package feed

import (
	"context"
	"fmt"

	"github.com/gilliek/go-opml/opml"
	"github.com/pkg/errors"

	"github.com/mxpv/podsync/pkg/config"
)

func BuildOPML(ctx context.Context, config *config.Config, db feedProvider, provider urlProvider) (string, error) {
	doc := opml.OPML{Version: "1.0"}
	doc.Head = opml.Head{Title: "Podsync feeds"}
	doc.Body = opml.Body{}

	for _, feed := range config.Feeds {
		f, err := db.GetFeed(ctx, feed.ID)
		if err != nil {
			return "", err
		}

		if feed.OPML {
			downloadURL, err := provider.URL(ctx, "", fmt.Sprintf("%s.xml", feed.ID))
			if err != nil {
				return "", errors.Wrapf(err, "failed to get feed URL for %q", feed.ID)
			}

			outline := opml.Outline{
				Title:  f.Title,
				Text:   f.Description,
				Type:   "rss",
				XMLURL: downloadURL,
			}

			doc.Body.Outlines = append(doc.Body.Outlines, outline)
		}
	}

	out, err := doc.XML()
	if err != nil {
		return "", errors.Wrap(err, "failed to marshal OPML")
	}

	return out, nil
}