/**
 * @module ol/format/WKT
 */
import Feature from '../Feature.js';
import GeometryCollection from '../geom/GeometryCollection.js';
import LineString from '../geom/LineString.js';
import MultiLineString from '../geom/MultiLineString.js';
import MultiPoint from '../geom/MultiPoint.js';
import MultiPolygon from '../geom/MultiPolygon.js';
import Point from '../geom/Point.js';
import Polygon from '../geom/Polygon.js';
import TextFeature from './TextFeature.js';
import {transformGeometryWithOptions} from './Feature.js';

/**
 * Geometry constructors
 * @enum {function (new:import("../geom/Geometry.js").default, Array, import("../geom/Geometry.js").GeometryLayout)}
 */
const GeometryConstructor = {
  'POINT': Point,
  'LINESTRING': LineString,
  'POLYGON': Polygon,
  'MULTIPOINT': MultiPoint,
  'MULTILINESTRING': MultiLineString,
  'MULTIPOLYGON': MultiPolygon,
};

/**
 * @typedef {Object} Options
 * @property {boolean} [splitCollection=false] Whether to split GeometryCollections into
 * multiple features on reading.
 */

/**
 * @typedef {Object} Token
 * @property {number} type Type.
 * @property {number|string} [value] Value.
 * @property {number} position Position.
 */

/**
 * @const
 * @type {string}
 */
const EMPTY = 'EMPTY';

/**
 * @const
 * @type {string}
 */
const Z = 'Z';

/**
 * @const
 * @type {string}
 */
const M = 'M';

/**
 * @const
 * @type {string}
 */
const ZM = 'ZM';

/**
 * @const
 * @enum {number}
 */
const TokenType = {
  START: 0,
  TEXT: 1,
  LEFT_PAREN: 2,
  RIGHT_PAREN: 3,
  NUMBER: 4,
  COMMA: 5,
  EOF: 6,
};

/**
 * @type {Object<import("../geom/Geometry.js").Type, string>}
 */
const wktTypeLookup = {
  Point: 'POINT',
  LineString: 'LINESTRING',
  Polygon: 'POLYGON',
  MultiPoint: 'MULTIPOINT',
  MultiLineString: 'MULTILINESTRING',
  MultiPolygon: 'MULTIPOLYGON',
  GeometryCollection: 'GEOMETRYCOLLECTION',
  Circle: 'CIRCLE',
};

/**
 * Class to tokenize a WKT string.
 */
class Lexer {
  /**
   * @param {string} wkt WKT string.
   */
  constructor(wkt) {
    /**
     * @type {string}
     */
    this.wkt = wkt;

    /**
     * @type {number}
     * @private
     */
    this.index_ = -1;
  }

  /**
   * @param {string} c Character.
   * @return {boolean} Whether the character is alphabetic.
   * @private
   */
  isAlpha_(c) {
    return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z');
  }

  /**
   * @param {string} c Character.
   * @param {boolean} [decimal] Whether the string number
   *     contains a dot, i.e. is a decimal number.
   * @return {boolean} Whether the character is numeric.
   * @private
   */
  isNumeric_(c, decimal) {
    decimal = decimal !== undefined ? decimal : false;
    return (c >= '0' && c <= '9') || (c == '.' && !decimal);
  }

  /**
   * @param {string} c Character.
   * @return {boolean} Whether the character is whitespace.
   * @private
   */
  isWhiteSpace_(c) {
    return c == ' ' || c == '\t' || c == '\r' || c == '\n';
  }

  /**
   * @return {string} Next string character.
   * @private
   */
  nextChar_() {
    return this.wkt.charAt(++this.index_);
  }

  /**
   * Fetch and return the next token.
   * @return {Token} Next string token.
   */
  nextToken() {
    const c = this.nextChar_();
    const position = this.index_;
    /** @type {number|string} */
    let value = c;
    let type;

    if (c == '(') {
      type = TokenType.LEFT_PAREN;
    } else if (c == ',') {
      type = TokenType.COMMA;
    } else if (c == ')') {
      type = TokenType.RIGHT_PAREN;
    } else if (this.isNumeric_(c) || c == '-') {
      type = TokenType.NUMBER;
      value = this.readNumber_();
    } else if (this.isAlpha_(c)) {
      type = TokenType.TEXT;
      value = this.readText_();
    } else if (this.isWhiteSpace_(c)) {
      return this.nextToken();
    } else if (c === '') {
      type = TokenType.EOF;
    } else {
      throw new Error('Unexpected character: ' + c);
    }

