snayke

ffi = require('ffi')

ffi.cdef([[
    void Sleep(int ms);
]])

user32 = ffi.load('user32')

ffi.cdef[[
    int GetKeyState(int nVirtKey);
]]

-- copypaste
local codes = {
    left  = 0x25,
    up    = 0x26,
    right = 0x27,
    down  = 0x28,
}

function keyIsDown(code)
    return user32.GetKeyState(code) < 0
end

ffi.cdef[[
    typedef struct _Point {
        int x, y;
    } point;
]]

local game = {}

game.field = {x = 1, y = 1, w = 50, h = 24}

function game:newApple()
    -- copypaste
    local field = self.field
    local apple = ffi.new('point')
    apple.x = math.random(field.x + 1, field.w + field.x - 2)
    apple.y = math.random(field.y + 1, field.h + field.y - 2)

    return apple
end

function game:newSnake()
    -- copypaste
    local snake = {}
    for i = 1, 3 do
        local p = ffi.new('point')
        p.x, p.y = 3 + 1, 3
        snake[i] = p
    end

    snake.direction = 'right'
    return snake
end

function game:init()
    self.snake = self:newSnake()
    self.apple = self:newApple()
end

function game:checkCollision(x, y)
    local f = self.field
    if x < 1 or x > f.w or y < 1 or y > f.h then
        return 'wall'
    end

    for i = 1, #self.snake - 1 do
        local p = self.snake[i]
        if x == p.x and y == p.y then
            return 'snake'
        end
    end

    if x == self.apple.x and y == self.apple.y then
        return 'apple'
    end
end


function game:update()
    local snake = self.snake

    for key, code in pairs(codes) do
        if keyIsDown(code) then
            snake.direction = key
        end
    end

    local head = snake[#snake]
    local dir  = snake.direction

    local vx, vy = head.x, head.y

    -- copypaste
    if dir == 'left'  then vx = vx - 1 end
    if dir == 'right' then vx = vx + 1 end
    if dir == 'up'    then vy = vy - 1 end
    if dir == 'down'  then vy = vy + 1 end

    local newPoint = ffi.new('point')
    newPoint.x, newPoint.y = vx, vy
    table.insert(snake, newPoint)

    local tile = self:checkCollision(vx, vy)
    if tile == 'wall' or tile == 'snake' then
        self:init()
    end

    if tile == 'apple' then
        self.apple = self:newApple()
    else
        table.remove(snake, 1)
    end
end

local term = require('terminal_stuff')


function game:drawBorder()
    term:setTextColor(80, 80, 80)
    local field = self.field
    term:setPosition(field.x, field.y)


    -- copypaste
    io.write(term:line(field.w, '#'))
    io.write(term:line(field.h, '#', 'v'))
    io.write(term:line(-field.w, '#'))
    io.write(term:line(-field.h, '#', 'v'))

end

function game:drawSnake()
    term:setTextColor(255, 255, 255)
    for i, v in ipairs(self.snake) do
        term:setPosition(v.x, v.y)
        io.write('$')
    end
end

function game:drawApple()
    term:setTextColor(255, 255, 0)
    term:setPosition(self.apple.x, self.apple.y)
    io.write('O')
end

game:init()

os.execute('chcp 65001')
term:hideCursor()

while true do
    term:cls()

    game:update()
    game:drawBorder()
    game:drawSnake()
    game:drawApple()

    ffi.C.Sleep(200)
end