import { Injectable, Logger } from '@nestjs/common';
import { ConfigService } from '@nestjs/config';
import { Cron } from '@nestjs/schedule';
import { ImapFlow } from 'imapflow';

@Injectable()
export class ImapFolderService {
  private readonly logger = new Logger(ImapFolderService.name);

  constructor(private readonly configService: ConfigService) {}

  private createClient(): ImapFlow {
    return new ImapFlow({
      host: this.configService.get<string>('IMAP_HOST', ''),
      port: this.configService.get<number>('IMAP_PORT', 993),
      secure: this.configService.get<string>('IMAP_USE_SSL', 'true') === 'true',
      auth: {
        user: this.configService.get<string>('IMAP_USERNAME', ''),
        pass: this.configService.get<string>('IMAP_PASSWORD', ''),
      },
      logger: false,
    });
  }

  @Cron('0 3 * * *', { timeZone: 'Europe/Berlin' })
  async cleanupImportedEmails(): Promise<void> {
    if (!this.configService.get<string>('IMAP_HOST')) return;
    const importedFolder = this.configService.get<string>(
      'IMAP_IMPORTED_FOLDER',
      'importiert',
    );
    const trashFolder = this.configService.get<string>(
      'IMAP_TRASH_FOLDER',
      'Trash',
    );
    const client = this.createClient();
    try {
      await client.connect();

      // E-Mails älter als 90 Tage in Papierkorb verschieben
      try {
        await client.mailboxOpen(importedFolder);
        const cutoff = new Date();
        cutoff.setDate(cutoff.getDate() - 90);
        const oldUids = await client.search({ before: cutoff }, { uid: true });
        if (Array.isArray(oldUids) && oldUids.length > 0) {
          await client.messageMove(oldUids, trashFolder, { uid: true });
          this.logger.log(
            `${oldUids.length} alte E-Mail(s) aus "${importedFolder}" in "${trashFolder}" verschoben.`,
          );
        }
      } catch (err: any) {
        this.logger.warn(
          `Bereinigung "${importedFolder}" nicht möglich: ${err.message}`,
        );
      }

      // Papierkorb leeren
      try {
        await client.mailboxOpen(trashFolder);
        const trashUids = await client.search({ all: true }, { uid: true });
        if (Array.isArray(trashUids) && trashUids.length > 0) {
          await client.messageDelete(trashUids, { uid: true });
          this.logger.log(
            `${trashUids.length} E-Mail(s) aus "${trashFolder}" gelöscht.`,
          );
        }
      } catch (err: any) {
        this.logger.warn(
          `Papierkorb "${trashFolder}" konnte nicht geleert werden: ${err.message}`,
        );
      }
    } catch (err: any) {
      this.logger.error(`IMAP-Cleanup fehlgeschlagen: ${err.message}`);
    } finally {
      await client.logout().catch(() => {});
    }
  }

  async moveProcessedInboxToImportiert(messageIds: string[]): Promise<number> {
    if (!this.configService.get<string>('IMAP_HOST') || messageIds.length === 0)
      return 0;

    const importedFolder = this.configService.get<string>(
      'IMAP_IMPORTED_FOLDER',
      'importiert',
    );
    const client = this.createClient();
    let movedCount = 0;

    try {
      await client.connect();

      const mailboxes = await client.list();
      if (!mailboxes.some((m) => m.path === importedFolder)) {
        await client.mailboxCreate(importedFolder);
        this.logger.log(`IMAP-Ordner "${importedFolder}" erstellt.`);
      }

      const status = await client.mailboxOpen('INBOX');
      if (status.exists === 0) return 0;

      const normalize = (id: string) => id.replace(/^<|>$/g, '').toLowerCase();
      const idSet = new Set(messageIds.map(normalize));
      const uidsToMove: number[] = [];

      for await (const msg of client.fetch('1:*', {
        uid: true,
        envelope: true,
      })) {
        const msgId = msg.envelope?.messageId;
        if (msgId && idSet.has(normalize(msgId))) {
          uidsToMove.push(msg.uid);
        }
      }

      if (uidsToMove.length > 0) {
        await client.messageMove(uidsToMove, importedFolder, { uid: true });
        movedCount = uidsToMove.length;
        this.logger.log(
          `${movedCount} E-Mail(s) aus INBOX → "${importedFolder}" verschoben.`,
        );
      }
    } catch (err: any) {
      this.logger.error(
        `moveProcessedInboxToImportiert fehlgeschlagen: ${err.message}`,
      );
    } finally {
      await client.logout().catch(() => {});
    }

    return movedCount;
  }

  async moveToImportiert(messageId: string): Promise<void> {
    if (!this.configService.get<string>('IMAP_HOST')) return;

    const importedFolder = this.configService.get<string>(
      'IMAP_IMPORTED_FOLDER',
      'importiert',
    );
    const client = this.createClient();
    try {
      await client.connect();

      const mailboxes = await client.list();
      if (!mailboxes.some((m) => m.path === importedFolder)) {
        await client.mailboxCreate(importedFolder);
        this.logger.log(`IMAP-Ordner "${importedFolder}" erstellt.`);
      }

      await client.mailboxOpen('INBOX');
      const uids = await client.search(
        { header: { 'message-id': messageId } },
        { uid: true },
      );
      if (Array.isArray(uids) && uids.length > 0) {
        await client.messageMove(uids, importedFolder, { uid: true });
        this.logger.log(
          `E-Mail ${messageId} → "${importedFolder}" verschoben.`,
        );
      } else {
        this.logger.warn(
          `E-Mail ${messageId} nicht in INBOX gefunden (bereits verschoben?).`,
        );
      }
    } catch (err: any) {
      this.logger.error(`IMAP moveToImportiert fehlgeschlagen: ${err.message}`);
    } finally {
      await client.logout().catch(() => {});
    }
  }
}