// Copyright 2025 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// SPDX-License-Identifier: Apache-2.0

package main

import (
	"flag"
	"os"
	"os/exec"
	"path/filepath"
	"testing"
)

var update = flag.Bool("update", false, "update golden")

func Test(t *testing.T) {
	if _, err := exec.LookPath("diff"); err != nil {
		t.Skip("skipping; no diff program")
	}
	const pkgPath = "test"
	outDir := t.TempDir()
	err := run(
		filepath.Join("testdata", "test.json"),
		pkgPath,
		filepath.Join("testdata", "test.config"),
		outDir)
	if err != nil {
		t.Fatal(err)
	}
	outFile := filepath.Join(outDir, pkgPath, "gen.go")
	goldenFile := filepath.Join("testdata", "golden")
	if *update {
		if err := os.Rename(outFile, goldenFile); err != nil {
			t.Fatal(err)
		}
		t.Log("updated golden")
	} else {
		out, err := exec.Command("diff", "-u", goldenFile, outFile).CombinedOutput()
		if err != nil {
			t.Fatalf("%v\n%s", err, out)
		}
		if len(out) > 0 {
			t.Errorf("%s", out)
		}
	}
}

func TestTypeParamArgs(t *testing.T) {
	tests := []struct {
		in   string
		want string
	}{
		{"", ""},
		{"[]", ""},
		{"[State any]", "[State]"},
		{"  [State any]  ", "[State]"},
		{"[A any, B comparable]", "[A, B]"},
		{"[K, V any]", "[K, V]"},
	}
	for _, tt := range tests {
		t.Run(tt.in, func(t *testing.T) {
			if got := typeParamArgs(tt.in); got != tt.want {
				t.Errorf("typeParamArgs(%q) = %q, want %q", tt.in, got, tt.want)
			}
		})
	}
}

func TestSkipOmitEmpty(t *testing.T) {
	tests := []struct {
		name     string
		schema   string
		field    string
		expected bool
	}{
		{
			name:     "ChunkIndexOK",
			schema:   "ModelResponseChunk",
			field:    "index",
			expected: true,
		},
		{
			name:     "ChunkNoIndex",
			schema:   "ModelResponseChunk",
			field:    "text",
			expected: false,
		},
		{
			name:     "NotChunkSchema",
			schema:   "RequestHeader",
			field:    "ID",
			expected: false,
		},
		{
			name:     "ChunkNoField",
			schema:   "ModelResponseChunk",
			field:    "",
			expected: false,
		},
		{
			name:     "EmptySchema",
			schema:   "",
			field:    "index",
			expected: false,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			actual := skipOmitEmpty(tt.schema, tt.field)
			if actual != tt.expected {
				t.Errorf("skipOmitEmpty(schema: %q, field: %q) = %v, want %v",
					tt.schema, tt.field, actual, tt.expected)
			}
		})
	}
}
