import { NextRequest } from 'next/server';
import { db } from '@/lib/db';
import { auth, computeProjectAccess, projectAccessInclude } from '@/lib/auth';
import { apiErrors, successResponse } from '@/lib/api-response';
import { rateLimit } from '@/lib/rate-limit';
import { logError } from '@/lib/logger';

type RouteParams = { params: Promise<{ videoId: string }> };

// GET /api/watch/[videoId]/progress - Get watch progress for the current user
export async function GET(request: NextRequest, { params }: RouteParams) {
    try {
        const session = await auth();
        
        if (!session?.user?.id) {
            return apiErrors.unauthorized('Authentication required');
        }

        const { videoId } = await params;

        // Get the video and its active version (project access data pre-fetched in same query)
        const userId = session.user.id;
        const video = await db.video.findUnique({
            where: { id: videoId },
            include: {
                project: { include: projectAccessInclude(userId) },
                versions: {
                    where: { isActive: true },
                    take: 1,
                },
            },
        });

        if (!video) {
            return apiErrors.notFound('Video');
        }

        const access = computeProjectAccess(video.project, userId);

        if (!access.hasAccess) {
            return apiErrors.forbidden('Access denied');
        }

        const activeVersion = video.versions[0];
        if (!activeVersion) {
            return apiErrors.notFound('Video version');
        }

        // Get watch progress for this user and version
        const progress = await db.watchProgress.findUnique({
            where: {
                userId_versionId: {
                    userId: session.user.id,
                    versionId: activeVersion.id,
                },
            },
        });

        return successResponse({
            progress: progress ? progress.progress : 0,
            duration: progress?.duration || activeVersion.duration || 0,
            percentage: progress?.percentage || 0,
            updatedAt: progress?.updatedAt || null,
        });
    } catch (error) {
        logError('Error fetching watch progress:', error);
        return apiErrors.internalError('Failed to fetch watch progress');
    }
}

// POST /api/watch/[videoId]/progress - Save watch progress for the current user
export async function POST(request: NextRequest, { params }: RouteParams) {
    try {
        // Rate limit watch progress updates (30 per minute to allow pause + periodic + visibility changes)
        const limited = await rateLimit(request, 'watch-progress');
        if (limited) return limited;
        
        const session = await auth();
        
        if (!session?.user?.id) {
            return apiErrors.unauthorized('Authentication required');
        }

        const { videoId } = await params;
        const body = await request.json();
        const { progress, duration, versionId } = body;

        const MAX_VIDEO_SECONDS = 86_400; // 24 hours — reasonable upper bound for any video

        if (typeof progress !== 'number' || !isFinite(progress) || progress < 0 || progress > MAX_VIDEO_SECONDS) {
            return apiErrors.badRequest('Invalid progress value');
        }

        if (duration !== undefined && (typeof duration !== 'number' || !isFinite(duration) || duration < 0 || duration > MAX_VIDEO_SECONDS)) {
            return apiErrors.badRequest('Invalid duration value');
        }

        if (versionId !== undefined && typeof versionId !== 'string') {
            return apiErrors.badRequest('Invalid versionId');
        }

        // Always load the requested video and validate access before writing progress.
        // If versionId is provided, verify it belongs to this video; otherwise resolve active version.
        // Project access data is pre-fetched in the same query — no extra round-trips.
        const userId = session.user.id;
        const video = await db.video.findUnique({
            where: { id: videoId },
            include: {
                project: { include: projectAccessInclude(userId) },
                versions: {
                    where: versionId ? { id: versionId } : { isActive: true },
                    take: 1,
                },
            },
        });

        if (!video) {
            return apiErrors.notFound('Video');
        }

        const access = computeProjectAccess(video.project, userId);
        if (!access.hasAccess) {
            return apiErrors.forbidden('Access denied');
        }

        const targetVersion = video.versions[0];
        if (!targetVersion) {
            return apiErrors.notFound('Video version');
        }

        // Calculate percentage
        const safeDuration = duration || 0;
        const percentage = safeDuration > 0 ? Math.min(100, (progress / safeDuration) * 100) : 0;

        // Client already filters tiny deltas (<2s) before sending — safe to upsert directly.
        const watchProgress = await db.watchProgress.upsert({
            where: {
                userId_versionId: {
                    userId: session.user.id,
                    versionId: targetVersion.id,
                },
            },
            update: {
                progress,
                duration: safeDuration,
                percentage,
            },
            create: {
                userId: session.user.id,
                versionId: targetVersion.id,
                progress,
                duration: safeDuration,
                percentage,
            },
        });

        return successResponse({
            success: true,
            progress: watchProgress.progress,
            percentage: watchProgress.percentage,
        });
    } catch (error) {
        logError('Error saving watch progress:', error);
        return apiErrors.internalError('Failed to save watch progress');
    }
}