package middleware

import (
	"encoding/base64"
	"log/slog"
	"net/http"
	"net/http/httptest"
	"os"
	"testing"

	"github.com/gorilla/sessions"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"sneak.berlin/go/webhooker/internal/config"
	"sneak.berlin/go/webhooker/internal/session"
)

// testMiddleware creates a Middleware with minimal dependencies for testing.
// It uses a real session.Session backed by an in-memory cookie store.
func testMiddleware(t *testing.T, env string) (*Middleware, *session.Session) {
	t.Helper()

	log := slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{Level: slog.LevelDebug}))

	cfg := &config.Config{
		Environment: env,
	}

	// Create a real session manager with a known key
	key := make([]byte, 32)
	for i := range key {
		key[i] = byte(i)
	}
	store := sessions.NewCookieStore(key)
	store.Options = &sessions.Options{
		Path:     "/",
		MaxAge:   86400 * 7,
		HttpOnly: true,
		Secure:   false,
		SameSite: http.SameSiteLaxMode,
	}

	sessManager := newTestSession(t, store, cfg, log)

	m := &Middleware{
		log: log,
		params: &MiddlewareParams{
			Config: cfg,
		},
		session: sessManager,
	}

	return m, sessManager
}

// newTestSession creates a session.Session with a pre-configured cookie store
// for testing. This avoids needing the fx lifecycle and database.
func newTestSession(t *testing.T, store *sessions.CookieStore, cfg *config.Config, log *slog.Logger) *session.Session {
	t.Helper()
	return session.NewForTest(store, cfg, log)
}

// --- Logging Middleware Tests ---

func TestLogging_SetsStatusCode(t *testing.T) {
	t.Parallel()
	m, _ := testMiddleware(t, config.EnvironmentDev)

	handler := m.Logging()(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
		w.WriteHeader(http.StatusCreated)
		if _, err := w.Write([]byte("created")); err != nil {
			return
		}
	}))

	req := httptest.NewRequest(http.MethodGet, "/test", nil)
	w := httptest.NewRecorder()

	handler.ServeHTTP(w, req)

	assert.Equal(t, http.StatusCreated, w.Code)
	assert.Equal(t, "created", w.Body.String())
}

func TestLogging_DefaultStatusOK(t *testing.T) {
	t.Parallel()
	m, _ := testMiddleware(t, config.EnvironmentDev)

	handler := m.Logging()(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
		if _, err := w.Write([]byte("ok")); err != nil {
			return
		}
	}))

	req := httptest.NewRequest(http.MethodGet, "/", nil)
	w := httptest.NewRecorder()

	handler.ServeHTTP(w, req)

	// When no explicit WriteHeader is called, default is 200
	assert.Equal(t, http.StatusOK, w.Code)
}

func TestLogging_PassesThroughToNext(t *testing.T) {
	t.Parallel()
	m, _ := testMiddleware(t, config.EnvironmentDev)

	var called bool
	handler := m.Logging()(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
		called = true
		w.WriteHeader(http.StatusOK)
	}))

	req := httptest.NewRequest(http.MethodPost, "/api/webhook", nil)
	w := httptest.NewRecorder()

	handler.ServeHTTP(w, req)

	assert.True(t, called, "logging middleware should call the next handler")
}

// --- LoggingResponseWriter Tests ---

func TestLoggingResponseWriter_CapturesStatusCode(t *testing.T) {
	t.Parallel()

	w := httptest.NewRecorder()
	lrw := NewLoggingResponseWriter(w)

	// Default should be 200
	assert.Equal(t, http.StatusOK, lrw.statusCode)

	// WriteHeader should capture the status code
	lrw.WriteHeader(http.StatusNotFound)
	assert.Equal(t, http.StatusNotFound, lrw.statusCode)

	// Underlying writer should also get the status code
	assert.Equal(t, http.StatusNotFound, w.Code)
}

func TestLoggingResponseWriter_WriteDelegatesToUnderlying(t *testing.T) {
	t.Parallel()

	w := httptest.NewRecorder()
	lrw := NewLoggingResponseWriter(w)

	n, err := lrw.Write([]byte("hello world"))
	require.NoError(t, err)
	assert.Equal(t, 11, n)
	assert.Equal(t, "hello world", w.Body.String())
}

// --- CORS Middleware Tests ---

func TestCORS_DevMode_AllowsAnyOrigin(t *testing.T) {
	t.Parallel()
	m, _ := testMiddleware(t, config.EnvironmentDev)

	handler := m.CORS()(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
		w.WriteHeader(http.StatusOK)
	}))

	// Preflight request
	req := httptest.NewRequest(http.MethodOptions, "/api/test", nil)
	req.Header.Set("Origin", "http://localhost:3000")
	req.Header.Set("Access-Control-Request-Method", "POST")
	w := httptest.NewRecorder()

	handler.ServeHTTP(w, req)

