/**
 * @license
 * Copyright 2017 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */

/**
 * Object representing a map of variables and their types.
 *
 * @class
 */
// Former goog.module ID: Blockly.VariableMap

// Unused import preserved for side-effects. Remove if unneeded.
import './events/events_var_delete.js';
// Unused import preserved for side-effects. Remove if unneeded.
import './events/events_var_rename.js';

import type {Block} from './block.js';
import * as dialog from './dialog.js';
import * as eventUtils from './events/utils.js';
import * as registry from './registry.js';
import {Msg} from './msg.js';
import {Names} from './names.js';
import * as idGenerator from './utils/idgenerator.js';
import {IVariableModel, IVariableState} from './interfaces/i_variable_model.js';
import type {Workspace} from './workspace.js';
import type {IVariableMap} from './interfaces/i_variable_map.js';

/**
 * Class for a variable map.  This contains a dictionary data structure with
 * variable types as keys and lists of variables as values.  The list of
 * variables are the type indicated by the key.
 */
export class VariableMap
  implements IVariableMap<IVariableModel<IVariableState>>
{
  /**
   * A map from variable type to map of IDs to variables. The maps contain
   * all of the named variables in the workspace, including variables that are
   * not currently in use.
   */
  private variableMap = new Map<
    string,
    Map<string, IVariableModel<IVariableState>>
  >();

  /** @param workspace The workspace this map belongs to. */
  constructor(public workspace: Workspace) {}

  /** Clear the variable map.  Fires events for every deletion. */
  clear() {
    for (const variables of this.variableMap.values()) {
      for (const variable of variables.values()) {
        this.deleteVariable(variable);
      }
    }
    if (this.variableMap.size !== 0) {
      throw Error('Non-empty variable map');
    }
  }

  /* Begin functions for renaming variables. */
  /**
   * Rename the given variable by updating its name in the variable map.
   *
   * @param variable Variable to rename.
   * @param newName New variable name.
   * @returns The newly renamed variable.
   */
  renameVariable(
    variable: IVariableModel<IVariableState>,
    newName: string,
  ): IVariableModel<IVariableState> {
    if (variable.getName() === newName) return variable;
    const type = variable.getType();
    const conflictVar = this.getVariable(newName, type);
    const blocks = this.workspace.getAllBlocks(false);
    const existingGroup = eventUtils.getGroup();
    if (!existingGroup) {
      eventUtils.setGroup(true);
    }
    try {
      // The IDs may match if the rename is a simple case change (name1 ->
      // Name1).
      if (!conflictVar || conflictVar.getId() === variable.getId()) {
        this.renameVariableAndUses_(variable, newName, blocks);
      } else {
        this.renameVariableWithConflict_(
          variable,
          newName,
          conflictVar,
          blocks,
        );
      }
    } finally {
      eventUtils.setGroup(existingGroup);
    }
    return variable;
  }

  changeVariableType(
    variable: IVariableModel<IVariableState>,
    newType: string,
  ): IVariableModel<IVariableState> {
    this.variableMap.get(variable.getType())?.delete(variable.getId());
    variable.setType(newType);
    const newTypeVariables =
      this.variableMap.get(newType) ??
      new Map<string, IVariableModel<IVariableState>>();
    newTypeVariables.set(variable.getId(), variable);
    if (!this.variableMap.has(newType)) {
      this.variableMap.set(newType, newTypeVariables);
    }

    return variable;
  }

  /**
   * Rename a variable by updating its name in the variable map. Identify the
   * variable to rename with the given ID.
   *
   * @param id ID of the variable to rename.
   * @param newName New variable name.
   */
  renameVariableById(id: string, newName: string) {
    const variable = this.getVariableById(id);
    if (!variable) {
      throw Error("Tried to rename a variable that didn't exist. ID: " + id);
    }

    this.renameVariable(variable, newName);
  }

  /**
   * Update the name of the given variable and refresh all references to it.
   * The new name must not conflict with any existing variable names.
   *
   * @param variable Variable to rename.
   * @param newName New variable name.
   * @param blocks The list of all blocks in the workspace.
   */
  private renameVariableAndUses_(
    variable: IVariableModel<IVariableState>,
    newName: string,
    blocks: Block[],
  ) {
    eventUtils.fire(
      new (eventUtils.get(eventUtils.VAR_RENAME))(variable, newName),
    );
    variable.setName(newName);
    for (let i = 0; i < blocks.length; i++) {
      blocks[i].updateVarName(variable);
    }
  }