    return {position: position, value: value, type: type};
  }

  /**
   * @return {number} Numeric token value.
   * @private
   */
  readNumber_() {
    let c;
    const index = this.index_;
    let decimal = false;
    let scientificNotation = false;
    do {
      if (c == '.') {
        decimal = true;
      } else if (c == 'e' || c == 'E') {
        scientificNotation = true;
      }
      c = this.nextChar_();
    } while (
      this.isNumeric_(c, decimal) ||
      // if we haven't detected a scientific number before, 'e' or 'E'
      // hint that we should continue to read
      (!scientificNotation && (c == 'e' || c == 'E')) ||
      // once we know that we have a scientific number, both '-' and '+'
      // are allowed
      (scientificNotation && (c == '-' || c == '+'))
    );
    return parseFloat(this.wkt.substring(index, this.index_--));
  }

  /**
   * @return {string} String token value.
   * @private
   */
  readText_() {
    let c;
    const index = this.index_;
    do {
      c = this.nextChar_();
    } while (this.isAlpha_(c));
    return this.wkt.substring(index, this.index_--).toUpperCase();
  }
}

/**
 * Class to parse the tokens from the WKT string.
 */
class Parser {
  /**
   * @param {Lexer} lexer The lexer.
   */
  constructor(lexer) {
    /**
     * @type {Lexer}
     * @private
     */
    this.lexer_ = lexer;

    /**
     * @type {Token}
     * @private
     */
    this.token_ = {
      position: 0,
      type: TokenType.START,
    };

    /**
     * @type {import("../geom/Geometry.js").GeometryLayout}
     * @private
     */
    this.layout_ = 'XY';
  }

  /**
   * Fetch the next token form the lexer and replace the active token.
   * @private
   */
  consume_() {
    this.token_ = this.lexer_.nextToken();
  }

  /**
   * Tests if the given type matches the type of the current token.
   * @param {TokenType} type Token type.
   * @return {boolean} Whether the token matches the given type.
   */
  isTokenType(type) {
    return this.token_.type == type;
  }

  /**
   * If the given type matches the current token, consume it.
   * @param {TokenType} type Token type.
   * @return {boolean} Whether the token matches the given type.
   */
  match(type) {
    const isMatch = this.isTokenType(type);
    if (isMatch) {
      this.consume_();
    }
    return isMatch;
  }

  /**
   * Try to parse the tokens provided by the lexer.
   * @return {import("../geom/Geometry.js").default} The geometry.
   */
  parse() {
    this.consume_();
    return this.parseGeometry_();
  }

  /**
   * Try to parse the dimensional info.
   * @return {import("../geom/Geometry.js").GeometryLayout} The layout.
   * @private
   */
  parseGeometryLayout_() {
    /** @type {import("../geom/Geometry.js").GeometryLayout} */
    let layout = 'XY';
    const dimToken = this.token_;
    if (this.isTokenType(TokenType.TEXT)) {
      const dimInfo = dimToken.value;
      if (dimInfo === Z) {
        layout = 'XYZ';
      } else if (dimInfo === M) {
        layout = 'XYM';
      } else if (dimInfo === ZM) {
        layout = 'XYZM';
      }
      if (layout !== 'XY') {
        this.consume_();
      }
    }
    return layout;
  }

  /**
   * @return {Array<import("../geom/Geometry.js").default>} A collection of geometries.
   * @private
   */
  parseGeometryCollectionText_() {
    if (this.match(TokenType.LEFT_PAREN)) {
      const geometries = [];
      do {
        geometries.push(this.parseGeometry_());
      } while (this.match(TokenType.COMMA));
      if (this.match(TokenType.RIGHT_PAREN)) {
        return geometries;
      }
    }
    throw new Error(this.formatErrorMessage_());
  }

  /**
   * @return {Array<number>} All values in a point.
   * @private
   */
  parsePointText_() {
    if (this.match(TokenType.LEFT_PAREN)) {
      const coordinates = this.parsePoint_();
      if (this.match(TokenType.RIGHT_PAREN)) {
        return coordinates;
      }
    }
    throw new Error(this.formatErrorMessage_());
  }

  /**
   * @return {Array<Array<number>>} All points in a linestring.
   * @private
   */
  parseLineStringText_() {
    if (this.match(TokenType.LEFT_PAREN)) {
      const coordinates = this.parsePointList_();
      if (this.match(TokenType.RIGHT_PAREN)) {
        return coordinates;
      }
    }
    throw new Error(this.formatErrorMessage_());
  }

  /**
   * @return {Array<Array<Array<number>>>} All points in a polygon.
   * @private
   */
  parsePolygonText_() {
    if (this.match(TokenType.LEFT_PAREN)) {
      const coordinates = this.parseLineStringTextList_();
      if (this.match(TokenType.RIGHT_PAREN)) {
        return coordinates;
      }
    }
    throw new Error(this.formatErrorMessage_());
  }

