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

package atspi

import (
	"context"
	"errors"
	"sync"
	"testing"
)

func TestNavigationDocumentConcurrentReplacementKeepsViewsImmutable(t *testing.T) {
	tree, _ := NewAccessibleTree(testID("/root"), documentTestNodes())
	ref, _ := tree.Reference(testID("/heading"))
	var workers sync.WaitGroup
	workers.Add(1)
	go func() {
		defer workers.Done()
		for range 100 {
			nodes := documentTestNodes()
			for index := range nodes {
				nodes[index].Snapshot.Name = "Replacement"
			}
			if err := tree.Replace(testID("/root"), nodes); err != nil {
				t.Error(err)
				return
			}
		}
	}()
	defer workers.Wait()
	for range 100 {
		view, err := tree.NavigationDocument(context.Background(), ref)
		if err != nil {
			t.Fatal(err)
		}
		replaced := view.Context.Ancestors[0].Name == "Replacement"
		for _, node := range view.Nodes {
			if (node.Snapshot.Name == "Replacement") != replaced {
				t.Fatal("mixed replacement data in shared view")
			}
		}
		if err := tree.ValidateDocumentRange(context.Background(), view, 0, len(view.Nodes)-1); err != nil && !errors.Is(err, ErrStaleObject) {
			t.Fatal(err)
		}
	}
}

func TestNavigationDocumentSharesOnlyImmutableData(t *testing.T) {
	tree, _ := NewAccessibleTree(testID("/root"), documentTestNodes())
	ref, _ := tree.Reference(testID("/heading"))
	first, err := tree.NavigationDocument(context.Background(), ref)
	if err != nil {
		t.Fatal(err)
	}
	second, err := tree.NavigationDocument(context.Background(), ref)
	if err != nil || !first.SameContent(second) || &first.Nodes[0] != &second.Nodes[0] {
		t.Fatal("unchanged document data was rebuilt", err)
	}
	copy, err := tree.Document(context.Background(), ref)
	if err != nil {
		t.Fatal(err)
	}
	copy.Nodes[0].Snapshot.Name = "Changed copy"
	if first.Nodes[0].Snapshot.Name == "Changed copy" {
		t.Fatal("owned snapshot modified shared navigation data")
	}
	for index, node := range first.Nodes {
		if got, ok := first.Index(node.Reference.ID()); !ok || got != index {
			t.Fatalf("index for %v = %d, %v", node.Reference.ID(), got, ok)
		}
		if end := first.SubtreeEnd(index); end < index || end >= len(first.Nodes) {
			t.Fatalf("invalid subtree end %d", end)
		}
	}
}

func TestNavigationDocumentValidatesOnlyTraversedBranches(t *testing.T) {
	for _, test := range []struct {
		name       string
		invalidate func(*AccessibleTree)
		want       error
	}{
		{"text", func(tree *AccessibleTree) { tree.InvalidateText(testID("/link")) }, ErrStaleText},
		{"semantics", func(tree *AccessibleTree) { tree.InvalidateSnapshot(testID("/link")) }, ErrStaleSnapshot},
		{"geometry", func(tree *AccessibleTree) { tree.InvalidateGeometry(testID("/inner")) }, ErrStaleGeometry},
		{"children", func(tree *AccessibleTree) { tree.MarkChildrenChanged(testID("/inner")) }, ErrIncompleteTree},
	} {
		t.Run(test.name, func(t *testing.T) {
			tree, _ := NewAccessibleTree(testID("/root"), documentTestNodes())
			ref, _ := tree.Reference(testID("/heading"))
			view, err := tree.NavigationDocument(context.Background(), ref)
			if err != nil {
				t.Fatal(err)
			}
			test.invalidate(tree)
			current, err := tree.NavigationDocument(context.Background(), ref)
			if err != nil || !current.SameContent(view) {
				t.Fatal("unrelated dirty branch rebuilt document", err)
			}
			heading, _ := view.Index(ref.ID())
			if err := tree.ValidateDocumentRange(context.Background(), view, heading, heading); err != nil {
				t.Fatal("unrelated update blocked current heading", err)
			}
			if err := tree.ValidateDocumentRange(context.Background(), view, heading, len(view.Nodes)-1); !errors.Is(err, test.want) {
				t.Fatalf("traversed stale branch: %v, want %v", err, test.want)
			}
		})
	}
}

func TestNavigationDocumentRejectsRetiredViewsAndCanceledMoves(t *testing.T) {
	tree, _ := NewAccessibleTree(testID("/root"), documentTestNodes())
	ref, _ := tree.Reference(testID("/heading"))
	view, _ := tree.NavigationDocument(context.Background(), ref)
	ctx, cancel := context.WithCancel(context.Background())
	cancel()
	if err := tree.ValidateDocumentRange(ctx, view, 0, 0); !errors.Is(err, context.Canceled) {
		t.Fatal(err)
	}
	if err := tree.Replace(testID("/root"), documentTestNodes()); err != nil {
		t.Fatal(err)
	}
	if err := tree.ValidateDocumentRange(context.Background(), view, 0, 0); !errors.Is(err, ErrStaleObject) {
		t.Fatal("replacement retained old view", err)
	}
	fresh, _ := tree.NavigationDocument(context.Background(), ref)
	if fresh.SameContent(view) {
		t.Fatal("replacement reused navigation data")
	}
	tree.Invalidate(testID("/link"))
	if err := tree.ValidateDocumentRange(context.Background(), fresh, 0, 0); !errors.Is(err, ErrStaleObject) {
		t.Fatal("removal retained old topology", err)
	}
}

func TestNavigationDocumentValidatesDerivedRowDependencies(t *testing.T) {
	node := func(path, role string, children ...ObjectID) TreeNode {
		n := testNode(path, path, children...)
		n.Snapshot.Role = role
		return n
	}
	nodes := []TreeNode{node("/doc", "document web", testID("/table")), node("/table", "table", testID("/first"), testID("/second")), node("/first", "table cell", testID("/text")), node("/text", "static"), node("/second", "table cell")}
	for _, index := range []int{2, 4} {
		nodes[index].Snapshot.TablePositionKnown = true
		nodes[index].Snapshot.TableColumnIndex = index/2 - 1
	}
	tree, err := NewAccessibleTree(testID("/doc"), nodes)
	if err != nil {
		t.Fatal(err)
	}
	ref, _ := tree.Reference(testID("/text"))
	view, err := tree.NavigationDocument(context.Background(), ref)
	if err != nil {
		t.Fatal(err)
	}
	index, _ := view.Index(ref.ID())
	tree.InvalidateText(testID("/second"))
	if err := tree.ValidateDocumentRange(context.Background(), view, index, index); !errors.Is(err, ErrStaleText) {
		t.Fatal("cached full row ignored a changed sibling cell", err)
	}
}