const create_style = (map) => {
    const css = `
        * {
            --scale: 100;
            --aspect: ${map.width/map.height};
            --scaleX: calc(var(--scale) * 1vw);
            --scaleY: calc(var(--scale) * 1vh);
        }
        
        body {
            background-color: #191919;
            width: 100vw;
            height: 100vh;
            display: flex;
        }
        
        #container {
            width: calc(var(--scaleY) * var(--aspect));
            height: var(--scaleY);
            margin-top: calc((100vh - var(--scaleY))/2);
            margin-left: calc(50vw - var(--scaleY)*var(--aspect)/2);
            position: relative;
        }
        
        #container img {
            display: inline-block;
            width: ${100/map.width}%;
            height: ${100/map.height}%;
        }

        @media (max-aspect-ratio: ${map.width}/${map.height}) {
            #container {
                width: var(--scaleX);
                height: calc(var(--scaleX) / var(--aspect));
                margin-left: calc((100vw - var(--scaleX))/2);
                margin-top: calc(50vh - var(--scaleX)/var(--aspect)/2);
            }
        }`;

    map.style.innerHTML = css
}

const Direction = {
    EMPTY: 0,
    WALL_HZ: 1,
    WALL_VT: 2,
    TURN_Q1: 3,
    TURN_Q2: 4,
    TURN_Q3: 5,
    TURN_Q4: 6,
    TEE_NORTH: 7,
    TEE_EAST: 8,
    TEE_SOUTH: 9,
    TEE_WEST: 10,
    CROSS: 11,
    DOT: 12,
    WALL_END_NORTH: 13,
    WALL_END_SOUTH: 14,
    WALL_END_EAST: 15,
    WALL_END_WEST: 16
}

const place_tile = (container, type) => {

    const img = document.createElement("img")

    let image_src, class_name;
    switch(type) {
        case Direction.EMPTY:
            image_src = "/static/empty.png"
            class_name = ""
            break
        case Direction.WALL_HZ:
            image_src = "/static/wall.png"
            class_name = ""
            break
        case Direction.WALL_VT:
            image_src = "/static/wall.png"
            class_name = "rotate90"
            break
        case Direction.TURN_Q1:
            image_src = "/static/turn.png" 
            class_name = ""
            break
        case Direction.TURN_Q2:
            image_src = "/static/turn.png" 
            class_name = "rotate270"
            break
        case Direction.TURN_Q3:
            image_src = "/static/turn.png" 
            class_name = "rotate180"
            break
        case Direction.TURN_Q4:
            image_src = "/static/turn.png" 
            class_name = "rotate90"
            break
        case Direction.TEE_NORTH:
            image_src = "/static/tee.png"
            class_name = "rotate180"
            break
        case Direction.TEE_EAST:
            image_src = "/static/tee.png"
            class_name = "rotate270"
            break
        case Direction.TEE_SOUTH:
            image_src = "/static/tee.png"
            class_name = ""
            break
        case Direction.TEE_WEST:
            image_src = "/static/tee.png"
            class_name = "rotate90"
            break
        case Direction.CROSS:
            image_src = "/static/cross.png"
            class_name = ""
            break
        case Direction.DOT:
            image_src = "/static/dot.png"
            class_name = ""
            break
        case Direction.WALL_END_NORTH:
            image_src = "/static/wall_end.png"
            class_name = ""
            break;
        case Direction.WALL_END_EAST:
            image_src = "/static/wall_end.png"
            class_name = "rotate90"
            break;
        case Direction.WALL_END_SOUTH:
            image_src = "/static/wall_end.png"
            class_name = "rotate180"
            break;
        case Direction.WALL_END_WEST:
            image_src = "/static/wall_end.png"
            class_name = "rotate270"
            break;
    }

    img.setAttribute("class", class_name)
    img.setAttribute("src", image_src)
    
    container.appendChild(img)
}

const get_point = (width, height, data, x, y) => {
    if (x < 0 || x >= width || y < 0 || y >= height) {
        return 0
    } else {
        return data[y * width + x]
    }
}

const gen_walls = (width, height, data) => {

    let walls = Array(width * height)
    for (let y = 0; y < height; y++) {
        for (let x = 0; x < width; x++) {
            
            let north = get_point(width, height, data, x, y-1)
            let south = get_point(width, height, data, x, y+1)
            let east = get_point(width, height, data, x+1, y)
            let west = get_point(width, height, data, x-1, y)
            let current = get_point(width, height, data, x, y)

            let point = Direction.EMPTY
            
            if (!current) {
                walls[y * width + x] = point
                continue
            }

            if (north && south && east && west) {
                point = Direction.CROSS
            } else if (east && west && north) {
                point = Direction.TEE_NORTH
            } else if (east && west && south) {
                point = Direction.TEE_SOUTH
            } else if (north && south && east) {
                point = Direction.TEE_EAST
            } else if (north && south && west) {
                point = Direction.TEE_WEST
            } else if (east && west) {
                point = Direction.WALL_HZ
            } else if (north && south) {
                point = Direction.WALL_VT   
            } else if (west && south) {
                point = Direction.TURN_Q1
            } else if (south && east) {
                point = Direction.TURN_Q2
            } else if (east && north) {
                point = Direction.TURN_Q3
            } else if (north && west) {
                point = Direction.TURN_Q4
            } else if (north) {
                point = Direction.WALL_END_NORTH
            } else if (east) {
                point = Direction.WALL_END_EAST
            } else if (south) {
                point = Direction.WALL_END_SOUTH
            } else if (west) {
                point = Direction.WALL_END_WEST
            } else {
                point = Direction.DOT
            }

            walls[y * width + x] = point

        }
    }

    return walls
}

const gen_map = (map) => {
    let walls = gen_walls(map.width, map.height, map.data)
    for (let y = 0; y < map.height; y++) {
        for (let x = 0; x < map.width; x++) {
            place_tile(map.container, walls[y * map.width + x])
        }
    }

}

export class Map {

    constructor(width, height, data) {
        this.width = width
        this.height = height
        this.data = data
        this.container = document.body.appendChild(document.createElement("div"))
        this.container.id = "container"
        this.style = document.body.appendChild(document.createElement("style"))

        create_style(this)
        gen_map(this)
    }

    destroy() {
        this.container.remove()
        this.style.remove()
    }

}