/*---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *  Licensed under the MIT License. See License.txt in the project root for license information.
 *--------------------------------------------------------------------------------------------*/

import type { Event, IStringDictionary } from '@difizen/mana-common';
import { objects, types, URI } from '@difizen/mana-common';
import { Syringe } from '@difizen/mana-syringe';

import { Registry } from '../platform';

// import type { IWorkspaceFolder } from 'vs/platform/workspace/common/workspace';
// import { createDecorator } from 'vs/platform/instantiation/common/instantiation';
import type { IConfigurationRegistry } from './configurationRegistry';
import {
  Extensions,
  overrideIdentifierFromKey,
  OVERRIDE_PROPERTY_PATTERN,
} from './configurationRegistry';

// export const IConfigurationService = createDecorator<IConfigurationService>('configurationService');
export const IConfigurationService = Syringe.defineToken('IConfigurationService');

export function isConfigurationOverrides(thing: any): thing is IConfigurationOverrides {
  return (
    thing &&
    typeof thing === 'object' &&
    (!thing.overrideIdentifier || typeof thing.overrideIdentifier === 'string') &&
    (!thing.resource || thing.resource instanceof URI)
  );
}

export interface IConfigurationOverrides {
  overrideIdentifier?: string | null;
  resource?: URI | null;
}

export enum ConfigurationTarget {
  USER = 1,
  USER_LOCAL,
  USER_REMOTE,
  WORKSPACE,
  WORKSPACE_FOLDER,
  DEFAULT,
  MEMORY,
}
export function ConfigurationTargetToString(configurationTarget: ConfigurationTarget) {
  switch (configurationTarget) {
    case ConfigurationTarget.USER:
      return 'USER';
    case ConfigurationTarget.USER_LOCAL:
      return 'USER_LOCAL';
    case ConfigurationTarget.USER_REMOTE:
      return 'USER_REMOTE';
    case ConfigurationTarget.WORKSPACE:
      return 'WORKSPACE';
    case ConfigurationTarget.WORKSPACE_FOLDER:
      return 'WORKSPACE_FOLDER';
    case ConfigurationTarget.DEFAULT:
      return 'DEFAULT';
    case ConfigurationTarget.MEMORY:
      return 'MEMORY';
  }
}

export interface IConfigurationChange {
  keys: string[];
  overrides: [string, string[]][];
}

export interface IConfigurationChangeEvent {
  readonly source: ConfigurationTarget;
  readonly affectedKeys: string[];
  readonly change: IConfigurationChange;

  affectsConfiguration: (
    configuration: string,
    overrides?: IConfigurationOverrides,
  ) => boolean;

  // Following data is used for telemetry
  readonly sourceConfig: any;
}

export interface IConfigurationValue<T> {
  readonly defaultValue?: T | undefined;
  readonly userValue?: T | undefined;
  readonly userLocalValue?: T | undefined;
  readonly userRemoteValue?: T | undefined;
  readonly workspaceValue?: T | undefined;
  readonly workspaceFolderValue?: T | undefined;
  readonly memoryValue?: T | undefined;
  readonly value?: T | undefined;

  readonly default?: { value?: T | undefined; override?: T | undefined } | undefined;
  readonly user?: { value?: T; override?: T } | undefined;
  readonly userLocal?: { value?: T; override?: T } | undefined;
  readonly userRemote?: { value?: T; override?: T } | undefined;
  readonly workspace?: { value?: T; override?: T } | undefined;
  readonly workspaceFolder?: { value?: T; override?: T } | undefined;
  readonly memory?: { value?: T; override?: T } | undefined;

  readonly overrideIdentifiers?: string[];
}

export interface IConfigurationService {
  readonly _serviceBrand: undefined;

  onDidChangeConfiguration: Event<IConfigurationChangeEvent>;

  getConfigurationData: () => IConfigurationData | null;

  /**
   * Fetches the value of the section for the given overrides.
   * Value can be of native type or an object keyed off the section name.
   *
   * @param section - Section of the configuraion. Can be `null` or `undefined`.
   * @param overrides - Overrides that has to be applied while fetching
   *
   */
  getValue: (<T>() => T) &
    (<T>(section: string) => T) &
    (<T>(overrides: IConfigurationOverrides) => T) &
    (<T>(section: string, overrides: IConfigurationOverrides) => T);

  updateValue: ((key: string, value: any) => Promise<void>) &
    ((key: string, value: any, overrides: IConfigurationOverrides) => Promise<void>) &
    ((key: string, value: any, target: ConfigurationTarget) => Promise<void>) &
    ((
      key: string,
      value: any,
      overrides: IConfigurationOverrides,
      target: ConfigurationTarget,
      donotNotifyError?: boolean,
    ) => Promise<void>);

