import {
  Injectable,
  NotFoundException,
  BadRequestException,
} from '@nestjs/common';
import { MongoPrismaService } from '@box/db/prisma/mongo-prisma.service';
import { ImageUploadService } from '../image-upload/image-upload.service';
import {
  VideoMediaListQueryDto,
  UpdateVideoMediaManageDto,
  UpdateVideoMediaStatusDto,
  BatchUpdateVideoMediaStatusDto,
} from './video-media.dto';

@Injectable()
export class VideoMediaService {
  constructor(
    private readonly prisma: MongoPrismaService,
    private readonly imageUploadService: ImageUploadService,
  ) {}

  async findAll(query: VideoMediaListQueryDto): Promise<any> {
    const page = query.page ?? 1;
    const pageSize = query.size ?? 20;
    const skip = (page - 1) * pageSize;
    const take = pageSize;

    const where: any = {};

    if (query.keyword) {
      where.OR = [
        { title: { contains: query.keyword, mode: 'insensitive' } },
        { filename: { contains: query.keyword, mode: 'insensitive' } },
      ];
    }

    if (query.categoryId) {
      where.categoryId = query.categoryId;
    }

    if (query.tagId) {
      where.tagIds = { has: query.tagId };
    }

    if (typeof query.listStatus === 'number') {
      where.listStatus = query.listStatus;
    }

    // filter by editedFrom and editedTo
    if (
      typeof query.editedFrom === 'number' ||
      typeof query.editedTo === 'number'
    ) {
      where.editedAt = {};
      if (typeof query.editedFrom === 'number') {
        where.editedAt.gte = BigInt(query.editedFrom);
      }
      if (typeof query.editedTo === 'number') {
        where.editedAt.lte = BigInt(query.editedTo);
      }
    }

    const [total, rows] = await Promise.all([
      this.prisma.videoMedia.count({ where }),
      this.prisma.videoMedia.findMany({
        where,
        skip,
        take,
        orderBy: { addedTime: 'desc' },
      }),
    ]);

    return {
      total,
      page,
      pageSize,
      items: rows.map((row) => ({
        id: row.id,
        title: row.title,
        filename: row.filename,
        videoTime: row.videoTime,
        size: row.size?.toString?.() ?? '0',
        coverImg: row.coverImg ?? '',
        categoryId: row.categoryId ?? null,
        tagIds: row.tagIds ?? [],
        listStatus: row.listStatus ?? 0,
        editedAt: Number(row.editedAt ?? 0),
        updatedAt: row.updatedAt ?? null,
        tags: row.tags ?? [],
        tagsFlat: row.tagsFlat ?? '',
        secondTags: row.secondTags ?? [],
        // NOTE: We keep list DTO backward compatible.
        // If you later want to show tag names in list, we can add e.g. `tagsFlat` or `tagNames` here.
      })),
    };
  }

  async findOne(id: string): Promise<any> {
    const video = await this.prisma.videoMedia.findUnique({
      where: { id },
    });

    if (!video) {
      throw new NotFoundException('Video not found');
    }

    const [category, tags] = await Promise.all([
      video.categoryId
        ? this.prisma.category.findUnique({
            where: { id: video.categoryId },
          })
        : null,
      video.tagIds && video.tagIds.length
        ? this.prisma.tag.findMany({
            where: { id: { in: video.tagIds } },
            orderBy: { seq: 'asc' },
          })
        : [],
    ]);

    return {
      id: video.id,
      title: video.title,
      filename: video.filename,
      videoTime: video.videoTime,
      size: video.size?.toString?.() ?? '0',
      coverImg: video.coverImg ?? '',
      type: video.type,
      formatType: video.formatType,
      contentType: video.contentType,
      country: video.country,
      status: video.status,
      desc: video.desc ?? '',
      categoryId: video.categoryId ?? null,
      tagIds: video.tagIds ?? [],
      listStatus: video.listStatus ?? 0,
      editedAt: Number(video.editedAt ?? 0),
      updatedAt: video.updatedAt ?? null,
      categoryName: category?.name ?? null,
      // Existing DTO: tags as {id, name}[]
      tags: video.tags ?? [],
      tagsFlat: video.tagsFlat ?? '',
      secondTags: video.secondTags ?? [],
    };
  }

  async updateManage(id: string, dto: UpdateVideoMediaManageDto) {
    const video = await this.prisma.videoMedia.findUnique({
      where: { id },
    });

    if (!video) {
      throw new NotFoundException('Video not found');
    }

    const updateData: any = {};

    if (typeof dto.title === 'string') {
      updateData.title = dto.title.trim();
    }

    let categoryId: string | null | undefined = dto.categoryId;
    const tagIds: string[] | undefined = dto.tagIds;

    if (dto.categoryId === null) {
      categoryId = null;
    }

    if (typeof categoryId !== 'undefined' || typeof tagIds !== 'undefined') {
      const { finalCategoryId, finalTagIds, tags, tagsFlat } =
        await this.validateCategoryAndTags(categoryId, tagIds);

      updateData.categoryId = finalCategoryId;
      updateData.tagIds = finalTagIds;
      updateData.tags = tags; // NEW: store denormalised tag names (lowercased)
      updateData.tagsFlat = tagsFlat; // existing: text for search
    }

    if (typeof dto.listStatus === 'number') {
      if (dto.listStatus !== 0 && dto.listStatus !== 1) {
        throw new BadRequestException('Invalid listStatus value');
      }
      updateData.listStatus = dto.listStatus;
    }

