package main

import (
	"reflect"
	"testing"
)

func TestJSONPatcher_Add(t *testing.T) {
	patcher := &JSONPatcher{}

	tests := []struct {
		name     string
		doc      map[string]interface{}
		patches  []PatchOperation
		expected map[string]interface{}
		wantErr  bool
	}{
		{
			name: "add simple field",
			doc:  map[string]interface{}{},
			patches: []PatchOperation{
				{Op: "add", Path: "/name", Value: "John"},
			},
			expected: map[string]interface{}{
				"name": "John",
			},
			wantErr: false,
		},
		{
			name: "add nested field",
			doc: map[string]interface{}{
				"user": map[string]interface{}{},
			},
			patches: []PatchOperation{
				{Op: "add", Path: "/user/name", Value: "Jane"},
			},
			expected: map[string]interface{}{
				"user": map[string]interface{}{
					"name": "Jane",
				},
			},
			wantErr: false,
		},
		{
			name: "add to existing field (overwrite)",
			doc: map[string]interface{}{
				"name": "Old Name",
			},
			patches: []PatchOperation{
				{Op: "add", Path: "/name", Value: "New Name"},
			},
			expected: map[string]interface{}{
				"name": "New Name",
			},
			wantErr: false,
		},
		{
			name: "add array field",
			doc:  map[string]interface{}{},
			patches: []PatchOperation{
				{Op: "add", Path: "/tags", Value: []interface{}{"tag1", "tag2"}},
			},
			expected: map[string]interface{}{
				"tags": []interface{}{"tag1", "tag2"},
			},
			wantErr: false,
		},
		{
			name: "add complex object",
			doc:  map[string]interface{}{},
			patches: []PatchOperation{
				{Op: "add", Path: "/metadata", Value: map[string]interface{}{
					"version": "1.0",
					"active":  true,
				}},
			},
			expected: map[string]interface{}{
				"metadata": map[string]interface{}{
					"version": "1.0",
					"active":  true,
				},
			},
			wantErr: false,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			result, err := patcher.ApplyPatches(tt.doc, tt.patches)
			if (err != nil) != tt.wantErr {
				t.Errorf("ApplyPatches() error = %v, wantErr %v", err, tt.wantErr)
				return
			}
			if !tt.wantErr && !reflect.DeepEqual(result, tt.expected) {
				t.Errorf("ApplyPatches() = %v, want %v", result, tt.expected)
			}
		})
	}
}

func TestJSONPatcher_Remove(t *testing.T) {
	patcher := &JSONPatcher{}

	tests := []struct {
		name     string
		doc      map[string]interface{}
		patches  []PatchOperation
		expected map[string]interface{}
		wantErr  bool
	}{
		{
			name: "remove simple field",
			doc: map[string]interface{}{
				"name": "John",
				"age":  30,
			},
			patches: []PatchOperation{
				{Op: "remove", Path: "/name"},
			},
			expected: map[string]interface{}{
				"age": 30,
			},
			wantErr: false,
		},
		{
			name: "remove nested field",
			doc: map[string]interface{}{
				"user": map[string]interface{}{
					"name": "Jane",
					"age":  25,
				},
			},
			patches: []PatchOperation{
				{Op: "remove", Path: "/user/name"},
			},
			expected: map[string]interface{}{
				"user": map[string]interface{}{
					"age": 25,
				},
			},
			wantErr: false,
		},
		{
			name: "remove non-existent field",
			doc: map[string]interface{}{
				"name": "John",
			},
			patches: []PatchOperation{
				{Op: "remove", Path: "/age"},
			},
			expected: nil,
			wantErr:  true,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			result, err := patcher.ApplyPatches(tt.doc, tt.patches)
			if (err != nil) != tt.wantErr {
				t.Errorf("ApplyPatches() error = %v, wantErr %v", err, tt.wantErr)
				return
			}
			if !tt.wantErr && !reflect.DeepEqual(result, tt.expected) {
				t.Errorf("ApplyPatches() = %v, want %v", result, tt.expected)
			}
		})
	}
}

