package middleware

import (
	"net/http"
	"net/http/httptest"
	"net/url"
	"strings"
	"testing"

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

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

	var gotToken string
	handler := m.CSRF()(http.HandlerFunc(func(_ http.ResponseWriter, r *http.Request) {
		gotToken = CSRFToken(r)
	}))

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

	handler.ServeHTTP(w, req)

	assert.NotEmpty(t, gotToken, "CSRF token should be set in context on GET")
	assert.Len(t, gotToken, csrfTokenLength*2, "CSRF token should be hex-encoded 32 bytes")
}

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

	// Use a separate handler for the GET to capture the token
	var token string
	getHandler := m.CSRF()(http.HandlerFunc(func(_ http.ResponseWriter, r *http.Request) {
		token = CSRFToken(r)
	}))

	// GET to establish the session and capture token
	getReq := httptest.NewRequest(http.MethodGet, "/form", nil)
	getW := httptest.NewRecorder()
	getHandler.ServeHTTP(getW, getReq)

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

	// POST handler that tracks whether it was called
	var called bool
	postHandler := m.CSRF()(http.HandlerFunc(func(_ http.ResponseWriter, _ *http.Request) {
		called = true
	}))

	// POST with valid token
	form := url.Values{csrfFormField: {token}}
	postReq := httptest.NewRequest(http.MethodPost, "/form", strings.NewReader(form.Encode()))
	postReq.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	for _, c := range cookies {
		postReq.AddCookie(c)
	}
	postW := httptest.NewRecorder()

	postHandler.ServeHTTP(postW, postReq)

	assert.True(t, called, "handler should be called with valid CSRF token")
}

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

	// GET handler to establish session
	getHandler := m.CSRF()(http.HandlerFunc(func(_ http.ResponseWriter, _ *http.Request) {
		// no-op — just establishes session
	}))

	getReq := httptest.NewRequest(http.MethodGet, "/form", nil)
	getW := httptest.NewRecorder()
	getHandler.ServeHTTP(getW, getReq)
	cookies := getW.Result().Cookies()

	// POST handler that tracks whether it was called
	var called bool
	postHandler := m.CSRF()(http.HandlerFunc(func(_ http.ResponseWriter, _ *http.Request) {
		called = true
	}))

	// POST without CSRF token
	postReq := httptest.NewRequest(http.MethodPost, "/form", nil)
	postReq.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	for _, c := range cookies {
		postReq.AddCookie(c)
	}
	postW := httptest.NewRecorder()

	postHandler.ServeHTTP(postW, postReq)

	assert.False(t, called, "handler should NOT be called without CSRF token")
	assert.Equal(t, http.StatusForbidden, postW.Code)
}

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

	// GET handler to establish session
	getHandler := m.CSRF()(http.HandlerFunc(func(_ http.ResponseWriter, _ *http.Request) {
		// no-op — just establishes session
	}))

	getReq := httptest.NewRequest(http.MethodGet, "/form", nil)
	getW := httptest.NewRecorder()
	getHandler.ServeHTTP(getW, getReq)
	cookies := getW.Result().Cookies()

	// POST handler that tracks whether it was called
	var called bool
	postHandler := m.CSRF()(http.HandlerFunc(func(_ http.ResponseWriter, _ *http.Request) {
		called = true
	}))

	// POST with wrong CSRF token
	form := url.Values{csrfFormField: {"invalid-token-value"}}
	postReq := httptest.NewRequest(http.MethodPost, "/form", strings.NewReader(form.Encode()))
	postReq.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	for _, c := range cookies {
		postReq.AddCookie(c)
	}
	postW := httptest.NewRecorder()

	postHandler.ServeHTTP(postW, postReq)

	assert.False(t, called, "handler should NOT be called with invalid CSRF token")
	assert.Equal(t, http.StatusForbidden, postW.Code)
}

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

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

	// GET requests should pass through without CSRF validation
	req := httptest.NewRequest(http.MethodGet, "/form", nil)
	w := httptest.NewRecorder()

	handler.ServeHTTP(w, req)

	assert.True(t, called, "GET requests should pass through CSRF middleware")
}

func TestCSRFToken_NoContext(t *testing.T) {
	t.Parallel()
	req := httptest.NewRequest(http.MethodGet, "/", nil)
	assert.Empty(t, CSRFToken(req), "CSRFToken should return empty string when no token in context")
}

func TestGenerateCSRFToken(t *testing.T) {
	t.Parallel()
	token, err := generateCSRFToken()
	require.NoError(t, err)
	assert.Len(t, token, csrfTokenLength*2, "token should be hex-encoded")

	// Verify uniqueness
	token2, err := generateCSRFToken()
	require.NoError(t, err)
	assert.NotEqual(t, token, token2, "each generated token should be unique")
}

func TestSecureCompare(t *testing.T) {
	t.Parallel()
	assert.True(t, secureCompare("abc", "abc"))
	assert.False(t, secureCompare("abc", "abd"))
	assert.False(t, secureCompare("abc", "ab"))
	assert.False(t, secureCompare("", "a"))
	assert.True(t, secureCompare("", ""))
}