package integration

import (
	"fmt"
	"io"
	"net/http/httptest"
	"testing"
	"time"

	"github.com/break/junhong_cmp_fiber/internal/middleware"
	"github.com/break/junhong_cmp_fiber/pkg/logger"
	"github.com/break/junhong_cmp_fiber/pkg/response"
	"github.com/gofiber/fiber/v2"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

// setupRateLimiterTestApp creates a Fiber app with rate limiter for testing
func setupRateLimiterTestApp(t *testing.T, max int, expiration time.Duration) *fiber.App {
	t.Helper()

	// Initialize logger
	appLogConfig := logger.LogRotationConfig{
		Filename:   "logs/app_test.log",
		MaxSize:    10,
		MaxBackups: 3,
		MaxAge:     7,
		Compress:   false,
	}
	accessLogConfig := logger.LogRotationConfig{
		Filename:   "logs/access_test.log",
		MaxSize:    10,
		MaxBackups: 3,
		MaxAge:     7,
		Compress:   false,
	}
	if err := logger.InitLoggers("info", false, appLogConfig, accessLogConfig); err != nil {
		t.Fatalf("failed to initialize logger: %v", err)
	}

	app := fiber.New()

	// Add rate limiter middleware (nil storage = in-memory)
	app.Use(middleware.RateLimiter(max, expiration, nil))

	// Add test route
	app.Get("/api/v1/test", func(c *fiber.Ctx) error {
		return response.Success(c, fiber.Map{
			"message": "success",
		})
	})

	return app
}

// TestRateLimiter_LimitExceeded tests that rate limiter returns 429 when limit is exceeded
func TestRateLimiter_LimitExceeded(t *testing.T) {
	// Create app with low limit for easy testing
	max := 5
	expiration := 1 * time.Minute
	app := setupRateLimiterTestApp(t, max, expiration)

	// Make requests up to the limit
	for i := 1; i <= max; i++ {
		req := httptest.NewRequest("GET", "/api/v1/test", nil)
		req.Header.Set("X-Forwarded-For", "192.168.1.100") // Simulate same IP

		resp, err := app.Test(req, -1)
		require.NoError(t, err)
		resp.Body.Close()

		assert.Equal(t, 200, resp.StatusCode, "Request %d should succeed", i)
	}

	// The next request should be rate limited
	req := httptest.NewRequest("GET", "/api/v1/test", nil)
	req.Header.Set("X-Forwarded-For", "192.168.1.100")

	resp, err := app.Test(req, -1)
	require.NoError(t, err)
	defer resp.Body.Close()

	// Should get 429 Too Many Requests
	assert.Equal(t, 429, resp.StatusCode, "Request should be rate limited")

	// Check response body
	body, err := io.ReadAll(resp.Body)
	require.NoError(t, err)
	t.Logf("Rate limit response: %s", string(body))

	// Should contain error code 1003
	assert.Contains(t, string(body), `"code":1003`, "Response should have too many requests error code")
	// Message is in Chinese: "请求过于频繁"
	assert.Contains(t, string(body), "请求过于频繁", "Response should have rate limit message")
}

// TestRateLimiter_ResetAfterExpiration tests that rate limit resets after window expiration
func TestRateLimiter_ResetAfterExpiration(t *testing.T) {
	// Create app with short expiration for testing
	max := 3
	expiration := 2 * time.Second
	app := setupRateLimiterTestApp(t, max, expiration)

	// Make requests up to the limit
	for i := 1; i <= max; i++ {
		req := httptest.NewRequest("GET", "/api/v1/test", nil)
		req.Header.Set("X-Forwarded-For", "192.168.1.101")

		resp, err := app.Test(req, -1)
		require.NoError(t, err)
		resp.Body.Close()

		assert.Equal(t, 200, resp.StatusCode, "Request %d should succeed", i)
	}

	// Next request should be rate limited
	req := httptest.NewRequest("GET", "/api/v1/test", nil)
	req.Header.Set("X-Forwarded-For", "192.168.1.101")

	resp, err := app.Test(req, -1)
	require.NoError(t, err)
	resp.Body.Close()

	assert.Equal(t, 429, resp.StatusCode, "Request should be rate limited")

	// Wait for rate limit window to expire
	t.Log("Waiting for rate limit window to reset...")
	time.Sleep(expiration + 500*time.Millisecond)

	// Request should succeed after reset
	req = httptest.NewRequest("GET", "/api/v1/test", nil)
	req.Header.Set("X-Forwarded-For", "192.168.1.101")

	resp, err = app.Test(req, -1)
	require.NoError(t, err)
	defer resp.Body.Close()

	assert.Equal(t, 200, resp.StatusCode, "Request should succeed after rate limit reset")

	body, err := io.ReadAll(resp.Body)
	require.NoError(t, err)

	assert.Contains(t, string(body), `"code":0`, "Response should be successful after reset")
}

// TestRateLimiter_PerIPRateLimiting tests that different IPs have separate rate limits
func TestRateLimiter_PerIPRateLimiting(t *testing.T) {
	max := 5
	expiration := 1 * time.Minute

	// Test with multiple different IPs
	ips := []string{
		"192.168.1.10",
		"192.168.1.20",
		"192.168.1.30",
	}

	for _, ip := range ips {
		ip := ip // Capture for closure
		t.Run(fmt.Sprintf("IP_%s", ip), func(t *testing.T) {
			// Create fresh app for each IP test to avoid shared limiter state
			freshApp := setupRateLimiterTestApp(t, max, expiration)

