package e2e

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"strings"
	"sync/atomic"
	"testing"
	"time"

	"github.com/gofiber/fiber/v2"
	"github.com/subconverter-go/internal/service"
)

type roundTripFunc func(*http.Request) (*http.Response, error)

func (f roundTripFunc) RoundTrip(req *http.Request) (*http.Response, error) {
	return f(req)
}

func newSubscriptionMockClient() *http.Client {
	var counter int32
	return &http.Client{
		Timeout: 5 * time.Second,
		Transport: roundTripFunc(func(req *http.Request) (*http.Response, error) {
			atomic.AddInt32(&counter, 1)
			body := subscriptionFixture(req.URL.String())
			status := http.StatusOK
			if body == "" {
				status = http.StatusNotFound
			}
			resp := &http.Response{
				StatusCode: status,
				Header:     make(http.Header),
				Body:       io.NopCloser(strings.NewReader(body)),
			}
			resp.Header.Set("Content-Type", "text/plain; charset=utf-8")
			return resp, nil
		}),
	}
}

func subscriptionFixture(u string) string {
	switch {
	case strings.Contains(u, "mock-subscribe.example.com"):
		return "ss://aes-256-cfb:password@192.168.1.1:8388\nvmess://eyJhZGQiOiIxOTIuMTY4LjEuMiIsICJwcyI6IlRlc3QgVk1lc3MiLCAicG9ydCI6NDQzLCAiaWQiOiI2YjZkZTQ3Zi1kZjQ1LTQ1M2ItODI1MS1hZjM0ZTM0ODc1Y2UifQ==\ntrojan://password@192.168.1.3:443"
	case strings.Contains(u, "example.com/upload"):
		return "uploaded"
	case strings.Contains(u, "ss-subscribe"):
		return "ss://aes-256-cfb:password@192.168.1.1:8388"
	case strings.Contains(u, "vmess-subscribe"):
		return "vmess://eyJhZGQiOiIxOTIuMTY4LjEuMiIsICJwcyI6IlRlc3QgVk1lc3MiLCAicG9ydCI6NDQzLCAiaWQiOiI2YjZkZTQ3Zi1kZjQ1LTQ1M2ItODI1MS1hZjM0ZTM0ODc1Y2UifQ=="
	case strings.Contains(u, "multi-source.example.com/first"):
		return "ss://aes-256-gcm:password@198.51.100.20:8443#multi-ss"
	case strings.Contains(u, "multi-source.example.com/second"):
		return "vmess://eyJhZGQiOiJtdWx0aS5leGFtcGxlLmNvbSIsICJhaWQiOiIwIiwgImhvc3QiOiJtdWx0aS5leGFtcGxlLmNvbSIsICJpZCI6IjEyMzQ1Njc4LTEyMzQtMTIzNC0xMjM0LTEyMzQ1Njc4OWFiYyIsICJuZXQiOiJ0Y3AiLCAicGF0aCI6Ii8iLCAicHMiOiJtdWx0aS12bWVzcyIsICJ0bHMiOiJ0bHMiLCAidHlwZSI6Im5vbmUiLCAidXJsX3Rlc3QiOiJodHRwOi8vd3d3Lmdvb2dsZS5jb20vZ2VuZXJhdGVfMjA0IiwgInYiOiIyIiwgInBvcnQiOiI0NDMiLCAic2N5IjoiYXV0byJ9"
	default:
		return ""
	}
}

func TestApplicationBaselineRoutes(t *testing.T) {
	app, _, cleanup := setupTestApplication(t)
	t.Cleanup(cleanup)

	server := app.GetHTTPServer()

	t.Run("health endpoint", func(t *testing.T) {
		resp := doRequest(t, server, http.MethodGet, "/health")
		defer resp.Body.Close()

		if resp.StatusCode != http.StatusOK {
			t.Fatalf("expected status 200, got %d", resp.StatusCode)
		}

		var body map[string]interface{}
		if err := json.NewDecoder(resp.Body).Decode(&body); err != nil {
			t.Fatalf("failed to decode body: %v", err)
		}

