package handler

import (
	"net/http"
	"net/http/httptest"
	"sync"
	"testing"

	middleware2 "github.com/Wei-Shaw/sub2api/internal/server/middleware"
	"github.com/Wei-Shaw/sub2api/internal/service"
	"github.com/gin-gonic/gin"
	"github.com/stretchr/testify/require"
)

func resetOpsErrorLoggerStateForTest(t *testing.T) {
	t.Helper()

	opsErrorLogMu.Lock()
	ch := opsErrorLogQueue
	opsErrorLogQueue = nil
	opsErrorLogStopping = true
	opsErrorLogMu.Unlock()

	if ch != nil {
		close(ch)
	}
	opsErrorLogWorkersWg.Wait()

	opsErrorLogOnce = sync.Once{}
	opsErrorLogStopOnce = sync.Once{}
	opsErrorLogWorkersWg = sync.WaitGroup{}
	opsErrorLogMu = sync.RWMutex{}
	opsErrorLogStopping = false

	opsErrorLogQueueLen.Store(0)
	opsErrorLogEnqueued.Store(0)
	opsErrorLogDropped.Store(0)
	opsErrorLogProcessed.Store(0)
	opsErrorLogSanitized.Store(0)
	opsErrorLogLastDropLogAt.Store(0)

	opsErrorLogShutdownCh = make(chan struct{})
	opsErrorLogShutdownOnce = sync.Once{}
	opsErrorLogDrained.Store(false)
}

func TestEnqueueOpsErrorLog_QueueFullDrop(t *testing.T) {
	resetOpsErrorLoggerStateForTest(t)

	// 禁止 enqueueOpsErrorLog 触发 workers，使用测试队列验证满队列降级。
	opsErrorLogOnce.Do(func() {})

	opsErrorLogMu.Lock()
	opsErrorLogQueue = make(chan opsErrorLogJob, 1)
	opsErrorLogMu.Unlock()

	ops := service.NewOpsService(nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil)
	entry := &service.OpsInsertErrorLogInput{ErrorPhase: "upstream", ErrorType: "upstream_error"}

	enqueueOpsErrorLog(ops, entry)
	enqueueOpsErrorLog(ops, entry)

	require.Equal(t, int64(1), OpsErrorLogEnqueuedTotal())
	require.Equal(t, int64(1), OpsErrorLogDroppedTotal())
	require.Equal(t, int64(1), OpsErrorLogQueueLength())
}

func TestEnqueueOpsErrorLog_EarlyReturnBranches(t *testing.T) {
	resetOpsErrorLoggerStateForTest(t)

	ops := service.NewOpsService(nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil)
	entry := &service.OpsInsertErrorLogInput{ErrorPhase: "upstream", ErrorType: "upstream_error"}

	// nil 入参分支
	enqueueOpsErrorLog(nil, entry)
	enqueueOpsErrorLog(ops, nil)
	require.Equal(t, int64(0), OpsErrorLogEnqueuedTotal())

	// shutdown 分支
	close(opsErrorLogShutdownCh)
	enqueueOpsErrorLog(ops, entry)
	require.Equal(t, int64(0), OpsErrorLogEnqueuedTotal())

	// stopping 分支
	resetOpsErrorLoggerStateForTest(t)
	opsErrorLogMu.Lock()
	opsErrorLogStopping = true
	opsErrorLogMu.Unlock()
	enqueueOpsErrorLog(ops, entry)
	require.Equal(t, int64(0), OpsErrorLogEnqueuedTotal())

	// queue nil 分支（防止启动 worker 干扰）
	resetOpsErrorLoggerStateForTest(t)
	opsErrorLogOnce.Do(func() {})
	opsErrorLogMu.Lock()
	opsErrorLogQueue = nil
	opsErrorLogMu.Unlock()
	enqueueOpsErrorLog(ops, entry)
	require.Equal(t, int64(0), OpsErrorLogEnqueuedTotal())
}

func TestOpsCaptureWriterPool_ResetOnRelease(t *testing.T) {
	gin.SetMode(gin.TestMode)

	rec := httptest.NewRecorder()
	c, _ := gin.CreateTestContext(rec)
	c.Request = httptest.NewRequest(http.MethodGet, "/test", nil)

	writer := acquireOpsCaptureWriter(c.Writer)
	require.NotNil(t, writer)
	_, err := writer.buf.WriteString("temp-error-body")
	require.NoError(t, err)

