/**
 * @module ol/source/Tile
 */
import {inherits} from '../index.js';
import {UNDEFINED} from '../functions.js';
import TileCache from '../TileCache.js';
import TileState from '../TileState.js';
import Event from '../events/Event.js';
import {equivalent} from '../proj.js';
import {toSize, scale as scaleSize} from '../size.js';
import Source from '../source/Source.js';
import {getKeyZXY, withinExtentAndZ} from '../tilecoord.js';
import {wrapX, getForProjection as getTileGridForProjection} from '../tilegrid.js';

/**
 * @typedef {Object} Options
 * @property {module:ol/source/Source~AttributionLike} [attributions]
 * @property {number} [cacheSize]
 * @property {module:ol/extent~Extent} [extent]
 * @property {boolean} [opaque]
 * @property {number} [tilePixelRatio]
 * @property {module:ol/proj~ProjectionLike} [projection]
 * @property {module:ol/source/State} [state]
 * @property {module:ol/tilegrid/TileGrid} [tileGrid]
 * @property {boolean} [wrapX=true]
 * @property {number} [transition]
 */


/**
 * @classdesc
 * Abstract base class; normally only used for creating subclasses and not
 * instantiated in apps.
 * Base class for sources providing images divided into a tile grid.
 *
 * @constructor
 * @abstract
 * @extends {module:ol/source/Source}
 * @param {module:ol/source/Tile~Options=} options SourceTile source options.
 * @api
 */
const TileSource = function(options) {

  Source.call(this, {
    attributions: options.attributions,
    extent: options.extent,
    projection: options.projection,
    state: options.state,
    wrapX: options.wrapX
  });

  /**
   * @private
   * @type {boolean}
   */
  this.opaque_ = options.opaque !== undefined ? options.opaque : false;

  /**
   * @private
   * @type {number}
   */
  this.tilePixelRatio_ = options.tilePixelRatio !== undefined ?
    options.tilePixelRatio : 1;

  /**
   * @protected
   * @type {module:ol/tilegrid/TileGrid}
   */
  this.tileGrid = options.tileGrid !== undefined ? options.tileGrid : null;

  /**
   * @protected
   * @type {module:ol/TileCache}
   */
  this.tileCache = new TileCache(options.cacheSize);

  /**
   * @protected
   * @type {module:ol/size~Size}
   */
  this.tmpSize = [0, 0];

  /**
   * @private
   * @type {string}
   */
  this.key_ = '';

  /**
   * @protected
   * @type {module:ol/Tile~Options}
   */
  this.tileOptions = {transition: options.transition};

};

inherits(TileSource, Source);


/**
 * @return {boolean} Can expire cache.
 */
TileSource.prototype.canExpireCache = function() {
  return this.tileCache.canExpireCache();
};


/**
 * @param {module:ol/proj/Projection} projection Projection.
 * @param {!Object.<string, module:ol/TileRange>} usedTiles Used tiles.
 */
TileSource.prototype.expireCache = function(projection, usedTiles) {
  const tileCache = this.getTileCacheForProjection(projection);
  if (tileCache) {
    tileCache.expireCache(usedTiles);
  }
};


/**
 * @param {module:ol/proj/Projection} projection Projection.
 * @param {number} z Zoom level.
 * @param {module:ol/TileRange} tileRange Tile range.
 * @param {function(module:ol/Tile):(boolean|undefined)} callback Called with each
 *     loaded tile.  If the callback returns `false`, the tile will not be
 *     considered loaded.
 * @return {boolean} The tile range is fully covered with loaded tiles.
 */
TileSource.prototype.forEachLoadedTile = function(projection, z, tileRange, callback) {
  const tileCache = this.getTileCacheForProjection(projection);
  if (!tileCache) {
    return false;
  }

  let covered = true;
  let tile, tileCoordKey, loaded;
  for (let x = tileRange.minX; x <= tileRange.maxX; ++x) {
    for (let y = tileRange.minY; y <= tileRange.maxY; ++y) {
      tileCoordKey = getKeyZXY(z, x, y);
      loaded = false;
      if (tileCache.containsKey(tileCoordKey)) {
        tile = /** @type {!module:ol/Tile} */ (tileCache.get(tileCoordKey));
        loaded = tile.getState() === TileState.LOADED;
        if (loaded) {
          loaded = (callback(tile) !== false);
        }
      }
      if (!loaded) {
        covered = false;
      }
    }
  }
  return covered;
};


/**
 * @param {module:ol/proj/Projection} projection Projection.
 * @return {number} Gutter.
 */
TileSource.prototype.getGutter = function(projection) {
  return 0;
};


/**
 * Return the key to be used for all tiles in the source.
 * @return {string} The key for all tiles.
 * @protected
 */
TileSource.prototype.getKey = function() {
  return this.key_;
};


