package database

import (
	"database/sql"
	"errors"
)

// GetSetting reads a key from the settings table, returning def if unset.
func GetSetting(db *sql.DB, key, def string) string {
	var v string
	err := db.QueryRow(`SELECT value FROM settings WHERE key = ?`, key).Scan(&v)
	if err != nil {
		return def
	}
	return v
}

func SetSetting(db *sql.DB, key, value string) error {
	_, err := db.Exec(`INSERT INTO settings (key, value, updated_at) VALUES (?, ?, strftime('%Y-%m-%dT%H:%M:%fZ','now'))
		ON CONFLICT (key) DO UPDATE SET value=excluded.value, updated_at=excluded.updated_at`, key, value)
	return err
}

// --- Scan state ---

type ScanState struct {
	ID                 string
	MusicFolderID      string
	Status             string
	StartedAt          sql.NullString
	FinishedAt         sql.NullString
	FilesSeen          int
	FilesTotalEstimate int
	FilesAdded         int
	FilesUpdated       int
	FilesRemoved       int
	ErrorMessage       string
	LastFullScanAt     sql.NullString
}

const scanStateSelect = `SELECT id, music_folder_id, status, started_at, finished_at, files_seen, files_total_estimate, files_added, files_updated, files_removed, error_message, last_full_scan_at FROM scan_state`

func GetScanState(db *sql.DB, folderID string) (*ScanState, error) {
	var s ScanState
	err := db.QueryRow(scanStateSelect+` WHERE music_folder_id = ?`, folderID).Scan(
		&s.ID, &s.MusicFolderID, &s.Status, &s.StartedAt, &s.FinishedAt, &s.FilesSeen, &s.FilesTotalEstimate,
		&s.FilesAdded, &s.FilesUpdated, &s.FilesRemoved, &s.ErrorMessage, &s.LastFullScanAt)
	if errors.Is(err, sql.ErrNoRows) {
		return nil, ErrNotFound
	}
	if err != nil {
		return nil, err
	}
	return &s, nil
}

func ListScanStates(db *sql.DB) ([]*ScanState, error) {
	rows, err := db.Query(scanStateSelect)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var out []*ScanState
	for rows.Next() {
		var s ScanState
		if err := rows.Scan(&s.ID, &s.MusicFolderID, &s.Status, &s.StartedAt, &s.FinishedAt, &s.FilesSeen, &s.FilesTotalEstimate,
			&s.FilesAdded, &s.FilesUpdated, &s.FilesRemoved, &s.ErrorMessage, &s.LastFullScanAt); err != nil {
			return nil, err
		}
		out = append(out, &s)
	}
	return out, rows.Err()
}

func StartScan(db *sql.DB, folderID string) error {
	_, err := db.Exec(`UPDATE scan_state SET status='scanning', started_at=strftime('%Y-%m-%dT%H:%M:%fZ','now'), finished_at=NULL,
		files_seen=0, files_added=0, files_updated=0, files_removed=0, error_message='' WHERE music_folder_id=?`, folderID)
	return err
}

func UpdateScanProgress(db *sql.DB, folderID string, filesSeen, filesAdded, filesUpdated int) error {
	_, err := db.Exec(`UPDATE scan_state SET files_seen=?, files_added=?, files_updated=? WHERE music_folder_id=?`,
		filesSeen, filesAdded, filesUpdated, folderID)
	return err
}

func FinishScan(db *sql.DB, folderID string, filesRemoved int, errMsg string) error {
	status := "idle"
	if errMsg != "" {
		status = "error"
	}
	_, err := db.Exec(`UPDATE scan_state SET status=?, finished_at=strftime('%Y-%m-%dT%H:%M:%fZ','now'), files_removed=?, error_message=?,
		last_full_scan_at=strftime('%Y-%m-%dT%H:%M:%fZ','now') WHERE music_folder_id=?`, status, filesRemoved, errMsg, folderID)
	return err
}