	releaseOpsCaptureWriter(writer)

	reused := acquireOpsCaptureWriter(c.Writer)
	defer releaseOpsCaptureWriter(reused)

	require.Zero(t, reused.buf.Len(), "writer should be reset before reuse")
}

func TestOpsErrorLoggerMiddleware_DoesNotBreakOuterMiddlewares(t *testing.T) {
	gin.SetMode(gin.TestMode)

	r := gin.New()
	r.Use(middleware2.Recovery())
	r.Use(middleware2.RequestLogger())
	r.Use(middleware2.Logger())
	r.GET("/v1/messages", OpsErrorLoggerMiddleware(nil), func(c *gin.Context) {
		c.Status(http.StatusNoContent)
	})

	rec := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet, "/v1/messages", nil)

	require.NotPanics(t, func() {
		r.ServeHTTP(rec, req)
	})
	require.Equal(t, http.StatusNoContent, rec.Code)
}

func TestIsKnownOpsErrorType(t *testing.T) {
	known := []string{
		"invalid_request_error",
		"authentication_error",
		"rate_limit_error",
		"billing_error",
		"subscription_error",
		"upstream_error",
		"overloaded_error",
		"api_error",
		"not_found_error",
		"forbidden_error",
	}
	for _, k := range known {
		require.True(t, isKnownOpsErrorType(k), "expected known: %s", k)
	}

	unknown := []string{"<nil>", "null", "", "random_error", "some_new_type", "<nil>\u003e"}
	for _, u := range unknown {
		require.False(t, isKnownOpsErrorType(u), "expected unknown: %q", u)
	}
}

func TestNormalizeOpsErrorType(t *testing.T) {
	tests := []struct {
		name    string
		errType string
		code    string
		want    string
	}{
		// Known types pass through.
		{"known invalid_request_error", "invalid_request_error", "", "invalid_request_error"},
		{"known rate_limit_error", "rate_limit_error", "", "rate_limit_error"},
		{"known upstream_error", "upstream_error", "", "upstream_error"},

		// Unknown/garbage types are rejected and fall through to code-based or default.
		{"nil literal from upstream", "<nil>", "", "api_error"},
		{"null string", "null", "", "api_error"},
		{"random string", "something_weird", "", "api_error"},

		// Unknown type but known code still maps correctly.
		{"nil with INSUFFICIENT_BALANCE code", "<nil>", "INSUFFICIENT_BALANCE", "billing_error"},
		{"nil with USAGE_LIMIT_EXCEEDED code", "<nil>", "USAGE_LIMIT_EXCEEDED", "subscription_error"},

		// Empty type falls through to code-based mapping.
		{"empty type with balance code", "", "INSUFFICIENT_BALANCE", "billing_error"},
		{"empty type with subscription code", "", "SUBSCRIPTION_NOT_FOUND", "subscription_error"},
		{"empty type no code", "", "", "api_error"},

		// Known type overrides conflicting code-based mapping.
		{"known type overrides conflicting code", "rate_limit_error", "INSUFFICIENT_BALANCE", "rate_limit_error"},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			got := normalizeOpsErrorType(tt.errType, tt.code)
			require.Equal(t, tt.want, got)
		})
	}
}

func TestClassifyOpsNoAvailableAccountsExcludedFromSLA(t *testing.T) {
	const message = "No available accounts"
	gin.SetMode(gin.TestMode)
	rec := httptest.NewRecorder()
	c, _ := gin.CreateTestContext(rec)

	markOpsRoutingCapacityLimited(c)

	errType := normalizeOpsErrorType("api_error", "")
	phase, isBusinessLimited, errorOwner, errorSource := classifyOpsErrorLog(c, errType, message, "", http.StatusServiceUnavailable)

	require.Equal(t, "api_error", errType)
	require.Equal(t, "routing", phase)
	require.True(t, isBusinessLimited)
	require.Equal(t, "platform", errorOwner)
	require.Equal(t, "gateway", errorSource)
}

func TestClassifyOpsRoutingCapacityMarkerExcludesMaskedSelectionFailureFromSLA(t *testing.T) {
	gin.SetMode(gin.TestMode)
	rec := httptest.NewRecorder()
	c, _ := gin.CreateTestContext(rec)

