package db

import (
	"context"
	"doudizhu-server/internal/models"
	"fmt"
	"time"

	"github.com/jackc/pgx/v5/pgxpool"
)

type Config struct {
	Host     string
	Port     int
	User     string
	Password string
	Database string
}

type DB struct {
	pool *pgxpool.Pool
}

func New(cfg Config) (*DB, error) {
	connStr := fmt.Sprintf(
		"host=%s port=%d user=%s password=%s dbname=%s sslmode=disable",
		cfg.Host, cfg.Port, cfg.User, cfg.Password, cfg.Database,
	)

	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()

	pool, err := pgxpool.New(ctx, connStr)
	if err != nil {
		return nil, fmt.Errorf("failed to connect to database: %w", err)
	}

	if err := pool.Ping(ctx); err != nil {
		pool.Close()
		return nil, fmt.Errorf("failed to ping database: %w", err)
	}

	return &DB{pool: pool}, nil
}

func (d *DB) Close() {
	if d.pool != nil {
		d.pool.Close()
	}
}

func (d *DB) CreateUser(ctx context.Context, user *models.User) error {
	query := `
		INSERT INTO users (id, username, password, nickname, created_at, updated_at)
		VALUES ($1, $2, $3, $4, $5, $5)
	`
	_, err := d.pool.Exec(ctx, query, user.ID, user.Username, user.Password, user.Nickname, time.Now())
	if err != nil {
		return fmt.Errorf("failed to create user: %w", err)
	}
	return nil
}

func (d *DB) GetUserByUsername(ctx context.Context, username string) (*models.User, error) {
	query := `
		SELECT id, username, password, nickname
		FROM users
		WHERE username = $1
	`
	user := &models.User{}
	err := d.pool.QueryRow(ctx, query, username).Scan(
		&user.ID, &user.Username, &user.Password, &user.Nickname,
	)
	if err != nil {
		return nil, fmt.Errorf("failed to get user: %w", err)
	}
	return user, nil
}

func (d *DB) GetUserByID(ctx context.Context, id string) (*models.User, error) {
	query := `
		SELECT id, username, password, nickname
		FROM users
		WHERE id = $1
	`
	user := &models.User{}
	err := d.pool.QueryRow(ctx, query, id).Scan(
		&user.ID, &user.Username, &user.Password, &user.Nickname,
	)
	if err != nil {
		return nil, fmt.Errorf("failed to get user: %w", err)
	}
	return user, nil
}

func (d *DB) UsernameExists(ctx context.Context, username string) (bool, error) {
	query := `SELECT EXISTS(SELECT 1 FROM users WHERE username = $1)`
	var exists bool
	err := d.pool.QueryRow(ctx, query, username).Scan(&exists)
	if err != nil {
		return false, fmt.Errorf("failed to check username: %w", err)
	}
	return exists, nil
}