/**
 * @license
 * Copyright 2012 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */

/**
 * @fileoverview Object representing a workspace.
 */
'use strict';

/**
 * Object representing a workspace.
 * @class
 */
goog.module('Blockly.Workspace');

const arrayUtils = goog.require('Blockly.utils.array');
const eventUtils = goog.require('Blockly.Events.utils');
const idGenerator = goog.require('Blockly.utils.idGenerator');
const math = goog.require('Blockly.utils.math');
const registry = goog.require('Blockly.registry');
/* eslint-disable-next-line no-unused-vars */
const toolbox = goog.requireType('Blockly.utils.toolbox');
/* eslint-disable-next-line no-unused-vars */
const {Abstract} = goog.requireType('Blockly.Events.Abstract');
/* eslint-disable-next-line no-unused-vars */
const {BlocklyOptions} = goog.requireType('Blockly.BlocklyOptions');
/* eslint-disable-next-line no-unused-vars */
const {Block} = goog.requireType('Blockly.Block');
/* eslint-disable-next-line no-unused-vars */
const {ConnectionDB} = goog.requireType('Blockly.ConnectionDB');
/* eslint-disable-next-line no-unused-vars */
const {IASTNodeLocation} = goog.require('Blockly.IASTNodeLocation');
/* eslint-disable-next-line no-unused-vars */
const {IConnectionChecker} = goog.requireType('Blockly.IConnectionChecker');
const {Options} = goog.require('Blockly.Options');
const {VariableMap} = goog.require('Blockly.VariableMap');
/* eslint-disable-next-line no-unused-vars */
const {VariableModel} = goog.requireType('Blockly.VariableModel');
/* eslint-disable-next-line no-unused-vars */
const {WorkspaceComment} = goog.requireType('Blockly.WorkspaceComment');
/** @suppress {extraRequire} */
goog.require('Blockly.ConnectionChecker');


/**
 * Database of all workspaces.
 * @private
 */
const WorkspaceDB_ = Object.create(null);

/**
 * Class for a workspace.  This is a data structure that contains blocks.
 * There is no UI, and can be created headlessly.
 * @implements {IASTNodeLocation}
 */
class Workspace {
  /**
   * @param {!Options=} opt_options Dictionary of options.
   * @alias Blockly.Workspace
   */
  constructor(opt_options) {
    /** @type {string} */
    this.id = idGenerator.genUid();
    WorkspaceDB_[this.id] = this;
    /** @type {!Options} */
    this.options =
        opt_options || new Options(/** @type {!BlocklyOptions} */ ({}));
    /** @type {boolean} */
    this.RTL = !!this.options.RTL;
    /** @type {boolean} */
    this.horizontalLayout = !!this.options.horizontalLayout;
    /** @type {toolbox.Position} */
    this.toolboxPosition = this.options.toolboxPosition;

    /**
     * Returns `true` if the workspace is visible and `false` if it's headless.
     * @type {boolean}
     */
    this.rendered = false;

    /**
     * Is this workspace the surface for a flyout?
     * @type {boolean}
     */
    this.isFlyout = false;

    /**
     * Is this workspace the surface for a mutator?
     * @type {boolean}
     * @package
     */
    this.isMutator = false;

    /**
     * Returns `true` if the workspace is currently in the process of a bulk
     * clear.
     * @type {boolean}
     * @package
     */
    this.isClearing = false;

    /**
     * Maximum number of undo events in stack. `0` turns off undo, `Infinity`
     * sets it to unlimited.
     * @type {number}
     */
    this.MAX_UNDO = 1024;

    /**
     * Set of databases for rapid lookup of connection locations.
     * @type {Array<!ConnectionDB>}
     */
    this.connectionDBList = null;

    const connectionCheckerClass = registry.getClassFromOptions(
        registry.Type.CONNECTION_CHECKER, this.options, true);
    /**
     * An object that encapsulates logic for safety, type, and dragging checks.
     * @type {!IConnectionChecker}
     */
    this.connectionChecker = new connectionCheckerClass(this);

