package contractgovernance

import (
	"io/fs"
	"os"
	"path/filepath"
	"regexp"
	"runtime"
	"strings"
	"testing"
)

func TestDeviceContractCompatibilityGuardrails(t *testing.T) {
	root := repositoryRoot(t)
	contract := readFile(t, filepath.Join(root, "openapi", "openapi.yaml"))

	versions := regexp.MustCompile(`(?m)^  /device/v([0-9]+)(?:/[^:]+)?:$`).FindAllStringSubmatch(contract, -1)
	if len(versions) < 10 {
		t.Fatalf("found only %d versioned device paths; contract scan likely stopped matching", len(versions))
	}
	v2Count, v3Count := 0, 0
	for _, match := range versions {
		switch match[1] {
		case "2":
			v2Count++
		case "3":
			v3Count++
		default:
			t.Fatalf("device path %q uses an unsupported compatibility generation", match[0])
		}
	}
	if v2Count < 10 || v3Count < 2 {
		t.Fatalf("device contract must preserve v2 and publish hardware-agent v3; v2=%d v3=%d", v2Count, v3Count)
	}
	for _, required := range []string{
		"rtc_credential_renewal:",
		"省略时保持旧版v2终端行为",
		"设备不得据此改变采集、编码、发布、订阅或播放逻辑",
	} {
		if !strings.Contains(contract, required) {
			t.Fatalf("OpenAPI is missing device compatibility rule %q", required)
		}
	}
	contractVersion := regexp.MustCompile(`(?m)^  version: ([0-9]+\.[0-9]+\.[0-9]+)$`).FindStringSubmatch(contract)
	if len(contractVersion) != 2 {
		t.Fatal("OpenAPI info.version must be a semantic version")
	}

	notes := readFile(t, filepath.Join(root, "docs", "device-api-compatibility.md"))
	if !strings.Contains(notes, "当前接口契约：OpenAPI "+contractVersion[1]) || !strings.Contains(notes, "/device/v2") || !strings.Contains(notes, "/device/v3") {
		t.Fatal("device compatibility notes are not synchronized with the current contract and next breaking version")
	}
}

func TestDeviceBehaviorDoesNotDependOnUserAgentOrEngineMode(t *testing.T) {
	root := repositoryRoot(t)
	for _, relative := range []string{"internal/deviceauth", "internal/httpapi", "internal/orchestration", "cmd/sim-device"} {
		directory := filepath.Join(root, filepath.FromSlash(relative))
		err := filepath.WalkDir(directory, func(path string, entry fs.DirEntry, walkErr error) error {
			if walkErr != nil {
				return walkErr
			}
			if entry.IsDir() || !strings.HasSuffix(entry.Name(), ".go") || strings.HasSuffix(entry.Name(), "_test.go") {
				return nil
			}
			contents := readFile(t, path)
			for _, forbidden := range []string{`Header.Get("User-Agent")`, ".UserAgent()"} {
				if strings.Contains(contents, forbidden) {
					t.Errorf("%s uses firmware User-Agent for behavior selection", filepath.ToSlash(path))
				}
			}
			if relative == "cmd/sim-device" && strings.Contains(contents, "engine_mode") {
				t.Errorf("%s makes the terminal aware of diagnostic-only engine_mode", filepath.ToSlash(path))
			}
			return nil
		})
		if err != nil {
			t.Fatalf("scan %s: %v", relative, err)
		}
	}
}

func repositoryRoot(t *testing.T) string {
	t.Helper()
	_, current, _, ok := runtime.Caller(0)
	if !ok {
		t.Fatal("resolve contract test location")
	}
	return filepath.Clean(filepath.Join(filepath.Dir(current), "..", ".."))
}

func readFile(t *testing.T, path string) string {
	t.Helper()
	contents, err := os.ReadFile(path)
	if err != nil {
		t.Fatalf("read %s: %v", path, err)
	}
	return string(contents)
}