package com.auction;

import java.sql.DriverManager;
import java.sql.SQLException;
import java.time.Instant;
import java.time.LocalDateTime;
import java.util.ArrayList;
import java.util.List;

/**
 * Service for persisting auctions, lots, and images into a SQLite database.
 * Data is typically populated by an external scraper process;
 * this service enriches it with image processing and monitoring.
 */
public class DatabaseService {

    private final String url;

    DatabaseService(String dbPath) {
        this.url = "jdbc:sqlite:" + dbPath;
    }

    /**
     * Creates tables if they do not already exist.
     * Schema supports data from external scraper and adds image processing results.
     */
    void ensureSchema() throws SQLException {
        try (var conn = DriverManager.getConnection(url); var stmt = conn.createStatement()) {
            // Auctions table (populated by external scraper)
            stmt.execute("""
                CREATE TABLE IF NOT EXISTS auctions (
                    auction_id INTEGER PRIMARY KEY,
                    title TEXT NOT NULL,
                    location TEXT,
                    city TEXT,
                    country TEXT,
                    url TEXT NOT NULL,
                    type TEXT,
                    lot_count INTEGER DEFAULT 0,
                    closing_time TEXT,
                    discovered_at INTEGER
                )""");

            // Lots table (populated by external scraper)
            stmt.execute("""
                CREATE TABLE IF NOT EXISTS lots (
                    lot_id INTEGER PRIMARY KEY,
                    sale_id INTEGER,
                    title TEXT,
                    description TEXT,
                    manufacturer TEXT,
                    type TEXT,
                    year INTEGER,
                    category TEXT,
                    current_bid REAL,
                    currency TEXT,
                    url TEXT,
                    closing_time TEXT,
                    closing_notified INTEGER DEFAULT 0,
                    FOREIGN KEY (sale_id) REFERENCES auctions(auction_id)
                )""");

            // Images table (populated by this process)
            stmt.execute("""
                CREATE TABLE IF NOT EXISTS images (
                    id INTEGER PRIMARY KEY AUTOINCREMENT,
                    lot_id INTEGER,
                    url TEXT,
                    file_path TEXT,
                    labels TEXT,
                    processed_at INTEGER,
                    FOREIGN KEY (lot_id) REFERENCES lots(lot_id)
                )""");

            // Indexes for performance
            stmt.execute("CREATE INDEX IF NOT EXISTS idx_auctions_country ON auctions(country)");
            stmt.execute("CREATE INDEX IF NOT EXISTS idx_lots_sale_id ON lots(sale_id)");
            stmt.execute("CREATE INDEX IF NOT EXISTS idx_images_lot_id ON images(lot_id)");
        }
    }

    /**
     * Inserts or updates an auction record (typically called by external scraper)
     */
    synchronized void upsertAuction(AuctionInfo auction) throws SQLException {
        var sql = """
            INSERT INTO auctions (auction_id, title, location, city, country, url, type, lot_count, closing_time, discovered_at)
            VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
            ON CONFLICT(auction_id) DO UPDATE SET
                title = excluded.title,
                location = excluded.location,
                city = excluded.city,
                country = excluded.country,
                url = excluded.url,
                type = excluded.type,
                lot_count = excluded.lot_count,
                closing_time = excluded.closing_time
            """;

        try (var conn = DriverManager.getConnection(url); var ps = conn.prepareStatement(sql)) {
            ps.setInt(1, auction.auctionId());
            ps.setString(2, auction.title());
            ps.setString(3, auction.location());
            ps.setString(4, auction.city());
            ps.setString(5, auction.country());
            ps.setString(6, auction.url());
            ps.setString(7, auction.type());
            ps.setInt(8, auction.lotCount());
            ps.setString(9, auction.closingTime() != null ? auction.closingTime().toString() : null);
            ps.setLong(10, Instant.now().getEpochSecond());
            ps.executeUpdate();
        }
    }

    /**
     * Retrieves all auctions from the database
     */
    synchronized List<AuctionInfo> getAllAuctions() throws SQLException {
        List<AuctionInfo> auctions = new ArrayList<>();
        var sql = "SELECT auction_id, title, location, city, country, url, type, lot_count, closing_time FROM auctions";

        try (var conn = DriverManager.getConnection(url); var stmt = conn.createStatement()) {
            var rs = stmt.executeQuery(sql);
            while (rs.next()) {
                var closingStr = rs.getString("closing_time");
                var closing = closingStr != null ? LocalDateTime.parse(closingStr) : null;

                auctions.add(new AuctionInfo(
                    rs.getInt("auction_id"),
                    rs.getString("title"),
                    rs.getString("location"),
                    rs.getString("city"),
                    rs.getString("country"),
                    rs.getString("url"),
                    rs.getString("type"),
                    rs.getInt("lot_count"),
                    closing
                ));
            }
        }
        return auctions;
    }

