package video

import (
	"fmt"
	"net/url"
	"regexp"
	"strings"
)

// EmbedInfo holds parsed video embed information.
type EmbedInfo struct {
	Provider string
	VideoID  string
	URL      string
}

var (
	youtubeRegexps = []*regexp.Regexp{
		regexp.MustCompile(`(?:youtube\.com/watch\?v=|youtu\.be/|youtube\.com/embed/)([a-zA-Z0-9_-]{11})`),
	}
	vimeoRegexp = regexp.MustCompile(`vimeo\.com/(\d+)`)
	loomRegexp  = regexp.MustCompile(`loom\.com/share/([a-zA-Z0-9]+)`)
)

// ParseEmbedURL parses a video URL and returns embed information.
func ParseEmbedURL(rawURL string) (*EmbedInfo, error) {
	parsed, err := url.Parse(rawURL)
	if err != nil {
		return nil, fmt.Errorf("invalid URL: %w", err)
	}

	host := strings.ToLower(parsed.Host)

	if strings.Contains(host, "youtube.com") || strings.Contains(host, "youtu.be") {
		for _, re := range youtubeRegexps {
			if matches := re.FindStringSubmatch(rawURL); len(matches) > 1 {
				return &EmbedInfo{Provider: "youtube", VideoID: matches[1], URL: rawURL}, nil
			}
		}
	}

	if strings.Contains(host, "vimeo.com") {
		if matches := vimeoRegexp.FindStringSubmatch(rawURL); len(matches) > 1 {
			return &EmbedInfo{Provider: "vimeo", VideoID: matches[1], URL: rawURL}, nil
		}
	}

	if strings.Contains(host, "loom.com") {
		if matches := loomRegexp.FindStringSubmatch(rawURL); len(matches) > 1 {
			return &EmbedInfo{Provider: "loom", VideoID: matches[1], URL: rawURL}, nil
		}
	}

	return nil, fmt.Errorf("unsupported video provider for URL: %s", rawURL)
}

// EmbedIframeURL returns the iframe embed URL for a video provider and ID.
func EmbedIframeURL(provider, videoID string) string {
	switch provider {
	case "youtube":
		return "https://www.youtube.com/embed/" + videoID
	case "vimeo":
		return "https://player.vimeo.com/video/" + videoID
	case "loom":
		return "https://www.loom.com/embed/" + videoID
	default:
		return ""
	}
}