// Copyright (c) 2026 Storm Dragon
// Authors: Storm Dragon, Angus Kola
// SPDX-License-Identifier: GPL-3.0-or-later

package app

import (
	"context"
	"fmt"
	"net/http"
	"net/http/httptest"
	"os"
	"os/exec"
	"strings"
	"testing"
	"time"

	"git.stormux.org/storm/cthulhu/internal/atspi"
	"git.stormux.org/storm/cthulhu/internal/review"
)

// Incremental games rebuild their text leaves on a fast timer. Arrow-key
// reading must keep progressing through the rebuilt lines instead of
// restarting at the first line after every tick, which is how the reported
// Exotic Matter Dimensions and Ordinal Pringles failures presented.
func TestNativeBrowserTickingNavigation(t *testing.T) {
	if os.Getenv("CTHULHU_NATIVE_BROWSER") != "1" {
		t.Skip("requires private browser session")
	}
	ctx, cancel := context.WithTimeout(context.Background(), 35*time.Second)
	defer cancel()
	page := `<!doctype html><title>Ticking navigation regression</title>
<h2>Rebuilt region</h2>
<p id="rebuilt"></p>
<p>After rebuilt region</p>
<button>Final action</button>
<p>Final paragraph</p>
<script>
"use strict";
let tick = 0;
const rebuilt = document.getElementById("rebuilt");
function render() {
  tick++;
  const lines = [];
  for (let line = 1; line <= 3; line++) {
    const span = document.createElement("span");
    span.textContent = "Rebuilt line " + line + " value " + (tick * 10 + line);
    lines.push(span, document.createElement("br"));
  }
  rebuilt.replaceChildren(...lines);
}
render();
setInterval(render, 300);
</script>`
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		fmt.Fprint(w, page)
	}))
	defer server.Close()
	adapter := atspi.New()
	if err := adapter.Start(ctx); err != nil {
		t.Fatal(err)
	}
	defer adapter.Stop(context.Background())
	command := func(args ...string) {
		t.Helper()
		if output, err := exec.CommandContext(ctx, "xdotool", args...).CombinedOutput(); err != nil {
			t.Fatalf("xdotool: %v: %s", err, output)
		}
	}
	command("key", "--clearmodifiers", "ctrl+l")
	command("type", "--clearmodifiers", "--delay", "0", server.URL)
	command("key", "Return")
	var document atspi.ObjectID
	for !document.Valid() {
		select {
		case event := <-adapter.Events():
			if event.Type == atspi.DocumentLoadCompleteEvent && event.Source.Name == "Ticking navigation regression" {
				document = event.Source.ID()
			}
		case <-ctx.Done():
			t.Fatal(ctx.Err())
		}
	}
	worker, err := review.NewWorker(adapter, 2*time.Second)
	if err != nil {
		t.Fatal(err)
	}
	if err := worker.Start(ctx); err != nil {
		t.Fatal(err)
	}
	defer worker.Stop(context.Background())
	worker.SyncFocus(document)
	next := func() (string, bool) {
		t.Helper()
		if err := worker.MoveDocumentCaret(review.CaretNextLine); err != nil {
			t.Fatal(err)
		}
		select {
		case result := <-worker.Results():
			got := result.DocumentCaretText
			if got == "" {
				got = result.DocumentPosition.Snapshot.Name
			}
			if result.Err != nil {
				t.Fatalf("next line on ticking page: %+v", result)
			}
			t.Logf("line=%q moved=%v elapsed=%s capture=%s reason=%v", got, result.Moved, result.Elapsed, result.CaptureDuration, result.CaptureReason)
			return got, result.Moved
		case <-ctx.Done():
			t.Fatal(ctx.Err())
			return "", false
		}
	}
	seen := []int{}
	previous := ""
	for range 14 {
		got, moved := next()
		if !moved {
			break
		}
		if got == previous && strings.HasPrefix(got, "Rebuilt line") {
			t.Fatalf("ticking line repeated instead of progressing: %q", got)
		}
		previous = got
		if line, ok := strings.CutPrefix(got, "Rebuilt line "); ok {
			var number int
			if _, err := fmt.Sscanf(line, "%d", &number); err == nil {
				seen = append(seen, number)
				// Let several ticks recreate every leaf before moving on.
				time.Sleep(700 * time.Millisecond)
			}
			continue
		}
		if strings.Contains(got, "After rebuilt region") {
			if fmt.Sprint(seen) != "[1 2 3]" {
				t.Fatalf("rebuilt lines visited = %v, want [1 2 3] in order", seen)
			}
			if final, _ := next(); !strings.Contains(final, "Final action") {
				t.Fatalf("line after rebuilt region = %q, want Final action", final)
			}
			return
		}
	}
	t.Fatalf("never reached text after the rebuilt region; rebuilt lines visited = %v", seen)
}