import { NextResponse } from 'next/server';
import { getAdminAuth, getAdminDb } from '@/lib/firebase/admin';
import { getAlloyDbClient } from '@/lib/db/alloydb';
import { GeminiLlmClient } from '@/lib/ai/gemini-client';
import { z } from 'zod';

const ThemeGroupingSchema = z.object({
  themes: z.array(z.object({
    theme: z.string().describe('A short, descriptive theme name (2-4 words)'),
    description: z.string().describe('A brief description of what this theme represents'),
    insightIds: z.array(z.string()).describe('Array of insight IDs that belong to this theme'),
  })),
});

export async function POST(
  request: Request,
  { params }: { params: Promise<{ projectId: string }> }
) {
  try {
    const { projectId } = await params;
    
    // Authentication (skip in development if no auth header)
    const authHeader = request.headers.get('Authorization');
    const isDevelopment = process.env.NODE_ENV === 'development';
    
    if (!isDevelopment || authHeader?.startsWith('Bearer ')) {
      if (!authHeader?.startsWith('Bearer ')) {
        return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
      }

      const token = authHeader.substring(7);
      const auth = getAdminAuth();
      const decoded = await auth.verifyIdToken(token);
      
      if (!decoded?.uid) {
        return NextResponse.json({ error: 'Invalid token' }, { status: 401 });
      }
    }

    // Get insights from request body
    const { insights } = await request.json();
    
    if (!insights || insights.length === 0) {
      return NextResponse.json({
        success: true,
        themes: [],
      });
    }

    console.log('[API /knowledge/themes] Grouping', insights.length, 'insights into themes');

    // Prepare insights for AI analysis
    const insightsContext = insights.map((insight: any, index: number) => 
      `[${insight.id}] ${insight.content?.substring(0, 200) || insight.title}`
    ).join('\n\n');

    // Use AI to group insights into themes
    const llm = new GeminiLlmClient();
    const systemPrompt = `You are an expert at analyzing and categorizing information. Given a list of insights/knowledge chunks, group them into meaningful themes. Each theme should represent a coherent topic or concept. Aim for 3-7 themes depending on the diversity of content.`;

    const userPrompt = `Analyze these insights and group them into themes:

${insightsContext}

Group these insights into themes. Each insight ID is in brackets at the start of each line. Return the themes with their associated insight IDs.`;

    try {
      const result = await llm.structuredCall({
        model: 'gemini',
        systemPrompt,
        messages: [{ role: 'user', content: userPrompt }],
        schema: ThemeGroupingSchema,
        temperature: 0.3,
      });

      console.log('[API /knowledge/themes] Generated', result.themes.length, 'themes');

      return NextResponse.json({
        success: true,
        themes: result.themes,
      });
    } catch (aiError) {
      console.error('[API /knowledge/themes] AI grouping failed:', aiError);
      // Fallback: create a single "Ungrouped" theme with all insights
      return NextResponse.json({
        success: true,
        themes: [{
          theme: 'All Insights',
          description: 'Ungrouped insights',
          insightIds: insights.map((i: any) => i.id),
        }],
      });
    }
  } catch (error) {
    console.error('[API /knowledge/themes] Error:', error);
    return NextResponse.json(
      { 
        error: 'Failed to group insights into themes',
        details: error instanceof Error ? error.message : String(error)
      },
      { status: 500 }
    );
  }
}