  /**
   * @return {Array<Array<number>>} All points in a multipoint.
   * @private
   */
  parseMultiPointText_() {
    if (this.match(TokenType.LEFT_PAREN)) {
      let coordinates;
      if (this.token_.type == TokenType.LEFT_PAREN) {
        coordinates = this.parsePointTextList_();
      } else {
        coordinates = this.parsePointList_();
      }
      if (this.match(TokenType.RIGHT_PAREN)) {
        return coordinates;
      }
    }
    throw new Error(this.formatErrorMessage_());
  }

  /**
   * @return {Array<Array<Array<number>>>} All linestring points
   *                                          in a multilinestring.
   * @private
   */
  parseMultiLineStringText_() {
    if (this.match(TokenType.LEFT_PAREN)) {
      const coordinates = this.parseLineStringTextList_();
      if (this.match(TokenType.RIGHT_PAREN)) {
        return coordinates;
      }
    }
    throw new Error(this.formatErrorMessage_());
  }

  /**
   * @return {Array<Array<Array<Array<number>>>>} All polygon points in a multipolygon.
   * @private
   */
  parseMultiPolygonText_() {
    if (this.match(TokenType.LEFT_PAREN)) {
      const coordinates = this.parsePolygonTextList_();
      if (this.match(TokenType.RIGHT_PAREN)) {
        return coordinates;
      }
    }
    throw new Error(this.formatErrorMessage_());
  }

  /**
   * @return {Array<number>} A point.
   * @private
   */
  parsePoint_() {
    const coordinates = [];
    const dimensions = this.layout_.length;
    for (let i = 0; i < dimensions; ++i) {
      const token = this.token_;
      if (this.match(TokenType.NUMBER)) {
        coordinates.push(/** @type {number} */ (token.value));
      } else {
        break;
      }
    }
    if (coordinates.length == dimensions) {
      return coordinates;
    }
    throw new Error(this.formatErrorMessage_());
  }

  /**
   * @return {Array<Array<number>>} An array of points.
   * @private
   */
  parsePointList_() {
    const coordinates = [this.parsePoint_()];
    while (this.match(TokenType.COMMA)) {
      coordinates.push(this.parsePoint_());
    }
    return coordinates;
  }

  /**
   * @return {Array<Array<number>>} An array of points.
   * @private
   */
  parsePointTextList_() {
    const coordinates = [this.parsePointText_()];
    while (this.match(TokenType.COMMA)) {
      coordinates.push(this.parsePointText_());
    }
    return coordinates;
  }

  /**
   * @return {Array<Array<Array<number>>>} An array of points.
   * @private
   */
  parseLineStringTextList_() {
    const coordinates = [this.parseLineStringText_()];
    while (this.match(TokenType.COMMA)) {
      coordinates.push(this.parseLineStringText_());
    }
    return coordinates;
  }

  /**
   * @return {Array<Array<Array<Array<number>>>>} An array of points.
   * @private
   */
  parsePolygonTextList_() {
    const coordinates = [this.parsePolygonText_()];
    while (this.match(TokenType.COMMA)) {
      coordinates.push(this.parsePolygonText_());
    }
    return coordinates;
  }

  /**
   * @return {boolean} Whether the token implies an empty geometry.
   * @private
   */
  isEmptyGeometry_() {
    const isEmpty =
      this.isTokenType(TokenType.TEXT) && this.token_.value == EMPTY;
    if (isEmpty) {
      this.consume_();
    }
    return isEmpty;
  }

  /**
   * Create an error message for an unexpected token error.
   * @return {string} Error message.
   * @private
   */
  formatErrorMessage_() {
    return (
      'Unexpected `' +
      this.token_.value +
      '` at position ' +
      this.token_.position +
      ' in `' +
      this.lexer_.wkt +
      '`'
    );
  }

