package envutil

import (
	"bufio"
	"fmt"
	"os"
	"strings"
)

func LoadDotEnv(path string) error {
	f, err := os.Open(path)
	if err != nil {
		if os.IsNotExist(err) {
			return nil
		}
		return fmt.Errorf("open .env: %w", err)
	}
	defer f.Close()

	scanner := bufio.NewScanner(f)
	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())
		if line == "" || strings.HasPrefix(line, "#") {
			continue
		}
		i := strings.Index(line, "=")
		if i <= 0 {
			continue
		}
		key := strings.TrimSpace(line[:i])
		value := strings.TrimSpace(line[i+1:])
		value = strings.Trim(value, "\"")
		if key == "" {
			continue
		}
		if _, exists := os.LookupEnv(key); !exists {
			_ = os.Setenv(key, value)
		}
	}
	if err := scanner.Err(); err != nil {
		return fmt.Errorf("scan .env: %w", err)
	}
	return nil
}