package app

import (
	"database/sql"
	"encoding/json"
	"fmt"
	"os"
	"path/filepath"

	_ "modernc.org/sqlite"
)

type Store struct{ db *sql.DB }

func OpenStore(dir string) (*Store, error) {
	if err := os.MkdirAll(dir, 0700); err != nil {
		return nil, err
	}
	p := filepath.Join(dir, "clashweb.sqlite")
	f, err := os.OpenFile(p, os.O_CREATE|os.O_RDWR, 0600)
	if err != nil {
		return nil, err
	}
	f.Close()
	db, err := sql.Open("sqlite", p)
	if err != nil {
		return nil, err
	}
	db.SetMaxOpenConns(1)
	_, err = db.Exec(`PRAGMA journal_mode=WAL; PRAGMA busy_timeout=5000;
	CREATE TABLE IF NOT EXISTS kv (key TEXT PRIMARY KEY, value TEXT NOT NULL);
	CREATE TABLE IF NOT EXISTS sessions (token_hash TEXT PRIMARY KEY, csrf TEXT NOT NULL, expires INTEGER NOT NULL);
	PRAGMA user_version=1;`)
	if err != nil {
		db.Close()
		return nil, err
	}
	return &Store{db: db}, nil
}

func (s *Store) Close() error { return s.db.Close() }
func (s *Store) Get(key string) (string, error) {
	var value string
	err := s.db.QueryRow("SELECT value FROM kv WHERE key=?", key).Scan(&value)
	if err == sql.ErrNoRows {
		return "", nil
	}
	return value, err
}
func (s *Store) Set(key, value string) error {
	_, err := s.db.Exec("INSERT INTO kv(key,value) VALUES(?,?) ON CONFLICT(key) DO UPDATE SET value=excluded.value", key, value)
	return err
}
func (s *Store) Load() (State, error) {
	text, err := s.Get("state")
	if err != nil {
		return State{}, err
	}
	if text == "" {
		return defaultState(), nil
	}
	var state State
	if err := json.Unmarshal([]byte(text), &state); err != nil {
		return State{}, fmt.Errorf("数据库中的配置损坏: %w", err)
	}
	return state, validateState(state)
}
func (s *Store) Save(state State) error {
	b, err := json.Marshal(state)
	if err != nil {
		return err
	}
	return s.Set("state", string(b))
}