import { lonLatToWorldTile, webMercatorToLonLat, type LonLatPoint } from './projection'

export interface TileZoomBounds {
  minX: number
  maxX: number
  minY: number
  maxY: number
}

export interface RemoteMapConfig {
  tileSource: string
  minZoom: number
  maxZoom: number
  defaultZoom: number
  initialCenterTileX: number
  initialCenterTileY: number
  projection: string
  projectionModeText: string
  magneticDeclinationDeg: number
  magneticDeclinationText: string
  tileFormat: string
  tileSize: number
  bounds: [number, number, number, number] | null
  tileBoundsByZoom: Record<number, TileZoomBounds>
  mapMetaUrl: string
  mapRootUrl: string
}

interface ParsedGameConfig {
  mapRoot: string
  mapMeta: string
  declinationDeg: number
}

interface ParsedMapMeta {
  tileSize: number
  minZoom: number
  maxZoom: number
  projection: string
  tileFormat: string
  tilePathTemplate: string
  bounds: [number, number, number, number] | null
}

function requestTextViaRequest(url: string): Promise<string> {
  return new Promise((resolve, reject) => {
    wx.request({
      url,
      method: 'GET',
      responseType: 'text' as any,
      success: (response) => {
        if (response.statusCode !== 200) {
          reject(new Error(`request失败: ${response.statusCode} ${url}`))
          return
        }

        if (typeof response.data === 'string') {
          resolve(response.data)
          return
        }

        resolve(JSON.stringify(response.data))
      },
      fail: () => {
        reject(new Error(`request失败: ${url}`))
      },
    })
  })
}

function requestTextViaDownload(url: string): Promise<string> {
  return new Promise((resolve, reject) => {
    const fileSystemManager = wx.getFileSystemManager()
    wx.downloadFile({
      url,
      success: (response) => {
        if (response.statusCode !== 200 || !response.tempFilePath) {
          reject(new Error(`download失败: ${response.statusCode} ${url}`))
          return
        }

        fileSystemManager.readFile({
          filePath: response.tempFilePath,
          encoding: 'utf8',
          success: (readResult) => {
            if (typeof readResult.data === 'string') {
              resolve(readResult.data)
              return
            }

            reject(new Error(`read失败: ${url}`))
          },
          fail: () => {
            reject(new Error(`read失败: ${url}`))
          },
        })
      },
      fail: () => {
        reject(new Error(`download失败: ${url}`))
      },
    })
  })
}

async function requestText(url: string): Promise<string> {
  try {
    return await requestTextViaRequest(url)
  } catch (requestError) {
    try {
      return await requestTextViaDownload(url)
    } catch (downloadError) {
      const requestMessage = requestError instanceof Error ? requestError.message : 'request失败'
      const downloadMessage = downloadError instanceof Error ? downloadError.message : 'download失败'
      throw new Error(`${requestMessage}; ${downloadMessage}`)
    }
  }
}

function clamp(value: number, min: number, max: number): number {
  return Math.max(min, Math.min(max, value))
}

function resolveUrl(baseUrl: string, relativePath: string): string {
  if (/^https?:\/\//i.test(relativePath)) {
    return relativePath
  }

  const originMatch = baseUrl.match(/^(https?:\/\/[^/]+)/i)
  const origin = originMatch ? originMatch[1] : ''
  if (relativePath.startsWith('/')) {
    return `${origin}${relativePath}`
  }

  const baseDir = baseUrl.slice(0, baseUrl.lastIndexOf('/') + 1)
  const normalizedRelativePath = relativePath.replace(/^\.\//, '')
  return `${baseDir}${normalizedRelativePath}`
}

function formatDeclinationText(declinationDeg: number): string {
  const suffix = declinationDeg < 0 ? 'W' : 'E'
  return `${Math.abs(declinationDeg).toFixed(2)}° ${suffix}`
}

function parseDeclinationValue(rawValue: unknown): number {
  const numericValue = Number(rawValue)
  return Number.isFinite(numericValue) ? -Math.abs(numericValue) : -6.91
}

function parseGameConfigFromJson(text: string): ParsedGameConfig {
  let parsed: Record<string, unknown>
  try {
    parsed = JSON.parse(text)
  } catch {
    throw new Error('game.json 解析失败')
  }

  const normalized: Record<string, unknown> = {}
  const keys = Object.keys(parsed)
  for (const key of keys) {
    normalized[key.toLowerCase()] = parsed[key]
  }

