// Copyright (C) 2021 nytpu
// SPDX-License-Identifier: AGPL-3.0-or-later
// For more license details, see LICENSE or <https://www.gnu.org/licenses/agpl-3.0.html>.

package fetch

import (
	"bytes"
	"crypto/sha256"
	"fmt"
	"io"
	"net/url"
	"time"

	//"github.com/mmcdole/gofeed"
	"github.com/prologic/go-gopher"

	"golang.nytpu.com/comitium/core"
)

// fetchGopher will make a request for a gopher resource
func fetchGopher(remoteURL *url.URL) (*gopher.Response, error) {
	resp, err := gopher.Get(remoteURL.String())
	if err != nil {
		return nil, err
	}
	return resp, nil
}

// newGopherFeed will fetch and create a new core.Feed given a gopher url
func newGopherFeed(remoteURL *url.URL, title string) (*core.Feed, error) {
	// TODO
	return nil, fmt.Errorf("Feeds served over gopher are currently unsupported.")
}

// updateGopherFeed will check an existing core.Feed for updates
func updateGopherFeed(*core.Feed) error {
	// TODO
	return fmt.Errorf("Feeds served over gopher are currently unsupported.")
}

// newGopherPage will create a new core.Page given a gopher url
func newGopherPage(remoteURL *url.URL, title string) (*core.Page, error) {
	var page core.Page
	page.Title = title
	page.Link = remoteURL

	err := updateGopherPage(&page)
	if err != nil {
		return nil, err
	}
	return &page, nil
}

// updateGopherPage wll check an existing core.Page for changes
func updateGopherPage(p *core.Page) error {
	resp, err := fetchGopher(p.Link)
	if err != nil {
		return err
	}
	defer resp.Body.Close()

	var reader io.Reader
	if len(resp.Dir.Items) > 0 {
		text, err := resp.Dir.ToText()
		if err != nil {
			return err
		}
		reader = io.LimitReader(bytes.NewReader(text), 1073741824) // 1 GiB
	} else {
		reader = io.LimitReader(resp.Body, 1073741824) // 1 GiB
	}

	h := sha256.New()
	if _, err := io.Copy(h, reader); err != nil {
		return err
	}
	newHash := fmt.Sprintf("%x", h.Sum(nil))
	if newHash != p.Hash {
		p.Hash = newHash
		p.Updated = time.Now()
	}
	return nil
}