    /**
     * @type {!Array<!Block>}
     * @private
     */
    this.topBlocks_ = [];
    /**
     * @type {!Array<!WorkspaceComment>}
     * @private
     */
    this.topComments_ = [];
    /**
     * @type {!Object}
     * @private
     */
    this.commentDB_ = Object.create(null);
    /**
     * @type {!Array<!Function>}
     * @private
     */
    this.listeners_ = [];
    /**
     * @type {!Array<!Abstract>}
     * @protected
     */
    this.undoStack_ = [];
    /**
     * @type {!Array<!Abstract>}
     * @protected
     */
    this.redoStack_ = [];
    /**
     * @type {!Object}
     * @private
     */
    this.blockDB_ = Object.create(null);
    /**
     * @type {!Object}
     * @private
     */
    this.typedBlocksDB_ = Object.create(null);

    /**
     * A map from variable type to list of variable names.  The lists contain
     * all of the named variables in the workspace, including variables that are
     * not currently in use.
     * @type {!VariableMap}
     * @private
     */
    this.variableMap_ = new VariableMap(this);

    /**
     * Blocks in the flyout can refer to variables that don't exist in the main
     * workspace.  For instance, the "get item in list" block refers to an
     * "item" variable regardless of whether the variable has been created yet.
     * A FieldVariable must always refer to a VariableModel.  We reconcile
     * these by tracking "potential" variables in the flyout.  These variables
     * become real when references to them are dragged into the main workspace.
     * @type {?VariableMap}
     * @private
     */
    this.potentialVariableMap_ = null;
  }

  /**
   * Dispose of this workspace.
   * Unlink from all DOM elements to prevent memory leaks.
   * @suppress {checkTypes}
   */
  dispose() {
    this.listeners_.length = 0;
    this.clear();
    // Remove from workspace database.
    delete WorkspaceDB_[this.id];
  }

  /**
   * Compare function for sorting objects (blocks, comments, etc) by position;
   *    top to bottom (with slight LTR or RTL bias).
   * @param {!Block | !WorkspaceComment} a The first object to
   *    compare.
   * @param {!Block | !WorkspaceComment} b The second object to
   *    compare.
   * @return {number} The comparison value. This tells Array.sort() how to
   *    change object a's index.
   * @private
   */
  sortObjects_(a, b) {
    const aXY = a.getRelativeToSurfaceXY();
    const bXY = b.getRelativeToSurfaceXY();
    return (aXY.y + Workspace.prototype.sortObjects_.offset * aXY.x) -
        (bXY.y + Workspace.prototype.sortObjects_.offset * bXY.x);
  }

  /**
   * Adds a block to the list of top blocks.
   * @param {!Block} block Block to add.
   */
  addTopBlock(block) {
    this.topBlocks_.push(block);
  }

  /**
   * Removes a block from the list of top blocks.
   * @param {!Block} block Block to remove.
   */
  removeTopBlock(block) {
    if (!arrayUtils.removeElem(this.topBlocks_, block)) {
      throw Error('Block not present in workspace\'s list of top-most blocks.');
    }
  }

  /**
   * Finds the top-level blocks and returns them.  Blocks are optionally sorted
   * by position; top to bottom (with slight LTR or RTL bias).
   * @param {boolean} ordered Sort the list if true.
   * @return {!Array<!Block>} The top-level block objects.
   */
  getTopBlocks(ordered) {
    // Copy the topBlocks_ list.
    const blocks = [].concat(this.topBlocks_);
    if (ordered && blocks.length > 1) {
      this.sortObjects_.offset = Math.sin(math.toRadians(Workspace.SCAN_ANGLE));
      if (this.RTL) {
        this.sortObjects_.offset *= -1;
      }
      blocks.sort(this.sortObjects_);
    }
    return blocks;
  }

  /**
   * Add a block to the list of blocks keyed by type.
   * @param {!Block} block Block to add.
   */
  addTypedBlock(block) {
    if (!this.typedBlocksDB_[block.type]) {
      this.typedBlocksDB_[block.type] = [];
    }
    this.typedBlocksDB_[block.type].push(block);
  }

  /**
   * Remove a block from the list of blocks keyed by type.
   * @param {!Block} block Block to remove.
   */
  removeTypedBlock(block) {
    arrayUtils.removeElem(this.typedBlocksDB_[block.type], block);
    if (!this.typedBlocksDB_[block.type].length) {
      delete this.typedBlocksDB_[block.type];
    }
  }

