import { NextRequest, NextResponse } from 'next/server';
import { adminDb } from '@/lib/firebase/admin';

export async function GET(request: NextRequest) {
  try {
    const projectId = request.nextUrl.searchParams.get('projectId');
    const sessionGapMinutes = parseInt(request.nextUrl.searchParams.get('gap') || '120'); // 2 hours default
    
    if (!projectId) {
      return NextResponse.json({ error: 'Missing projectId' }, { status: 400 });
    }

    // Get all conversations sorted by time
    const conversationsSnapshot = await adminDb
      .collection('projects')
      .doc(projectId)
      .collection('cursorConversations')
      .orderBy('createdAt', 'asc')
      .get();

    const conversations = conversationsSnapshot.docs.map(doc => {
      const data = doc.data();
      return {
        id: doc.id,
        name: data.name,
        createdAt: new Date(data.createdAt),
        relevanceScore: data.relevanceScore || 0
      };
    });

    // Group into sessions based on time gaps
    const sessions: any[] = [];
    let currentSession: any = null;

    for (const conv of conversations) {
      if (!currentSession) {
        // Start first session
        currentSession = {
          startTime: conv.createdAt,
          endTime: conv.createdAt,
          conversations: [conv],
          relevanceScores: [conv.relevanceScore]
        };
      } else {
        // Check time gap from last conversation
        const gapMs = conv.createdAt.getTime() - currentSession.endTime.getTime();
        const gapMinutes = gapMs / (1000 * 60);

        if (gapMinutes <= sessionGapMinutes) {
          // Same session
          currentSession.conversations.push(conv);
          currentSession.relevanceScores.push(conv.relevanceScore);
          currentSession.endTime = conv.createdAt;
        } else {
          // New session - close current and start new
          sessions.push(currentSession);
          currentSession = {
            startTime: conv.createdAt,
            endTime: conv.createdAt,
            conversations: [conv],
            relevanceScores: [conv.relevanceScore]
          };
        }
      }
    }

    // Add last session
    if (currentSession) {
      sessions.push(currentSession);
    }

    // Analyze each session
    const analyzedSessions = sessions.map((session, idx) => {
      const durationMinutes = Math.round((session.endTime.getTime() - session.startTime.getTime()) / (1000 * 60));
      
      // Calculate session relevance score (average of all conversations)
      const avgScore = session.relevanceScores.reduce((a: number, b: number) => a + b, 0) / session.relevanceScores.length;
      
      // Count negative/positive conversations
      const negative = session.relevanceScores.filter((s: number) => s < 0).length;
      const positive = session.relevanceScores.filter((s: number) => s > 0).length;
      const neutral = session.relevanceScores.filter((s: number) => s === 0).length;
      
      // Determine likely project based on majority
      let likelyProject = 'unknown';
      if (negative > positive && negative > neutral) {
        likelyProject = 'other (NHL/market)';
      } else if (positive > negative && positive > neutral) {
        likelyProject = 'vibn (likely)';
      } else if (positive > 0 || avgScore > 0) {
        likelyProject = 'vibn (mixed)';
      } else {
        likelyProject = 'unclear';
      }

      return {
        sessionNumber: idx + 1,
        startTime: session.startTime.toISOString(),
        endTime: session.endTime.toISOString(),
        durationMinutes,
        conversationCount: session.conversations.length,
        avgRelevanceScore: Math.round(avgScore * 100) / 100,
        scoreBreakdown: { negative, neutral, positive },
        likelyProject,
        conversationNames: session.conversations.slice(0, 5).map((c: any) => c.name)
      };
    });

    return NextResponse.json({
      totalConversations: conversations.length,
      totalSessions: sessions.length,
      sessionGapMinutes,
      sessions: analyzedSessions
    });

  } catch (error) {
    console.error('Error analyzing sessions:', error);
    return NextResponse.json(
      { error: 'Failed to analyze sessions', details: error instanceof Error ? error.message : String(error) },
      { status: 500 }
    );
  }
}