	markOpsRoutingCapacityLimited(c)

	phase, isBusinessLimited, errorOwner, errorSource := classifyOpsErrorLog(
		c,
		"api_error",
		"Service temporarily unavailable",
		"",
		http.StatusServiceUnavailable,
	)

	require.Equal(t, "routing", phase)
	require.True(t, isBusinessLimited)
	require.Equal(t, "platform", errorOwner)
	require.Equal(t, "gateway", errorSource)
}

func TestClassifyOpsAuthClientErrorsExcludedFromSLA(t *testing.T) {
	tests := []struct {
		name    string
		errType string
		message string
		code    string
		status  int
	}{
		{
			name:    "standard invalid API key",
			errType: "api_error",
			message: "Invalid API key",
			code:    "INVALID_API_KEY",
			status:  http.StatusUnauthorized,
		},
		{
			name:    "standard missing API key",
			errType: "api_error",
			message: "API key is required in Authorization header (Bearer scheme), x-api-key header, or x-goog-api-key header",
			code:    "API_KEY_REQUIRED",
			status:  http.StatusUnauthorized,
		},
		{
			name:    "google invalid API key",
			errType: "api_error",
			message: "Invalid API key",
			code:    "401",
			status:  http.StatusUnauthorized,
		},
		{
			name:    "google missing API key",
			errType: "api_error",
			message: "API key is required",
			code:    "401",
			status:  http.StatusUnauthorized,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			gin.SetMode(gin.TestMode)
			rec := httptest.NewRecorder()
			c, _ := gin.CreateTestContext(rec)

			errType := normalizeOpsErrorType(tt.errType, tt.code)
			phase, isBusinessLimited, errorOwner, errorSource := classifyOpsErrorLog(c, errType, tt.message, tt.code, tt.status)

			require.Equal(t, "api_error", errType)
			require.Equal(t, "auth", phase)
			require.True(t, isBusinessLimited)
			require.Equal(t, "client", errorOwner)
			require.Equal(t, "client_request", errorSource)
		})
	}
}

func TestClassifyOpsIPRestrictionAccessDeniedExcludedFromSLA(t *testing.T) {
	gin.SetMode(gin.TestMode)
	rec := httptest.NewRecorder()
	c, _ := gin.CreateTestContext(rec)
	service.MarkOpsClientBusinessLimited(c, service.OpsClientBusinessLimitedReasonIPRestriction)

	errType := normalizeOpsErrorType("api_error", "ACCESS_DENIED")
	phase, isBusinessLimited, errorOwner, errorSource := classifyOpsErrorLog(c, errType, "Access denied", "ACCESS_DENIED", http.StatusForbidden)

	require.Equal(t, "api_error", errType)
	require.Equal(t, "auth", phase)
	require.True(t, isBusinessLimited)
	require.Equal(t, "client", errorOwner)
	require.Equal(t, "client_request", errorSource)
}

func TestClassifyOpsOtherErrorsStillCountForSLA(t *testing.T) {
	gin.SetMode(gin.TestMode)
	rec := httptest.NewRecorder()
	c, _ := gin.CreateTestContext(rec)

	errType := normalizeOpsErrorType("api_error", "INTERNAL_ERROR")
	phase, isBusinessLimited, errorOwner, errorSource := classifyOpsErrorLog(c, errType, "Failed to validate API key", "INTERNAL_ERROR", http.StatusInternalServerError)

	require.Equal(t, "api_error", errType)
	require.Equal(t, "internal", phase)
	require.False(t, isBusinessLimited)
	require.Equal(t, "platform", errorOwner)
	require.Equal(t, "gateway", errorSource)
}

func TestClassifyOpsUnsupportedModelExcludedFromSLA(t *testing.T) {
	tests := []string{
		"No available accounts: no available accounts supporting model: made-up-model",
		"No available accounts: no available OpenAI accounts supporting model: made-up-model",
		"No available Gemini accounts: no available Gemini accounts supporting model: made-up-model",
		"No available accounts: no available accounts supporting model: made-up-model (channel pricing restriction)",
	}

	for _, message := range tests {
		t.Run(message, func(t *testing.T) {
			gin.SetMode(gin.TestMode)
			rec := httptest.NewRecorder()
			c, _ := gin.CreateTestContext(rec)
			markOpsRoutingCapacityLimited(c)