  const mapRoot = typeof normalized.map === 'string' ? normalized.map : ''
  const mapMeta = typeof normalized.mapmeta === 'string' ? normalized.mapmeta : ''
  if (!mapRoot || !mapMeta) {
    throw new Error('game.json 缺少 map 或 mapmeta 字段')
  }

  return {
    mapRoot,
    mapMeta,
    declinationDeg: parseDeclinationValue(normalized.declination),
  }
}

function parseGameConfigFromYaml(text: string): ParsedGameConfig {
  const config: Record<string, string> = {}
  const lines = text.split(/\r?\n/)

  for (const rawLine of lines) {
    const line = rawLine.trim()
    if (!line || line.startsWith('#')) {
      continue
    }

    const match = line.match(/^([A-Za-z0-9_-]+)\s*(?:=|:)\s*(.+)$/)
    if (!match) {
      continue
    }

    config[match[1].trim().toLowerCase()] = match[2].trim()
  }

  const mapRoot = config.map
  const mapMeta = config.mapmeta
  if (!mapRoot || !mapMeta) {
    throw new Error('game.yaml 缺少 map 或 mapmeta 字段')
  }

  return {
    mapRoot,
    mapMeta,
    declinationDeg: parseDeclinationValue(config.declination),
  }
}

function parseGameConfig(text: string, gameConfigUrl: string): ParsedGameConfig {
  const trimmedText = text.trim()
  const isJson =
    trimmedText.startsWith('{') ||
    trimmedText.startsWith('[') ||
    /\.json(?:[?#].*)?$/i.test(gameConfigUrl)

  return isJson ? parseGameConfigFromJson(trimmedText) : parseGameConfigFromYaml(trimmedText)
}

function extractStringField(text: string, key: string): string | null {
  const pattern = new RegExp(`"${key}"\\s*:\\s*"([^"]+)"`)
  const match = text.match(pattern)
  return match ? match[1] : null
}

function extractNumberField(text: string, key: string): number | null {
  const pattern = new RegExp(`"${key}"\\s*:\\s*(-?\\d+(?:\\.\\d+)?)`)
  const match = text.match(pattern)
  if (!match) {
    return null
  }

  const value = Number(match[1])
  return Number.isFinite(value) ? value : null
}

function extractNumberArrayField(text: string, key: string): number[] | null {
  const pattern = new RegExp(`"${key}"\\s*:\\s*\\[([^\\]]+)\\]`)
  const match = text.match(pattern)
  if (!match) {
    return null
  }

  const numberMatches = match[1].match(/-?\d+(?:\.\d+)?/g)
  if (!numberMatches || !numberMatches.length) {
    return null
  }

  const values = numberMatches
    .map((item) => Number(item))
    .filter((item) => Number.isFinite(item))

  return values.length ? values : null
}

function parseMapMeta(text: string): ParsedMapMeta {
  const tileSizeField = extractNumberField(text, 'tileSize')
  const tileSize = tileSizeField === null ? 256 : tileSizeField
  const minZoom = extractNumberField(text, 'minZoom')
  const maxZoom = extractNumberField(text, 'maxZoom')
  const projectionField = extractStringField(text, 'projection')
  const projection = projectionField === null ? 'EPSG:3857' : projectionField
  const tilePathTemplate = extractStringField(text, 'tilePathTemplate')
  const tileFormatFromField = extractStringField(text, 'tileFormat')
  const boundsValues = extractNumberArrayField(text, 'bounds')

  if (!Number.isFinite(minZoom) || !Number.isFinite(maxZoom) || !tilePathTemplate) {
    throw new Error('meta.json 缺少必要字段')
  }

  let tileFormat = tileFormatFromField || ''
  if (!tileFormat) {
    const extensionMatch = tilePathTemplate.match(/\.([A-Za-z0-9]+)$/)
    tileFormat = extensionMatch ? extensionMatch[1].toLowerCase() : 'png'
  }

  return {
    tileSize,
    minZoom: minZoom as number,
    maxZoom: maxZoom as number,
    projection,
    tileFormat,
    tilePathTemplate,
    bounds: boundsValues && boundsValues.length >= 4
      ? [boundsValues[0], boundsValues[1], boundsValues[2], boundsValues[3]]
      : null,
  }
}

