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

package review

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

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

type fragmentTextReader struct {
	caretTextReader
	bounds map[atspi.ObjectID]atspi.Rectangle
	err    error
}

func (reader fragmentTextReader) ReadDocumentCaret(ctx context.Context, ref atspi.ObjectReference, offset int, unit atspi.DocumentCaretUnit) (atspi.DocumentCaretText, error) {
	if reader.err != nil {
		return atspi.DocumentCaretText{}, reader.err
	}
	text, err := reader.caretTextReader.ReadDocumentCaret(ctx, ref, offset, unit)
	text.RawText, text.Bounds = text.Text, reader.bounds[ref.ID()]
	return text, err
}

func fragment_cursor(t *testing.T, boundary string) (*DocumentCursor, fragmentTextReader) {
	t.Helper()
	reader := fragmentTextReader{caretTextReader: caretTextReader{
		webID("/one"): "One ", webID("/two"): "two.", webID("/three"): "Three ", webID("/four"): "four.", webID("/after"): "Next paragraph",
	}, bounds: make(map[atspi.ObjectID]atspi.Rectangle)}
	for _, row := range []struct {
		path string
		x, y int32
	}{{"/one", 0, 10}, {"/two", 40, 10}, {"/three", 0, 30}, {"/four", 50, 30}, {"/after", 100, 30}} {
		reader.bounds[webID(row.path)] = atspi.Rectangle{X: row.x, Y: row.y, Width: 30, Height: 18}
	}
	node := func(path, role string, children ...string) atspi.TreeNode {
		snapshot := atspi.NewSnapshot(path, "", role, "", "")
		snapshot.BusName, snapshot.CharacterCount = webID(path).BusName, utf8.RuneCountInString(reader.caretTextReader[webID(path)])
		result := atspi.TreeNode{Snapshot: snapshot}
		for _, child := range children {
			result.Children = append(result.Children, webID(child))
		}
		return result
	}
	block := node("/paragraph", boundary, "/one", "/span", "/three", "/four")
	span := node("/span", "section", "/two")
	span.Snapshot.HTMLTag = "span"
	if boundary == "pre" || boundary == "code" {
		block.Snapshot.HTMLTag = boundary
	}
	if boundary == "entry" {
		block.Snapshot.Editable = true
	}
	tree, err := atspi.NewAccessibleTree(webID("/doc"), []atspi.TreeNode{
		node("/doc", "document web", "/paragraph", "/next"), block,
		node("/one", "static"), span, node("/two", "static"),
		node("/three", "static"), node("/four", "static"), node("/next", "paragraph", "/after"), node("/after", "static"),
	})
	if err != nil {
		t.Fatal(err)
	}
	cursor, err := NewDocumentCursor(tree)
	if err != nil {
		t.Fatal(err)
	}
	if _, err := cursor.SyncFocus(context.Background(), webID("/one")); err != nil {
		t.Fatal(err)
	}
	return cursor, reader
}

func TestDocumentFragmentLines(t *testing.T) {
	cursor, reader := fragment_cursor(t, "paragraph")
	ctx := context.Background()
	for _, step := range []struct {
		command    DocumentCaretCommand
		path, text string
		offset     int
	}{
		{CaretDocumentStart, "/one", "One two.", 0},
		{CaretNextCharacter, "/one", "n", 1},
		{CaretNextLine, "/three", "Three four.", 0},
		{CaretPreviousLine, "/one", "One two.", 0},
		{CaretLineEnd, "/two", ".", 3},
		{CaretLineStart, "/one", "O", 0},
		{CaretNextLine, "/three", "Three four.", 0},
		{CaretNextLine, "/after", "Next paragraph", 0},
		{CaretPreviousLine, "/three", "Three four.", 0},
	} {
		move, err := cursor.MoveCaret(ctx, reader, step.command)
		if err != nil || !move.Moved || move.Text != step.text || move.Position.Object.ID() != webID(step.path) || move.Position.Offset != step.offset {
			t.Fatalf("%s: %+v, %v; want %s:%d %q", step.command, move, err, step.path, step.offset, step.text)
		}
		if move.End > 0 && move.End > move.Position.Snapshot.CharacterCount {
			t.Fatal("joined offset escaped native object")
		}
	}
}

func TestDocumentFragmentSpacingAndPunctuation(t *testing.T) {
	for _, test := range []struct {
		first, second, want string
		x                   int32
	}{
		{"One ", "two.", "One two.", 40},
		{"One", "two.", "One two.", 40},
		{"Hello", ",", "Hello,", 30},
	} {
		cursor, reader := fragment_cursor(t, "paragraph")
		reader.caretTextReader[webID("/one")] = test.first
		reader.caretTextReader[webID("/two")] = test.second
		bounds := reader.bounds[webID("/two")]
		bounds.X = test.x
		reader.bounds[webID("/two")] = bounds
		// Range lengths come from the provider, just as in a native capture.
		doc, _ := cursor.tree.Document(context.Background(), cursor.places[0].object)
		var nodes []atspi.TreeNode
		for _, node := range doc.Nodes {
			if text, ok := reader.caretTextReader[node.Reference.ID()]; ok {
				node.Snapshot.CharacterCount = utf8.RuneCountInString(text)
			}
			nodes = append(nodes, atspi.TreeNode{Snapshot: node.Snapshot, Children: node.Children})
		}
		if err := cursor.tree.Replace(webID("/doc"), nodes); err != nil {
			t.Fatal(err)
		}
		move, err := cursor.MoveCaret(context.Background(), reader, CaretDocumentStart)
		if err != nil || move.Text != test.want {
			t.Fatalf("fragments %q/%q: %+v, %v; want %q", test.first, test.second, move, err, test.want)
		}
	}
}

