main.to

// import dependencies
include "src/libraries/graphics.to"

include "src/game_logic.to"


const window_name = "Snake"

// get the size of the board
const window_size = 1000
const long size = stringtoint(listen("Enter the size of the board: "))
const long cell_size = window_size / size

do sayln("Press WASD to move the snake")
do sayln("Press Space to start the game")

// create the window
const window = createWindow(window_name, window_size, window_size, 0)


make bool quit = false

// initialize delta time
make long last_time, clock_time, fps = time(), clock(), 0
make double dt = 0.0

// initialize the board (0 or below means empty, 1 or above means the snake is there)
const board = [0] * (size * size)

// initialize the snake and apple positions
const position = {x: size / 4, y: size / 2}
const apple = {x: size / 2, y: size / 2}

// start the snake with a length of 3
make long length = 3

// initialize the direction of the snake (0 = down, 1 = right, 2 = up, 3 = left)
make long direction = 1
make long next_direction = 1

// initialize the time since the last move
make double time_since_last_move, move_interval = 0, 1000.0 / 40.0

// initialize the random number generator
do srandom(time())

// wait for the user to press space to start the game
make bool started = false

// main game loop
do {
    // get events
    do updateState()

    // close window if user presses the close button
    set quit = true when ifQuit()

    // start the game if the user presses space
    set started = true when getKey(keys->KeySpace)
    
    // calculate fps
    set fps++

    do if (time() != last_time) then {
        do setWindowTitle(window, `{window_name} - FPS: {fps}`)
        set fps = 0
        set last_time = time()
    }

    // change direction of the snake based on user input
    set next_direction = 0 when getKey(keys->KeyS) && direction != 2
    set next_direction = 1 when getKey(keys->KeyD) && direction != 3
    set next_direction = 2 when getKey(keys->KeyW) && direction != 0
    set next_direction = 3 when getKey(keys->KeyA) && direction != 1

    // calculate delta time
    set dt = (clock() - clock_time) / (1000.0 / 60.0)
    set clock_time = clock()

    // update the game logic every move_interval
    set time_since_last_move += dt
    do {
        set time_since_last_move -= move_interval
        set quit = gameLogic() when started // update the game logic when the game has started
    } while time_since_last_move >= move_interval

    // draw the game to the window
    do draw() 

} while !quit // keep running the game loop until the user quits

// clean up and exit
do closeWindow(window)

do sayln("Game Over")
do pause()