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

package review

import (
	"context"
	"errors"
	"testing"
	"time"
	"unicode/utf8"

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

func mirroredCaretCursor(t *testing.T, text caretTextReader, multiple bool) *DocumentCursor {
	t.Helper()
	var nodes []atspi.TreeNode
	for _, path := range []string{"/doc", "/paragraph", "/text", "/other"} {
		snapshot := atspi.Snapshot{BusName: webID(path).BusName, Path: path, Role: "static", CharacterCount: utf8.RuneCountInString(text[webID(path)])}
		node := atspi.TreeNode{Snapshot: snapshot}
		if path == "/doc" {
			node.Snapshot.Role = "document web"
			node.Children = []atspi.ObjectID{webID("/paragraph")}
		}
		if path == "/paragraph" {
			node.Snapshot.Role = "paragraph"
			node.Children = []atspi.ObjectID{webID("/text")}
			if multiple {
				node.Children = append(node.Children, webID("/other"))
			}
		}
		if path == "/other" && !multiple {
			continue
		}
		nodes = append(nodes, node)
	}
	tree, err := atspi.NewAccessibleTree(webID("/doc"), nodes)
	if err != nil {
		t.Fatal(err)
	}
	cursor, err := NewDocumentCursor(tree)
	if err != nil {
		t.Fatal(err)
	}
	return cursor
}

func TestNativeCaretSelectionEndpointTransfersToTextChild(t *testing.T) {
	text := caretTextReader{webID("/paragraph"): "When autocomplete", webID("/text"): "When autocomplete"}
	cursor := mirroredCaretCursor(t, text, false)
	for _, offset := range []int{6, 11, 17, 9, 0} {
		if err := cursor.syncNativeCaret(context.Background(), text, webID("/paragraph"), offset); err != nil {
			t.Fatal(err)
		}
		move, err := cursor.MoveCaret(context.Background(), text, CaretPreviousCharacter)
		if err != nil {
			t.Fatal(err)
		}
		if offset > 0 && (move.Position.Object.ID() != webID("/text") || move.Position.Offset != offset-1) {
			t.Fatalf("offset %d: move = %+v", offset, move)
		}
	}
}

func TestNativeCaretRejectsAmbiguousOffsetDomains(t *testing.T) {
	for _, test := range []struct {
		name, child string
		multiple    bool
		offset      int
	}{
		{"different text same count", "other", false, 2},
		{"different count", "shorter", false, 2},
		{"embedded text", "hello", false, 2},
		{"multiple children", "hello", true, 2},
		{"invalid offset", "hello", false, 6},
	} {
		t.Run(test.name, func(t *testing.T) {
			parent := "hello"
			if test.name == "embedded text" {
				parent = "\ufffc"
			}
			text := caretTextReader{webID("/paragraph"): parent, webID("/text"): test.child}
			cursor := mirroredCaretCursor(t, text, test.multiple)
			if err := cursor.syncNativeCaret(context.Background(), text, webID("/paragraph"), test.offset); !errors.Is(err, atspi.ErrNoDocumentCaret) {
				t.Fatalf("sync = %v", err)
			}
		})
	}
}

func TestWorkerNativeCaretHandoffPrecedesNextArrow(t *testing.T) {
	text := caretTextReader{webID("/text"): "When autocomplete"}
	navigator := &boundaryNavigator{fakeCapturer: &fakeCapturer{}, caretTextReader: text}
	worker, err := NewWorker(navigator, time.Second)
	if err != nil {
		t.Fatal(err)
	}
	worker.SyncFocus(webID("/text"))
	cursor := newCaretTextCursor(t, text)
	syncResult, cursor := worker.syncDocumentCaret(context.Background(), cursor, request{nativeCaretFocus: webID("/text"), nativeCaretOffset: 11})
	if syncResult.Err != nil || syncResult.DocumentPosition.Offset != 11 {
		t.Fatalf("handoff = %+v", syncResult)
	}
	result, _ := worker.moveDocumentCaret(context.Background(), cursor, CaretNextCharacter, 0)
	if result.Err != nil || result.DocumentPosition.Offset != 12 || result.DocumentCaretText != "p" || navigator.offset != 12 {
		t.Fatalf("move after selection = %+v; native offset = %d", result, navigator.offset)
	}
	worker.SyncFocus(webID("/next"))
	stale, _ := worker.syncDocumentCaret(context.Background(), cursor, request{nativeCaretFocus: webID("/text"), nativeCaretOffset: 2})
	if !errors.Is(stale.Err, atspi.ErrStaleObject) {
		t.Fatalf("stale sync = %+v", stale)
	}
}