  inspect: <T>(
    key: string,
    overrides?: IConfigurationOverrides,
  ) => IConfigurationValue<T>;

  reloadConfiguration: (
    target?: ConfigurationTarget /** | IWorkspaceFolder **/,
  ) => Promise<void>;

  keys: () => {
    default: string[];
    user: string[];
    workspace: string[];
    workspaceFolder: string[];
    memory?: string[];
  };
}

export interface IConfigurationModel {
  contents: any;
  keys: string[];
  overrides: IOverrides[];
}

export interface IOverrides {
  keys: string[];
  contents: any;
  identifiers: string[];
}

export interface IConfigurationData {
  defaults: IConfigurationModel;
  user: IConfigurationModel;
  workspace: IConfigurationModel;
}

export interface IConfigurationCompareResult {
  added: string[];
  removed: string[];
  updated: string[];
  overrides: [string, string[]][];
}

export function compare(
  from: IConfigurationModel | undefined,
  to: IConfigurationModel | undefined,
): IConfigurationCompareResult {
  const added = to
    ? from
      ? to.keys.filter((key) => from.keys.indexOf(key) === -1)
      : [...to.keys]
    : [];
  const removed = from
    ? to
      ? from.keys.filter((key) => to.keys.indexOf(key) === -1)
      : [...from.keys]
    : [];
  const updated: string[] = [];

  if (to && from) {
    for (const key of from.keys) {
      if (to.keys.indexOf(key) !== -1) {
        const value1 = getConfigurationValue(from.contents, key);
        const value2 = getConfigurationValue(to.contents, key);
        if (!objects.objectEquals(value1, value2)) {
          updated.push(key);
        }
      }
    }
  }

  const overrides: [string, string[]][] = [];
  const byOverrideIdentifier = (
    overrides: IOverrides[],
  ): IStringDictionary<IOverrides> => {
    const result: IStringDictionary<IOverrides> = {};
    for (const override of overrides) {
      for (const identifier of override.identifiers) {
        result[keyFromOverrideIdentifier(identifier)] = override;
      }
    }
    return result;
  };
  const toOverridesByIdentifier: IStringDictionary<IOverrides> = to
    ? byOverrideIdentifier(to.overrides)
    : {};
  const fromOverridesByIdentifier: IStringDictionary<IOverrides> = from
    ? byOverrideIdentifier(from.overrides)
    : {};

  if (Object.keys(toOverridesByIdentifier).length) {
    for (const key of added) {
      const override = toOverridesByIdentifier[key];
      if (override) {
        overrides.push([overrideIdentifierFromKey(key), override.keys]);
      }
    }
  }
  if (Object.keys(fromOverridesByIdentifier).length) {
    for (const key of removed) {
      const override = fromOverridesByIdentifier[key];
      if (override) {
        overrides.push([overrideIdentifierFromKey(key), override.keys]);
      }
    }
  }

  if (
    Object.keys(toOverridesByIdentifier).length &&
    Object.keys(fromOverridesByIdentifier).length
  ) {
    for (const key of updated) {
      const fromOverride = fromOverridesByIdentifier[key];
      const toOverride = toOverridesByIdentifier[key];
      if (fromOverride && toOverride) {
        const result = compare(
          { contents: fromOverride.contents, keys: fromOverride.keys, overrides: [] },
          { contents: toOverride.contents, keys: toOverride.keys, overrides: [] },
        );
        overrides.push([
          overrideIdentifierFromKey(key),
          [...result.added, ...result.removed, ...result.updated],
        ]);
      }
    }
  }

  return { added, removed, updated, overrides };
}

export function toOverrides(
  raw: any,
  conflictReporter: (message: string) => void,
): IOverrides[] {
  const overrides: IOverrides[] = [];
  for (const key of Object.keys(raw)) {
    if (OVERRIDE_PROPERTY_PATTERN.test(key)) {
      const overrideRaw: any = {};
      for (const keyInOverrideRaw in raw[key]) {
        overrideRaw[keyInOverrideRaw] = raw[key][keyInOverrideRaw];
      }
      overrides.push({
        identifiers: [overrideIdentifierFromKey(key).trim()],
        keys: Object.keys(overrideRaw),
        contents: toValuesTree(overrideRaw, conflictReporter),
      });
    }
  }
  return overrides;
}

export function toValuesTree(
  properties: Record<string, any>,
  conflictReporter: (message: string) => void,
): any {
  const root = Object.create(null);

