import { Map } from "./gfx/map.js";

// enum
export const Key = {
    NOTHING: undefined,
    UP: 1,
    DOWN: 2,
    LEFT: 3,
    RIGHT: 4,
}

// enum
export const Rotation = {
    NOTHING: undefined,
    NORTH: 1,
    EAST: 2,
    SOUTH: 3,
    WEST: 4
}

export const ItemType = {
    DOT: 1
}

/**
 * @typedef {[number, number]} Vec2
 * 
 * @typedef {{[key: number]: Key}} InputMap
 * 
 * @typedef {{pos: Vec2, move_rot: Rotation, input_rot: Rotation, name?: string}} Player
 * @typedef {{start: boolean, key: Key, name?: string}} PlayerInput
 * @typedef {{players: {[key: number]: PlayerInput}, added?: number[], removed?: number[] }} Input
 * 
 * @typedef {{[key: number]: Player}} Players
 *
 * @typedef {{width: number, height: number, data: number[]}} Map
 * 
 * @typedef {{type: ItemType, pos: Vec2}} Item
 *
 * @typedef {{
 * 	started: boolean,
 * 	input: InputMap,
 * 	players: Players,
 * 	map: Map,
 * 	items_eaten: Item[]
 * }} GameState
 */

/** @type {GameState} */
export const initState = {
    started: false,
    input: {},
    players: [],
    map: {},
    items_eaten: []
}

let last = Date.now()
let fps_div = document.getElementById("fps")

export function advance(
    pastData = initState, 
    input = { players: {} }, 
    frame
) {
    let data = processInput(pastData, input, frame);

    if (frame % 60 == 0) {
        let now = Date.now()
        let fps = (now-last)/1000*60
        fps_div.innerHTML = fps.toFixed(2);
        last = now
    } 
	
	return data;
}

/**
 * @param {GameState} pastData
 * @param {Input} input
 * @param {number} frame
 */
function processInput(pastData, input) {
   
    /** @type {GameState} */
    let data = structuredClone(pastData)
     
    let startPressed = false;

    for(const added of input.added || []) {
        if (data.started || Object.keys(data.players).length >= 4) continue;
		console.log("added", added);
		data.input[added] ||= {
			pos: [1, 1],
            input_rot: Rotation.EAST,
            mov_rot: Rotation.EAST
		};
		if(!(added in data.players)) {
			data.players[added] = structuredClone(data.input[added])
		}
	}

	for(const id in input.players) {
		if(!input.players[id]) {
			continue;
		}

		if(id in data.players && input.players[id].name !== undefined) {
			let name = input.players[id].name;
			name = name.substring(0, 16);
			
			data.players[id] = {
				...data.players[id],
				name,
			};
            
		}

		startPressed ||= input.players[id].start;
		data.input[id] =  input.players[id].dir
	}

    const player_display = document.getElementById("players")
    for (const id in data.players) {
        if (data.players[id] === null) continue
        let name = data.players[id].name
        if (name === undefined) continue

        let element_id = 'span' + id 

        let element = player_display.children[element_id]
        if (element === null || element === undefined) {
            let span = document.createElement("span")
            span.innerHTML = `[${id}] ${name}`
            span.id = element_id
            player_display.appendChild(span)
        }
    }

    if (startPressed && !data.started) {
        init_map(data)
        data.started ||= startPressed;	
    }

    if (data.started) {
        update_players(data)
    }


    for(const removed of input.removed || []) {
		console.log("removed", removed);
		delete data.input[removed];
		delete data.players[removed];

        let element_id = 'span' + removed 
        let element = document.getElementById(element_id)
        if (element !== null && element !== undefined) element.remove()
	}


    return data
}

const init_map = (data) => {

    document.getElementById("lobby").style.display = "none"

    let width = 21
    let height = 21
    let m_data = [
        1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
        1,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,1,
        1,0,1,1,1,0,1,1,1,0,1,0,1,1,1,0,1,1,1,0,1,
        1,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,1,
        1,0,1,0,1,1,1,1,1,0,1,0,1,1,1,1,1,0,1,0,1,
        1,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,1,
        1,0,1,1,1,0,1,0,1,1,1,1,1,0,1,0,1,1,1,0,1,
        1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,
        1,1,1,0,1,0,1,0,1,1,1,1,1,0,1,0,1,0,1,1,1,
        1,0,0,0,0,0,1,0,1,2,2,2,1,0,1,0,0,0,0,0,1,
        1,0,1,1,1,0,1,0,1,2,2,2,1,0,1,0,1,1,1,0,1,
        1,0,0,0,0,0,1,0,1,2,2,2,1,0,1,0,0,0,0,0,1,
        1,1,1,0,1,0,1,0,1,1,2,1,1,0,1,0,1,0,1,1,1,
        1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,
        1,0,1,1,1,0,1,0,1,1,1,1,1,0,1,0,1,1,1,0,1,
        1,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,1,
        1,0,1,0,1,1,1,1,1,0,1,0,1,1,1,1,1,0,1,0,1,
        1,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,1,
        1,0,1,1,1,0,1,1,1,0,1,0,1,1,1,0,1,1,1,0,1,
        1,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,1,
        1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1
    ]