  /**
   * Update the name of the given variable to the same name as an existing
   * variable.  The two variables are coalesced into a single variable with the
   * ID of the existing variable that was already using newName. Refresh all
   * references to the variable.
   *
   * @param variable Variable to rename.
   * @param newName New variable name.
   * @param conflictVar The variable that was already using newName.
   * @param blocks The list of all blocks in the workspace.
   */
  private renameVariableWithConflict_(
    variable: IVariableModel<IVariableState>,
    newName: string,
    conflictVar: IVariableModel<IVariableState>,
    blocks: Block[],
  ) {
    const type = variable.getType();
    const oldCase = conflictVar.getName();

    if (newName !== oldCase) {
      // Simple rename to change the case and update references.
      this.renameVariableAndUses_(conflictVar, newName, blocks);
    }

    // These blocks now refer to a different variable.
    // These will fire change events.
    for (let i = 0; i < blocks.length; i++) {
      blocks[i].renameVarById(variable.getId(), conflictVar.getId());
    }
    // Finally delete the original variable, which is now unreferenced.
    eventUtils.fire(new (eventUtils.get(eventUtils.VAR_DELETE))(variable));
    // And remove it from the map.
    this.variableMap.get(type)?.delete(variable.getId());
  }

  /* End functions for renaming variables. */
  /**
   * Create a variable with a given name, optional type, and optional ID.
   *
   * @param name The name of the variable. This must be unique across variables
   *     and procedures.
   * @param 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 opt_id The unique ID of the variable. This will default to a UUID.
   * @returns The newly created variable.
   */
  createVariable(
    name: string,
    opt_type?: string,
    opt_id?: string,
  ): IVariableModel<IVariableState> {
    let variable = this.getVariable(name, opt_type);
    if (variable) {
      if (opt_id && variable.getId() !== opt_id) {
        throw Error(
          'Variable "' +
            name +
            '" is already in use and its id is "' +
            variable.getId() +
            '" which conflicts with the passed in ' +
            'id, "' +
            opt_id +
            '".',
        );
      }
      // The variable already exists and has the same ID.
      return variable;
    }
    if (opt_id && this.getVariableById(opt_id)) {
      throw Error('Variable id, "' + opt_id + '", is already in use.');
    }
    const id = opt_id || idGenerator.genUid();
    const type = opt_type || '';
    const VariableModel = registry.getObject(
      registry.Type.VARIABLE_MODEL,
      registry.DEFAULT,
      true,
    );
    if (!VariableModel) {
      throw new Error('No variable model is registered.');
    }
    variable = new VariableModel(this.workspace, name, type, id);

    const variables =
      this.variableMap.get(type) ??
      new Map<string, IVariableModel<IVariableState>>();
    variables.set(variable.getId(), variable);
    if (!this.variableMap.has(type)) {
      this.variableMap.set(type, variables);
    }
    eventUtils.fire(new (eventUtils.get(eventUtils.VAR_CREATE))(variable));

    return variable;
  }

  /**
   * Adds the given variable to this variable map.
   *
   * @param variable The variable to add.
   */
  addVariable(variable: IVariableModel<IVariableState>) {
    const type = variable.getType();
    if (!this.variableMap.has(type)) {
      this.variableMap.set(
        type,
        new Map<string, IVariableModel<IVariableState>>(),
      );
    }
    this.variableMap.get(type)?.set(variable.getId(), variable);
  }

  /* Begin functions for variable deletion. */
  /**
   * Delete a variable.
   *
   * @param variable Variable to delete.
   */
  deleteVariable(variable: IVariableModel<IVariableState>) {
    const variables = this.variableMap.get(variable.getType());
    if (!variables || !variables.has(variable.getId())) return;
    variables.delete(variable.getId());
    eventUtils.fire(new (eventUtils.get(eventUtils.VAR_DELETE))(variable));
    if (variables.size === 0) {
      this.variableMap.delete(variable.getType());
    }
  }

  /**
   * Delete a variables by the passed in ID and all of its uses from this
   * workspace. May prompt the user for confirmation.
   *
   * @param id ID of variable to delete.
   */
  deleteVariableById(id: string) {
    const variable = this.getVariableById(id);
    if (variable) {
      // Check whether this variable is a function parameter before deleting.
      const variableName = variable.getName();
      const uses = this.getVariableUsesById(id);
      for (let i = 0, block; (block = uses[i]); i++) {
        if (
          block.type === 'procedures_defnoreturn' ||
          block.type === 'procedures_defreturn'
        ) {
          const procedureName = String(block.getFieldValue('NAME'));
          const deleteText = Msg['CANNOT_DELETE_VARIABLE_PROCEDURE']
            .replace('%1', variableName)
            .replace('%2', procedureName);
          dialog.alert(deleteText);
          return;
        }
      }

      if (uses.length > 1) {
        // Confirm before deleting multiple blocks.
        const confirmText = Msg['DELETE_VARIABLE_CONFIRMATION']
          .replace('%1', String(uses.length))
          .replace('%2', variableName);
        dialog.confirm(confirmText, (ok) => {
          if (ok && variable) {
            this.deleteVariableInternal(variable, uses);
          }
        });
      } else {
        // No confirmation necessary for a single block.
        this.deleteVariableInternal(variable, uses);
      }
    } else {
      console.warn("Can't delete non-existent variable: " + id);
    }
  }

