package ratelimit

import (
	"context"
	"sync"
	"testing"
	"time"

	"github.com/hhs/camtalk/internal/config"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func TestTokenBucket_Allow_FirstRequest(t *testing.T) {
	bucket := newTokenBucket(5, 0.2)

	allowed, retryAfter := bucket.allow()

	assert.True(t, allowed)
	assert.Equal(t, time.Duration(0), retryAfter)
}

func TestTokenBucket_Allow_ConsumeUntilEmpty(t *testing.T) {
	bucket := newTokenBucket(3, 0.2)

	// 连续消耗 3 个令牌
	for i := 0; i < 3; i++ {
		allowed, _ := bucket.allow()
		assert.True(t, allowed, "request %d should be allowed", i+1)
	}

	// 第 4 个请求应被拒绝
	allowed, retryAfter := bucket.allow()
	assert.False(t, allowed)
	assert.Greater(t, retryAfter, time.Duration(0))
}

func TestTokenBucket_Allow_RetryAfterCorrect(t *testing.T) {
	bucket := newTokenBucket(1, 1.0) // 每秒 1 个令牌

	// 消耗唯一的令牌
	allowed, _ := bucket.allow()
	require.True(t, allowed)

	// 立即再次请求应被拒绝
	allowed, retryAfter := bucket.allow()
	assert.False(t, allowed)
	// retryAfter 应约为 1 秒（允许一定误差）
	assert.InDelta(t, 1000, retryAfter.Milliseconds(), 100)
}

func TestTokenBucket_Allow_RefillAfterWait(t *testing.T) {
	bucket := newTokenBucket(2, 10.0) // 每秒 10 个令牌（每 100ms 一个）

	// 消耗 2 个令牌
	bucket.allow()
	bucket.allow()

	// 等待 150ms，应补充至少 1 个令牌
	time.Sleep(150 * time.Millisecond)

	allowed, _ := bucket.allow()
	assert.True(t, allowed)
}

func TestTokenBucket_Allow_CapacityLimit(t *testing.T) {
	bucket := newTokenBucket(3, 1.0)

	// 等待足够长时间让桶"溢出"
	time.Sleep(100 * time.Millisecond)

	// 但最多只能消耗 capacity 个令牌
	for i := 0; i < 3; i++ {
		allowed, _ := bucket.allow()
		assert.True(t, allowed, "request %d should be allowed", i+1)
	}

	// 第 4 个应被拒绝
	allowed, _ := bucket.allow()
	assert.False(t, allowed)
}

func TestTokenBucket_Allow_ConcurrentSafe(t *testing.T) {
	bucket := newTokenBucket(100, 10.0)
	var wg sync.WaitGroup
	successCount := 0
	var mu sync.Mutex

	// 100 个并发请求
	for i := 0; i < 100; i++ {
		wg.Add(1)
		go func() {
			defer wg.Done()
			allowed, _ := bucket.allow()
			if allowed {
				mu.Lock()
				successCount++
				mu.Unlock()
			}
		}()
	}

	wg.Wait()

	// 应该正好 100 个成功（桶容量为 100）
	assert.Equal(t, 100, successCount)
}

func TestTokenBucket_Allow_ZeroCapacity(t *testing.T) {
	bucket := newTokenBucket(0, 1.0)

	allowed, retryAfter := bucket.allow()
	assert.False(t, allowed)
	assert.Greater(t, retryAfter, time.Duration(0))
}

func TestTokenBucket_Allow_ZeroRate(t *testing.T) {
	bucket := newTokenBucket(1, 0.0)

	// 第一个通过
	allowed, _ := bucket.allow()
	assert.True(t, allowed)

	// 第二个被拒绝，且 retryAfter 应为无限大（实际上会很大）
	allowed, retryAfter := bucket.allow()
	assert.False(t, allowed)
	// rate=0 时，retryAfter 理论上无限大，实际会是一个很大的值
	assert.Greater(t, retryAfter, 1*time.Hour)
}

func TestMemoryLimiter_Allow_DifferentKeys(t *testing.T) {
	cfg := config.RateLimitConfig{
		Enabled: true,
		Query:   config.BucketConfig{Capacity: 2, Rate: 1.0},
	}
	limiter := NewMemoryLimiter(cfg)
	defer limiter.Stop()

	ctx := context.Background()

	// user1 消耗 2 个令牌
	allowed, _ := limiter.Allow(ctx, "user1:query")
	assert.True(t, allowed)
	allowed, _ = limiter.Allow(ctx, "user1:query")
	assert.True(t, allowed)

	// user1 第 3 个被拒绝
	allowed, _ = limiter.Allow(ctx, "user1:query")
	assert.False(t, allowed)

	// user2 应该不受影响
	allowed, _ = limiter.Allow(ctx, "user2:query")
	assert.True(t, allowed)
}

func TestMemoryLimiter_Cleanup(t *testing.T) {
	cfg := config.RateLimitConfig{
		Enabled: true,
		Query:   config.BucketConfig{Capacity: 1, Rate: 1.0},
	}
	limiter := NewMemoryLimiter(cfg)
	defer limiter.Stop()

	ctx := context.Background()

	// 创建一个桶
	limiter.Allow(ctx, "user1:query")

	// 验证桶已创建
	limiter.mu.RLock()
	initialCount := len(limiter.buckets)
	limiter.mu.RUnlock()
	assert.Equal(t, 1, initialCount)

	// 手动触发清理（模拟 10 分钟后）
	limiter.mu.Lock()
	for _, bucket := range limiter.buckets {
		bucket.mu.Lock()
		bucket.lastRefill = time.Now().Add(-11 * time.Minute)
		bucket.mu.Unlock()
	}
	limiter.mu.Unlock()

	limiter.removeInactiveBuckets()

	// 验证桶已被清理
	limiter.mu.RLock()
	finalCount := len(limiter.buckets)
	limiter.mu.RUnlock()
	assert.Equal(t, 0, finalCount)
}

func TestMemoryLimiter_Stop(t *testing.T) {
	cfg := config.RateLimitConfig{
		Enabled: true,
		Query:   config.BucketConfig{Capacity: 1, Rate: 1.0},
	}
	limiter := NewMemoryLimiter(cfg)

	// 多次调用 Stop 不应 panic
	limiter.Stop()
	limiter.Stop()
}