    data.map = new Map(width, height, m_data)
    data.map.show()
}

const MOVE_SPEED = .1

const round_pos = (pos) => {
    return [Math.round(pos[0]), Math.round(pos[1])]
}

const is_stable_pos = (pos) => {
    let rpos = round_pos(pos)
    return Math.abs(rpos[0] - pos[0]) < .05 && Math.abs(rpos[1] - pos[1]) < .05
}

const get_tile = (map, pos, ox, oy) => {
    let x = Math.round(pos[0] + ox)
    let y = Math.round(pos[1] + oy)
    if (x < 0 || x >= map.width || y < 0 || y >= map.height) return 1
    return map.data[y * map.width + x]
}

const get_tile_with_rot = (map, pos, rot) => {
    let collider = 1
    switch(rot) {
	    case Rotation.NORTH:
            collider = get_tile(map, pos, 0, -.51)
            break
        case Rotation.SOUTH:
            collider = get_tile(map, pos, 0, .51)
            break
        case Rotation.WEST:
            collider = get_tile(map, pos, -.51, 0)
            break
        case Rotation.EAST:
            collider = get_tile(map, pos, .51, 0)
            break
    }
    return collider
}

const get_rot = (dir) => {
    switch (dir) {
        case Key.UP: return Rotation.NORTH
        case Key.DOWN: return Rotation.SOUTH
        case Key.LEFT: return Rotation.WEST
        case Key.RIGHT: return Rotation.EAST
        case Key.NOTHING: return Rotation.NOTHING
    }
}

const increment_pos = (pos, rot, speed) => {
    switch (rot) {
        case Rotation.NORTH:
            pos[1] -= speed
            break
        case Rotation.SOUTH:
            pos[1] += speed
            break
        case Rotation.WEST:
            pos[0] -= speed
            break
        case Rotation.EAST:
            pos[0] += speed
            break
    }
}

export const get_item_key = (x, y, w) => {
    let nx = Math.round(x * 2)
    let ny = Math.round(y * 2)
    let key = ny * w * 2 + nx
    return key
}

const ceil_half = (n) => {
    return Math.ceil(n*2)/2
}

const floor_half = (n) => {
    return Math.floor(n*2)/2
}

/**
 * @param {GameState} data
 */
const update_players = (data) => {

	for(const id in data.input) { // move players
		if(!(id in data.players)) {
			console.log("what. player undefined???", id);
			continue;
		}

        let input_key = data.input[id]
        let input_dir = get_rot(input_key)
        let move_dir = data.players[id].move_rot
        let current_pos = data.players[id].pos

        let tile_in_front_with_turn = get_tile_with_rot(data.map, current_pos, input_dir) 
        if (tile_in_front_with_turn == 1 || tile_in_front_with_turn == 2) {
            input_dir = Rotation.NOTHING
        }

        let turning = input_dir != Key.NOTHING && input_dir != move_dir
        
        data.players[id].input_rot = input_dir

        if (turning && is_stable_pos(current_pos)) {
            current_pos = round_pos(current_pos)
            data.players[id].move_rot = input_dir
            move_dir = input_dir
        }

        let move_pos = structuredClone(current_pos)
        increment_pos(move_pos, move_dir, MOVE_SPEED)
        
        let tile_in_front = get_tile_with_rot(data.map, current_pos, move_dir)
        if (tile_in_front != 1 && tile_in_front != 2) {
            data.players[id].pos = move_pos
        } else {
            data.players[id].pos = round_pos(current_pos)
        }

        // eat items
        let pos = data.players[id].pos
        for (let x = ceil_half(pos[0]-.5); x <= floor_half(pos[0]+.5); x += .5) {
            for (let y = ceil_half(pos[1]-.5); y <= floor_half(pos[1]+.5); y += .5) {
                let item_key = get_item_key(x, y, data.map.width)
                let item = data.map.items[item_key]
                if (item) {
                    data.items_eaten.push(item_key)
                    delete data.map.items[item_key]
                }
            }
        }

    }

}