		status, ok := body["status"].(string)
		if !ok || status == "" {
			t.Fatalf("expected status field in response, got: %v", body)
		}
	})

	t.Run("version endpoint", func(t *testing.T) {
		resp := doRequest(t, server, http.MethodGet, "/version")
		defer resp.Body.Close()

		if resp.StatusCode != http.StatusOK {
			t.Fatalf("expected status 200, got %d", resp.StatusCode)
		}

		var body map[string]interface{}
		if err := json.NewDecoder(resp.Body).Decode(&body); err != nil {
			t.Fatalf("failed to decode body: %v", err)
		}

		serviceName, ok := body["service"].(string)
		if !ok || serviceName == "" {
			t.Fatalf("expected service field in response, got: %v", body)
		}
	})

	t.Run("subscription endpoint", func(t *testing.T) {
		resp := doRequest(t, server, http.MethodGet, "/sub?target=clash&url=https://mock-subscribe.example.com")
		defer resp.Body.Close()

		if resp.StatusCode != http.StatusOK {
			t.Fatalf("expected status 200, got %d", resp.StatusCode)
		}

		contentType := resp.Header.Get("Content-Type")
		if contentType == "" {
			t.Fatalf("expected content type header, got empty")
		}

		data, err := io.ReadAll(resp.Body)
		if err != nil {
			t.Fatalf("failed to read body: %v", err)
		}
		if len(data) == 0 {
			t.Fatalf("expected non-empty body from /sub endpoint")
		}
	})
}

func setupTestApplication(t *testing.T) (*service.Application, string, func()) {
	t.Helper()

	defaultConfig := `server:
  host: "127.0.0.1"
  port: 26500
logging:
  level: "error"
  format: "text"
`

	return setupTestApplicationWithConfig(t, defaultConfig)
}

func setupTestApplicationWithConfig(t *testing.T, configYAML string) (*service.Application, string, func()) {
	t.Helper()

	originalWD, err := os.Getwd()
	if err != nil {
		t.Fatalf("failed to get working directory: %v", err)
	}

	projectRoot, err := findProjectRoot(originalWD)
	if err != nil {
		t.Fatalf("failed to locate project root: %v", err)
	}

	if err := os.Chdir(projectRoot); err != nil {
		t.Fatalf("failed to change directory to project root: %v", err)
	}

	t.Cleanup(func() {
		_ = os.Chdir(originalWD)
	})

	configDir := t.TempDir()
	configPath := filepath.Join(configDir, "config.yaml")

	if err := os.WriteFile(configPath, []byte(configYAML), 0o644); err != nil {
		t.Fatalf("failed to write temp config: %v", err)
	}

	app, err := service.NewApplication(configPath)
	if err != nil {
		t.Fatalf("failed to create application: %v", err)
	}

	if engine := app.GetConversionEngine(); engine != nil {
		engine.SetHTTPClient(newSubscriptionMockClient())
	}

	cleanup := func() {
		_ = app.Stop()
		_ = os.Remove(configPath)
	}

	return app, configPath, cleanup
}

func doRequest(t *testing.T, app *fiber.App, method, target string) *http.Response {
	t.Helper()
	return doRequestWithBody(t, app, method, target, nil, nil)
}

func doRequestWithBody(t *testing.T, app *fiber.App, method, target string, body io.Reader, headers map[string]string) *http.Response {
	t.Helper()
	req := httptest.NewRequest(method, target, body)
	for k, v := range headers {
		req.Header.Set(k, v)
	}
	resp, err := app.Test(req, -1)
	if err != nil {
		t.Fatalf("fiber test request failed: %v", err)
	}
	return resp
}

func findProjectRoot(start string) (string, error) {
	dir := start
	for {
		if _, err := os.Stat(filepath.Join(dir, "go.mod")); err == nil {
			return dir, nil
		}
		parent := filepath.Dir(dir)
		if parent == dir {
			return "", fmt.Errorf("go.mod not found from %s", start)
		}
		dir = parent
	}
}