  /**
   * @return {import("../geom/Geometry.js").default} The geometry.
   * @private
   */
  parseGeometry_() {
    const token = this.token_;
    if (this.match(TokenType.TEXT)) {
      const geomType = /** @type {string} */ (token.value);
      this.layout_ = this.parseGeometryLayout_();
      const isEmpty = this.isEmptyGeometry_();
      if (geomType == 'GEOMETRYCOLLECTION') {
        if (isEmpty) {
          return new GeometryCollection([]);
        }
        const geometries = this.parseGeometryCollectionText_();
        return new GeometryCollection(geometries);
      }
      const ctor = GeometryConstructor[geomType];
      if (!ctor) {
        throw new Error('Invalid geometry type: ' + geomType);
      }

      let coordinates;

      if (isEmpty) {
        if (geomType == 'POINT') {
          coordinates = [NaN, NaN];
        } else {
          coordinates = [];
        }
      } else {
        switch (geomType) {
          case 'POINT': {
            coordinates = this.parsePointText_();
            break;
          }
          case 'LINESTRING': {
            coordinates = this.parseLineStringText_();
            break;
          }
          case 'POLYGON': {
            coordinates = this.parsePolygonText_();
            break;
          }
          case 'MULTIPOINT': {
            coordinates = this.parseMultiPointText_();
            break;
          }
          case 'MULTILINESTRING': {
            coordinates = this.parseMultiLineStringText_();
            break;
          }
          case 'MULTIPOLYGON': {
            coordinates = this.parseMultiPolygonText_();
            break;
          }
          default:
            break;
        }
      }

      return new ctor(coordinates, this.layout_);
    }
    throw new Error(this.formatErrorMessage_());
  }
}

/**
 * @classdesc
 * Geometry format for reading and writing data in the `WellKnownText` (WKT)
 * format.
 *
 * @api
 */
class WKT extends TextFeature {
  /**
   * @param {Options} [options] Options.
   */
  constructor(options) {
    super();

    options = options ? options : {};

    /**
     * Split GeometryCollection into multiple features.
     * @type {boolean}
     * @private
     */
    this.splitCollection_ =
      options.splitCollection !== undefined ? options.splitCollection : false;
  }

  /**
   * Parse a WKT string.
   * @param {string} wkt WKT string.
   * @return {import("../geom/Geometry.js").default}
   *     The geometry created.
   * @private
   */
  parse_(wkt) {
    const lexer = new Lexer(wkt);
    const parser = new Parser(lexer);
    return parser.parse();
  }

  /**
   * @protected
   * @param {string} text Text.
   * @param {import("./Feature.js").ReadOptions} [options] Read options.
   * @return {import("../Feature.js").default} Feature.
   */
  readFeatureFromText(text, options) {
    const geom = this.readGeometryFromText(text, options);
    const feature = new Feature();
    feature.setGeometry(geom);
    return feature;
  }

  /**
   * @param {string} text Text.
   * @param {import("./Feature.js").ReadOptions} [options] Read options.
   * @protected
   * @return {Array<Feature>} Features.
   */
  readFeaturesFromText(text, options) {
    let geometries = [];
    const geometry = this.readGeometryFromText(text, options);
    if (this.splitCollection_ && geometry.getType() == 'GeometryCollection') {
      geometries = /** @type {GeometryCollection} */ (
        geometry
      ).getGeometriesArray();
    } else {
      geometries = [geometry];
    }
    const features = [];
    for (let i = 0, ii = geometries.length; i < ii; ++i) {
      const feature = new Feature();
      feature.setGeometry(geometries[i]);
      features.push(feature);
    }
    return features;
  }

  /**
   * @param {string} text Text.
   * @param {import("./Feature.js").ReadOptions} [options] Read options.
   * @protected
   * @return {import("../geom/Geometry.js").default} Geometry.
   */
  readGeometryFromText(text, options) {
    const geometry = this.parse_(text);
    return transformGeometryWithOptions(geometry, false, options);
  }

  /**
   * @param {import("../Feature.js").default} feature Features.
   * @param {import("./Feature.js").WriteOptions} [options] Write options.
   * @protected
   * @return {string} Text.
   */
  writeFeatureText(feature, options) {
    const geometry = feature.getGeometry();
    if (geometry) {
      return this.writeGeometryText(geometry, options);
    }
    return '';
  }

  /**
   * @param {Array<import("../Feature.js").default>} features Features.
   * @param {import("./Feature.js").WriteOptions} [options] Write options.
   * @protected
   * @return {string} Text.
   */
  writeFeaturesText(features, options) {
    if (features.length == 1) {
      return this.writeFeatureText(features[0], options);
    }
    const geometries = [];
    for (let i = 0, ii = features.length; i < ii; ++i) {
      geometries.push(features[i].getGeometry());
    }
    const collection = new GeometryCollection(geometries);
    return this.writeGeometryText(collection, options);
  }

  /**
   * @param {import("../geom/Geometry.js").default} geometry Geometry.
   * @param {import("./Feature.js").WriteOptions} [options] Write options.
   * @protected
   * @return {string} Text.
   */
  writeGeometryText(geometry, options) {
    return encode(transformGeometryWithOptions(geometry, true, options));
  }
}

