import * as Utils from './utils.js'

export const viewport = {
    width: 256,
    height: 256,
    zoom_level: 0,
    xoffset: 0,
    yoffset: 0,
}

//计算所有情况下的底图大小，包括非整数z
export function calTileSize() {
    let etsize = 256
    const zoom_level = viewport.zoom_level
    if (zoom_level != Math.floor(zoom_level)) {
        etsize = 256 * Math.pow(2, zoom_level - Math.floor(zoom_level + 1))
    }
    return etsize
}

export function calTileNum(coord) {
    return Math.floor(coord / calTileSize())
}

export function setViewportSize(width, height) {
    viewport.width = width
    viewport.height = height
}

export function updateOffset() {
    const z = viewport.zoom_level
}

export function map2viewport(mx, my) {
    const vx = mx + viewport.xoffset
    const vy = my + viewport.yoffset
    return { x: vx, y: vy }
}

export function viewport2map(vx, vy) {
    const mx = vx - viewport.xoffset
    const my = vy - viewport.yoffset
    return { x: mx, y: my }
}

export function setViewportCenterByWgs84(lat, lon, z) {
    viewport.zoom_level = z
    const size = calTileSize()
    const mx = Utils.lon2x(lon, z) * size
    const my = Utils.lat2y(lat, z) * size
    console.log('测试', mx, my)
    // const { vx, vy } = map2viewport(mx, my)
    const cx = viewport.width / 2
    const cy = viewport.height / 2
    viewport.xoffset = cx - mx
    viewport.yoffset = cy - my
}

export function setViewportCenterByMap(mx, my, z) {
    viewport.zoom_level = z
    const cx = viewport.width / 2
    const cy = viewport.height / 2
    viewport.xoffset = cx - mx
    viewport.yoffset = cy - my
}

export function updateZoomLevel(vx, vy, newz) {
    const oldz = viewport.zoom_level
    const mxy = viewport2map(vx, vy)
    viewport.zoom_level = newz
    const scale = Math.pow(2, newz - oldz)
    const newmxy = { x: mxy.x * scale, y: mxy.y * scale }
    viewport.xoffset = vx - newmxy.x
    viewport.yoffset = vy - newmxy.y
}

// //test
// setViewportSize(512, 512)
// setViewportCenter(0, 0, 0)
// console.log(map2viewport(0, 0))
// console.log(map2viewport(128, 128))

export function viewport2wgs84(vx, vy) {
    const mlc = viewport2map(vx, vy)
    const z = viewport.zoom_level
    //数据超界处理, 这里对应缩放等级的地图的大小是
    const limit = calTileSize() * Math.pow(2, z)
    if (vx <= 0 || vy <= 0 || vx >= limit || vy >= limit) {
        throw `OutMapRange limit ${limit}`
    }
    const lat = Utils.tile2lat(mlc.y / 256, z)
    const lon = Utils.tile2long(mlc.x / 256, z)
    return { lat: lat, lon: lon }
}

export function wgs84toviewport(lat, lon) {
    //数据超界处理  经度自动限制在 -180 180
    //85.0511287798066  (2*Math.atan(Math.pow(Math.E,Math.PI))-Math.PI/2)/Math.PI*180
    const latlimit = 85.051128
    const lonp = lon - Math.floor((lon + 180) / 360) * 360
    if (lat < 0 - latlimit || lat > latlimit) {
        throw 'OutMapRange'
    }
    const z = viewport.zoom_level
    const my = Utils.lat2y(lat, z) * 256
    const mx = Utils.lon2x(lonp, z) * 256
    const vp = map2viewport(mx, my)
    return { x: vp.x, y: vp.y }
}