	// In dev mode, CORS should allow any origin
	assert.Equal(t, "*", w.Header().Get("Access-Control-Allow-Origin"))
}

func TestCORS_ProdMode_NoOp(t *testing.T) {
	t.Parallel()
	m, _ := testMiddleware(t, config.EnvironmentProd)

	var called bool
	handler := m.CORS()(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
		called = true
		w.WriteHeader(http.StatusOK)
	}))

	req := httptest.NewRequest(http.MethodGet, "/api/test", nil)
	req.Header.Set("Origin", "http://evil.com")
	w := httptest.NewRecorder()

	handler.ServeHTTP(w, req)

	assert.True(t, called, "prod CORS middleware should pass through to handler")
	// In prod, no CORS headers should be set (no-op middleware)
	assert.Empty(t, w.Header().Get("Access-Control-Allow-Origin"),
		"prod mode should not set CORS headers")
}

// --- RequireAuth Middleware Tests ---

func TestRequireAuth_NoSession_RedirectsToLogin(t *testing.T) {
	t.Parallel()
	m, _ := testMiddleware(t, config.EnvironmentDev)

	var called bool
	handler := m.RequireAuth()(http.HandlerFunc(func(_ http.ResponseWriter, _ *http.Request) {
		called = true
	}))

	req := httptest.NewRequest(http.MethodGet, "/dashboard", nil)
	w := httptest.NewRecorder()

	handler.ServeHTTP(w, req)

	assert.False(t, called, "handler should not be called for unauthenticated request")
	assert.Equal(t, http.StatusSeeOther, w.Code)
	assert.Equal(t, "/pages/login", w.Header().Get("Location"))
}

func TestRequireAuth_AuthenticatedSession_PassesThrough(t *testing.T) {
	t.Parallel()
	m, sessManager := testMiddleware(t, config.EnvironmentDev)

	var called bool
	handler := m.RequireAuth()(http.HandlerFunc(func(_ http.ResponseWriter, _ *http.Request) {
		called = true
	}))

	// Create an authenticated session by making a request, setting session data,
	// and saving the session cookie
	setupReq := httptest.NewRequest(http.MethodGet, "/setup", nil)
	setupW := httptest.NewRecorder()

	sess, err := sessManager.Get(setupReq)
	require.NoError(t, err)
	sessManager.SetUser(sess, "user-123", "testuser")
	require.NoError(t, sessManager.Save(setupReq, setupW, sess))

	// Extract the cookie from the setup response
	cookies := setupW.Result().Cookies()
	require.NotEmpty(t, cookies, "session cookie should be set")

	// Make the actual request with the session cookie
	req := httptest.NewRequest(http.MethodGet, "/dashboard", nil)
	for _, c := range cookies {
		req.AddCookie(c)
	}
	w := httptest.NewRecorder()

	handler.ServeHTTP(w, req)

	assert.True(t, called, "handler should be called for authenticated request")
}

func TestRequireAuth_UnauthenticatedSession_RedirectsToLogin(t *testing.T) {
	t.Parallel()
	m, sessManager := testMiddleware(t, config.EnvironmentDev)

	var called bool
	handler := m.RequireAuth()(http.HandlerFunc(func(_ http.ResponseWriter, _ *http.Request) {
		called = true
	}))

	// Create a session but don't authenticate it
	setupReq := httptest.NewRequest(http.MethodGet, "/setup", nil)
	setupW := httptest.NewRecorder()

	sess, err := sessManager.Get(setupReq)
	require.NoError(t, err)
	// Don't call SetUser — session exists but is not authenticated
	require.NoError(t, sessManager.Save(setupReq, setupW, sess))

	cookies := setupW.Result().Cookies()
	require.NotEmpty(t, cookies)

	req := httptest.NewRequest(http.MethodGet, "/dashboard", nil)
	for _, c := range cookies {
		req.AddCookie(c)
	}
	w := httptest.NewRecorder()

	handler.ServeHTTP(w, req)

	assert.False(t, called, "handler should not be called for unauthenticated session")
	assert.Equal(t, http.StatusSeeOther, w.Code)
	assert.Equal(t, "/pages/login", w.Header().Get("Location"))
}

// --- Helper Tests ---

func TestIpFromHostPort(t *testing.T) {
	t.Parallel()

	tests := []struct {
		name     string
		input    string
		expected string
	}{
		{"ipv4 with port", "192.168.1.1:8080", "192.168.1.1"},
		{"ipv6 with port", "[::1]:8080", "::1"},
		{"invalid format", "not-a-host-port", ""},
		{"empty string", "", ""},
		{"localhost", "127.0.0.1:80", "127.0.0.1"},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			t.Parallel()
			result := ipFromHostPort(tt.input)
			assert.Equal(t, tt.expected, result)
		})
	}
}

