import "https://deno.land/x/xhr@0.1.0/mod.ts";
import { serve } from "https://deno.land/std@0.168.0/http/server.ts";
import { createClient } from "https://esm.sh/@supabase/supabase-js@2.38.1";

const corsHeaders = {
  'Access-Control-Allow-Origin': '*',
  'Access-Control-Allow-Headers': 'authorization, x-client-info, apikey, content-type',
};

const OPENAI_API_KEY = Deno.env.get('OPENAI_API_KEY');
const SUPABASE_URL = Deno.env.get('SUPABASE_URL') || "https://ffwcnetryatmpcnjkegg.supabase.co";
const SUPABASE_SERVICE_ROLE_KEY = Deno.env.get('SUPABASE_SERVICE_ROLE_KEY') || "";

serve(async (req) => {
  // Handle CORS preflight requests
  if (req.method === 'OPTIONS') {
    return new Response(null, { headers: corsHeaders });
  }

  try {
    const { uploadId, userId, filePath, fileType } = await req.json();
    
    // Create Supabase client with service role key to bypass RLS
    const supabase = createClient(SUPABASE_URL, SUPABASE_SERVICE_ROLE_KEY, {
      auth: {
        persistSession: false,
      },
    });

    // Fetch the file content from Supabase Storage
    const { data: fileData, error: fileError } = await supabase
      .storage
      .from('documents')
      .download(filePath);

    if (fileError) {
      console.error('Error downloading file:', fileError);
      return new Response(
        JSON.stringify({ error: 'Error downloading file' }),
        { status: 500, headers: { ...corsHeaders, 'Content-Type': 'application/json' } }
      );
    }

    // Convert file content to text
    const text = await fileData.text();

    // Extract tasks using OpenAI
    const tasks = await extractTasksWithOpenAI(text, uploadId, userId);

    // Save extracted tasks to the database
    for (const task of tasks) {
      const { error: taskError } = await supabase
        .from('tasks')
        .insert(task);

      if (taskError) {
        console.error('Error inserting task:', taskError);
      }
    }

    // Update upload status to 'Completed'
    const { error: updateError } = await supabase
      .from('uploads')
      .update({ status: 'Completed' })
      .eq('id', uploadId);

    if (updateError) {
      console.error('Error updating upload status:', updateError);
      return new Response(
        JSON.stringify({ error: 'Error updating upload status' }),
        { status: 500, headers: { ...corsHeaders, 'Content-Type': 'application/json' } }
      );
    }

    return new Response(
      JSON.stringify({ success: true, tasksExtracted: tasks.length }),
      { headers: { ...corsHeaders, 'Content-Type': 'application/json' } }
    );

  } catch (error) {
    console.error('Error processing document:', error);
    return new Response(
      JSON.stringify({ error: error.message }),
      { status: 500, headers: { ...corsHeaders, 'Content-Type': 'application/json' } }
    );
  }
});

async function extractTasksWithOpenAI(text: string, uploadId: string, userId: string) {
  try {
    // Call OpenAI API to extract tasks
    const response = await fetch('https://api.openai.com/v1/chat/completions', {
      method: 'POST',
      headers: {
        'Authorization': `Bearer ${OPENAI_API_KEY}`,
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({
        model: 'gpt-4o-mini',
        messages: [
          {
            role: 'system',
            content: `
              You are a specialized task extractor for IT security and compliance policy documents.
              Your job is to identify specific actionable tasks from policy documents.
              For each task, extract the following information:
              1. Task name (short, clear description of what needs to be done)
              2. Description (more detailed explanation)
              3. Priority (High, Medium, Low)
              4. Due date (if mentioned)
              
              Format your response as a valid JSON array of task objects with these properties:
              [
                {
                  "task_name": "string",
                  "description": "string",
                  "priority": "string",
                  "due_date": "ISO date string or null"
                }
              ]
              
              If no due date is mentioned for a task, return null for that field.
              Only return the JSON array, nothing else.
            `
          },
          {
            role: 'user',
            content: text
          }
        ]
      }),
    });

    const data = await response.json();
    const extractedTasksJson = data.choices[0].message.content;
    
    // Parse the extracted tasks
    const extractedTasks = JSON.parse(extractedTasksJson);
    
    // Format tasks for database insertion
    return extractedTasks.map((task: any) => ({
      upload_id: uploadId,
      user_id: userId,
      task_name: task.task_name,
      description: task.description,
      priority: task.priority,
      due_date: task.due_date,
      status: 'Open'
    }));
  } catch (error) {
    console.error('Error extracting tasks with OpenAI:', error);
    throw new Error('Failed to extract tasks from document');
  }
}