// Copyright 2022 - 2023 Gnuxie <Gnuxie@protonmail.com>
// Copyright 2019 - 2021 The Matrix.org Foundation C.I.C.
//
// SPDX-License-Identifier: Apache-2.0
//
// SPDX-FileAttributionText: <text>
// This modified file incorporates work from mjolnir
// https://github.com/matrix-org/mjolnir
// </text>

import {
  StandardClientsInRoomMap,
  DefaultEventDecoder,
  ClientsInRoomMap,
  Task,
  Logger,
  ActionException,
  ActionExceptionKind,
  ConfigRecoverableError,
} from "@the-draupnir-project/matrix-protection-suite";
import {
  BotSDKMatrixAccountData,
  ClientCapabilityFactory,
  MatrixSendClient,
  RoomStateManagerFactory,
  SafeMatrixEmitter,
  joinedRoomsSafe,
} from "@the-draupnir-project/matrix-protection-suite-for-matrix-bot-sdk";
import { IConfig } from "./config";
import { Draupnir } from "./Draupnir";
import { DraupnirFactory } from "./draupnirfactory/DraupnirFactory";
import { WebAPIs } from "./webapis/WebAPIs";
import {
  isStringUserID,
  StringUserID,
  MatrixRoomID,
} from "@the-draupnir-project/matrix-basic-types";
import { Err, Ok, Result, isError } from "@gnuxie/typescript-result";
import {
  DraupnirRestartError,
  SafeModeToggle,
  SafeModeToggleOptions,
} from "./safemode/SafeModeToggle";
import { SafeModeDraupnir } from "./safemode/DraupnirSafeMode";
import { ResultError } from "@gnuxie/typescript-result";
import { SafeModeCause, SafeModeReason } from "./safemode/SafeModeCause";
import { SafeModeBootOption } from "./safemode/BootOption";
import { TopLevelStores } from "./backingstore/DraupnirStores";
import { patchMatrixClient } from "./utils";
import {
  loadZeroTouchDeployRoomFromConfig,
  ZERO_TOUCH_DEPLOY_ROOM_ACCOUNT_DATA_TYPE,
  ZeroTouchDeployRoomAccountDataSchema,
} from "./managedRoomAccountData";

const log = new Logger("DraupnirBotMode");

export function constructWebAPIs(draupnir: Draupnir): WebAPIs {
  return new WebAPIs(
    draupnir.reportManager,
    draupnir.config,
    draupnir.synapseHTTPAntispam
  );
}

/**
 * The bot mode toggle allows the entrypoint, either src/index.ts or
 * manual test scripts, to setup and control Draupnir.
 * This includes the webAPIS that accompany Draupnir in bot mode.
 *
 * The appservice also implements `SafeModeToggle` but has different requirements.
 * This interface is exlusively used by the entrypoints to draupnir's bot mode.
 */
interface BotModeTogle extends SafeModeToggle, AsyncDisposable {
  encryptionInitialized(): Promise<void>;
  startFromScratch(
    options?: SafeModeToggleOptions
  ): Promise<Result<Draupnir | SafeModeDraupnir>>;
  maybeRecoverWithSafeMode(
    error: ResultError,
    options?: SafeModeToggleOptions
  ): Promise<Result<SafeModeDraupnir>>;
}

export class DraupnirBotModeToggle implements BotModeTogle {
  private draupnir: Draupnir | null = null;
  private safeModeDraupnir: SafeModeDraupnir | null = null;
  private webAPIs: WebAPIs | null = null;

