// Content Service - Main orchestrator for content operations
// Path: src/modules/content/content.service.ts

import { Injectable, Logger } from '@nestjs/common';
import { PrismaService } from '../../database/prisma.service';
import { MasterContentService } from './services/master-content.service';
import { BuildingBlocksService } from './services/building-blocks.service';
import { WritingStylesService } from './services/writing-styles.service';
import { ContentVariationsService } from './services/content-variations.service';
import { PlatformAdaptersService } from './services/platform-adapters.service';
import { SocialPlatform, ContentStatus } from '@prisma/client';

export interface CreateContentDto {
    masterContentId: string;
    platform: SocialPlatform;
    body?: string;
    scheduledAt?: Date;
}

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

    constructor(
        private readonly prisma: PrismaService,
        private readonly masterContent: MasterContentService,
        private readonly buildingBlocks: BuildingBlocksService,
        private readonly writingStyles: WritingStylesService,
        private readonly variations: ContentVariationsService,
        private readonly platforms: PlatformAdaptersService,
    ) { }

    /**
     * Create platform-specific content from master content
     */
    async createFromMaster(userId: string, dto: CreateContentDto) {
        const master = await this.masterContent.getById(dto.masterContentId);
        if (!master) {
            throw new Error('Master content not found');
        }

        // Get platform config
        const platformConfig = this.platforms.getConfig(dto.platform);

        // Adapt content for platform
        let body = dto.body || master.body || '';
        body = this.platforms.format(body, dto.platform);

        // Validate content
        const validation = this.platforms.validate(body, dto.platform);
        if (!validation.valid) {
            this.logger.warn(`Content validation issues: ${validation.issues.join(', ')}`);
        }

        // Create content record
        const content = await this.prisma.content.create({
            data: {
                userId,
                masterContentId: dto.masterContentId,
                type: dto.platform as any,
                body,
                status: dto.scheduledAt ? ContentStatus.SCHEDULED : ContentStatus.DRAFT,
                scheduledAt: dto.scheduledAt,
            },
        });

        return {
            content,
            platformConfig,
            validation,
        };
    }

    /**
     * Get user's content with filters
     */
    async getByUser(
        userId?: string,
        options?: {
            platform?: SocialPlatform;
            status?: ContentStatus;
            limit?: number;
            offset?: number;
            sortBy?: string;
            sortOrder?: 'asc' | 'desc';
        },
    ) {
        // Build dynamic orderBy
        const sortField = options?.sortBy || 'createdAt';
        const sortDir = options?.sortOrder || 'desc';
        const validSortFields = ['createdAt', 'updatedAt', 'type', 'status', 'publishedAt'];
        const orderBy = validSortFields.includes(sortField)
            ? { [sortField]: sortDir }
            : { createdAt: 'desc' as const };

        const where = {
            ...(userId && { userId }),
            ...(options?.platform && { type: options.platform as any }),
            ...(options?.status && { status: options.status }),
        };

        const [items, total] = await Promise.all([
            this.prisma.content.findMany({
                where,
                orderBy,
                take: options?.limit || 100,
                skip: options?.offset || 0,
                include: {
                    masterContent: { select: { id: true, title: true, type: true } },
                    variants: { select: { id: true, name: true, isWinner: true } },
                    _count: { select: { variants: true } },
                },
            }),
            this.prisma.content.count({ where }),
        ]);

        return { items, total };
    }

    /**
     * Get content by ID
     */
    async getById(id: string) {
        return this.prisma.content.findUnique({
            where: { id },
            include: {
                masterContent: true,
                variants: true,
                approvals: true,
            },
        });
    }

    /**
     * Update content
     */
    async update(id: string, data: { body?: string; status?: ContentStatus; scheduledAt?: Date; imageUrl?: string }) {
        return this.prisma.content.update({
            where: { id },
            data,
        });
    }

    /**
     * Publish content (mark as published)
     */
    async publish(id: string, publishedUrl?: string) {
        return this.prisma.content.update({
            where: { id },
            data: {
                status: ContentStatus.PUBLISHED,
                publishedAt: new Date(),
                publishedUrl,
            },
        });
    }

    /**
     * Delete all related records for given content IDs, then delete the content.
     * Uses a transaction to ensure atomicity.
     */
    private async cascadeDeleteContents(ids: string[]) {
        return this.prisma.$transaction(async (tx) => {
            // Delete all dependent relations first
            await tx.citation.deleteMany({ where: { contentId: { in: ids } } });
            await tx.contentVariant.deleteMany({ where: { contentId: { in: ids } } });
            await tx.media.deleteMany({ where: { contentId: { in: ids } } });
            await tx.scheduledPost.deleteMany({ where: { contentId: { in: ids } } });
            await tx.contentApproval.deleteMany({ where: { contentId: { in: ids } } });
            await tx.contentAnalytics.deleteMany({ where: { contentId: { in: ids } } });
            await tx.contentSeo.deleteMany({ where: { contentId: { in: ids } } });
            await tx.contentPsychology.deleteMany({ where: { contentId: { in: ids } } });
            await tx.contentSource.deleteMany({ where: { contentId: { in: ids } } });

            // Now delete the content itself
            const result = await tx.content.deleteMany({ where: { id: { in: ids } } });
            return result.count;
        });
    }

    /**
     * Delete content (with cascade)
     */
    async delete(id: string) {
        const deleted = await this.cascadeDeleteContents([id]);
        return { deleted };
    }

    /**
     * Bulk delete content items (with cascade)
     */
    async bulkDelete(ids: string[]) {
        const deleted = await this.cascadeDeleteContents(ids);
        return { deleted };
    }

    /**
     * Get content calendar for user
     */
    async getCalendar(userId: string, startDate: Date, endDate: Date) {
        return this.prisma.content.findMany({
            where: {
                userId,
                OR: [
                    { scheduledAt: { gte: startDate, lte: endDate } },
                    { publishedAt: { gte: startDate, lte: endDate } },
                ],
            },
            orderBy: [{ scheduledAt: 'asc' }, { publishedAt: 'asc' }],
            select: {
                id: true,
                type: true,
                status: true,
                scheduledAt: true,
                publishedAt: true,
                masterContent: { select: { title: true } },
            },
        });
    }

    /**
     * Get content analytics
     */
    async getAnalytics(userId: string, period: 'week' | 'month' | 'year') {
        const now = new Date();
        let startDate: Date;

        switch (period) {
            case 'week':
                startDate = new Date(now.getTime() - 7 * 24 * 60 * 60 * 1000);
                break;
            case 'month':
                startDate = new Date(now.getTime() - 30 * 24 * 60 * 60 * 1000);
                break;
            case 'year':
                startDate = new Date(now.getTime() - 365 * 24 * 60 * 60 * 1000);
                break;
        }

        const contents = await this.prisma.content.findMany({
            where: {
                userId,
                publishedAt: { gte: startDate },
            },
            include: {
                variants: true,
            },
        });

        // Aggregate by platform
        const byPlatform = contents.reduce(
            (acc, content) => {
                if (!acc[content.type]) {
                    acc[content.type] = { count: 0, totalEngagement: 0 };
                }
                acc[content.type].count++;
                acc[content.type].totalEngagement += content.variants.reduce(
                    (sum, v) => sum + (v.engagements || 0),
                    0,
                );
                return acc;
            },
            {} as Record<string, { count: number; totalEngagement: number }>,
        );

        return {
            totalPublished: contents.length,
            byPlatform,
            period,
        };
    }
}