/**
 * @param {Point} geom Point geometry.
 * @return {string} Coordinates part of Point as WKT.
 */
function encodePointGeometry(geom) {
  const coordinates = geom.getCoordinates();
  if (coordinates.length === 0) {
    return '';
  }
  return coordinates.join(' ');
}

/**
 * @param {MultiPoint} geom MultiPoint geometry.
 * @return {string} Coordinates part of MultiPoint as WKT.
 */
function encodeMultiPointGeometry(geom) {
  const array = [];
  const components = geom.getPoints();
  for (let i = 0, ii = components.length; i < ii; ++i) {
    array.push('(' + encodePointGeometry(components[i]) + ')');
  }
  return array.join(',');
}

/**
 * @param {GeometryCollection} geom GeometryCollection geometry.
 * @return {string} Coordinates part of GeometryCollection as WKT.
 */
function encodeGeometryCollectionGeometry(geom) {
  const array = [];
  const geoms = geom.getGeometries();
  for (let i = 0, ii = geoms.length; i < ii; ++i) {
    array.push(encode(geoms[i]));
  }
  return array.join(',');
}

/**
 * @param {LineString|import("../geom/LinearRing.js").default} geom LineString geometry.
 * @return {string} Coordinates part of LineString as WKT.
 */
function encodeLineStringGeometry(geom) {
  const coordinates = geom.getCoordinates();
  const array = [];
  for (let i = 0, ii = coordinates.length; i < ii; ++i) {
    array.push(coordinates[i].join(' '));
  }
  return array.join(',');
}

/**
 * @param {MultiLineString} geom MultiLineString geometry.
 * @return {string} Coordinates part of MultiLineString as WKT.
 */
function encodeMultiLineStringGeometry(geom) {
  const array = [];
  const components = geom.getLineStrings();
  for (let i = 0, ii = components.length; i < ii; ++i) {
    array.push('(' + encodeLineStringGeometry(components[i]) + ')');
  }
  return array.join(',');
}

/**
 * @param {Polygon} geom Polygon geometry.
 * @return {string} Coordinates part of Polygon as WKT.
 */
function encodePolygonGeometry(geom) {
  const array = [];
  const rings = geom.getLinearRings();
  for (let i = 0, ii = rings.length; i < ii; ++i) {
    array.push('(' + encodeLineStringGeometry(rings[i]) + ')');
  }
  return array.join(',');
}

/**
 * @param {MultiPolygon} geom MultiPolygon geometry.
 * @return {string} Coordinates part of MultiPolygon as WKT.
 */
function encodeMultiPolygonGeometry(geom) {
  const array = [];
  const components = geom.getPolygons();
  for (let i = 0, ii = components.length; i < ii; ++i) {
    array.push('(' + encodePolygonGeometry(components[i]) + ')');
  }
  return array.join(',');
}

/**
 * @param {import("../geom/SimpleGeometry.js").default} geom SimpleGeometry geometry.
 * @return {string} Potential dimensional information for WKT type.
 */
function encodeGeometryLayout(geom) {
  const layout = geom.getLayout();
  let dimInfo = '';
  if (layout === 'XYZ' || layout === 'XYZM') {
    dimInfo += Z;
  }
  if (layout === 'XYM' || layout === 'XYZM') {
    dimInfo += M;
  }
  return dimInfo;
}

/**
 * @const
 * @type {Object<string, function(import("../geom/Geometry.js").default): string>}
 */
const GeometryEncoder = {
  'Point': encodePointGeometry,
  'LineString': encodeLineStringGeometry,
  'Polygon': encodePolygonGeometry,
  'MultiPoint': encodeMultiPointGeometry,
  'MultiLineString': encodeMultiLineStringGeometry,
  'MultiPolygon': encodeMultiPolygonGeometry,
  'GeometryCollection': encodeGeometryCollectionGeometry,
};

/**
 * Encode a geometry as WKT.
 * @param {import("../geom/Geometry.js").default} geom The geometry to encode.
 * @return {string} WKT string for the geometry.
 */
function encode(geom) {
  const type = geom.getType();
  const geometryEncoder = GeometryEncoder[type];
  const enc = geometryEncoder(geom);
  let wktType = wktTypeLookup[type];
  if (typeof (/** @type {?} */ (geom).getFlatCoordinates) === 'function') {
    const dimInfo = encodeGeometryLayout(
      /** @type {import("../geom/SimpleGeometry.js").default} */ (geom)
    );
    if (dimInfo.length > 0) {
      wktType += ' ' + dimInfo;
    }
  }
  if (enc.length === 0) {
    return wktType + ' ' + EMPTY;
  }
  return wktType + '(' + enc + ')';
}

export default WKT;