  private constructor(
    private readonly clientUserID: StringUserID,
    private readonly managementRoom: MatrixRoomID,
    private readonly clientsInRoomMap: ClientsInRoomMap,
    private readonly roomStateManagerFactory: RoomStateManagerFactory,
    private readonly draupnirFactory: DraupnirFactory,
    private readonly matrixEmitter: SafeMatrixEmitter,
    private readonly config: IConfig
  ) {
    this.matrixEmitter.on("room.invite", (roomID, event) => {
      this.clientsInRoomMap.handleTimelineEvent(roomID, event);
    });
    this.matrixEmitter.on("room.event", (roomID, event) => {
      this.roomStateManagerFactory.handleTimelineEvent(roomID, event);
      this.clientsInRoomMap.handleTimelineEvent(roomID, event);
    });
    this.matrixEmitter.on("room.leave", (roomID, event) => {
      this.roomStateManagerFactory.handleTimelineEvent(roomID, event);
      this.clientsInRoomMap.handleTimelineEvent(roomID, event);
    });
  }
  public static async create(
    client: MatrixSendClient,
    matrixEmitter: SafeMatrixEmitter,
    config: IConfig,
    stores: TopLevelStores
  ): Promise<DraupnirBotModeToggle> {
    patchMatrixClient();
    const clientUserID = await client.getUserId();
    if (!isStringUserID(clientUserID)) {
      throw new TypeError(`${clientUserID} is not a valid mxid`);
    }
    const clientsInRoomMap = new StandardClientsInRoomMap();
    // needed to have accurate join infomration.
    (
      await clientsInRoomMap.makeClientRooms(clientUserID, async () =>
        joinedRoomsSafe(client)
      )
    ).expect("Unable to create ClientRooms");
    const clientCapabilityFactory = new ClientCapabilityFactory(
      clientsInRoomMap,
      DefaultEventDecoder
    );
    const clientPlatform = clientCapabilityFactory.makeClientPlatform(
      clientUserID,
      client
    );
    const managementRoom = (
      await loadZeroTouchDeployRoomFromConfig(
        config.managementRoom,
        config.initialManager,
        new BotSDKMatrixAccountData(
          ZERO_TOUCH_DEPLOY_ROOM_ACCOUNT_DATA_TYPE,
          ZeroTouchDeployRoomAccountDataSchema,
          client
        ),
        clientPlatform,
        clientUserID,
        {
          // Draupnir doesn't allow permalinks for the config.managementRoom,
          allowPermalinkForRoomConfig: false,
          configuredRoomPropertyName: "config.managementRoom",
          configuredInitialManagerPropertyName: "config.initialManager",
        }
      )
    ).expect("Failed to load or create the Draupnir management room");
    const clientProvider = async (userID: StringUserID) => {
      if (userID !== clientUserID) {
        throw new TypeError(`Bot mode shouldn't be requesting any other mxids`);
      }
      return client;
    };
    const roomStateManagerFactory = new RoomStateManagerFactory(
      clientsInRoomMap,
      clientProvider,
      DefaultEventDecoder,
      stores.roomStateBackingStore,
      stores.hashStore
    );
    const draupnirFactory = new DraupnirFactory(
      clientsInRoomMap,
      clientCapabilityFactory,
      clientProvider,
      roomStateManagerFactory,
      stores
    );
    return new DraupnirBotModeToggle(
      clientUserID,
      managementRoom,
      clientsInRoomMap,
      roomStateManagerFactory,
      draupnirFactory,
      matrixEmitter,
      config
    );
  }
  public async switchToDraupnir(
    options?: SafeModeToggleOptions
  ): Promise<Result<Draupnir, DraupnirRestartError | ResultError>> {
    if (this.draupnir !== null) {
      return ResultError.Result(
        `There is a draupnir for ${this.clientUserID} already running`
      );
    }
    this.stopSafeModeDraupnir();
    const draupnirResult = await this.draupnirFactory.makeDraupnir(
      this.clientUserID,
      this.managementRoom,
      this.config,
      this
    );
    if (isError(draupnirResult)) {
      const safeModeResult = await this.maybeRecoverWithSafeMode(
        draupnirResult.error,
        options
      );
      if (isError(safeModeResult)) {
        return safeModeResult;
      } else {
        return DraupnirRestartError.Result(
          "Draupnir failed to start, switching to safe mode.",
          { safeModeDraupnir: safeModeResult.ok }
        );
      }
    }
    this.draupnir = draupnirResult.ok;
    this.draupnir.start();
    if (options?.sendStatusOnStart) {
      void Task(this.draupnir.startupComplete());
      try {
        this.webAPIs = constructWebAPIs(this.draupnir);
        await this.webAPIs.start();
      } catch (e) {
        if (e instanceof Error) {
          await this.stopDraupnir();
          log.error("Failed to start webAPIs", e);
          return ActionException.Result("Failed to start webAPIs", {
            exceptionKind: ActionExceptionKind.Unknown,
            exception: e,
          });
        } else {
          throw new TypeError("Someone is throwing garbage.");
        }
      }
    }
    return draupnirResult;
  }
  public async switchToSafeMode(
    cause: SafeModeCause,
    options?: SafeModeToggleOptions
  ): Promise<Result<SafeModeDraupnir>> {
    if (this.safeModeDraupnir !== null) {
      return ResultError.Result(
        `There is a safe mode draupnir for ${this.clientUserID} already running`
      );
    }
    const safeModeResult = await this.draupnirFactory.makeSafeModeDraupnir(
      this.clientUserID,
      this.managementRoom,
      this.config,
      cause,
      this
    );
    if (isError(safeModeResult)) {
      return safeModeResult;
    }
    await this.stopDraupnir();
    this.safeModeDraupnir = safeModeResult.ok;
    this.safeModeDraupnir.start();
    if (options?.sendStatusOnStart) {
      this.safeModeDraupnir.startupComplete();
    }
    return safeModeResult;
  }

  public async startFromScratch(
    options?: SafeModeToggleOptions
  ): Promise<Result<Draupnir | SafeModeDraupnir>> {
    const draupnirResult = await this.switchToDraupnir(options ?? {});
    if (isError(draupnirResult)) {
      if (draupnirResult.error instanceof DraupnirRestartError) {
        return Ok(draupnirResult.error.safeModeDraupnir);
      } else {
        return draupnirResult;
      }
    }
    return draupnirResult;
  }

  public async maybeRecoverWithSafeMode(
    error: ResultError,
    options?: SafeModeToggleOptions
  ): Promise<Result<SafeModeDraupnir>> {
    switch (this.config.safeMode?.bootOption) {
      case SafeModeBootOption.Never:
        return Err(error);
      case SafeModeBootOption.RecoveryOnly:
        if (!(error instanceof ConfigRecoverableError)) {
          return Err(error);
        }
      // fallthrough
      default:
        log.error(
          "Failed to start draupnir, switching to safe mode as configured",
          error
        );
        return await this.switchToSafeMode(
          {
            reason: SafeModeReason.InitializationError,
            error: error,
          },
          options ?? {}
        );
    }
  }

  public async encryptionInitialized(): Promise<void> {
    if (this.draupnir !== null) {
      this.webAPIs = constructWebAPIs(this.draupnir);
      await this.webAPIs.start();
      await this.draupnir.startupComplete();
    } else if (this.safeModeDraupnir !== null) {
      this.safeModeDraupnir.startupComplete();
    }
  }

  private async stopDraupnir(): Promise<void> {
    this.draupnir?.stop();
    this.draupnir = null;
    await this.webAPIs?.stop();
    this.webAPIs = null;
  }

  private stopSafeModeDraupnir(): void {
    this.safeModeDraupnir?.stop();
    this.safeModeDraupnir = null;
  }

  public async [Symbol.asyncDispose](): Promise<void> {
    await this.stopDraupnir();
    this.stopSafeModeDraupnir();
  }
}