  /**
   * Finds the blocks with the associated type and returns them. Blocks are
   * optionally sorted by position; top to bottom (with slight LTR or RTL bias).
   * @param {string} type The type of block to search for.
   * @param {boolean} ordered Sort the list if true.
   * @return {!Array<!Block>} The blocks of the given type.
   */
  getBlocksByType(type, ordered) {
    if (!this.typedBlocksDB_[type]) {
      return [];
    }
    const blocks = this.typedBlocksDB_[type].slice(0);
    if (ordered && blocks.length > 1) {
      this.sortObjects_.offset = Math.sin(math.toRadians(Workspace.SCAN_ANGLE));
      if (this.RTL) {
        this.sortObjects_.offset *= -1;
      }
      blocks.sort(this.sortObjects_);
    }

    return blocks.filter(function(block) {
      return !block.isInsertionMarker();
    });
  }

  /**
   * Adds a comment to the list of top comments.
   * @param {!WorkspaceComment} comment comment to add.
   * @package
   */
  addTopComment(comment) {
    this.topComments_.push(comment);

    // Note: If the comment database starts to hold block comments, this may
    // need to move to a separate function.
    if (this.commentDB_[comment.id]) {
      console.warn(
          'Overriding an existing comment on this workspace, with id "' +
          comment.id + '"');
    }
    this.commentDB_[comment.id] = comment;
  }

  /**
   * Removes a comment from the list of top comments.
   * @param {!WorkspaceComment} comment comment to remove.
   * @package
   */
  removeTopComment(comment) {
    if (!arrayUtils.removeElem(this.topComments_, comment)) {
      throw Error(
          'Comment not present in workspace\'s list of top-most ' +
          'comments.');
    }
    // Note: If the comment database starts to hold block comments, this may
    // need to move to a separate function.
    delete this.commentDB_[comment.id];
  }

  /**
   * Finds the top-level comments and returns them.  Comments are optionally
   * sorted by position; top to bottom (with slight LTR or RTL bias).
   * @param {boolean} ordered Sort the list if true.
   * @return {!Array<!WorkspaceComment>} The top-level comment objects.
   * @package
   */
  getTopComments(ordered) {
    // Copy the topComments_ list.
    const comments = [].concat(this.topComments_);
    if (ordered && comments.length > 1) {
      this.sortObjects_.offset = Math.sin(math.toRadians(Workspace.SCAN_ANGLE));
      if (this.RTL) {
        this.sortObjects_.offset *= -1;
      }
      comments.sort(this.sortObjects_);
    }
    return comments;
  }

  /**
   * Find all blocks in workspace.  Blocks are optionally sorted
   * by position; top to bottom (with slight LTR or RTL bias).
   * @param {boolean} ordered Sort the list if true.
   * @return {!Array<!Block>} Array of blocks.
   */
  getAllBlocks(ordered) {
    let blocks;
    if (ordered) {
      // Slow, but ordered.
      const topBlocks = this.getTopBlocks(true);
      blocks = [];
      for (let i = 0; i < topBlocks.length; i++) {
        blocks.push.apply(blocks, topBlocks[i].getDescendants(true));
      }
    } else {
      // Fast, but in no particular order.
      blocks = this.getTopBlocks(false);
      for (let i = 0; i < blocks.length; i++) {
        blocks.push.apply(blocks, blocks[i].getChildren(false));
      }
    }

    // Insertion markers exist on the workspace for rendering reasons, but
    // aren't "real" blocks from a developer perspective.
    const filtered = blocks.filter(function(block) {
      return !block.isInsertionMarker();
    });

    return filtered;
  }

  /**
   * Dispose of all blocks and comments in workspace.
   */
  clear() {
    this.isClearing = true;
    try {
      const existingGroup = eventUtils.getGroup();
      if (!existingGroup) {
        eventUtils.setGroup(true);
      }
      while (this.topBlocks_.length) {
        this.topBlocks_[0].dispose(false);
      }
      while (this.topComments_.length) {
        this.topComments_[this.topComments_.length - 1].dispose();
      }
      if (!existingGroup) {
        eventUtils.setGroup(false);
      }
      this.variableMap_.clear();
      if (this.potentialVariableMap_) {
        this.potentialVariableMap_.clear();
      }
    } finally {
      this.isClearing = false;
    }
  }

