package database

import (
	"context"
	"database/sql"
	"fmt"
	"time"
)

type FileRepository struct {
	db *DB
}

func NewFileRepository(db *DB) *FileRepository {
	return &FileRepository{db: db}
}

func (r *FileRepository) Create(ctx context.Context, tx *sql.Tx, file *File) error {
	query := `
		INSERT INTO files (path, mtime, ctime, size, mode, uid, gid, link_target)
		VALUES (?, ?, ?, ?, ?, ?, ?, ?)
		ON CONFLICT(path) DO UPDATE SET
			mtime = excluded.mtime,
			ctime = excluded.ctime,
			size = excluded.size,
			mode = excluded.mode,
			uid = excluded.uid,
			gid = excluded.gid,
			link_target = excluded.link_target
	`

	var err error
	if tx != nil {
		_, err = tx.ExecContext(ctx, query, file.Path, file.MTime.Unix(), file.CTime.Unix(), file.Size, file.Mode, file.UID, file.GID, file.LinkTarget)
	} else {
		_, err = r.db.ExecWithLock(ctx, query, file.Path, file.MTime.Unix(), file.CTime.Unix(), file.Size, file.Mode, file.UID, file.GID, file.LinkTarget)
	}

	if err != nil {
		return fmt.Errorf("inserting file: %w", err)
	}

	return nil
}

func (r *FileRepository) GetByPath(ctx context.Context, path string) (*File, error) {
	query := `
		SELECT path, mtime, ctime, size, mode, uid, gid, link_target
		FROM files
		WHERE path = ?
	`

	var file File
	var mtimeUnix, ctimeUnix int64
	var linkTarget sql.NullString

	err := r.db.conn.QueryRowContext(ctx, query, path).Scan(
		&file.Path,
		&mtimeUnix,
		&ctimeUnix,
		&file.Size,
		&file.Mode,
		&file.UID,
		&file.GID,
		&linkTarget,
	)

	if err == sql.ErrNoRows {
		return nil, nil
	}
	if err != nil {
		return nil, fmt.Errorf("querying file: %w", err)
	}

	file.MTime = time.Unix(mtimeUnix, 0)
	file.CTime = time.Unix(ctimeUnix, 0)
	if linkTarget.Valid {
		file.LinkTarget = linkTarget.String
	}

	return &file, nil
}

func (r *FileRepository) ListModifiedSince(ctx context.Context, since time.Time) ([]*File, error) {
	query := `
		SELECT path, mtime, ctime, size, mode, uid, gid, link_target
		FROM files
		WHERE mtime >= ?
		ORDER BY path
	`

	rows, err := r.db.conn.QueryContext(ctx, query, since.Unix())
	if err != nil {
		return nil, fmt.Errorf("querying files: %w", err)
	}
	defer CloseRows(rows)

	var files []*File
	for rows.Next() {
		var file File
		var mtimeUnix, ctimeUnix int64
		var linkTarget sql.NullString

		err := rows.Scan(
			&file.Path,
			&mtimeUnix,
			&ctimeUnix,
			&file.Size,
			&file.Mode,
			&file.UID,
			&file.GID,
			&linkTarget,
		)
		if err != nil {
			return nil, fmt.Errorf("scanning file: %w", err)
		}

		file.MTime = time.Unix(mtimeUnix, 0)
		file.CTime = time.Unix(ctimeUnix, 0)
		if linkTarget.Valid {
			file.LinkTarget = linkTarget.String
		}

		files = append(files, &file)
	}

	return files, rows.Err()
}

func (r *FileRepository) Delete(ctx context.Context, tx *sql.Tx, path string) error {
	query := `DELETE FROM files WHERE path = ?`

	var err error
	if tx != nil {
		_, err = tx.ExecContext(ctx, query, path)
	} else {
		_, err = r.db.ExecWithLock(ctx, query, path)
	}

	if err != nil {
		return fmt.Errorf("deleting file: %w", err)
	}

	return nil
}

func (r *FileRepository) ListByPrefix(ctx context.Context, prefix string) ([]*File, error) {
	query := `
		SELECT path, mtime, ctime, size, mode, uid, gid, link_target
		FROM files
		WHERE path LIKE ? || '%'
		ORDER BY path
	`

	rows, err := r.db.conn.QueryContext(ctx, query, prefix)
	if err != nil {
		return nil, fmt.Errorf("querying files: %w", err)
	}
	defer CloseRows(rows)

	var files []*File
	for rows.Next() {
		var file File
		var mtimeUnix, ctimeUnix int64
		var linkTarget sql.NullString

		err := rows.Scan(
			&file.Path,
			&mtimeUnix,
			&ctimeUnix,
			&file.Size,
			&file.Mode,
			&file.UID,
			&file.GID,
			&linkTarget,
		)
		if err != nil {
			return nil, fmt.Errorf("scanning file: %w", err)
		}

		file.MTime = time.Unix(mtimeUnix, 0)
		file.CTime = time.Unix(ctimeUnix, 0)
		if linkTarget.Valid {
			file.LinkTarget = linkTarget.String
		}

		files = append(files, &file)
	}

	return files, rows.Err()
}