import { Injectable } from '@nestjs/common';
import { PrismaService } from '../prisma/prisma.service';

@Injectable()
export class RoomPackService {
  constructor(private prisma: PrismaService) {}

  /**
   * Create room pack (called when room is created)
   */
  async create(roomId: string, sourcePackId?: string) {
    const name = `Room Pack ${Date.now()}`;
    const description = sourcePackId
      ? 'Copied from source pack'
      : 'Custom room questions';

    let questions: any = [];
    let questionCount = 0;

    // If source pack provided, copy questions
    if (sourcePackId) {
      const sourcePack = await this.prisma.questionPack.findUnique({
        where: { id: sourcePackId },
        select: { questions: true, questionCount: true },
      });

      if (sourcePack && sourcePack.questions) {
        questions = sourcePack.questions;
        questionCount = sourcePack.questionCount;
      }
    }

    return this.prisma.roomPack.create({
      data: {
        roomId,
        name,
        description,
        sourcePackId,
        questions,
        questionCount,
      },
    });
  }

  /**
   * Get room pack by roomId
   */
  async findByRoomId(roomId: string) {
    return this.prisma.roomPack.findUnique({
      where: { roomId },
      include: { sourcePack: true },
    });
  }

  /**
   * Update room pack questions
   */
  async updateQuestions(roomId: string, questions: any[]) {
    const questionCount = Array.isArray(questions) ? questions.length : 0;

    return this.prisma.roomPack.update({
      where: { roomId },
      data: {
        questions,
        questionCount,
        updatedAt: new Date(),
      },
    });
  }

  /**
   * Add questions from another pack (import/copy)
   */
  async importQuestions(roomId: string, sourcePackId: string, questionIndices: number[]) {
    const roomPack = await this.findByRoomId(roomId);
    const sourcePack = await this.prisma.questionPack.findUnique({
      where: { id: sourcePackId },
      select: { questions: true },
    });

    if (!roomPack) {
      throw new Error('Room pack not found');
    }

    if (!sourcePack || !sourcePack.questions || !Array.isArray(sourcePack.questions)) {
      throw new Error('Source pack not found or invalid');
    }

    // Get existing questions
    const existingQuestions = Array.isArray(roomPack.questions)
      ? (roomPack.questions as any[])
      : [];

    // Import selected questions (create copies)
    const sourceQuestions = sourcePack.questions as any[];
    const questionsToImport = questionIndices
      .map(idx => sourceQuestions[idx])
      .filter(Boolean)
      .map(q => ({ ...q })); // Deep copy

    const updatedQuestions = [...existingQuestions, ...questionsToImport];

    return this.updateQuestions(roomId, updatedQuestions);
  }

  /**
   * Soft delete room pack
   */
  async softDelete(roomId: string) {
    return this.prisma.roomPack.update({
      where: { roomId },
      data: { deletedAt: new Date() },
    });
  }

  /**
   * Hard delete room pack (for cleanup)
   */
  async hardDelete(roomId: string) {
    return this.prisma.roomPack.delete({
      where: { roomId },
    });
  }
}