package main

import (
	"os"
	"path/filepath"
	"testing"

	"github.com/stretchr/testify/require"
)

func TestLoadConfigGivesDefaultsWithoutAFile(t *testing.T) {
	dir := t.TempDir()
	config, err := loadConfig(dir)
	require.NoError(t, err)
	require.Equal(t, defaultConfig(), config)
	require.NoFileExists(t, filepath.Join(dir, "config.json"))
}

func TestLoadConfigKeepsDefaultsForMissingFields(t *testing.T) {
	dir := t.TempDir()
	configWriteTest(t, dir, `{"endpoint": "api", "compactor": {"effort": "xhigh"}}`)

	config, err := loadConfig(dir)
	require.NoError(t, err)
	require.Equal(t, Config{
		Endpoint: configEndpointAPI,
		Compactor: ModelConfig{
			Model:  "gpt-6.1-sol",
			Effort: "xhigh",
		},
	}, config)
}

func TestLoadConfigRejectsInvalidFiles(t *testing.T) {
	testCases := []struct {
		name string
		text string
	}{
		{
			name: "unknown field",
			text: `{"endpont": "api"}`,
		},
		{
			name: "unknown nested field",
			text: `{"compactor": {"modle": "x"}}`,
		},
		{
			name: "endpoint URL",
			text: `{"endpoint": "https://example.com/v1/responses"}`,
		},
		{
			name: "empty model",
			text: `{"compactor": {"model": ""}}`,
		},
		{
			name: "second object",
			text: `{} {}`,
		},
		{
			name: "broken JSON",
			text: `{"endpoint": `,
		},
	}

	for _, tc := range testCases {
		t.Run(tc.name, func(t *testing.T) {
			dir := t.TempDir()
			configWriteTest(t, dir, tc.text)

			_, err := loadConfig(dir)
			require.Error(t, err)
		})
	}
}

func configWriteTest(t *testing.T, dir, text string) {
	t.Helper()

	err := os.WriteFile(filepath.Join(dir, "config.json"), []byte(text), 0o600)
	require.NoError(t, err)
}