// Copyright (c) 2024, Přemysl Eric Janouch <p@janouch.name>
// SPDX-License-Identifier: 0BSD

package main

import (
	"bufio"
	"context"
	"encoding/binary"
	"flag"
	"fmt"
	"io"
	"log"
	"net"
	"net/url"
	"os"

	"fyne.io/fyne/v2"
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/container"
	"fyne.io/fyne/v2/widget"
)

var (
	debug          = flag.Bool("debug", false, "enable debug output")
	projectName    = "xA"
	projectVersion = "?"
	addressConnect string
)

// -----------------------------------------------------------------------------

func relayReadFrame(r io.Reader) []byte {
	var length uint32
	if err := binary.Read(r, binary.BigEndian, &length); err != nil {
		log.Println("Event receive failed: " + err.Error())
		return nil
	}
	b := make([]byte, length)
	if _, err := io.ReadFull(r, b); err != nil {
		log.Println("Event receive failed: " + err.Error())
		return nil
	}

	if *debug {
		log.Printf("<? %v\n", b)

		var m RelayEventMessage
		if after, ok := m.ConsumeFrom(b); !ok {
			log.Println("Event deserialization failed")
			return nil
		} else if len(after) != 0 {
			log.Println("Event deserialization failed: trailing data")
			return nil
		}

		j, err := m.MarshalJSON()
		if err != nil {
			log.Println("Event marshalling failed: " + err.Error())
			return nil
		}

		log.Printf("<- %s\n", j)
	}
	return b
}

func relayMakeReceiver(ctx context.Context, conn net.Conn) <-chan []byte {
	// The usual event message rarely gets above 1 kilobyte,
	// thus this is set to buffer up at most 1 megabyte or so.
	p := make(chan []byte, 1000)
	r := bufio.NewReaderSize(conn, 65536)
	go func() {
		defer close(p)
		for {
			j := relayReadFrame(r)
			if j == nil {
				return
			}
			select {
			case p <- j:
			case <-ctx.Done():
				return
			}
		}
	}()
	return p
}

func main() {
	flag.Usage = func() {
		fmt.Fprintf(flag.CommandLine.Output(),
			"Usage: %s [OPTION...] CONNECT\n\n", os.Args[0])
		flag.PrintDefaults()
	}

	flag.Parse()
	if flag.NArg() < 1 || flag.NArg() > 1 {
		flag.Usage()
		os.Exit(1)
	}

	addressConnect = flag.Arg(0)

	// TODO(p): First, test Fyne's GUI capabilities.

	a := app.New()
	w := a.NewWindow(projectName)

	// TODO(p): There should also be a widget.NewLabel() next to the entry.
	//  - Probably another Border, even though this seems odd.
	var (
		richtext   = widget.NewRichText()
		richscroll = container.NewVScroll(richtext)
		entry      = widget.NewMultiLineEntry()
	)
	w.SetContent(container.NewBorder(nil, entry, nil, nil, richscroll))

	testURL, _ := url.Parse("https://x.com")
	richtext.Segments = []widget.RichTextSegment{
		&widget.ParagraphSegment{Texts: []widget.RichTextSegment{
			&widget.TextSegment{Text: "Test"},
			&widget.HyperlinkSegment{Text: "X", URL: testURL},
			&widget.TextSegment{
				Text:  " is a website, certainly",
				Style: widget.RichTextStyleInline,
			},
		}},
		&widget.TextSegment{Style: widget.RichTextStyleParagraph},
		&widget.SeparatorSegment{},
		&widget.TextSegment{Text: "Paragraph"},
	}
	richtext.Wrapping = fyne.TextWrapWord
	richtext.Refresh()

	w.ShowAndRun()
}