			errType := normalizeOpsErrorType("api_error", "")
			phase, isBusinessLimited, errorOwner, errorSource := classifyOpsErrorLog(c, errType, message, "", http.StatusServiceUnavailable)

			require.Equal(t, "api_error", errType)
			require.Equal(t, "routing", phase)
			require.True(t, isBusinessLimited)
			require.Equal(t, "platform", errorOwner)
			require.Equal(t, "gateway", errorSource)
		})
	}
}

func TestClassifyOpsUnmarkedNoAvailableTextStillCountsForSLA(t *testing.T) {
	gin.SetMode(gin.TestMode)
	rec := httptest.NewRecorder()
	c, _ := gin.CreateTestContext(rec)

	phase, isBusinessLimited, errorOwner, errorSource := classifyOpsErrorLog(
		c,
		"api_error",
		"No available accounts",
		"",
		http.StatusServiceUnavailable,
	)

	require.Equal(t, "routing", phase)
	require.False(t, isBusinessLimited)
	require.Equal(t, "platform", errorOwner)
	require.Equal(t, "gateway", errorSource)
}

func TestClassifyOpsUpstreamAuthTextStillCountsForSLA(t *testing.T) {
	gin.SetMode(gin.TestMode)
	rec := httptest.NewRecorder()
	c, _ := gin.CreateTestContext(rec)
	service.SetOpsUpstreamError(c, http.StatusUnauthorized, "Invalid API key", "")

	phase, isBusinessLimited, errorOwner, errorSource := classifyOpsErrorLog(
		c,
		"api_error",
		"Invalid API key",
		"401",
		http.StatusUnauthorized,
	)

	require.Equal(t, "upstream", phase)
	require.False(t, isBusinessLimited)
	require.Equal(t, "provider", errorOwner)
	require.Equal(t, "upstream_http", errorSource)
}

func TestClassifyOpsUpstreamNoAvailableTextStillCountsForSLA(t *testing.T) {
	gin.SetMode(gin.TestMode)
	rec := httptest.NewRecorder()
	c, _ := gin.CreateTestContext(rec)
	service.SetOpsUpstreamError(c, http.StatusServiceUnavailable, "No available accounts", "")

	phase, isBusinessLimited, errorOwner, errorSource := classifyOpsErrorLog(
		c,
		"api_error",
		"No available accounts",
		"",
		http.StatusServiceUnavailable,
	)

	require.Equal(t, "upstream", phase)
	require.False(t, isBusinessLimited)
	require.Equal(t, "provider", errorOwner)
	require.Equal(t, "upstream_http", errorSource)
}

func TestSetOpsEndpointContext_SetsContextKeys(t *testing.T) {
	gin.SetMode(gin.TestMode)
	rec := httptest.NewRecorder()
	c, _ := gin.CreateTestContext(rec)
	c.Request = httptest.NewRequest(http.MethodPost, "/v1/messages", nil)

	setOpsEndpointContext(c, "claude-3-5-sonnet-20241022", int16(2)) // stream

	v, ok := c.Get(opsUpstreamModelKey)
	require.True(t, ok)
	vStr, ok := v.(string)
	require.True(t, ok)
	require.Equal(t, "claude-3-5-sonnet-20241022", vStr)

	rt, ok := c.Get(opsRequestTypeKey)
	require.True(t, ok)
	rtVal, ok := rt.(int16)
	require.True(t, ok)
	require.Equal(t, int16(2), rtVal)
}

func TestSetOpsEndpointContext_EmptyModelNotStored(t *testing.T) {
	gin.SetMode(gin.TestMode)
	rec := httptest.NewRecorder()
	c, _ := gin.CreateTestContext(rec)
	c.Request = httptest.NewRequest(http.MethodPost, "/v1/messages", nil)

	setOpsEndpointContext(c, "", int16(1))

	_, ok := c.Get(opsUpstreamModelKey)
	require.False(t, ok, "empty upstream model should not be stored")

	rt, ok := c.Get(opsRequestTypeKey)
	require.True(t, ok)
	rtVal, ok := rt.(int16)
	require.True(t, ok)
	require.Equal(t, int16(1), rtVal)
}

func TestSetOpsEndpointContext_NilContext(t *testing.T) {
	require.NotPanics(t, func() {
		setOpsEndpointContext(nil, "model", int16(1))
	})
}