import { Injectable, OnApplicationBootstrap } from "@nestjs/common";
import { InjectRepository } from "@nestjs/typeorm";
import { LessThan, Repository } from "typeorm";
import { SessionEntity } from "./session.entity";
import { TraceLogger } from "../common/trace-logger";
import type { Cookie } from "playwright";
import {
  PaginationQueryDto,
  PaginatedResult,
} from "../common/dto/pagination.dto";

export type SessionOrderBy =
  | "id"
  | "sessionName"
  | "status"
  | "lastUsedAt"
  | "createdAt"
  | "updatedAt";

@Injectable()
export class SessionService implements OnApplicationBootstrap {
  private readonly logger = new TraceLogger(SessionService.name);

  constructor(
    @InjectRepository(SessionEntity)
    private readonly repo: Repository<SessionEntity>,
  ) {}

  async onApplicationBootstrap(): Promise<void> {
    const result = await this.repo.update(
      { status: "open" },
      { status: "closed" },
    );
    if ((result.affected ?? 0) > 0) {
      this.logger.log(
        `${result.affected} open session(s) closed on startup (no Playwright context available)`,
      );
    }
  }

  async upsert(
    sessionName: string,
    token: string,
    cookies: Cookie[],
    localStorage: Record<string, string>,
  ): Promise<SessionEntity> {
    const now = new Date();
    const existing = await this.repo.findOneBy({ sessionName });

    if (existing) {
      existing.token = token;
      existing.cookies = JSON.stringify(cookies);
      existing.localStorage = JSON.stringify(localStorage);
      existing.status = "open";
      existing.lastUsedAt = now;
      return this.repo.save(existing);
    }

    return this.repo.save(
      this.repo.create({
        sessionName,
        token,
        cookies: JSON.stringify(cookies),
        localStorage: JSON.stringify(localStorage),
        status: "open",
        lastUsedAt: now,
      }),
    );
  }

  findBySessionName(sessionName: string): Promise<SessionEntity | null> {
    return this.repo.findOneBy({ sessionName });
  }

  findById(id: number): Promise<SessionEntity | null> {
    return this.repo.findOneBy({ id });
  }

  async markOpen(sessionName: string): Promise<void> {
    await this.repo.update({ sessionName }, { status: "open" });
  }

  async markClosed(sessionName: string): Promise<void> {
    await this.repo.update({ sessionName }, { status: "closed" });
  }

  async touchLastUsed(sessionName: string): Promise<void> {
    await this.repo.update({ sessionName }, { lastUsedAt: new Date() });
  }

  findExpiredOpen(cutoff: Date): Promise<SessionEntity[]> {
    return this.repo
      .createQueryBuilder("s")
      .where("s.status = :status", { status: "open" })
      .andWhere("(s.lastUsedAt IS NULL OR s.lastUsedAt < :cutoff)", { cutoff })
      .getMany();
  }

  findOldClosed(cutoff: Date): Promise<SessionEntity[]> {
    return this.repo.find({
      where: { status: "closed", updatedAt: LessThan(cutoff) },
    });
  }

  async findAll(
    query: PaginationQueryDto<SessionOrderBy> = {},
  ): Promise<
    PaginatedResult<
      Pick<
        SessionEntity,
        | "id"
        | "sessionName"
        | "status"
        | "lastUsedAt"
        | "createdAt"
        | "updatedAt"
      >
    >
  > {
    const page = query.page ?? 1;
    const limit = query.limit ?? 20;
    const orderBy = query.orderBy ?? "id";
    const orderDir = query.orderDir ?? "ASC";
    const [data, total] = await this.repo.findAndCount({
      select: [
        "id",
        "sessionName",
        "status",
        "lastUsedAt",
        "createdAt",
        "updatedAt",
      ],
      order: { [orderBy]: orderDir },
      skip: (page - 1) * limit,
      take: limit,
    });
    return { data, total, page, limit };
  }

  async remove(id: number): Promise<void> {
    await this.repo.delete(id);
  }
}