n"; // Emits the cursor position as: "ESC [ <r> ; <c> R" Where <r> = row and <c> = column.
    QueryDeviceAttributes   :: "\e[0c";
    QueryWindowSizeInChars  :: "\e[18t"; // Emits the window size as: "ESC [ 8 <r> ; <c> t" Where <r> = row and <c> = column.
    
}

start :: () {
    OS_prepare_terminal();
    write_strings(Commands.HideCursor, Commands.SaveCursorPosition, Commands.EnterAlternateBuffer, Commands.SetUTF8);
    isTUIActive = true;
}

stop :: () {
    isTUIActive = false;
    write_strings(Commands.EnterMainBuffer, Commands.RestoreCursorPosition, Commands.ShowCursor);
    OS_reset_terminal();
}

draw_box :: (x: int, y: int, width: int, height: int, to_standard_error := false) {


    // TODO Hardcoded box starting at 1,1... fix this!

    write_strings(
        // Commands.EnterNormalMode,
        Commands.EnterDrawingMode,
        "\e[1;1H",       // Move to position 1,1
        // TODO // Move pointer to top-left corner.
        Drawings.CornerTL,
        to_standard_error = to_standard_error);

    for 1..width-2 {
        write_string(Drawings.LineH, to_standard_error = to_standard_error);
    }
    write_string(Drawings.CornerTR, to_standard_error = to_standard_error);


    // TODO Take care of the temporary allocations.
    for idx: 2..height-1 {
        tmpL := tprint("\e[%;%H", idx, 1);
        tmpR := tprint("\e[%;%H", idx, width);
        write_strings(
            tmpL,
            Drawings.LineV,
            tmpR,
            Drawings.LineV,
            to_standard_error = to_standard_error);
    }

    tmpBL := tprint("\e[%;%H", height, 1);
    write_strings(
        tmpBL,
        Drawings.CornerBL,
        to_standard_error = to_standard_error);
    for 1..width-2 {
        write_string(Drawings.LineH, to_standard_error = to_standard_error);
    }
    write_string(Drawings.CornerBR, to_standard_error = to_standard_error);
    
    write_strings(
        // TODO // print
        Commands.EnterNormalMode,
        to_standard_error = to_standard_error);
}

clear_screen :: inline () {
    write_string(Commands.ClearScreen);
}

get_terminal_size :: () -> rows: int, columns: int {
    rows, columns := OS_get_terminal_size();
    return rows, columns;
}

// read_input: () -> string {
    // return OS_read_input();
// }

// get_cursor_position :: () -> row: int, column: int {
//     assert(isTUIActive, "TUI is not active."); // TODO
//     write_string(TUI.Commands.QueryCursorPosition); // Returned "\e[21;1R"
//     read_input()
// }


// read_input: () -> string;

#if OS == .WINDOWS {

    // #run read_input = () -> string {
    read_input :: () -> string {
        MAX_BYTES_TO_READ :: 1024;
        temp : [MAX_BYTES_TO_READ] u8;
        result: string = ---;
        bytes_read : s32;
        
        if !ReadConsoleA( stdin, temp.data, xx temp.count, *bytes_read )
            return "";
    
        result.data  = alloc(bytes_read);
        result.count = bytes_read;
        memcpy(result.data, temp.data, bytes_read);
        return result;
    };
}
else #if OS == .LINUX || OS == .MACOS {
    #import "Basic";
    #import "POSIX";

    read_input :: () -> string {
        buffer: [8192] u8;
        bytes_read := read(STDIN_FILENO, buffer.data, buffer.count-1);
        str := to_string(buffer.data, bytes_read);
        return str;
    };
}