import db from "../db";
import { backupModel, databaseModel, serverModel } from "../db/models";
import type {
  CreateBackupSchema,
  GetAllBackupQuery,
  RestoreBackupSchema,
} from "../schemas/backup.schema";
import { and, count, desc, eq, inArray } from "drizzle-orm";
import DatabaseService from "./database.service";
import { HTTPException } from "hono/http-exception";
import ServerService from "./server.service";

export default class BackupService {
  private databaseService = new DatabaseService();

  /**
   * Get all backups
   */
  async getAll(query: GetAllBackupQuery = {}) {
    const { serverId, databaseId } = query;
    const page = query.page || 1;
    const limit = query.limit || 10;

    const where = and(
      serverId ? eq(backupModel.serverId, serverId) : undefined,
      databaseId ? eq(backupModel.databaseId, databaseId) : undefined
    );

    const [totalRows] = await db
      .select({ count: count() })
      .from(backupModel)
      .where(where)
      .limit(1);

    const backups = await db.query.backup.findMany({
      where,
      with: {
        database: { columns: { name: true } },
      },
      orderBy: desc(serverModel.createdAt),
      limit,
      offset: (page - 1) * limit,
    });

    return { count: totalRows.count, rows: backups };
  }

  async getOrFail(id: string) {
    const backup = await db.query.backup.findFirst({
      where: eq(backupModel.id, id),
    });
    if (!backup) {
      throw new HTTPException(404, { message: "Backup not found." });
    }
    return backup;
  }

  /**
   * Queue new backup
   */
  async create(data: CreateBackupSchema) {
    if (data.databaseId) {
      const database = await this.databaseService.getOrFail(data.databaseId);
      await this.checkPendingBackup(database.id);

      const [result] = await db
        .insert(backupModel)
        .values({
          type: "backup",
          serverId: database.serverId,
          databaseId: database.id,
        })
        .returning();

      return result;
    } else if (data.serverId) {
      const databases = await db.query.database.findMany({
        where: and(
          eq(databaseModel.serverId, data.serverId),
          eq(databaseModel.isActive, true)
        ),
      });
      if (!databases.length) {
        throw new HTTPException(400, {
          message: "No active databases found for this server.",
        });
      }

      const values = databases.map((d) => ({
        type: "backup",
        serverId: d.serverId,
        databaseId: d.id,
      }));

      const result = await db
        .insert(backupModel)
        .values(values as never)
        .returning();

      return result;
    }

    return null;
  }

  async restore(data: RestoreBackupSchema) {
    const backup = await this.getOrFail(data.backupId);
    await this.checkPendingBackup(backup.databaseId);

    if (!backup.key) {
      throw new HTTPException(400, {
        message: "Cannot restore backup without file key.",
      });
    }

    const [result] = await db
      .insert(backupModel)
      .values({
        type: "restore",
        serverId: backup.serverId,
        databaseId: backup.databaseId,
        key: backup.key,
        hash: backup.hash,
        size: backup.size,
      })
      .returning();

    return result;
  }

  async checkPendingBackup(databaseId: string) {
    const hasOngoingBackup = await db.query.backup.findFirst({
      where: and(
        eq(backupModel.databaseId, databaseId),
        inArray(backupModel.status, ["pending", "running"])
      ),
    });
    if (hasOngoingBackup) {
      throw new HTTPException(400, {
        message: "There is already an ongoing backup for this database",
      });
    }
  }
}