  /* Begin functions that are just pass-throughs to the variable map. */

  /**
   * Rename a variable by updating its name in the variable map. Identify the
   * variable to rename with the given ID.
   * @param {string} id ID of the variable to rename.
   * @param {string} newName New variable name.
   */
  renameVariableById(id, newName) {
    this.variableMap_.renameVariableById(id, newName);
  }

  /**
   * Create a variable with a given name, optional type, and optional ID.
   * @param {string} name The name of the variable. This must be unique across
   *     variables and procedures.
   * @param {?string=} opt_type The type of the variable like 'int' or 'string'.
   *     Does not need to be unique. Field_variable can filter variables based
   * on their type. This will default to '' which is a specific type.
   * @param {?string=} opt_id The unique ID of the variable. This will default
   *     to a UUID.
   * @return {!VariableModel} The newly created variable.
   */
  createVariable(name, opt_type, opt_id) {
    return this.variableMap_.createVariable(name, opt_type, opt_id);
  }

  /**
   * Find all the uses of the given variable, which is identified by ID.
   * @param {string} id ID of the variable to find.
   * @return {!Array<!Block>} Array of block usages.
   */
  getVariableUsesById(id) {
    return this.variableMap_.getVariableUsesById(id);
  }

  /**
   * Delete a variables by the passed in ID and all of its uses from this
   * workspace. May prompt the user for confirmation.
   * @param {string} id ID of variable to delete.
   */
  deleteVariableById(id) {
    this.variableMap_.deleteVariableById(id);
  }

  /**
   * Find the variable by the given name and return it. Return null if not
   * found.
   * @param {string} name The name to check for.
   * @param {string=} opt_type The type of the variable.  If not provided it
   *     defaults to the empty string, which is a specific type.
   * @return {?VariableModel} The variable with the given name.
   */
  getVariable(name, opt_type) {
    // TODO (#1559): Possibly delete this function after resolving #1559.
    return this.variableMap_.getVariable(name, opt_type);
  }

  /**
   * Find the variable by the given ID and return it. Return null if not found.
   * @param {string} id The ID to check for.
   * @return {?VariableModel} The variable with the given ID.
   */
  getVariableById(id) {
    return this.variableMap_.getVariableById(id);
  }

  /**
   * Find the variable with the specified type. If type is null, return list of
   *     variables with empty string type.
   * @param {?string} type Type of the variables to find.
   * @return {!Array<!VariableModel>} The sought after variables of the
   *     passed in type. An empty array if none are found.
   */
  getVariablesOfType(type) {
    return this.variableMap_.getVariablesOfType(type);
  }

  /**
   * Return all variable types.
   * @return {!Array<string>} List of variable types.
   * @package
   */
  getVariableTypes() {
    return this.variableMap_.getVariableTypes(this);
  }

  /**
   * Return all variables of all types.
   * @return {!Array<!VariableModel>} List of variable models.
   */
  getAllVariables() {
    return this.variableMap_.getAllVariables();
  }

  /**
   * Returns all variable names of all types.
   * @return {!Array<string>} List of all variable names of all types.
   */
  getAllVariableNames() {
    return this.variableMap_.getAllVariableNames();
  }

  /* End functions that are just pass-throughs to the variable map. */

  /**
   * Returns the horizontal offset of the workspace.
   * Intended for LTR/RTL compatibility in XML.
   * Not relevant for a headless workspace.
   * @return {number} Width.
   */
  getWidth() {
    return 0;
  }

  /**
   * Obtain a newly created block.
   * @param {!string} prototypeName Name of the language object containing
   *     type-specific functions for this block.
   * @param {string=} opt_id Optional ID.  Use this ID if provided, otherwise
   *     create a new ID.
   * @return {!Block} The created block.
   */
  newBlock(prototypeName, opt_id) {
    const {Block} = goog.module.get('Blockly.Block');
    return new Block(this, prototypeName, opt_id);
  }