/**
 * Set the value to be used as the key for all tiles in the source.
 * @param {string} key The key for tiles.
 * @protected
 */
TileSource.prototype.setKey = function(key) {
  if (this.key_ !== key) {
    this.key_ = key;
    this.changed();
  }
};


/**
 * @param {module:ol/proj/Projection} projection Projection.
 * @return {boolean} Opaque.
 */
TileSource.prototype.getOpaque = function(projection) {
  return this.opaque_;
};


/**
 * @inheritDoc
 */
TileSource.prototype.getResolutions = function() {
  return this.tileGrid.getResolutions();
};


/**
 * @abstract
 * @param {number} z Tile coordinate z.
 * @param {number} x Tile coordinate x.
 * @param {number} y Tile coordinate y.
 * @param {number} pixelRatio Pixel ratio.
 * @param {module:ol/proj/Projection} projection Projection.
 * @return {!module:ol/Tile} Tile.
 */
TileSource.prototype.getTile = function(z, x, y, pixelRatio, projection) {};


/**
 * Return the tile grid of the tile source.
 * @return {module:ol/tilegrid/TileGrid} Tile grid.
 * @api
 */
TileSource.prototype.getTileGrid = function() {
  return this.tileGrid;
};


/**
 * @param {module:ol/proj/Projection} projection Projection.
 * @return {!module:ol/tilegrid/TileGrid} Tile grid.
 */
TileSource.prototype.getTileGridForProjection = function(projection) {
  if (!this.tileGrid) {
    return getTileGridForProjection(projection);
  } else {
    return this.tileGrid;
  }
};


/**
 * @param {module:ol/proj/Projection} projection Projection.
 * @return {module:ol/TileCache} Tile cache.
 * @protected
 */
TileSource.prototype.getTileCacheForProjection = function(projection) {
  const thisProj = this.getProjection();
  if (thisProj && !equivalent(thisProj, projection)) {
    return null;
  } else {
    return this.tileCache;
  }
};


/**
 * Get the tile pixel ratio for this source. Subclasses may override this
 * method, which is meant to return a supported pixel ratio that matches the
 * provided `pixelRatio` as close as possible.
 * @param {number} pixelRatio Pixel ratio.
 * @return {number} Tile pixel ratio.
 */
TileSource.prototype.getTilePixelRatio = function(pixelRatio) {
  return this.tilePixelRatio_;
};


/**
 * @param {number} z Z.
 * @param {number} pixelRatio Pixel ratio.
 * @param {module:ol/proj/Projection} projection Projection.
 * @return {module:ol/size~Size} Tile size.
 */
TileSource.prototype.getTilePixelSize = function(z, pixelRatio, projection) {
  const tileGrid = this.getTileGridForProjection(projection);
  const tilePixelRatio = this.getTilePixelRatio(pixelRatio);
  const tileSize = toSize(tileGrid.getTileSize(z), this.tmpSize);
  if (tilePixelRatio == 1) {
    return tileSize;
  } else {
    return scaleSize(tileSize, tilePixelRatio, this.tmpSize);
  }
};


/**
 * Returns a tile coordinate wrapped around the x-axis. When the tile coordinate
 * is outside the resolution and extent range of the tile grid, `null` will be
 * returned.
 * @param {module:ol/tilecoord~TileCoord} tileCoord Tile coordinate.
 * @param {module:ol/proj/Projection=} opt_projection Projection.
 * @return {module:ol/tilecoord~TileCoord} Tile coordinate to be passed to the tileUrlFunction or
 *     null if no tile URL should be created for the passed `tileCoord`.
 */
TileSource.prototype.getTileCoordForTileUrlFunction = function(tileCoord, opt_projection) {
  const projection = opt_projection !== undefined ?
    opt_projection : this.getProjection();
  const tileGrid = this.getTileGridForProjection(projection);
  if (this.getWrapX() && projection.isGlobal()) {
    tileCoord = wrapX(tileGrid, tileCoord, projection);
  }
  return withinExtentAndZ(tileCoord, tileGrid) ? tileCoord : null;
};


/**
 * @inheritDoc
 */
TileSource.prototype.refresh = function() {
  this.tileCache.clear();
  this.changed();
};


/**
 * Marks a tile coord as being used, without triggering a load.
 * @param {number} z Tile coordinate z.
 * @param {number} x Tile coordinate x.
 * @param {number} y Tile coordinate y.
 * @param {module:ol/proj/Projection} projection Projection.
 */
TileSource.prototype.useTile = UNDEFINED;


/**
 * @classdesc
 * Events emitted by {@link module:ol/source/Tile~TileSource} instances are instances of this
 * type.
 *
 * @constructor
 * @extends {module:ol/events/Event}
 * @param {string} type Type.
 * @param {module:ol/Tile} tile The tile.
 */
export const TileSourceEvent = function(type, tile) {

  Event.call(this, type);

  /**
   * The tile related to the event.
   * @type {module:ol/Tile}
   * @api
   */
  this.tile = tile;

};
inherits(TileSourceEvent, Event);

export default TileSource;