-- Snake Game for SimpleOS
-- CC: Tweaked compatible

local w, h = term.getSize()
h = h - 1 -- Leave room for score

-- Game state
local snake = {}
local direction = "right"
local food = {}
local score = 0
local gameOver = false
local speed = 0.15

-- Initialize game
local function init()
    snake = {
        {x = math.floor(w/2), y = math.floor(h/2)},
        {x = math.floor(w/2) - 1, y = math.floor(h/2)},
        {x = math.floor(w/2) - 2, y = math.floor(h/2)}
    }
    direction = "right"
    score = 0
    gameOver = false
    spawnFood()
end

-- Spawn food at random location
function spawnFood()
    local valid = false
    while not valid do
        food = {x = math.random(1, w), y = math.random(1, h)}
        valid = true
        for _, segment in ipairs(snake) do
            if segment.x == food.x and segment.y == food.y then
                valid = false
                break
            end
        end
    end
end

-- Draw game
local function draw()
    term.setBackgroundColor(colors.black)
    term.clear()
    
    -- Draw border
    term.setBackgroundColor(colors.gray)
    for x = 1, w do
        term.setCursorPos(x, h + 1)
        term.write(" ")
    end
    
    -- Draw score
    term.setCursorPos(1, h + 1)
    term.setTextColor(colors.white)
    term.write("Score: " .. score .. "  [Q]uit")
    
    -- Draw food
    term.setBackgroundColor(colors.black)
    term.setCursorPos(food.x, food.y)
    term.setTextColor(colors.red)
    term.write("@")
    
    -- Draw snake
    for i, segment in ipairs(snake) do
        term.setCursorPos(segment.x, segment.y)
        if i == 1 then
            term.setTextColor(colors.lime)
            term.write("O")
        else
            term.setTextColor(colors.green)
            term.write("o")
        end
    end
end

-- Move snake
local function move()
    local head = {x = snake[1].x, y = snake[1].y}
    
    if direction == "up" then head.y = head.y - 1
    elseif direction == "down" then head.y = head.y + 1
    elseif direction == "left" then head.x = head.x - 1
    elseif direction == "right" then head.x = head.x + 1
    end
    
    -- Wrap around
    if head.x < 1 then head.x = w
    elseif head.x > w then head.x = 1
    elseif head.y < 1 then head.y = h
    elseif head.y > h then head.y = 1
    end
    
    -- Check self collision
    for _, segment in ipairs(snake) do
        if segment.x == head.x and segment.y == head.y then
            gameOver = true
            return
        end
    end
    
    -- Add new head
    table.insert(snake, 1, head)
    
    -- Check food
    if head.x == food.x and head.y == food.y then
        score = score + 10
        spawnFood()
        if speed > 0.05 then
            speed = speed - 0.005
        end
    else
        table.remove(snake)
    end
end

-- Game over screen
local function showGameOver()
    term.setBackgroundColor(colors.black)
    term.setTextColor(colors.red)
    term.setCursorPos(math.floor(w/2) - 4, math.floor(h/2))
    term.write("GAME OVER")
    term.setTextColor(colors.white)
    term.setCursorPos(math.floor(w/2) - 6, math.floor(h/2) + 1)
    term.write("Score: " .. score)
    term.setCursorPos(math.floor(w/2) - 10, math.floor(h/2) + 3)
    term.write("Press ENTER to restart")
    term.setCursorPos(math.floor(w/2) - 7, math.floor(h/2) + 4)
    term.write("Press Q to quit")
end

-- Main game loop
local function run()
    init()
    
    while true do
        draw()
        
        if gameOver then
            showGameOver()
            while true do
                local event, key = os.pullEvent("key")
                if key == keys.enter then
                    init()
                    break
                elseif key == keys.q then
                    return
                end
            end
        end
        
        local timer = os.startTimer(speed)
        
        while true do
            local event, p1 = os.pullEvent()
            
            if event == "key" then
                if p1 == keys.up and direction ~= "down" then
                    direction = "up"
                elseif p1 == keys.down and direction ~= "up" then
                    direction = "down"
                elseif p1 == keys.left and direction ~= "right" then
                    direction = "left"
                elseif p1 == keys.right and direction ~= "left" then
                    direction = "right"
                elseif p1 == keys.q then
                    return
                end
            elseif event == "timer" and p1 == timer then
                break
            end
        end
        
        move()
    end
end

run()