  /**
   * Deletes a variable and all of its uses from this workspace without asking
   * the user for confirmation.
   *
   * @param variable Variable to delete.
   * @param uses An array of uses of the variable.
   * @internal
   */
  deleteVariableInternal(
    variable: IVariableModel<IVariableState>,
    uses: Block[],
  ) {
    const existingGroup = eventUtils.getGroup();
    if (!existingGroup) {
      eventUtils.setGroup(true);
    }
    try {
      for (let i = 0; i < uses.length; i++) {
        uses[i].dispose(true);
      }
      this.deleteVariable(variable);
    } finally {
      eventUtils.setGroup(existingGroup);
    }
  }
  /* End functions for variable deletion. */
  /**
   * Find the variable by the given name and type and return it.  Return null if
   *     it is not found.
   *
   * @param name The name to check for.
   * @param opt_type The type of the variable.  If not provided it defaults to
   *     the empty string, which is a specific type.
   * @returns The variable with the given name, or null if it was not found.
   */
  getVariable(
    name: string,
    opt_type?: string,
  ): IVariableModel<IVariableState> | null {
    const type = opt_type || '';
    const variables = this.variableMap.get(type);
    if (!variables) return null;

    return (
      [...variables.values()].find((variable) =>
        Names.equals(variable.getName(), name),
      ) ?? null
    );
  }

  /**
   * Find the variable by the given ID and return it.  Return null if not found.
   *
   * @param id The ID to check for.
   * @returns The variable with the given ID.
   */
  getVariableById(id: string): IVariableModel<IVariableState> | null {
    for (const variables of this.variableMap.values()) {
      if (variables.has(id)) {
        return variables.get(id) ?? null;
      }
    }
    return null;
  }

  /**
   * Get a list containing all of the variables of a specified type. If type is
   *     null, return list of variables with empty string type.
   *
   * @param type Type of the variables to find.
   * @returns The sought after variables of the passed in type. An empty array
   *     if none are found.
   */
  getVariablesOfType(type: string | null): IVariableModel<IVariableState>[] {
    type = type || '';
    const variables = this.variableMap.get(type);
    if (!variables) return [];

    return [...variables.values()];
  }

  /**
   * Returns a list of unique types of variables in this variable map.
   *
   * @returns A list of unique types of variables in this variable map.
   */
  getTypes(): string[] {
    return [...this.variableMap.keys()];
  }

  /**
   * Return all variable and potential variable types.  This list always
   * contains the empty string.
   *
   * @param ws The workspace used to look for potential variables. This can be
   *     different than the workspace stored on this object if the passed in ws
   *     is a flyout workspace.
   * @returns List of variable types.
   * @internal
   */
  getVariableTypes(ws: Workspace | null): string[] {
    const variableTypes = new Set<string>(this.variableMap.keys());
    if (ws && ws.getPotentialVariableMap()) {
      for (const key of ws.getPotentialVariableMap()!.variableMap.keys()) {
        variableTypes.add(key);
      }
    }
    if (!variableTypes.has('')) {
      variableTypes.add('');
    }
    return Array.from(variableTypes.values());
  }

  /**
   * Return all variables of all types.
   *
   * @returns List of variable models.
   */
  getAllVariables(): IVariableModel<IVariableState>[] {
    let allVariables: IVariableModel<IVariableState>[] = [];
    for (const variables of this.variableMap.values()) {
      allVariables = allVariables.concat(...variables.values());
    }
    return allVariables;
  }

  /**
   * Returns all of the variable names of all types.
   *
   * @returns All of the variable names of all types.
   */
  getAllVariableNames(): string[] {
    const names: string[] = [];
    for (const variables of this.variableMap.values()) {
      for (const variable of variables.values()) {
        names.push(variable.getName());
      }
    }
    return names;
  }

  /**
   * Find all the uses of a named variable.
   *
   * @param id ID of the variable to find.
   * @returns Array of block usages.
   */
  getVariableUsesById(id: string): Block[] {
    const uses = [];
    const blocks = this.workspace.getAllBlocks(false);
    // Iterate through every block and check the name.
    for (let i = 0; i < blocks.length; i++) {
      const blockVariables = blocks[i].getVarModels();
      if (blockVariables) {
        for (let j = 0; j < blockVariables.length; j++) {
          if (blockVariables[j].getId() === id) {
            uses.push(blocks[i]);
          }
        }
      }
    }
    return uses;
  }
}

registry.register(registry.Type.VARIABLE_MAP, registry.DEFAULT, VariableMap);