			// Each IP should be able to make 'max' successful requests
			for i := 1; i <= max; i++ {
				req := httptest.NewRequest("GET", "/api/v1/test", nil)
				req.Header.Set("X-Forwarded-For", ip)

				resp, err := freshApp.Test(req, -1)
				require.NoError(t, err)
				resp.Body.Close()

				assert.Equal(t, 200, resp.StatusCode, "IP %s request %d should succeed", ip, i)
			}

			// The next request for this IP should be rate limited
			req := httptest.NewRequest("GET", "/api/v1/test", nil)
			req.Header.Set("X-Forwarded-For", ip)

			resp, err := freshApp.Test(req, -1)
			require.NoError(t, err)
			resp.Body.Close()

			assert.Equal(t, 429, resp.StatusCode, "IP %s should be rate limited", ip)
		})
	}
}

// TestRateLimiter_ConcurrentRequests tests rate limiter with concurrent requests from same IP
func TestRateLimiter_ConcurrentRequests(t *testing.T) {
	// Create app with limit
	max := 10
	expiration := 1 * time.Minute
	app := setupRateLimiterTestApp(t, max, expiration)

	// Make concurrent requests
	concurrentRequests := 15
	results := make(chan int, concurrentRequests)

	for i := 0; i < concurrentRequests; i++ {
		go func() {
			req := httptest.NewRequest("GET", "/api/v1/test", nil)
			req.Header.Set("X-Forwarded-For", "192.168.1.200")

			resp, err := app.Test(req, -1)
			if err != nil {
				results <- 0
				return
			}
			defer resp.Body.Close()

			results <- resp.StatusCode
		}()
	}

	// Collect results
	var successCount, rateLimitedCount int
	for i := 0; i < concurrentRequests; i++ {
		status := <-results
		if status == 200 {
			successCount++
		} else if status == 429 {
			rateLimitedCount++
		}
	}

	t.Logf("Concurrent requests: %d success, %d rate limited", successCount, rateLimitedCount)

	// Should have exactly 'max' successful requests
	assert.Equal(t, max, successCount, "Should have exactly max successful requests")

	// Remaining requests should be rate limited
	assert.Equal(t, concurrentRequests-max, rateLimitedCount, "Remaining requests should be rate limited")
}

// TestRateLimiter_DifferentLimits tests rate limiter configuration with different limits
func TestRateLimiter_DifferentLimits(t *testing.T) {
	tests := []struct {
		name       string
		max        int
		expiration time.Duration
	}{
		{
			name:       "low_limit",
			max:        2,
			expiration: 1 * time.Minute,
		},
		{
			name:       "medium_limit",
			max:        10,
			expiration: 1 * time.Minute,
		},
		{
			name:       "high_limit",
			max:        100,
			expiration: 1 * time.Minute,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			app := setupRateLimiterTestApp(t, tt.max, tt.expiration)

			// Make requests up to limit
			for i := 1; i <= tt.max; i++ {
				req := httptest.NewRequest("GET", "/api/v1/test", nil)
				req.Header.Set("X-Forwarded-For", fmt.Sprintf("192.168.1.%d", 50+i))

				resp, err := app.Test(req, -1)
				require.NoError(t, err)
				resp.Body.Close()

				assert.Equal(t, 200, resp.StatusCode)
			}

			// Next request should be rate limited
			req := httptest.NewRequest("GET", "/api/v1/test", nil)
			req.Header.Set("X-Forwarded-For", fmt.Sprintf("192.168.1.%d", 50))

			resp, err := app.Test(req, -1)
			require.NoError(t, err)
			resp.Body.Close()

			assert.Equal(t, 429, resp.StatusCode, "Should be rate limited after %d requests", tt.max)
		})
	}
}

// TestRateLimiter_ShortWindow tests rate limiter with very short time window
func TestRateLimiter_ShortWindow(t *testing.T) {
	// Create app with short window
	max := 3
	expiration := 1 * time.Second
	app := setupRateLimiterTestApp(t, max, expiration)

	// Make first batch of requests
	for i := 1; i <= max; i++ {
		req := httptest.NewRequest("GET", "/api/v1/test", nil)
		req.Header.Set("X-Forwarded-For", "192.168.1.250")

		resp, err := app.Test(req, -1)
		require.NoError(t, err)
		resp.Body.Close()

		assert.Equal(t, 200, resp.StatusCode)
	}

	// Should be rate limited now
	req := httptest.NewRequest("GET", "/api/v1/test", nil)
	req.Header.Set("X-Forwarded-For", "192.168.1.250")

	resp, err := app.Test(req, -1)
	require.NoError(t, err)
	resp.Body.Close()

	assert.Equal(t, 429, resp.StatusCode)

	// Wait for window to expire
	time.Sleep(expiration + 200*time.Millisecond)

	// Should be able to make requests again
	for i := 1; i <= max; i++ {
		req := httptest.NewRequest("GET", "/api/v1/test", nil)
		req.Header.Set("X-Forwarded-For", "192.168.1.250")

		resp, err := app.Test(req, -1)
		require.NoError(t, err)
		resp.Body.Close()

		assert.Equal(t, 200, resp.StatusCode, "Request %d should succeed after window reset", i)
	}
}