import { Injectable, OnDestroy } from "@angular/core";
import {
  catchError,
  combineLatest,
  concatMap,
  EMPTY,
  filter,
  from,
  map,
  of,
  Subject,
  switchMap,
  takeUntil,
  timeout,
  TimeoutError,
  timer,
  withLatestFrom,
} from "rxjs";

import { AuthService } from "@bitwarden/common/auth/abstractions/auth.service";
import { AuthenticationStatus } from "@bitwarden/common/auth/enums/authentication-status";
import { FeatureFlag } from "@bitwarden/common/enums/feature-flag.enum";
import { ConfigService } from "@bitwarden/common/platform/abstractions/config/config.service";
import { I18nService } from "@bitwarden/common/platform/abstractions/i18n.service";
import { LogService } from "@bitwarden/common/platform/abstractions/log.service";
import { CommandDefinition, MessageListener } from "@bitwarden/common/platform/messaging";
import { CipherService } from "@bitwarden/common/vault/abstractions/cipher.service";
import { CipherType } from "@bitwarden/common/vault/enums";
import { DialogService, ToastService } from "@bitwarden/components";

import { ApproveSshRequestComponent } from "../components/approve-ssh-request";

import { DesktopSettingsService } from "./desktop-settings.service";

@Injectable({
  providedIn: "root",
})
export class SshAgentService implements OnDestroy {
  SSH_REFRESH_INTERVAL = 1000;
  SSH_VAULT_UNLOCK_REQUEST_TIMEOUT = 1000 * 60;
  SSH_REQUEST_UNLOCK_POLLING_INTERVAL = 100;

  private destroy$ = new Subject<void>();

  constructor(
    private cipherService: CipherService,
    private logService: LogService,
    private dialogService: DialogService,
    private messageListener: MessageListener,
    private authService: AuthService,
    private toastService: ToastService,
    private i18nService: I18nService,
    private desktopSettingsService: DesktopSettingsService,
    private configService: ConfigService,
  ) {}

  async init() {
    const isSshAgentFeatureEnabled = await this.configService.getFeatureFlag(FeatureFlag.SSHAgent);
    if (isSshAgentFeatureEnabled) {
      await ipc.platform.sshAgent.init();

      this.messageListener
        .messages$(new CommandDefinition("sshagent.signrequest"))
        .pipe(
          withLatestFrom(this.authService.activeAccountStatus$),
          // This switchMap handles unlocking the vault if it is locked:
          //   - If the vault is locked, we will wait for it to be unlocked.
          //   - If the vault is not unlocked within the timeout, we will abort the flow.
          //   - If the vault is unlocked, we will continue with the flow.
          // switchMap is used here to prevent multiple requests from being processed at the same time,
          // and will cancel the previous request if a new one is received.
          switchMap(([message, status]) => {
            if (status !== AuthenticationStatus.Unlocked) {
              ipc.platform.focusWindow();
              this.toastService.showToast({
                variant: "info",
                title: null,
                message: this.i18nService.t("sshAgentUnlockRequired"),
              });
              return this.authService.activeAccountStatus$.pipe(
                filter((status) => status === AuthenticationStatus.Unlocked),
                timeout(this.SSH_VAULT_UNLOCK_REQUEST_TIMEOUT),
                catchError((error: unknown) => {
                  if (error instanceof TimeoutError) {
                    this.toastService.showToast({
                      variant: "error",
                      title: null,
                      message: this.i18nService.t("sshAgentUnlockTimeout"),
                    });
                    const requestId = message.requestId as number;
                    // Abort flow by sending a false response.
                    // Returning an empty observable this will prevent the rest of the flow from executing
                    return from(ipc.platform.sshAgent.signRequestResponse(requestId, false)).pipe(
                      map(() => EMPTY),
                    );
                  }

                  throw error;
                }),
                map(() => message),
              );
            }

            return of(message);
          }),
          // This switchMap handles fetching the ciphers from the vault.
          switchMap((message) =>
            from(this.cipherService.getAllDecrypted()).pipe(
              map((ciphers) => [message, ciphers] as const),
            ),
          ),
          // This concatMap handles showing the dialog to approve the request.
          concatMap(([message, decryptedCiphers]) => {
            const cipherId = message.cipherId as string;
            const requestId = message.requestId as number;

            if (decryptedCiphers === undefined) {
              return of(false).pipe(
                switchMap((result) =>
                  ipc.platform.sshAgent.signRequestResponse(requestId, Boolean(result)),
                ),
              );
            }

            const cipher = decryptedCiphers.find((cipher) => cipher.id == cipherId);

            ipc.platform.focusWindow();
            const dialogRef = ApproveSshRequestComponent.open(
              this.dialogService,
              cipher.name,
              this.i18nService.t("unknownApplication"),
            );

            return dialogRef.closed.pipe(
              switchMap((result) => {
                return ipc.platform.sshAgent.signRequestResponse(requestId, Boolean(result));
              }),
            );
          }),
          takeUntil(this.destroy$),
        )
        .subscribe();

      combineLatest([
        timer(0, this.SSH_REFRESH_INTERVAL),
        this.desktopSettingsService.sshAgentEnabled$,
      ])
        .pipe(
          concatMap(async ([, enabled]) => {
            if (!enabled) {
              await ipc.platform.sshAgent.setKeys([]);
              return;
            }

            const ciphers = await this.cipherService.getAllDecrypted();
            if (ciphers == null) {
              await ipc.platform.sshAgent.lock();
              return;
            }

            const sshCiphers = ciphers.filter(
              (cipher) => cipher.type === CipherType.SshKey && !cipher.isDeleted,
            );
            const keys = sshCiphers.map((cipher) => {
              return {
                name: cipher.name,
                privateKey: cipher.sshKey.privateKey,
                cipherId: cipher.id,
              };
            });
            await ipc.platform.sshAgent.setKeys(keys);
          }),
          takeUntil(this.destroy$),
        )
        .subscribe();
    }
  }

  ngOnDestroy() {
    this.destroy$.next();
    this.destroy$.complete();
  }
}