//
// WASM-4: https://wasm4.org/docs

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// │ Platform Constants                                                        │
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// └───────────────────────────────────────────────────────────────────────────┘

pub const SCREEN_SIZE: u32 = 160;

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// │ Memory Addresses                                                          │
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pub const PALETTE: &[4]u32 = 0x04;
pub const DRAW_COLORS: &u16 = 0x14;
pub const GAMEPAD1: (u8) = 0x16;
pub const GAMEPAD2: (u8) = 0x17;
pub const GAMEPAD3: (u8) = 0x18;
pub const GAMEPAD4: (u8) = 0x19;
pub const MOUSE_X: (i16) = 0x1a;
pub const MOUSE_Y: (i16) = 0x1c;
pub const MOUSE_BUTTONS: (u8) = 0x1e;
pub const SYSTEM_FLAGS: &u8 = 0x1f;
pub const NETPLAY: (u8) = 0x20;
pub const FRAMEBUFFER: &[6400]u8 = 0xa0;

pub const BUTTON_1: u8 = 1;
pub const BUTTON_2: u8 = 2;
pub const BUTTON_LEFT: u8 = 16;
pub const BUTTON_RIGHT: u8 = 32;
pub const BUTTON_UP: u8 = 64;
pub const BUTTON_DOWN: u8 = 128;

pub const MOUSE_LEFT: u8 = 1;
pub const MOUSE_RIGHT: u8 = 2;
pub const MOUSE_MIDDLE: u8 = 4;

pub const SYSTEM_PRESERVE_FRAMEBUFFER: u8 = 1;
pub const SYSTEM_HIDE_GAMEPAD_OVERLAY: u8 = 2;

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// │                                                                           │
// │ Drawing Functions                                                         │
// │                                                                           │
// └───────────────────────────────────────────────────────────────────────────┘

/// Copies pixels to the framebuffer.
pub extern fn blit(sprite: []u8, x: i32, y: i32, width: u32, height: u32,
    flags: u32);

/// Copies a subregion within a larger sprite atlas to the framebuffer.
pub extern fn blitSub(sprite: []u8, x: i32, y: i32, width: u32, height: u32,
    src_x: u32, src_y: u32, stride: u32, flags: u32);

pub const BLIT_2BPP: u32 = 1;
pub const BLIT_1BPP: u32 = 0;
pub const BLIT_FLIP_X: u32 = 2;
pub const BLIT_FLIP_Y: u32 = 4;
pub const BLIT_ROTATE: u32 = 8;

/// Draws a line between two points.
pub extern fn line(x1: i32, y1: i32, x2: i32, y2: i32);

/// Draws an oval (or circle).
pub extern fn oval(x: i32, y: i32, width: u32, height: u32);

/// Draws a rectangle.
pub extern fn rect(x: i32, y: i32, width: u32, height: u32);

/// Draws text using the built-in system font.
pub fn text(text: []u8, x: i32, y: i32)
{
    textUtf8(text, |text|, x, y);
}
extern fn textUtf8(text: []u8, length: usize, x: i32, y: i32);

/// Draws a vertical line
pub extern fn vline(x: i32, y: i32, len: u32);

/// Draws a horizontal line
pub extern fn hline(x: i32, y: i32, len: u32);

// ┌───────────────────────────────────────────────────────────────────────────┐
// │                                                                           │
// │ Sound Functions                                                           │
// │                                                                           │
// └───────────────────────────────────────────────────────────────────────────┘

/// Plays a sound tone.
pub extern fn tone(frequency: u32, duration: u32, volume: u32, flags: u32);

pub const TONE_PULSE1: u32 = 0;
pub const TONE_PULSE2: u32 = 1;
pub const TONE_TRIANGLE: u32 = 2;
pub const TONE_NOISE: u32 = 3;
pub const TONE_MODE1: u32 = 0;
pub const TONE_MODE2: u32 = 4;
pub const TONE_MODE3: u32 = 8;
pub const TONE_MODE4: u32 = 12;
pub const TONE_PAN_LEFT: u32 = 16;
pub const TONE_PAN_RIGHT: u32 = 32;

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// │ Storage Functions                                                         │
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// └───────────────────────────────────────────────────────────────────────────┘

/// Reads up to `size` bytes from persistent storage into the pointer `dest`.
pub extern fn diskr(dest: &[]u8, size: u32) -> u32;

/// Writes up to `size` bytes from the pointer `src` into persistent storage.
pub extern fn diskw(src: []u8, size: u32) -> u32;

// ┌───────────────────────────────────────────────────────────────────────────┐
// │                                                                           │
// │ Other Functions                                                           │
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// └───────────────────────────────────────────────────────────────────────────┘

/// Prints a message to the debug console.
pub fn trace(text: []u8)
{
    traceUtf8(text, |text|);
}
extern fn traceUtf8(text: []u8, length: usize);