package middleware

import (
	"context"
	"net/http/httptest"
	"testing"
	"time"

	"github.com/gin-gonic/gin"

	"fileshare/internal/cache"
)

// failingCache 模拟缓存故障（Get/Incr 均返回非 ErrNotFound 错误）。
type failingCache struct{ cache.Cache }

func (f *failingCache) Get(_ context.Context, _ string) (string, error) {
	return "", context.DeadlineExceeded
}
func (f *failingCache) Set(_ context.Context, _, _ string, _ time.Duration) error {
	return context.DeadlineExceeded
}
func (f *failingCache) Incr(_ context.Context, _ string, _ time.Duration) (int64, error) {
	return 0, context.DeadlineExceeded
}

func newLimiterTest(c *gin.Context, cacheImpl cache.Cache, count int) *RateLimiter {
	return NewRateLimiter(cacheImpl, map[string]LimitRule{
		LimitLogin: {Count: count, Window: time.Minute},
	})
}

func ginTestContext() *gin.Context {
	gin.SetMode(gin.TestMode)
	c, _ := gin.CreateTestContext(httptest.NewRecorder())
	c.Request = httptest.NewRequest("POST", "/admin/login", nil)
	return c
}

// TestRateLimiterFallbackOnCacheFailure L9：缓存故障时限流降级为进程内计数，
// 超过上限后 Check 拒绝（此前 fail-open 会一直放行）。
func TestRateLimiterFallbackOnCacheFailure(t *testing.T) {
	c := ginTestContext()
	rl := newLimiterTest(c, &failingCache{cache.NewMemory()}, 3)
	for i := 0; i < 3; i++ {
		if ok, _ := rl.Check(c, LimitLogin); !ok {
			t.Fatalf("第 %d 次检查不应拒绝", i+1)
		}
		rl.Add(c, LimitLogin)
	}
	if ok, _ := rl.Check(c, LimitLogin); ok {
		t.Fatal("缓存故障降级下，超过上限后 Check 应拒绝（fail-close）")
	}
}

// TestRateLimiterNormalCacheCounting 正常缓存路径行为不变。
func TestRateLimiterNormalCacheCounting(t *testing.T) {
	c := ginTestContext()
	rl := newLimiterTest(c, cache.NewMemory(), 2)
	for i := 0; i < 2; i++ {
		rl.Add(c, LimitLogin)
	}
	if ok, _ := rl.Check(c, LimitLogin); ok {
		t.Fatal("达到上限后 Check 应拒绝")
	}
}