  for (const key in properties) {
    addToValueTree(root, key, properties[key], conflictReporter);
  }

  return root;
}

export function addToValueTree(
  settingsTreeRoot: any,
  key: string,
  value: any,
  conflictReporter: (message: string) => void,
): void {
  const segments = key.split('.');
  const last = segments.pop()!;

  let curr = settingsTreeRoot;
  for (let i = 0; i < segments.length; i++) {
    const s = segments[i];
    let obj = curr[s];
    switch (typeof obj) {
      case 'undefined':
        obj = curr[s] = Object.create(null);
        break;
      case 'object':
        break;
      default:
        conflictReporter(
          `Ignoring ${key} as ${segments.slice(0, i + 1).join('.')} is ${JSON.stringify(
            obj,
          )}`,
        );
        return;
    }
    curr = obj;
  }

  if (typeof curr === 'object' && curr !== null) {
    try {
      curr[last] = value; // workaround https://github.com/microsoft/vscode/issues/13606
    } catch (e) {
      conflictReporter(
        `Ignoring ${key} as ${segments.join('.')} is ${JSON.stringify(curr)}`,
      );
    }
  } else {
    conflictReporter(
      `Ignoring ${key} as ${segments.join('.')} is ${JSON.stringify(curr)}`,
    );
  }
}

export function removeFromValueTree(valueTree: any, key: string): void {
  const segments = key.split('.');
  doRemoveFromValueTree(valueTree, segments);
}

function doRemoveFromValueTree(valueTree: any, segments: string[]): void {
  const first = segments.shift()!;
  if (segments.length === 0) {
    // Reached last segment
    delete valueTree[first];
    return;
  }

  if (Object.keys(valueTree).indexOf(first) !== -1) {
    const value = valueTree[first];
    if (typeof value === 'object' && !Array.isArray(value)) {
      doRemoveFromValueTree(value, segments);
      if (Object.keys(value).length === 0) {
        delete valueTree[first];
      }
    }
  }
}

/**
 * A helper function to get the configuration value with a specific settings path (e.g. config.some.setting)
 */
export function getConfigurationValue<T>(
  config: any,
  settingPath: string,
  defaultValue?: T,
): T {
  function accessSetting(config: any, path: string[]): any {
    let current = config;
    for (const component of path) {
      if (typeof current !== 'object' || current === null) {
        return undefined;
      }
      current = current[component];
    }
    return <T>current;
  }

  const path = settingPath.split('.');
  const result = accessSetting(config, path);

  return typeof result === 'undefined' ? defaultValue : result;
}

export function merge(base: any, add: any, overwrite: boolean): void {
  Object.keys(add).forEach((key) => {
    if (key !== '__proto__') {
      if (key in base) {
        if (types.isObject(base[key]) && types.isObject(add[key])) {
          merge(base[key], add[key], overwrite);
        } else if (overwrite) {
          base[key] = add[key];
        }
      } else {
        base[key] = add[key];
      }
    }
  });
}

export function getConfigurationKeys(): string[] {
  const properties = Registry.as<IConfigurationRegistry>(
    Extensions.Configuration,
  ).getConfigurationProperties();
  return Object.keys(properties);
}

export function getDefaultValues(): any {
  const valueTreeRoot: any = Object.create(null);
  const properties = Registry.as<IConfigurationRegistry>(
    Extensions.Configuration,
  ).getConfigurationProperties();

  for (const key in properties) {
    const value = properties[key].default;
    addToValueTree(valueTreeRoot, key, value, (message) =>
      console.error(`Conflict in default settings: ${message}`),
    );
  }

  return valueTreeRoot;
}

export function keyFromOverrideIdentifier(overrideIdentifier: string): string {
  return `[${overrideIdentifier}]`;
}

export function getMigratedSettingValue<T>(
  configurationService: IConfigurationService,
  currentSettingName: string,
  legacySettingName: string,
): T {
  const setting = configurationService.inspect<T>(currentSettingName);
  const legacySetting = configurationService.inspect<T>(legacySettingName);

  if (
    typeof setting.userValue !== 'undefined' ||
    typeof setting.workspaceValue !== 'undefined' ||
    typeof setting.workspaceFolderValue !== 'undefined'
  ) {
    return setting.value!;
  }
  if (
    typeof legacySetting.userValue !== 'undefined' ||
    typeof legacySetting.workspaceValue !== 'undefined' ||
    typeof legacySetting.workspaceFolderValue !== 'undefined'
  ) {
    return legacySetting.value!;
  }
  return setting.defaultValue!;
}