  /**
   * The number of blocks that may be added to the workspace before reaching
   *     the maxBlocks.
   * @return {number} Number of blocks left.
   */
  remainingCapacity() {
    if (isNaN(this.options.maxBlocks)) {
      return Infinity;
    }

    return this.options.maxBlocks - this.getAllBlocks(false).length;
  }

  /**
   * The number of blocks of the given type that may be added to the workspace
   *    before reaching the maxInstances allowed for that type.
   * @param {string} type Type of block to return capacity for.
   * @return {number} Number of blocks of type left.
   */
  remainingCapacityOfType(type) {
    if (!this.options.maxInstances) {
      return Infinity;
    }

    const maxInstanceOfType = (this.options.maxInstances[type] !== undefined) ?
        this.options.maxInstances[type] :
        Infinity;

    return maxInstanceOfType - this.getBlocksByType(type, false).length;
  }

  /**
   * Check if there is remaining capacity for blocks of the given counts to be
   *    created. If the total number of blocks represented by the map is more
   * than the total remaining capacity, it returns false. If a type count is
   * more than the remaining capacity for that type, it returns false.
   * @param {!Object} typeCountsMap A map of types to counts (usually
   *     representing
   *    blocks to be created).
   * @return {boolean} True if there is capacity for the given map,
   *    false otherwise.
   */
  isCapacityAvailable(typeCountsMap) {
    if (!this.hasBlockLimits()) {
      return true;
    }
    let copyableBlocksCount = 0;
    for (const type in typeCountsMap) {
      if (typeCountsMap[type] > this.remainingCapacityOfType(type)) {
        return false;
      }
      copyableBlocksCount += typeCountsMap[type];
    }
    if (copyableBlocksCount > this.remainingCapacity()) {
      return false;
    }
    return true;
  }

  /**
   * Checks if the workspace has any limits on the maximum number of blocks,
   *    or the maximum number of blocks of specific types.
   * @return {boolean} True if it has block limits, false otherwise.
   */
  hasBlockLimits() {
    return this.options.maxBlocks !== Infinity || !!this.options.maxInstances;
  }

  /**
   * Gets the undo stack for workplace.
   * @return {!Array<!Abstract>} undo stack
   * @package
   */
  getUndoStack() {
    return this.undoStack_;
  }

  /**
   * Gets the redo stack for workplace.
   * @return {!Array<!Abstract>} redo stack
   * @package
   */
  getRedoStack() {
    return this.redoStack_;
  }

  /**
   * Undo or redo the previous action.
   * @param {boolean} redo False if undo, true if redo.
   */
  undo(redo) {
    const inputStack = redo ? this.redoStack_ : this.undoStack_;
    const outputStack = redo ? this.undoStack_ : this.redoStack_;
    const inputEvent = inputStack.pop();
    if (!inputEvent) {
      return;
    }
    let events = [inputEvent];
    // Do another undo/redo if the next one is of the same group.
    while (inputStack.length && inputEvent.group &&
           inputEvent.group === inputStack[inputStack.length - 1].group) {
      events.push(inputStack.pop());
    }
    // Push these popped events on the opposite stack.
    for (let i = 0; i < events.length; i++) {
      const event = events[i];
      outputStack.push(event);
    }
    events = eventUtils.filter(events, redo);
    eventUtils.setRecordUndo(false);
    try {
      for (let i = 0; i < events.length; i++) {
        const event = events[i];
        event.run(redo);
      }
    } finally {
      eventUtils.setRecordUndo(true);
    }
  }

  /**
   * Clear the undo/redo stacks.
   */
  clearUndo() {
    this.undoStack_.length = 0;
    this.redoStack_.length = 0;
    // Stop any events already in the firing queue from being undoable.
    eventUtils.clearPendingUndo();
  }

  /**
   * When something in this workspace changes, call a function.
   * Note that there may be a few recent events already on the stack.  Thus the
   * new change listener might be called with events that occurred a few
   * milliseconds before the change listener was added.
   * @param {!Function} func Function to call.
   * @return {!Function} Obsolete return value, ignore.
   */
  addChangeListener(func) {
    this.listeners_.push(func);
    return func;
  }