function getBoundsCorners(
  bounds: [number, number, number, number],
  projection: string,
): { northWest: LonLatPoint; southEast: LonLatPoint; center: LonLatPoint } {
  if (projection === 'EPSG:3857') {
    const minX = bounds[0]
    const minY = bounds[1]
    const maxX = bounds[2]
    const maxY = bounds[3]
    return {
      northWest: webMercatorToLonLat({ x: minX, y: maxY }),
      southEast: webMercatorToLonLat({ x: maxX, y: minY }),
      center: webMercatorToLonLat({ x: (minX + maxX) / 2, y: (minY + maxY) / 2 }),
    }
  }

  if (projection === 'EPSG:4326') {
    const minLon = bounds[0]
    const minLat = bounds[1]
    const maxLon = bounds[2]
    const maxLat = bounds[3]
    return {
      northWest: { lon: minLon, lat: maxLat },
      southEast: { lon: maxLon, lat: minLat },
      center: { lon: (minLon + maxLon) / 2, lat: (minLat + maxLat) / 2 },
    }
  }

  throw new Error(`暂不支持的投影: ${projection}`)
}

function buildTileBoundsByZoom(
  bounds: [number, number, number, number] | null,
  projection: string,
  minZoom: number,
  maxZoom: number,
): Record<number, TileZoomBounds> {
  const boundsByZoom: Record<number, TileZoomBounds> = {}
  if (!bounds) {
    return boundsByZoom
  }

  const corners = getBoundsCorners(bounds, projection)
  for (let zoom = minZoom; zoom <= maxZoom; zoom += 1) {
    const northWestWorld = lonLatToWorldTile(corners.northWest, zoom)
    const southEastWorld = lonLatToWorldTile(corners.southEast, zoom)
    const minX = Math.floor(Math.min(northWestWorld.x, southEastWorld.x))
    const maxX = Math.ceil(Math.max(northWestWorld.x, southEastWorld.x)) - 1
    const minY = Math.floor(Math.min(northWestWorld.y, southEastWorld.y))
    const maxY = Math.ceil(Math.max(northWestWorld.y, southEastWorld.y)) - 1

    boundsByZoom[zoom] = {
      minX,
      maxX,
      minY,
      maxY,
    }
  }

  return boundsByZoom
}

function getProjectionModeText(projection: string): string {
  return `${projection} -> XYZ Tile -> Camera -> Screen`
}

export function isTileWithinBounds(
  tileBoundsByZoom: Record<number, TileZoomBounds> | null | undefined,
  zoom: number,
  x: number,
  y: number,
): boolean {
  if (!tileBoundsByZoom) {
    return true
  }

  const bounds = tileBoundsByZoom[zoom]
  if (!bounds) {
    return true
  }

  return x >= bounds.minX && x <= bounds.maxX && y >= bounds.minY && y <= bounds.maxY
}

export async function loadRemoteMapConfig(gameConfigUrl: string): Promise<RemoteMapConfig> {
  const gameConfigText = await requestText(gameConfigUrl)
  const gameConfig = parseGameConfig(gameConfigText, gameConfigUrl)
  const mapMetaUrl = resolveUrl(gameConfigUrl, gameConfig.mapMeta)
  const mapRootUrl = resolveUrl(gameConfigUrl, gameConfig.mapRoot)
  const mapMetaText = await requestText(mapMetaUrl)
  const mapMeta = parseMapMeta(mapMetaText)

  const defaultZoom = clamp(17, mapMeta.minZoom, mapMeta.maxZoom)
  const boundsCorners = mapMeta.bounds ? getBoundsCorners(mapMeta.bounds, mapMeta.projection) : null
  const centerWorldTile = boundsCorners
    ? lonLatToWorldTile(boundsCorners.center, defaultZoom)
    : { x: 0, y: 0 }

  return {
    tileSource: resolveUrl(mapRootUrl, mapMeta.tilePathTemplate),
    minZoom: mapMeta.minZoom,
    maxZoom: mapMeta.maxZoom,
    defaultZoom,
    initialCenterTileX: Math.round(centerWorldTile.x),
    initialCenterTileY: Math.round(centerWorldTile.y),
    projection: mapMeta.projection,
    projectionModeText: getProjectionModeText(mapMeta.projection),
    magneticDeclinationDeg: gameConfig.declinationDeg,
    magneticDeclinationText: formatDeclinationText(gameConfig.declinationDeg),
    tileFormat: mapMeta.tileFormat,
    tileSize: mapMeta.tileSize,
    bounds: mapMeta.bounds,
    tileBoundsByZoom: buildTileBoundsByZoom(mapMeta.bounds, mapMeta.projection, mapMeta.minZoom, mapMeta.maxZoom),
    mapMetaUrl,
    mapRootUrl,
  }
}