package main

import (
	"fmt"
	"log"
	"net/http"
	"os"

	"golang.org/x/net/html"

	"gioui.org/app"
	"gioui.org/font/gofont"
	"gioui.org/io/system"
	"gioui.org/layout"
	"gioui.org/op"
	"gioui.org/unit"
	"gioui.org/widget/material"
)

// FeedItem represents a single RSS entry
type FeedItem struct {
	Title string
	Link  string
}

// Simple RSS fetcher (parses only <item><title> and <link>)
func fetchRSS(url string) ([]FeedItem, error) {
	resp, err := http.Get(url)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	doc, err := html.Parse(resp.Body)
	if err != nil {
		return nil, err
	}

	var items []FeedItem
	var f func(*html.Node)
	f = func(n *html.Node) {
		if n.Type == html.ElementNode && n.Data == "item" {
			var item FeedItem
			for c := n.FirstChild; c != nil; c = c.NextSibling {
				if c.Type == html.ElementNode {
					switch c.Data {
					case "title":
						if c.FirstChild != nil {
							item.Title = c.FirstChild.Data
						}
					case "link":
						if c.FirstChild != nil {
							item.Link = c.FirstChild.Data
						}
					}
				}
			}
			items = append(items, item)
		}
		for c := n.FirstChild; c != nil; c = c.NextSibling {
			f(c)
		}
	}
	f(doc)
	return items, nil
}

func main() {
	go func() {
		w := app.NewWindow(
			app.Title("MiniRSS"),
			app.Size(unit.Dp(400), unit.Dp(600)),
		)
		if err := loop(w); err != nil {
			log.Fatal(err)
		}
		os.Exit(0)
	}()
	app.Main()
}

func loop(w *app.Window) error {
	th := material.NewTheme(gofont.Collection())

	// Replace with any RSS feed you want to test
	feedURL := "https://xkcd.com/atom.xml"
	items, err := fetchRSS(feedURL)
	if err != nil {
		return fmt.Errorf("failed to fetch RSS: %w", err)
	}

	list := layout.List{
		Axis: layout.Vertical,
	}

	var ops op.Ops
	for {
		e := <-w.Events()
		switch e := e.(type) {
		case system.DestroyEvent:
			return e.Err
		case system.FrameEvent:
			gtx := layout.NewContext(&ops, e)

			list.Layout(gtx, len(items), func(gtx layout.Context, i int) layout.Dimensions {
				title := material.H6(th, items[i].Title)
				return title.Layout(gtx)
			})

			e.Frame(gtx.Ops)
		}
	}
}