    /**
     * Retrieves auctions by country code
     */
    synchronized List<AuctionInfo> getAuctionsByCountry(String countryCode) throws SQLException {
        List<AuctionInfo> auctions = new ArrayList<>();
        var sql = "SELECT auction_id, title, location, city, country, url, type, lot_count, closing_time "
                + "FROM auctions WHERE country = ?";

        try (var conn = DriverManager.getConnection(url); var ps = conn.prepareStatement(sql)) {
            ps.setString(1, countryCode);
            var rs = ps.executeQuery();
            while (rs.next()) {
                var closingStr = rs.getString("closing_time");
                var closing = closingStr != null ? LocalDateTime.parse(closingStr) : null;

                auctions.add(new AuctionInfo(
                    rs.getInt("auction_id"),
                    rs.getString("title"),
                    rs.getString("location"),
                    rs.getString("city"),
                    rs.getString("country"),
                    rs.getString("url"),
                    rs.getString("type"),
                    rs.getInt("lot_count"),
                    closing
                ));
            }
        }
        return auctions;
    }

    /**
     * Inserts or updates a lot record (typically called by external scraper)
     */
    synchronized void upsertLot(Lot lot) throws SQLException {
        var sql = """
            INSERT INTO lots (lot_id, sale_id, title, description, manufacturer, type, year, category, current_bid, currency, url, closing_time, closing_notified)
            VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
            ON CONFLICT(lot_id) DO UPDATE SET
                sale_id = excluded.sale_id,
                title = excluded.title,
                description = excluded.description,
                manufacturer = excluded.manufacturer,
                type = excluded.type,
                year = excluded.year,
                category = excluded.category,
                current_bid = excluded.current_bid,
                currency = excluded.currency,
                url = excluded.url,
                closing_time = excluded.closing_time
            """;

        try (var conn = DriverManager.getConnection(url); var ps = conn.prepareStatement(sql)) {
            ps.setInt(1, lot.lotId());
            ps.setInt(2, lot.saleId());
            ps.setString(3, lot.title());
            ps.setString(4, lot.description());
            ps.setString(5, lot.manufacturer());
            ps.setString(6, lot.type());
            ps.setInt(7, lot.year());
            ps.setString(8, lot.category());
            ps.setDouble(9, lot.currentBid());
            ps.setString(10, lot.currency());
            ps.setString(11, lot.url());
            ps.setString(12, lot.closingTime() != null ? lot.closingTime().toString() : null);
            ps.setInt(13, lot.closingNotified() ? 1 : 0);
            ps.executeUpdate();
        }
    }

    /**
     * Inserts a new image record with object detection labels
     */
    synchronized void insertImage(int lotId, String url, String filePath, List<String> labels) throws SQLException {
        var sql = "INSERT INTO images (lot_id, url, file_path, labels, processed_at) VALUES (?, ?, ?, ?, ?)";
        try (var conn = DriverManager.getConnection(this.url); var ps = conn.prepareStatement(sql)) {
            ps.setInt(1, lotId);
            ps.setString(2, url);
            ps.setString(3, filePath);
            ps.setString(4, String.join(",", labels));
            ps.setLong(5, Instant.now().getEpochSecond());
            ps.executeUpdate();
        }
    }

    /**
     * Retrieves images for a specific lot
     */
    synchronized List<ImageRecord> getImagesForLot(int lotId) throws SQLException {
        List<ImageRecord> images = new ArrayList<>();
        var sql = "SELECT id, lot_id, url, file_path, labels FROM images WHERE lot_id = ?";

        try (var conn = DriverManager.getConnection(url); var ps = conn.prepareStatement(sql)) {
            ps.setInt(1, lotId);
            var rs = ps.executeQuery();
            while (rs.next()) {
                images.add(new ImageRecord(
                    rs.getInt("id"),
                    rs.getInt("lot_id"),
                    rs.getString("url"),
                    rs.getString("file_path"),
                    rs.getString("labels")
                ));
            }
        }
        return images;
    }

    /**
     * Retrieves all lots that are active and need monitoring
     */
    synchronized List<Lot> getActiveLots() throws SQLException {
        List<Lot> list = new ArrayList<>();
        var sql = "SELECT lot_id, sale_id, title, description, manufacturer, type, year, category, " +
                  "current_bid, currency, url, closing_time, closing_notified FROM lots";

        try (var conn = DriverManager.getConnection(url); var stmt = conn.createStatement()) {
            var rs = stmt.executeQuery(sql);
            while (rs.next()) {
                var closingStr = rs.getString("closing_time");
                var closing = closingStr != null ? LocalDateTime.parse(closingStr) : null;

                list.add(new Lot(
                    rs.getInt("sale_id"),
                    rs.getInt("lot_id"),
                    rs.getString("title"),
                    rs.getString("description"),
                    rs.getString("manufacturer"),
                    rs.getString("type"),
                    rs.getInt("year"),
                    rs.getString("category"),
                    rs.getDouble("current_bid"),
                    rs.getString("currency"),
                    rs.getString("url"),
                    closing,
                    rs.getInt("closing_notified") != 0
                ));
            }
        }
        return list;
    }

    /**
     * Retrieves all lots from the database
     */
    synchronized List<Lot> getAllLots() throws SQLException {
        return getActiveLots();
    }