type fragmentReadAllCapturer struct {
	*readAllCapturer
	fragmentTextReader
}

func (capturer *fragmentReadAllCapturer) ReadDocumentCaret(ctx context.Context, ref atspi.ObjectReference, offset int, unit atspi.DocumentCaretUnit) (atspi.DocumentCaretText, error) {
	return capturer.fragmentTextReader.ReadDocumentCaret(ctx, ref, offset, unit)
}

func TestReadAllFragmentLinesAndRemainder(t *testing.T) {
	cursor, reader := fragment_cursor(t, "paragraph")
	ctx := context.Background()
	if _, err := cursor.MoveCaret(ctx, reader, CaretNextCharacter); err != nil {
		t.Fatal(err)
	}
	capturer := &fragmentReadAllCapturer{readAllCapturer: &readAllCapturer{tree: cursor.tree}, fragmentTextReader: reader}
	worker, _ := NewWorker(capturer, time.Second)
	worker.SyncFocus(webID("/one"))
	result := worker.readAll(ctx, cursor)
	if result.Err != nil || len(result.ReadAllLines) != 3 {
		t.Fatalf("read all: %+v", result)
	}
	for index, want := range []string{"ne two.", "Three four.", "Next paragraph"} {
		if got := result.ReadAllLines[index].Contents[0].Text; got != want {
			t.Fatalf("line %d: %q, want %q", index, got, want)
		}
	}
	if cursor.places[0].offset != 1 {
		t.Fatal("assembly moved the user's cursor")
	}
	result.ReadAllProgress(1)
	request := <-worker.requests
	followed, ok := worker.followReadAll(ctx, cursor, request)
	if !ok {
		t.Fatal("progress lost ownership")
	}
	move, err := followed.MoveCaret(ctx, reader, CaretNextLine)
	if err != nil || move.Text != "Next paragraph" {
		t.Fatalf("Down after progress: %+v, %v", move, err)
	}
}

func TestDocumentFragmentBoundaries(t *testing.T) {
	for _, boundary := range []string{"heading", "link", "table cell", "pre", "code", "entry"} {
		t.Run(boundary, func(t *testing.T) {
			cursor, reader := fragment_cursor(t, boundary)
			move, err := cursor.MoveCaret(context.Background(), reader, CaretDocumentStart)
			want := "One two."
			if boundary == "pre" || boundary == "code" || boundary == "entry" {
				want = "One "
			}
			if boundary == "entry" {
				want = ""
			}
			if err != nil || move.Text != want {
				t.Fatalf("%s: %+v, %v; want %q", boundary, move, err, want)
			}
		})
	}
}

func TestDocumentFragmentErrorsDoNotMoveCursor(t *testing.T) {
	for _, failure := range []error{context.Canceled, atspi.ErrStaleObject} {
		cursor, reader := fragment_cursor(t, "paragraph")
		reader.err = failure
		before := cursor.places[0]
		_, err := cursor.MoveCaret(context.Background(), reader, CaretNextLine)
		if !errors.Is(err, failure) || cursor.places[0] != before {
			t.Fatalf("error %v: %v; changed cursor", failure, err)
		}
	}
}

type wrappedFragmentReader struct{ fragmentTextReader }

func (reader wrappedFragmentReader) ReadDocumentCaret(ctx context.Context, ref atspi.ObjectReference, offset int, unit atspi.DocumentCaretUnit) (atspi.DocumentCaretText, error) {
	text, err := reader.fragmentTextReader.ReadDocumentCaret(ctx, ref, offset, unit)
	if ref.ID() == webID("/one") && offset >= 6 {
		text.Bounds.Y = 30
	}
	return text, err
}

func TestDocumentFragmentLineAcrossWrappedObject(t *testing.T) {
	cursor, base := fragment_cursor(t, "paragraph")
	base.caretTextReader[webID("/one")] = "First\nSecond "
	base.bounds[webID("/two")] = atspi.Rectangle{X: 60, Y: 30, Width: 30, Height: 18}
	base.bounds[webID("/three")] = atspi.Rectangle{X: 0, Y: 50, Width: 30, Height: 18}
	base.bounds[webID("/four")] = atspi.Rectangle{X: 50, Y: 50, Width: 30, Height: 18}
	ref, _ := cursor.tree.Reference(webID("/one"))
	doc, err := cursor.tree.Document(context.Background(), ref)
	if err != nil {
		t.Fatal(err)
	}
	nodes := make([]atspi.TreeNode, 0, len(doc.Nodes))
	for _, node := range doc.Nodes {
		if node.Reference == ref {
			node.Snapshot.CharacterCount = utf8.RuneCountInString(base.caretTextReader[webID("/one")])
		}
		nodes = append(nodes, atspi.TreeNode{Snapshot: node.Snapshot, Children: node.Children})
	}
	if err := cursor.tree.Replace(webID("/doc"), nodes); err != nil {
		t.Fatal(err)
	}
	reader := wrappedFragmentReader{base}
	for _, step := range []struct {
		command DocumentCaretCommand
		want    string
	}{
		{CaretDocumentStart, "First"}, {CaretNextLine, "Second two."},
		{CaretPreviousLine, "First"}, {CaretNextLine, "Second two."}, {CaretNextLine, "Three four."},
	} {
		move, err := cursor.MoveCaret(context.Background(), reader, step.command)
		if err != nil || strings.TrimSpace(move.Text) != step.want {
			t.Fatalf("%s: %+v, %v; want %q", step.command, move, err, step.want)
		}
	}
}