func TestJSONPatcher_Replace(t *testing.T) {
	patcher := &JSONPatcher{}

	tests := []struct {
		name     string
		doc      map[string]interface{}
		patches  []PatchOperation
		expected map[string]interface{}
		wantErr  bool
	}{
		{
			name: "replace simple field",
			doc: map[string]interface{}{
				"name": "John",
			},
			patches: []PatchOperation{
				{Op: "replace", Path: "/name", Value: "Jane"},
			},
			expected: map[string]interface{}{
				"name": "Jane",
			},
			wantErr: false,
		},
		{
			name: "replace nested field",
			doc: map[string]interface{}{
				"user": map[string]interface{}{
					"name": "John",
				},
			},
			patches: []PatchOperation{
				{Op: "replace", Path: "/user/name", Value: "Jane"},
			},
			expected: map[string]interface{}{
				"user": map[string]interface{}{
					"name": "Jane",
				},
			},
			wantErr: false,
		},
		{
			name: "replace non-existent field",
			doc: map[string]interface{}{
				"name": "John",
			},
			patches: []PatchOperation{
				{Op: "replace", Path: "/age", Value: 30},
			},
			expected: nil,
			wantErr:  true,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			result, err := patcher.ApplyPatches(tt.doc, tt.patches)
			if (err != nil) != tt.wantErr {
				t.Errorf("ApplyPatches() error = %v, wantErr %v", err, tt.wantErr)
				return
			}
			if !tt.wantErr && !reflect.DeepEqual(result, tt.expected) {
				t.Errorf("ApplyPatches() = %v, want %v", result, tt.expected)
			}
		})
	}
}

func TestJSONPatcher_Test(t *testing.T) {
	patcher := &JSONPatcher{}

	tests := []struct {
		name     string
		doc      map[string]interface{}
		patches  []PatchOperation
		expected map[string]interface{}
		wantErr  bool
	}{
		{
			name: "test field success",
			doc: map[string]interface{}{
				"name": "John",
			},
			patches: []PatchOperation{
				{Op: "test", Path: "/name", Value: "John"},
			},
			expected: map[string]interface{}{
				"name": "John",
			},
			wantErr: false,
		},
		{
			name: "test field failure",
			doc: map[string]interface{}{
				"name": "John",
			},
			patches: []PatchOperation{
				{Op: "test", Path: "/name", Value: "Jane"},
			},
			expected: nil,
			wantErr:  true,
		},
		{
			name: "test non-existent field",
			doc: map[string]interface{}{
				"name": "John",
			},
			patches: []PatchOperation{
				{Op: "test", Path: "/age", Value: 30},
			},
			expected: nil,
			wantErr:  true,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			result, err := patcher.ApplyPatches(tt.doc, tt.patches)
			if (err != nil) != tt.wantErr {
				t.Errorf("ApplyPatches() error = %v, wantErr %v", err, tt.wantErr)
				return
			}
			if !tt.wantErr && !reflect.DeepEqual(result, tt.expected) {
				t.Errorf("ApplyPatches() = %v, want %v", result, tt.expected)
			}
		})
	}
}

func TestJSONPatcher_Move(t *testing.T) {
	patcher := &JSONPatcher{}

	tests := []struct {
		name     string
		doc      map[string]interface{}
		patches  []PatchOperation
		expected map[string]interface{}
		wantErr  bool
	}{
		{
			name: "move field",
			doc: map[string]interface{}{
				"firstName": "John",
				"lastName":  "Doe",
			},
			patches: []PatchOperation{
				{Op: "move", From: "/firstName", Path: "/name"},
			},
			expected: map[string]interface{}{
				"lastName": "Doe",
				"name":     "John",
			},
			wantErr: false,
		},
		{
			name: "move non-existent field",
			doc: map[string]interface{}{
				"name": "John",
			},
			patches: []PatchOperation{
				{Op: "move", From: "/age", Path: "/userAge"},
			},
			expected: nil,
			wantErr:  true,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			result, err := patcher.ApplyPatches(tt.doc, tt.patches)
			if (err != nil) != tt.wantErr {
				t.Errorf("ApplyPatches() error = %v, wantErr %v", err, tt.wantErr)
				return
			}
			if !tt.wantErr && !reflect.DeepEqual(result, tt.expected) {
				t.Errorf("ApplyPatches() = %v, want %v", result, tt.expected)
			}
		})
	}
}

func TestJSONPatcher_Copy(t *testing.T) {
	patcher := &JSONPatcher{}

	tests := []struct {
		name     string
		doc      map[string]interface{}
		patches  []PatchOperation
		expected map[string]interface{}
		wantErr  bool
	}{
		{
			name: "copy field",
			doc: map[string]interface{}{
				"name": "John",
			},
			patches: []PatchOperation{
				{Op: "copy", From: "/name", Path: "/displayName"},
			},
			expected: map[string]interface{}{
				"name":        "John",
				"displayName": "John",
			},
			wantErr: false,
		},
		{
			name: "copy non-existent field",
			doc: map[string]interface{}{
				"name": "John",
			},
			patches: []PatchOperation{
				{Op: "copy", From: "/age", Path: "/userAge"},
			},
			expected: nil,
			wantErr:  true,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			result, err := patcher.ApplyPatches(tt.doc, tt.patches)
			if (err != nil) != tt.wantErr {
				t.Errorf("ApplyPatches() error = %v, wantErr %v", err, tt.wantErr)
				return
			}
			if !tt.wantErr && !reflect.DeepEqual(result, tt.expected) {
				t.Errorf("ApplyPatches() = %v, want %v", result, tt.expected)
			}
		})
	}
}