// --- MetricsAuth Tests ---

func TestMetricsAuth_ValidCredentials(t *testing.T) {
	t.Parallel()

	log := slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{Level: slog.LevelDebug}))
	cfg := &config.Config{
		Environment:     config.EnvironmentDev,
		MetricsUsername: "admin",
		MetricsPassword: "secret",
	}

	key := make([]byte, 32)
	store := sessions.NewCookieStore(key)
	store.Options = &sessions.Options{Path: "/", MaxAge: 86400}

	sessManager := session.NewForTest(store, cfg, log)

	m := &Middleware{
		log: log,
		params: &MiddlewareParams{
			Config: cfg,
		},
		session: sessManager,
	}

	var called bool
	handler := m.MetricsAuth()(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
		called = true
		w.WriteHeader(http.StatusOK)
	}))

	req := httptest.NewRequest(http.MethodGet, "/metrics", nil)
	req.SetBasicAuth("admin", "secret")
	w := httptest.NewRecorder()

	handler.ServeHTTP(w, req)

	assert.True(t, called, "handler should be called with valid basic auth")
	assert.Equal(t, http.StatusOK, w.Code)
}

func TestMetricsAuth_InvalidCredentials(t *testing.T) {
	t.Parallel()

	log := slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{Level: slog.LevelDebug}))
	cfg := &config.Config{
		Environment:     config.EnvironmentDev,
		MetricsUsername: "admin",
		MetricsPassword: "secret",
	}

	key := make([]byte, 32)
	store := sessions.NewCookieStore(key)
	store.Options = &sessions.Options{Path: "/", MaxAge: 86400}

	sessManager := session.NewForTest(store, cfg, log)

	m := &Middleware{
		log: log,
		params: &MiddlewareParams{
			Config: cfg,
		},
		session: sessManager,
	}

	var called bool
	handler := m.MetricsAuth()(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
		called = true
		w.WriteHeader(http.StatusOK)
	}))

	req := httptest.NewRequest(http.MethodGet, "/metrics", nil)
	req.SetBasicAuth("admin", "wrong-password")
	w := httptest.NewRecorder()

	handler.ServeHTTP(w, req)

	assert.False(t, called, "handler should not be called with invalid basic auth")
	assert.Equal(t, http.StatusUnauthorized, w.Code)
}

func TestMetricsAuth_NoCredentials(t *testing.T) {
	t.Parallel()

	log := slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{Level: slog.LevelDebug}))
	cfg := &config.Config{
		Environment:     config.EnvironmentDev,
		MetricsUsername: "admin",
		MetricsPassword: "secret",
	}

	key := make([]byte, 32)
	store := sessions.NewCookieStore(key)
	store.Options = &sessions.Options{Path: "/", MaxAge: 86400}

	sessManager := session.NewForTest(store, cfg, log)

	m := &Middleware{
		log: log,
		params: &MiddlewareParams{
			Config: cfg,
		},
		session: sessManager,
	}

	var called bool
	handler := m.MetricsAuth()(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
		called = true
	}))

	req := httptest.NewRequest(http.MethodGet, "/metrics", nil)
	// No basic auth header
	w := httptest.NewRecorder()

	handler.ServeHTTP(w, req)

	assert.False(t, called, "handler should not be called without credentials")
	assert.Equal(t, http.StatusUnauthorized, w.Code)
}

// --- CORS Dev Mode Detailed Tests ---

func TestCORS_DevMode_AllowsMethods(t *testing.T) {
	t.Parallel()
	m, _ := testMiddleware(t, config.EnvironmentDev)

	handler := m.CORS()(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
		w.WriteHeader(http.StatusOK)
	}))

	// Preflight for POST
	req := httptest.NewRequest(http.MethodOptions, "/api/webhooks", nil)
	req.Header.Set("Origin", "http://localhost:5173")
	req.Header.Set("Access-Control-Request-Method", "POST")
	w := httptest.NewRecorder()

	handler.ServeHTTP(w, req)

	allowMethods := w.Header().Get("Access-Control-Allow-Methods")
	assert.Contains(t, allowMethods, "POST")
}

// --- Base64 key validation for completeness ---

func TestSessionKeyFormat(t *testing.T) {
	t.Parallel()

	// Verify that the session initialization correctly validates key format.
	// A proper 32-byte key encoded as base64 should work.
	key := make([]byte, 32)
	for i := range key {
		key[i] = byte(i + 1)
	}
	encoded := base64.StdEncoding.EncodeToString(key)
	decoded, err := base64.StdEncoding.DecodeString(encoded)
	require.NoError(t, err)
	assert.Len(t, decoded, 32)
}