package domain

import (
	"errors"
	"net/url"
	"strings"
)

// NormalizeOpenAICompatibleBaseEndpoint trims and validates a source-neutral
// OpenAI-compatible provider base endpoint.
func NormalizeOpenAICompatibleBaseEndpoint(endpoint string) (string, error) {
	endpoint = strings.TrimSpace(endpoint)
	if endpoint == "" {
		return "", errors.New("endpoint must not be blank")
	}
	if strings.Contains(endpoint, "#") {
		return "", errors.New("endpoint must not contain a fragment")
	}

	parsed, err := url.Parse(endpoint)
	if err != nil {
		return "", errors.New("endpoint must be a valid URL")
	}
	parsed.Scheme = strings.ToLower(parsed.Scheme)
	if parsed.Scheme != "http" && parsed.Scheme != "https" {
		return "", errors.New("endpoint must use http or https")
	}
	if !parsed.IsAbs() || parsed.Hostname() == "" {
		return "", errors.New("endpoint must be absolute and include a host")
	}
	if parsed.User != nil {
		return "", errors.New("endpoint must not contain user information")
	}
	if parsed.RawQuery != "" || parsed.ForceQuery {
		return "", errors.New("endpoint must not contain a query string")
	}

	return parsed.String(), nil
}