func TestJSONPatcher_Complex(t *testing.T) {
	patcher := &JSONPatcher{}

	tests := []struct {
		name     string
		doc      map[string]interface{}
		patches  []PatchOperation
		expected map[string]interface{}
		wantErr  bool
	}{
		{
			name: "multiple operations",
			doc: map[string]interface{}{
				"name": "John",
				"age":  30,
			},
			patches: []PatchOperation{
				{Op: "replace", Path: "/name", Value: "Jane"},
				{Op: "add", Path: "/email", Value: "jane@example.com"},
				{Op: "remove", Path: "/age"},
			},
			expected: map[string]interface{}{
				"name":  "Jane",
				"email": "jane@example.com",
			},
			wantErr: false,
		},
		{
			name: "test then modify",
			doc: map[string]interface{}{
				"version": "1.0",
				"name":    "App",
			},
			patches: []PatchOperation{
				{Op: "test", Path: "/version", Value: "1.0"},
				{Op: "replace", Path: "/version", Value: "1.1"},
				{Op: "add", Path: "/updated", Value: true},
			},
			expected: map[string]interface{}{
				"version": "1.1",
				"name":    "App",
				"updated": true,
			},
			wantErr: false,
		},
		{
			name: "failed test stops execution",
			doc: map[string]interface{}{
				"version": "1.0",
				"name":    "App",
			},
			patches: []PatchOperation{
				{Op: "test", Path: "/version", Value: "2.0"}, // This will fail
				{Op: "replace", Path: "/version", Value: "1.1"},
			},
			expected: nil,
			wantErr:  true,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			result, err := patcher.ApplyPatches(tt.doc, tt.patches)
			if (err != nil) != tt.wantErr {
				t.Errorf("ApplyPatches() error = %v, wantErr %v", err, tt.wantErr)
				return
			}
			if !tt.wantErr && !reflect.DeepEqual(result, tt.expected) {
				t.Errorf("ApplyPatches() = %v, want %v", result, tt.expected)
			}
		})
	}
}

func TestJSONPatcher_ParsePath(t *testing.T) {
	patcher := &JSONPatcher{}

	tests := []struct {
		name     string
		path     string
		expected []string
	}{
		{
			name:     "empty path",
			path:     "",
			expected: []string{},
		},
		{
			name:     "root path",
			path:     "/",
			expected: []string{""},
		},
		{
			name:     "simple path",
			path:     "/name",
			expected: []string{"name"},
		},
		{
			name:     "nested path",
			path:     "/user/name",
			expected: []string{"user", "name"},
		},
		{
			name:     "path with escaped characters",
			path:     "/user/first~0name",
			expected: []string{"user", "first~name"},
		},
		{
			name:     "path with escaped slash",
			path:     "/user/first~1name",
			expected: []string{"user", "first/name"},
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			result := patcher.parsePath(tt.path)
			if !reflect.DeepEqual(result, tt.expected) {
				t.Errorf("parsePath() = %v, want %v", result, tt.expected)
			}
		})
	}
}

func TestJSONPatcher_InvalidOperations(t *testing.T) {
	patcher := &JSONPatcher{}

	tests := []struct {
		name    string
		doc     map[string]interface{}
		patches []PatchOperation
		wantErr bool
	}{
		{
			name: "invalid operation",
			doc:  map[string]interface{}{},
			patches: []PatchOperation{
				{Op: "invalid", Path: "/name", Value: "John"},
			},
			wantErr: true,
		},
		{
			name: "invalid path format",
			doc:  map[string]interface{}{},
			patches: []PatchOperation{
				{Op: "add", Path: "name", Value: "John"}, // Missing leading slash
			},
			wantErr: true,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			_, err := patcher.ApplyPatches(tt.doc, tt.patches)
			if (err != nil) != tt.wantErr {
				t.Errorf("ApplyPatches() error = %v, wantErr %v", err, tt.wantErr)
			}
		})
	}
}