package server

import (
	"context"
	"crypto/md5"
	"fmt"
	"io"
	"log/slog"
	"os"
	"path/filepath"
	"slices"

	"git.lastassault.de/speatzle/morffix/constants"
)

func hashFile(ctx context.Context, id uint) error {
	slog.InfoContext(ctx, "Hashing File", "id", id)

	var filePath string
	var libraryPath string
	var oldHash []byte
	err := db.QueryRow(ctx, "SELECT f.path, l.path, md5 FROM files f INNER JOIN libraries l ON l.id = f.library_id WHERE f.id = $1", id).Scan(&filePath, &libraryPath, &oldHash)
	if err != nil {
		return fmt.Errorf("Get File: %w", err)
	}

	fullPath := filepath.Join(libraryPath, filePath)

	file, err := os.Open(fullPath)
	if err != nil {
		return fmt.Errorf("Opening File: %w", err)
	}

	hash := md5.New()
	if _, err := io.Copy(hash, file); err != nil {
		return fmt.Errorf("Reading File: %w", err)
	}
	newHash := hash.Sum(nil)

	if slices.Compare[[]byte](newHash, oldHash) != 0 {
		// File has changed
		// TODO Queue healthcheck / transcode if enabled
	}

	tx, err := db.Begin(ctx)
	if err != nil {
		return fmt.Errorf("Begin Transaction: %w", err)
	}
	defer tx.Rollback(ctx)

	_, err = tx.Exec(ctx, "UPDATE files SET status = $2, md5 = $3 WHERE id = $1", id, constants.FILE_STATUS_EXISTS, newHash)
	if err != nil {
		return fmt.Errorf("Updating File in DB: %w", err)
	}

	err = tx.Commit(ctx)
	if err != nil {
		return fmt.Errorf("Committing Changes: %w", err)
	}
	slog.InfoContext(ctx, "Hashing File Done", "id", id)
	return nil
}