// Cthulhu screen reader.
// Copyright (c) 2026 Storm Dragon
// Authors: Storm Dragon, Angus Kola
//
// This program is free software: you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the Free
// Software Foundation, either version 3 of the License, or (at your option)
// any later version.
//
// This program is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
// more details.
//
// You should have received a copy of the GNU General Public License along with
// this program. If not, see <https://www.gnu.org/licenses/gpl-3.0.html>.

package atspi

import (
	"errors"
	"math"
	"sync"
	"testing"
)

func TestRectangleIntersection(t *testing.T) {
	tests := []struct {
		name                string
		first, second, want Rectangle
		ok                  bool
	}{
		{"overlap", Rectangle{10, 20, 30, 40}, Rectangle{20, 30, 50, 60}, Rectangle{20, 30, 20, 30}, true},
		{"negative monitor", Rectangle{-100, -50, 90, 40}, Rectangle{-80, -30, 50, 50}, Rectangle{-80, -30, 50, 20}, true},
		{"touching edge", Rectangle{0, 0, 10, 10}, Rectangle{10, 0, 5, 5}, Rectangle{}, false},
		{"disjoint", Rectangle{0, 0, 10, 10}, Rectangle{20, 0, 5, 5}, Rectangle{}, false},
		{"empty", Rectangle{}, Rectangle{0, 0, 10, 10}, Rectangle{}, false},
		{"negative size", Rectangle{0, 0, -1, 10}, Rectangle{0, 0, 10, 10}, Rectangle{}, false},
		{"unavailable position", Rectangle{math.MinInt32, 0, 10, 10}, Rectangle{math.MinInt32, 0, 10, 10}, Rectangle{}, false},
		{"edge overflow", Rectangle{math.MaxInt32 - 5, 0, 10, 10}, Rectangle{math.MaxInt32 - 2, 1, 10, 10}, Rectangle{math.MaxInt32 - 2, 1, 7, 9}, true},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			got, ok := tt.first.Intersection(tt.second)
			if ok != tt.ok || got != tt.want {
				t.Fatalf("intersection = %v %v, want %v %v", got, ok, tt.want, tt.ok)
			}
		})
	}
}

func TestTreeGeometryInvalidationPreservesHierarchy(t *testing.T) {
	nodes := []TreeNode{
		testNode("/root", "Window", testID("/first"), testID("/second")),
		testNode("/first", "First"),
		testNode("/second", "Second", testID("/child")),
		testNode("/child", "Child"),
	}
	geometry := Geometry{Bounds: Rectangle{-10, 20, 30, 40}, BoundsKnown: true, VisibilityKnown: true, Visible: true, Showing: true}
	for i := range nodes {
		nodes[i].Geometry = geometry
	}
	tree, err := NewAccessibleTree(testID("/root"), nodes)
	if err != nil {
		t.Fatal(err)
	}
	second, _ := tree.Reference(testID("/second"))
	child, _, _ := tree.FirstChild(second)
	first, _ := tree.Reference(testID("/first"))
	if count := tree.InvalidateGeometry(second.ID()); count != 2 {
		t.Fatalf("invalidated %d", count)
	}
	if count := tree.InvalidateGeometry(second.ID()); count != 0 {
		t.Fatalf("repeat invalidated %d", count)
	}
	for _, ref := range []ObjectReference{second, child} {
		if _, err := tree.Geometry(ref); !errors.Is(err, ErrStaleGeometry) {
			t.Fatalf("geometry = %v", err)
		}
		if _, err := tree.Resolve(ref); err != nil {
			t.Fatalf("geometry invalidation destroyed identity: %v", err)
		}
	}
	if got, err := tree.Geometry(first); err != nil || got != geometry {
		t.Fatalf("unrelated geometry = %v %v", got, err)
	}
	if got, ok, err := tree.FirstChild(second); err != nil || !ok || got != child {
		t.Fatalf("child = %v %v %v", got, ok, err)
	}
	nodes[2].Geometry.Bounds.X = 25
	if err := tree.Replace(testID("/root"), nodes); err != nil {
		t.Fatal(err)
	}
	if got, err := tree.Geometry(second); err != nil || got.Bounds.X != 25 {
		t.Fatalf("recapture = %v %v", got, err)
	}
	tree.Invalidate(second.ID())
	if _, err := tree.Geometry(child); !errors.Is(err, ErrStaleObject) {
		t.Fatalf("removed geometry = %v", err)
	}
}

func TestTreeRejectsMalformedGeometry(t *testing.T) {
	for _, geometry := range []Geometry{
		{Showing: true},
		{Bounds: Rectangle{0, 0, 10, 10}},
		{BoundsKnown: true},
		{Bounds: Rectangle{0, 0, 10, 10}, BoundsKnown: true, VisibilityKnown: true, Visible: true},
	} {
		node := testNode("/root", "Window")
		node.Geometry = geometry
		if _, err := NewAccessibleTree(testID("/root"), []TreeNode{node}); !errors.Is(err, ErrInvalidTree) {
			t.Fatalf("accepted malformed geometry %v: %v", geometry, err)
		}
	}
}

func TestTreeGeometryConcurrentInvalidation(t *testing.T) {
	tree := testTree(t)
	ref, _ := tree.Reference(testID("/second"))
	var readers sync.WaitGroup
	for range 8 {
		readers.Add(1)
		go func() {
			defer readers.Done()
			for range 100 {
				if _, err := tree.Geometry(ref); err != nil && !errors.Is(err, ErrStaleGeometry) {
					t.Errorf("geometry: %v", err)
					return
				}
			}
		}()
	}
	tree.InvalidateGeometry(ref.ID())
	readers.Wait()
}