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

package review

import (
	"context"
	"strings"
	"testing"

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

type blockCaretReader struct {
	caretTextReader
	calls, blocks int
	malformed     bool
}

func (reader *blockCaretReader) ReadDocumentCaret(ctx context.Context, object atspi.ObjectReference, offset int, unit atspi.DocumentCaretUnit) (atspi.DocumentCaretText, error) {
	reader.calls++
	return reader.caretTextReader.ReadDocumentCaret(ctx, object, offset, unit)
}

func (reader *blockCaretReader) ReadDocumentCharacters(_ context.Context, object atspi.ObjectReference, offset int) (atspi.DocumentCaretText, error) {
	reader.calls++
	reader.blocks++
	runes := []rune(reader.caretTextReader[object.ID()])
	start := offset / 128 * 128
	end := min(len(runes), start+128)
	raw := string(runes[start:end])
	if reader.malformed {
		raw = ""
	}
	return atspi.DocumentCaretText{Start: start, End: end, RawText: raw, CharacterCount: len(runes)}, nil
}

func TestDocumentWordSpacesUseBoundedBlocks(t *testing.T) {
	values := caretTextReader{webID("/text"): "A" + strings.Repeat(" \t\n\u2003", 250) + "猫"}
	cursor := newCaretTextCursor(t, values)
	reader := &blockCaretReader{caretTextReader: values}
	for _, step := range []struct {
		command DocumentCaretCommand
		text    string
	}{{CaretNextWord, "猫"}, {CaretPreviousWord, "猫"}, {CaretPreviousWord, "A \t\n\u2003"}} {
		move, err := cursor.MoveCaret(context.Background(), reader, step.command)
		// Native word providers include varying trailing whitespace. Retain
		// their text and verify the actual requested word and Unicode offset.
		if err != nil || !strings.HasPrefix(move.Text, strings.TrimSpace(step.text)) {
			t.Fatalf("%s: %+v error=%v", step.command, move, err)
		}
	}
	t.Logf("three word commands across 1000 whitespace characters: %d reads, %d blocks", reader.calls, reader.blocks)
	if reader.blocks == 0 || reader.calls > 50 {
		t.Fatalf("word traversal used %d reads (%d blocks)", reader.calls, reader.blocks)
	}
}

func TestDocumentCharacterMovementDoesNotReadBlocks(t *testing.T) {
	values := caretTextReader{webID("/text"): "A B"}
	cursor := newCaretTextCursor(t, values)
	reader := &blockCaretReader{caretTextReader: values}
	move, err := cursor.MoveCaret(context.Background(), reader, CaretNextCharacter)
	if err != nil || move.Text != " " || reader.blocks != 0 || reader.calls != 1 {
		t.Fatalf("move=%+v error=%v calls=%d blocks=%d", move, err, reader.calls, reader.blocks)
	}
}

func TestDocumentWordMalformedBlockCannotSkipText(t *testing.T) {
	values := caretTextReader{webID("/text"): "A  B"}
	cursor := newCaretTextCursor(t, values)
	reader := &blockCaretReader{caretTextReader: values, malformed: true}
	move, err := cursor.MoveCaret(context.Background(), reader, CaretNextWord)
	if err != nil || move.Text != "B" || move.Position.Offset != 4 {
		t.Fatalf("move=%+v error=%v", move, err)
	}
}