#import "Basic";
#import "String";

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 :: () {
    // TODO Required to do unlocking input.
    tcgetattr(STDIN_FILENO, *__term);
    term_new := __term;

    term_new.c_iflag &= 0xFFFFFA14;// ~(IGNBRK | BRKINT | PARMRK | ISTRIP | INLCR | IGNCR | ICRNL | IXON);
    term_new.c_oflag &= 0xFFFFFFFE;// ~OPOST;
    term_new.c_lflag &= 0xFFFF7FB4;// ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
    term_new.c_cflag &= 0xFFFFFECF;// ~(CSIZE | PARENB);
    term_new.c_cflag |= 0x00000030;

    tcsetattr(STDIN_FILENO, 0, *term_new);
    
    write_strings(Commands.HideCursor, Commands.SaveCursorPosition, Commands.EnterAlternateBuffer, Commands.SetUTF8);
}

stop :: () {
    write_strings(Commands.EnterMainBuffer, Commands.RestoreCursorPosition, Commands.ShowCursor);

    tcsetattr(STDIN_FILENO, 0, *__term); // return echo
}

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

    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);
}

// read_input: () -> string;

#if OS == .LINUX {
    #import "Basic";
    #import "POSIX";

	__term : My_Termios;

	My_Termios :: struct {
		c_iflag : u32;      // Input modes.
		c_oflag : u32;      // Output modes.
		c_cflag : u32;      // Control modes.
		c_lflag : u32;      // Local modes.
		unknown_pad : u8;
		c_cc : [32]u8;      // Special characters.
		c_ispeed : u32;     // Input baud rates.
		c_ospeed : u32;     // Output baud rates.
	}

    // Required to do unlocking input.
	libc :: #system_library "libc";
	tcsetattr :: (fd : s32, optional_actions : s32, termios_p : *My_Termios) -> s32 #foreign libc;
	tcgetattr :: (fd : s32, termios_p : *My_Termios) -> s32 #foreign libc;	



    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;
    };

    get_cena :: () -> rows: int, columns: int {
        buffer: [512] u8;
        write_string(Commands.QueryWindowSizeInChars);
        bytes_read := read(STDIN_FILENO, buffer.data, buffer.count-1);
        
        str := to_string(buffer.data, bytes_read);
        
        // Result: [8;79;156t
        assert(
            buffer.data[0] == #char "\e" &&
            buffer.data[1] == #char "[" &&
            buffer.data[2] == #char "8",
            "Query windows size in chars returned invalid response.");

        parts := split(str, ";");
        rows := parse_int(*parts[1]);
        columns := parse_int(*parts[2]);
        return rows, columns;
    }

}
else #if OS == .WINDOWS {
    #import "Windows";
    
    kernel32 :: #system_library "kernel32";
    
    stdin, stdout  : HANDLE;

    stdin = GetStdHandle( STD_INPUT_HANDLE );

    ReadConsoleA  :: (
        hConsoleHandle: HANDLE,
        buff : *u8,
        chars_to_read : s32,
        chars_read : *s32,
        lpInputControl := *void
    ) -> bool #foreign kernel32;

    // #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;
    };
}