  /**
   * Stop listening for this workspace's changes.
   * @param {!Function} func Function to stop calling.
   */
  removeChangeListener(func) {
    arrayUtils.removeElem(this.listeners_, func);
  }

  /**
   * Fire a change event.
   * @param {!Abstract} event Event to fire.
   */
  fireChangeListener(event) {
    if (event.recordUndo) {
      this.undoStack_.push(event);
      this.redoStack_.length = 0;
      while (this.undoStack_.length > this.MAX_UNDO && this.MAX_UNDO >= 0) {
        this.undoStack_.shift();
      }
    }
    for (let i = 0; i < this.listeners_.length; i++) {
      const func = this.listeners_[i];
      func(event);
    }
  }

  /**
   * Find the block on this workspace with the specified ID.
   * @param {string} id ID of block to find.
   * @return {?Block} The sought after block, or null if not found.
   */
  getBlockById(id) {
    return this.blockDB_[id] || null;
  }

  /**
   * Set a block on this workspace with the specified ID.
   * @param {string} id ID of block to set.
   * @param {Block} block The block to set.
   * @package
   */
  setBlockById(id, block) {
    this.blockDB_[id] = block;
  }

  /**
   * Delete a block off this workspace with the specified ID.
   * @param {string} id ID of block to delete.
   * @package
   */
  removeBlockById(id) {
    delete this.blockDB_[id];
  }

  /**
   * Find the comment on this workspace with the specified ID.
   * @param {string} id ID of comment to find.
   * @return {?WorkspaceComment} The sought after comment, or null if not
   *     found.
   * @package
   */
  getCommentById(id) {
    return this.commentDB_[id] || null;
  }

  /**
   * Checks whether all value and statement inputs in the workspace are filled
   * with blocks.
   * @param {boolean=} opt_shadowBlocksAreFilled An optional argument
   *     controlling whether shadow blocks are counted as filled. Defaults to
   *     true.
   * @return {boolean} True if all inputs are filled, false otherwise.
   */
  allInputsFilled(opt_shadowBlocksAreFilled) {
    const blocks = this.getTopBlocks(false);
    for (let i = 0; i < blocks.length; i++) {
      const block = blocks[i];
      if (!block.allInputsFilled(opt_shadowBlocksAreFilled)) {
        return false;
      }
    }
    return true;
  }

  /**
   * Return the variable map that contains "potential" variables.
   * These exist in the flyout but not in the workspace.
   * @return {?VariableMap} The potential variable map.
   * @package
   */
  getPotentialVariableMap() {
    return this.potentialVariableMap_;
  }

  /**
   * Create and store the potential variable map for this workspace.
   * @package
   */
  createPotentialVariableMap() {
    this.potentialVariableMap_ = new VariableMap(this);
  }

  /**
   * Return the map of all variables on the workspace.
   * @return {!VariableMap} The variable map.
   */
  getVariableMap() {
    return this.variableMap_;
  }

  /**
   * Set the map of all variables on the workspace.
   * @param {!VariableMap} variableMap The variable map.
   * @package
   */
  setVariableMap(variableMap) {
    this.variableMap_ = variableMap;
  }

  /**
   * Find the workspace with the specified ID.
   * @param {string} id ID of workspace to find.
   * @return {?Workspace} The sought after workspace or null if not found.
   */
  static getById(id) {
    return WorkspaceDB_[id] || null;
  }

  /**
   * Find all workspaces.
   * @return {!Array<!Workspace>} Array of workspaces.
   */
  static getAll() {
    const workspaces = [];
    for (const workspaceId in WorkspaceDB_) {
      workspaces.push(WorkspaceDB_[workspaceId]);
    }
    return workspaces;
  }
}

/**
 * Angle away from the horizontal to sweep for blocks.  Order of execution is
 * generally top to bottom, but a small angle changes the scan to give a bit of
 * a left to right bias (reversed in RTL).  Units are in degrees.
 * See: https://tvtropes.org/pmwiki/pmwiki.php/Main/DiagonalBilling
 */
Workspace.SCAN_ANGLE = 3;

exports.Workspace = Workspace;