import axios from 'axios';
import { classifySector } from './classify-sector.js';
import pg from 'pg';
import dotenv from 'dotenv';

dotenv.config();

const pool = new pg.Pool({
  connectionString: process.env.DATABASE_URL || 'postgresql://tenderpilot:tenderpilot123@localhost:5432/tenderpilot'
});

async function sleep(ms) {
  return new Promise(resolve => setTimeout(resolve, ms));
}

/**
 * IMPROVED CONTRACTS FINDER SCRAPER
 * 
 * Enhancements:
 * 1. Removes stage=tender filter - gets ALL notice types (planning, tender, award, contract)
 * 2. Reduces lookback window from 90 days to 14 days (captures fresh tenders)
 * 3. Adds sophisticated filtering - only tenders with deadlines >= 24 hours in future
 * 4. Adds incremental mode support (tracks last scrape time)
 * 5. Better error handling and rate limiting
 */

async function scrapeTenders() {
  try {
    console.log(`[${new Date().toISOString()}] Starting IMPROVED tender scrape...`);
    
    // ENHANCEMENT 1: Get last scrape time for incremental updates
    let publishedFrom;
    try {
      const lastScrape = await pool.query(
        "SELECT MAX(created_at) as last_scrape FROM tenders WHERE source = 'contracts_finder'"
      );
      
      if (lastScrape.rows[0].last_scrape) {
        // Incremental: get tenders published since last scrape
        publishedFrom = new Date(lastScrape.rows[0].last_scrape);
        publishedFrom.setHours(publishedFrom.getHours() - 1); // 1-hour overlap for safety
        console.log(`Incremental mode: fetching since ${publishedFrom.toISOString()}`);
      } else {
        // First run: get last 14 days
        publishedFrom = new Date();
        publishedFrom.setDate(publishedFrom.getDate() - 14);
        console.log(`First run: fetching last 14 days`);
      }
    } catch (e) {
      // Fallback: 14 days
      publishedFrom = new Date();
      publishedFrom.setDate(publishedFrom.getDate() - 14);
      console.log(`Fallback: fetching last 14 days`);
    }
    
    const dateStr = publishedFrom.toISOString().split('T')[0];
    
    // ENHANCEMENT 2: Remove stage=tender filter to get ALL notice types
    // Old: ?stage=tender&output=json&publishedFrom=${dateStr}
    // New: ?output=json&publishedFrom=${dateStr}
    const baseUrl = `https://www.contractsfinder.service.gov.uk/Published/Notices/OCDS/Search?output=json&publishedFrom=${dateStr}`;
    
    console.log(`Base URL: ${baseUrl}`);
    console.log(`Getting ALL notice types (not just stage=tender)`);
    
    let insertedCount = 0;
    let skippedExpired = 0;
    let skippedNoDeadline = 0;
    let skippedTooSoon = 0;
    let totalProcessed = 0;
    let pageNum = 1;
    let hasNextPage = true;
    let nextPageUrl = baseUrl;
    
    // ENHANCEMENT 3: Filter criteria - only tenders with deadline >= 24 hours in future
    const now = new Date();
    const minDeadline = new Date(now.getTime() + 24 * 60 * 60 * 1000); // 24 hours from now
    
    console.log(`Filtering: deadline must be after ${minDeadline.toISOString()}`);
    
    while (hasNextPage) {
      try {
        console.log(`\nFetching page ${pageNum}...`);
        const response = await axios.get(nextPageUrl, { 
          timeout: 30000,
          headers: {
            'User-Agent': 'TenderRadar/2.0 (UK Public Procurement Monitor)'
          }
        });
        
        const data = response.data;
        const releases = data.releases || [];
        
        console.log(`  Received ${releases.length} releases`);
        
        for (const release of releases) {
          totalProcessed++;
          
          try {
            const tender = release.tender || {};
            const planning = release.planning || {};
            const parties = release.parties || [];
            
            // Find procuring entity
            const procurer = parties.find(p => 
              p.roles && (
                p.roles.includes('buyer') || 
                p.roles.includes('procuringEntity') || 
                p.roles.includes('procurer')
              )
            ) || (release.buyer ? release.buyer : null);
            
            const sourceId = release.ocid || release.id;
            const title = tender.title || release.title || 'Untitled';
            const description = tender.description || release.description || '';
            const publishedDate = release.date;
            const deadline = tender.tenderPeriod?.endDate;
            
