package middleware

import (
	"encoding/json"
	"fmt"
	"math/rand"
	"net/http"
	"net/http/httptest"
	"testing"
	"time"

	"perms-system-server/internal/response"
	"perms-system-server/internal/testutil"

	"github.com/zeromicro/go-zero/core/stores/redis"
	"github.com/zeromicro/go-zero/rest/httpx"

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

func init() {
	response.Setup()
}

func uniqueIP() string {
	return fmt.Sprintf("10.%d.%d.%d", rand.Intn(256), rand.Intn(256), rand.Intn(256))
}

func newTestRedis() *redis.Redis {
	cfg := testutil.GetTestConfig()
	return redis.MustNewRedis(cfg.CacheRedis.Nodes[0].RedisConf)
}

func newTestMiddleware(rds *redis.Redis, quota int) *RateLimitMiddleware {
	prefix := fmt.Sprintf("test_rl_%d_%d", time.Now().UnixNano(), rand.Intn(100000))
	return NewRateLimitMiddleware(rds, 60, quota, prefix)
}

// TC-0536: 正常请求(未超限)
func TestRateLimit_NormalRequest(t *testing.T) {
	rds := newTestRedis()
	m := newTestMiddleware(rds, 10)

	nextCalled := false
	handler := m.Handle(func(w http.ResponseWriter, r *http.Request) {
		nextCalled = true
		w.WriteHeader(http.StatusOK)
	})

	req := httptest.NewRequest(http.MethodPost, "/api/auth/login", nil)
	req.Header.Set("X-Forwarded-For", uniqueIP())
	w := httptest.NewRecorder()

	handler(w, req)
	assert.True(t, nextCalled, "next handler should be called")
	assert.Equal(t, http.StatusOK, w.Code)
}

// TC-0537: 超限请求被拒绝
func TestRateLimit_OverQuotaRejected(t *testing.T) {
	rds := newTestRedis()
	m := newTestMiddleware(rds, 2)
	ip := uniqueIP()

	handler := m.Handle(func(w http.ResponseWriter, r *http.Request) {
		httpx.OkJson(w, nil)
	})

	for i := 0; i < 2; i++ {
		req := httptest.NewRequest(http.MethodPost, "/api/auth/login", nil)
		req.Header.Set("X-Forwarded-For", ip)
		w := httptest.NewRecorder()
		handler(w, req)
	}

	req := httptest.NewRequest(http.MethodPost, "/api/auth/login", nil)
	req.Header.Set("X-Forwarded-For", ip)
	w := httptest.NewRecorder()
	handler(w, req)

	var body response.Body
	err := json.Unmarshal(w.Body.Bytes(), &body)
	require.NoError(t, err)
	assert.Equal(t, 429, body.Code)
	assert.Equal(t, "请求过于频繁，请稍后再试", body.Msg)
}

// TC-0538: IP从X-Forwarded-For获取
func TestRateLimit_IPFromXForwardedFor(t *testing.T) {
	rds := newTestRedis()
	m := newTestMiddleware(rds, 1)
	ip := uniqueIP()

	var gotNext bool
	handler := m.Handle(func(w http.ResponseWriter, r *http.Request) {
		gotNext = true
		w.WriteHeader(http.StatusOK)
	})

	req := httptest.NewRequest(http.MethodPost, "/api/auth/login", nil)
	req.Header.Set("X-Forwarded-For", ip)
	req.Header.Set("X-Real-IP", uniqueIP())
	w := httptest.NewRecorder()
	handler(w, req)
	assert.True(t, gotNext)

	gotNext = false
	req2 := httptest.NewRequest(http.MethodPost, "/api/auth/login", nil)
	req2.Header.Set("X-Forwarded-For", ip)
	req2.Header.Set("X-Real-IP", uniqueIP())
	w2 := httptest.NewRecorder()
	handler(w2, req2)
	assert.False(t, gotNext, "should be rate limited by X-Forwarded-For IP")
}

// TC-0539: IP从X-Real-IP获取
func TestRateLimit_IPFromXRealIP(t *testing.T) {
	rds := newTestRedis()
	m := newTestMiddleware(rds, 1)
	ip := uniqueIP()

	var gotNext bool
	handler := m.Handle(func(w http.ResponseWriter, r *http.Request) {
		gotNext = true
		w.WriteHeader(http.StatusOK)
	})

	req := httptest.NewRequest(http.MethodPost, "/api/auth/login", nil)
	req.Header.Set("X-Real-IP", ip)
	w := httptest.NewRecorder()
	handler(w, req)
	assert.True(t, gotNext)

	gotNext = false
	req2 := httptest.NewRequest(http.MethodPost, "/api/auth/login", nil)
	req2.Header.Set("X-Real-IP", ip)
	w2 := httptest.NewRecorder()
	handler(w2, req2)
	assert.False(t, gotNext, "should be rate limited by X-Real-IP")
}

// TC-0540: IP从RemoteAddr获取
func TestRateLimit_IPFromRemoteAddr(t *testing.T) {
	rds := newTestRedis()
	m := newTestMiddleware(rds, 1)
	ip := uniqueIP()
	remoteAddr := ip + ":12345"

	var gotNext bool
	handler := m.Handle(func(w http.ResponseWriter, r *http.Request) {
		gotNext = true
		w.WriteHeader(http.StatusOK)
	})

	req := httptest.NewRequest(http.MethodPost, "/api/auth/login", nil)
	req.RemoteAddr = remoteAddr
	w := httptest.NewRecorder()
	handler(w, req)
	assert.True(t, gotNext)

	gotNext = false
	req2 := httptest.NewRequest(http.MethodPost, "/api/auth/login", nil)
	req2.RemoteAddr = remoteAddr
	w2 := httptest.NewRecorder()
	handler(w2, req2)
	assert.False(t, gotNext, "should be rate limited by RemoteAddr")
}

// TC-0541: 不同IP独立限流
func TestRateLimit_DifferentIPsIndependent(t *testing.T) {
	rds := newTestRedis()
	m := newTestMiddleware(rds, 1)
	ip1 := uniqueIP()
	ip2 := uniqueIP()

	var nextCount int
	handler := m.Handle(func(w http.ResponseWriter, r *http.Request) {
		nextCount++
		w.WriteHeader(http.StatusOK)
	})

	req1 := httptest.NewRequest(http.MethodPost, "/api/auth/login", nil)
	req1.Header.Set("X-Forwarded-For", ip1)
	handler(httptest.NewRecorder(), req1)
	assert.Equal(t, 1, nextCount)

	req2 := httptest.NewRequest(http.MethodPost, "/api/auth/login", nil)
	req2.Header.Set("X-Forwarded-For", ip2)
	handler(httptest.NewRecorder(), req2)
	assert.Equal(t, 2, nextCount, "different IPs should have independent quotas")

	req3 := httptest.NewRequest(http.MethodPost, "/api/auth/login", nil)
	req3.Header.Set("X-Forwarded-For", ip1)
	handler(httptest.NewRecorder(), req3)
	assert.Equal(t, 2, nextCount, "ip1 should be over quota")

	req4 := httptest.NewRequest(http.MethodPost, "/api/auth/login", nil)
	req4.Header.Set("X-Forwarded-For", ip2)
	handler(httptest.NewRecorder(), req4)
	assert.Equal(t, 2, nextCount, "ip2 should be over quota")
}