    /**
     * Gets the total number of images in the database
     */
    synchronized int getImageCount() throws SQLException {
        var sql = "SELECT COUNT(*) as count FROM images";
        try (var conn = DriverManager.getConnection(url); var stmt = conn.createStatement()) {
            var rs = stmt.executeQuery(sql);
            if (rs.next()) {
                return rs.getInt("count");
            }
        }
        return 0;
    }

    /**
     * Updates the current bid of a lot (used by monitoring service)
     */
    synchronized void updateLotCurrentBid(Lot lot) throws SQLException {
        try (var conn = DriverManager.getConnection(url);
             var ps = conn.prepareStatement("UPDATE lots SET current_bid = ? WHERE lot_id = ?")) {
            ps.setDouble(1, lot.currentBid());
            ps.setInt(2, lot.lotId());
            ps.executeUpdate();
        }
    }

    /**
     * Updates the closingNotified flag of a lot
     */
    synchronized void updateLotNotificationFlags(Lot lot) throws SQLException {
        try (var conn = DriverManager.getConnection(url);
             var ps = conn.prepareStatement("UPDATE lots SET closing_notified = ? WHERE lot_id = ?")) {
            ps.setInt(1, lot.closingNotified() ? 1 : 0);
            ps.setInt(2, lot.lotId());
            ps.executeUpdate();
        }
    }

    /**
     * Imports auctions from scraper's schema format.
     * Reads from scraper's tables and converts to monitor format using adapter.
     *
     * @return List of imported auctions
     */
    synchronized List<AuctionInfo> importAuctionsFromScraper() throws SQLException {
        List<AuctionInfo> imported = new ArrayList<>();
        var sql = "SELECT auction_id, title, location, url, lots_count, first_lot_closing_time, scraped_at " +
                  "FROM auctions WHERE location LIKE '%NL%'";

        try (var conn = DriverManager.getConnection(url); var stmt = conn.createStatement()) {
            var rs = stmt.executeQuery(sql);
            while (rs.next()) {
                try {
                    var auction = ScraperDataAdapter.fromScraperAuction(rs);
                    upsertAuction(auction);
                    imported.add(auction);
                } catch (Exception e) {
                    System.err.println("Failed to import auction: " + e.getMessage());
                }
            }
        } catch (SQLException e) {
            // Table might not exist in scraper format - that's ok
            Console.println("ℹ️  Scraper auction table not found or incompatible schema");
        }

        return imported;
    }

    /**
     * Imports lots from scraper's schema format.
     * Reads from scraper's tables and converts to monitor format using adapter.
     *
     * @return List of imported lots
     */
    synchronized List<Lot> importLotsFromScraper() throws SQLException {
        List<Lot> imported = new ArrayList<>();
        var sql = "SELECT lot_id, auction_id, title, description, category, " +
                  "current_bid, closing_time, url " +
                  "FROM lots";

        try (var conn = DriverManager.getConnection(url); var stmt = conn.createStatement()) {
            var rs = stmt.executeQuery(sql);
            while (rs.next()) {
                try {
                    var lot = ScraperDataAdapter.fromScraperLot(rs);
                    upsertLot(lot);
                    imported.add(lot);
                } catch (Exception e) {
                    System.err.println("Failed to import lot: " + e.getMessage());
                }
            }
        } catch (SQLException e) {
            // Table might not exist in scraper format - that's ok
            Console.println("ℹ️  Scraper lots table not found or incompatible schema");
        }

        return imported;
    }

    /**
     * Imports image URLs from scraper's schema.
     * The scraper populates the images table with URLs but doesn't download them.
     * This method retrieves undownloaded images for processing.
     *
     * @return List of image URLs that need to be downloaded
     */
    synchronized List<ImageImportRecord> getUnprocessedImagesFromScraper() throws SQLException {
        List<ImageImportRecord> images = new ArrayList<>();
        var sql = """
            SELECT i.lot_id, i.url, l.auction_id
            FROM images i
            LEFT JOIN lots l ON i.lot_id = l.lot_id
            WHERE i.downloaded = 0 OR i.local_path IS NULL
            """;

        try (var conn = DriverManager.getConnection(url); var stmt = conn.createStatement()) {
            var rs = stmt.executeQuery(sql);
            while (rs.next()) {
                String lotIdStr = rs.getString("lot_id");
                String auctionIdStr = rs.getString("auction_id");

                int lotId = ScraperDataAdapter.extractNumericId(lotIdStr);
                int saleId = ScraperDataAdapter.extractNumericId(auctionIdStr);

                images.add(new ImageImportRecord(
                    lotId,
                    saleId,
                    rs.getString("url")
                ));
            }
        } catch (SQLException e) {
            Console.println("ℹ️  No unprocessed images found in scraper format");
        }

        return images;
    }

    /**
     * Simple record for image data from database
     */
    record ImageRecord(int id, int lotId, String url, String filePath, String labels) {}

    /**
     * Record for importing images from scraper format
     */
    record ImageImportRecord(int lotId, int saleId, String url) {}
}