package db

import (
	"database/sql"
	"fmt"
	"net"
	"strings"
	"time"

	_ "github.com/jackc/pgx/v5/stdlib"
)

type PostgresConfig struct {
	Address         string
	Username        string
	Password        string
	Database        string
	SSLMode         string
	MaxOpenConns    int
	MaxIdleConns    int
	ConnMaxLifetime string
	ConnMaxIdleTime string
}

func NewPostgres(cfg PostgresConfig) (*sql.DB, error) {
	if cfg.Address == "" {
		return nil, fmt.Errorf("database address is required")
	}
	if cfg.Username == "" {
		return nil, fmt.Errorf("database username is required")
	}
	if cfg.Database == "" {
		return nil, fmt.Errorf("database name is required")
	}

	host, port := parseAddress(cfg.Address)
	if host == "" {
		return nil, fmt.Errorf("database address is invalid")
	}

	connMaxLifetime, err := parseDuration(cfg.ConnMaxLifetime)
	if err != nil {
		return nil, fmt.Errorf("conn_max_lifetime: %w", err)
	}
	connMaxIdleTime, err := parseDuration(cfg.ConnMaxIdleTime)
	if err != nil {
		return nil, fmt.Errorf("conn_max_idle_time: %w", err)
	}

	dsn := fmt.Sprintf(
		"host=%s port=%s user=%s password=%s dbname=%s sslmode=%s",
		host, port, cfg.Username, cfg.Password, cfg.Database, cfg.SSLMode,
	)

	db, err := sql.Open("pgx", dsn)
	if err != nil {
		return nil, fmt.Errorf("open postgres: %w", err)
	}

	db.SetMaxOpenConns(cfg.MaxOpenConns)
	db.SetMaxIdleConns(cfg.MaxIdleConns)
	db.SetConnMaxLifetime(connMaxLifetime)
	db.SetConnMaxIdleTime(connMaxIdleTime)

	if err := db.Ping(); err != nil {
		return nil, fmt.Errorf("ping postgres: %w", err)
	}

	return db, nil
}

func parseAddress(address string) (string, string) {
	address = strings.TrimSpace(address)
	if address == "" {
		return "", ""
	}

	if strings.Contains(address, ":") {
		host, port, err := net.SplitHostPort(address)
		if err == nil && host != "" && port != "" {
			return host, port
		}
	}

	return address, "5432"
}

func parseDuration(value string) (time.Duration, error) {
	if strings.TrimSpace(value) == "" {
		return 0, nil
	}
	return time.ParseDuration(value)
}