    updateData.editedAt = BigInt(Date.now());
    updateData.updatedAt = new Date();

    await this.prisma.videoMedia.update({
      where: { id },
      data: updateData,
    });

    return this.findOne(id);
  }

  async updateStatus(id: string, dto: UpdateVideoMediaStatusDto) {
    const video = await this.prisma.videoMedia.findUnique({
      where: { id },
    });

    if (!video) {
      throw new NotFoundException('Video not found');
    }

    if (dto.listStatus !== 0 && dto.listStatus !== 1) {
      throw new BadRequestException('Invalid listStatus value');
    }

    const editedAt = BigInt(Date.now());
    const updatedAt = new Date();

    await this.prisma.videoMedia.update({
      where: { id },
      data: {
        listStatus: dto.listStatus,
        editedAt,
        updatedAt,
      },
    });

    return {
      id,
      listStatus: dto.listStatus,
      editedAt: editedAt.toString(),
    };
  }

  async batchUpdateStatus(dto: BatchUpdateVideoMediaStatusDto) {
    if (!dto.ids?.length) {
      throw new BadRequestException('ids cannot be empty');
    }

    if (dto.listStatus !== 0 && dto.listStatus !== 1) {
      throw new BadRequestException('Invalid listStatus value');
    }

    const editedAt = BigInt(Date.now());
    const updatedAt = new Date();

    const result = await this.prisma.videoMedia.updateMany({
      where: { id: { in: dto.ids } },
      data: {
        listStatus: dto.listStatus,
        editedAt,
        updatedAt,
      },
    });

    return {
      affected: result.count,
      listStatus: dto.listStatus,
      editedAt: editedAt.toString(),
    };
  }

  /**
   * Upload and update VideoMedia cover image.
   */
  async updateCover(id: string, file: Express.Multer.File) {
    // Ensure video exists
    const video = await this.prisma.videoMedia.findUnique({
      where: { id },
    });

    if (!video) {
      throw new NotFoundException('Video not found');
    }

    // Upload image
    const { key, imgSource } = await this.imageUploadService.uploadCoverImage(
      'video-cover',
      file,
    );

    const editedAt = BigInt(Date.now());
    const updatedAt = new Date();

    // Update VideoMedia record
    const updated = await this.prisma.videoMedia.update({
      where: { id },
      data: {
        coverImg: key,
        imgSource,
        editedAt,
        updatedAt,
      },
    });

    return {
      id: updated.id,
      coverImg: updated.coverImg,
      imgSource: updated.imgSource,
      editedAt: editedAt.toString(),
    };
  }

  private async validateCategoryAndTags(
    categoryId: string | null | undefined,
    tagIds: string[] | undefined,
  ): Promise<{
    finalCategoryId: string | null;
    finalTagIds: string[];
    tags: string[]; // NEW: denormalised tag names (lowercased)
    tagsFlat: string; // NEW: concatenated names for search
  }> {
    let finalCategoryId: string | null =
      typeof categoryId === 'undefined' ? (undefined as any) : categoryId;
    let finalTagIds: string[] = [];
    let tags: string[] = []; // NEW
    let tagsFlat = '';

    // Normalize tagIds: remove duplicates
    if (Array.isArray(tagIds)) {
      const unique = [...new Set(tagIds)];
      if (unique.length > 5) {
        throw new BadRequestException('Tag count cannot exceed 5');
      }
      finalTagIds = unique;
    }

    // If tags are provided but categoryId is null/undefined -> error
    if (finalTagIds.length > 0 && !finalCategoryId) {
      throw new BadRequestException(
        'Category is required when tags are provided.',
      );
    }

    // Validate category if present
    if (typeof finalCategoryId !== 'undefined' && finalCategoryId !== null) {
      const category = await this.prisma.category.findUnique({
        where: { id: finalCategoryId },
      });

      if (!category) {
        throw new BadRequestException('Category not found');
      }
      if (category.status !== 1) {
        throw new BadRequestException('Category is disabled');
      }
    }

    if (finalTagIds.length > 0) {
      const tagEntities = await this.prisma.tag.findMany({
        where: { id: { in: finalTagIds } },
      });

      if (tagEntities.length !== finalTagIds.length) {
        throw new BadRequestException('Some tags do not exist');
      }

      const distinctCategoryIds = [
        ...new Set(tagEntities.map((t) => t.categoryId.toString())),
      ];

      if (distinctCategoryIds.length > 1) {
        throw new BadRequestException(
          'All tags must belong to the same category',
        );
      }

      const tagCategoryId = distinctCategoryIds[0];

      if (finalCategoryId && tagCategoryId !== finalCategoryId) {
        throw new BadRequestException(
          'Tags do not belong to the specified category',
        );
      }

      // If categoryId was not provided but tags exist, infer from tags
      if (!finalCategoryId) {
        finalCategoryId = tagCategoryId;
      }

      // Build tags & tagsFlat: lowercased names
      const tagNames = tagEntities
        .map((t) => t.name?.trim())
        .filter(Boolean) as string[];

      tags = tagNames.map((name) => name.toLowerCase()); // NEW

      tagsFlat = tags.join(' '); // e.g. "funny hot 2025"
    }

    if (typeof finalCategoryId === 'undefined') {
      finalCategoryId = null;
    }

    return {
      finalCategoryId,
      finalTagIds,
      tags,
      tagsFlat,
    };
  }
}