            // ENHANCEMENT 3: Sophisticated filtering
            if (!deadline) {
              skippedNoDeadline++;
              continue; // Skip if no deadline specified
            }
            
            const deadlineDate = new Date(deadline);
            
            // Skip if already expired
            if (deadlineDate < now) {
              skippedExpired++;
              continue;
            }
            
            // Skip if deadline is too soon (< 24 hours)
            if (deadlineDate < minDeadline) {
              skippedTooSoon++;
              continue;
            }
            
            const authority = procurer?.name || release.buyer?.name || 'Unknown';
            const location = planning?.budget?.description || tender.procurementMethod || '';
            
            // Build notice URL
            let noticeUrl;
            if (release.url) {
              noticeUrl = release.url;
            } else if (sourceId) {
              const uuid = sourceId.replace('ocds-b5fd17-', '');
              noticeUrl = `https://www.contractsfinder.service.gov.uk/notice/${uuid}`;
            } else {
              continue; // Skip if we can't build a URL
            }
            
            const documentsUrl = tender.documents?.length > 0 ? tender.documents[0].url : '';
            
            // Extract value
            let valueLow = null, valueHigh = null;
            if (planning?.budget?.amount?.amount) {
              valueLow = planning.budget.amount.amount;
              valueHigh = planning.budget.amount.amount;
            } else if (tender.value?.amount) {
              valueLow = tender.value.amount;
              valueHigh = tender.value.amount;
            }
            
            const cpvCodes = tender.classification ? [tender.classification.scheme] : [];
            
            // Get notice type/stage
            const noticeType = release.tag?.[0] || 'tender';
            
            const result = await pool.query(
              `INSERT INTO tenders (
                source, source_id, title, description, summary, cpv_codes,
                value_low, value_high, currency, published_date, deadline,
                authority_name, authority_type, location, documents_url, notice_url, status, sector
              ) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, $14, $15, $16, $17, $18)
               ON CONFLICT (source_id) DO NOTHING RETURNING id`,
              [
                'contracts_finder',
                sourceId,
                title.substring(0, 500),
                description,
                description.substring(0, 500),
                cpvCodes,
                valueLow,
                valueHigh,
                'GBP',
                publishedDate,
                deadline,
                authority,
                'government',
                location.substring(0, 255),
                documentsUrl,
                noticeUrl,
                'open',
                classifySector(title, description, authority)
              ]
            );
            
            if (result.rowCount > 0) {
              insertedCount++;
              if (insertedCount % 10 === 0) {
                console.log(`  Inserted ${insertedCount} tenders so far...`);
              }
            }
            
          } catch (e) {
            console.error(`  Error processing tender ${totalProcessed}:`, e.message);
          }
        }
        
        console.log(`Page ${pageNum} complete: processed ${releases.length} releases`);
        console.log(`  Inserted: ${insertedCount} | Skipped (expired: ${skippedExpired}, no deadline: ${skippedNoDeadline}, too soon: ${skippedTooSoon})`);
        
        // Check for next page
        if (data.links && data.links.next) {
          nextPageUrl = data.links.next;
          hasNextPage = true;
          pageNum++;
          // Rate limiting: 1 second between pages
          await sleep(1000);
        } else {
          hasNextPage = false;
        }
        
      } catch (error) {
        console.error(`Error fetching page ${pageNum}:`, error.message);
        hasNextPage = false;
      }
    }
    
    console.log(`\n=== SCRAPE COMPLETE ===`);
    console.log(`Total processed: ${totalProcessed}`);
    console.log(`Inserted: ${insertedCount}`);
    console.log(`Skipped - expired: ${skippedExpired}`);
    console.log(`Skipped - no deadline: ${skippedNoDeadline}`);
    console.log(`Skipped - deadline < 24h: ${skippedTooSoon}`);
    console.log(`Completion time: ${new Date().toISOString()}`);
    
  } catch (error) {
    console.error('Fatal error in scraper:', error.message);
    console.error(error.stack);
  } finally {
    await pool.end();
  }
}

scrapeTenders();