package service

import (
	"bytes"
	"context"
	"encoding/json"
	"net/http/httptest"
	"testing"

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

	"github.com/gochat/gochat/internal/model"
	"github.com/gochat/gochat/internal/repository"
	"github.com/gochat/gochat/internal/security"
)

// --- Registry Tests ---

func TestWebhookProcessorRegistry_RegisterAndGet(t *testing.T) {
	signer := security.NewWebhookSignatureService(security.DefaultWebhookSignatureConfig())
	reg := NewWebhookProcessorRegistry(signer, nil, nil)

	slackProc, ok := reg.Get(model.HookTypeSlack)
	assert.True(t, ok, "Slack processor should be registered")
	assert.Equal(t, model.HookTypeSlack, slackProc.HookType())

	shopifyProc, ok := reg.Get(model.HookTypeShopify)
	assert.True(t, ok, "Shopify processor should be registered")
	assert.Equal(t, model.HookTypeShopify, shopifyProc.HookType())

	linearProc, ok := reg.Get(model.HookTypeLinear)
	assert.True(t, ok, "Linear processor should be registered")
	assert.Equal(t, model.HookTypeLinear, linearProc.HookType())

	notionProc, ok := reg.Get(model.HookTypeNotion)
	assert.True(t, ok, "Notion processor should be registered")
	assert.Equal(t, model.HookTypeNotion, notionProc.HookType())

	webhookProc, ok := reg.Get(model.HookTypeWebhook)
	assert.True(t, ok, "Generic webhook processor should be registered")
	assert.Equal(t, model.HookTypeWebhook, webhookProc.HookType())

	_, ok = reg.Get(model.HookType("unknown"))
	assert.False(t, ok, "Unknown hook type should not be registered")
}

func TestWebhookProcessorRegistry_ListTypes(t *testing.T) {
	signer := security.NewWebhookSignatureService(security.DefaultWebhookSignatureConfig())
	reg := NewWebhookProcessorRegistry(signer, nil, nil)
	types := reg.ListTypes()
	assert.Len(t, types, 5)
}

func TestWebhookProcessorRegistry_CustomRegistration(t *testing.T) {
	signer := security.NewWebhookSignatureService(security.DefaultWebhookSignatureConfig())
	reg := &WebhookProcessorRegistry{processors: make(map[model.HookType]WebhookEventProcessor)}
	reg.Register(NewSlackEventProcessor(nil, nil, signer))
	proc, ok := reg.Get(model.HookTypeSlack)
	assert.True(t, ok)
	assert.NotNil(t, proc)
}

// --- Slack Processor Tests ---

func TestSlackEventProcessor_URLVerification(t *testing.T) {
	signer := security.NewWebhookSignatureService(security.DefaultWebhookSignatureConfig())
	proc := NewSlackEventProcessor(nil, nil, signer)
	hook := &model.IntegrationHook{ID: 1, HookType: model.HookTypeSlack, Status: model.HookStatusActive}

	payload := map[string]interface{}{
		"type":       "url_verification",
		"challenge":  "test_challenge_token_123",
		"token":      "verification_token",
	}

	err := proc.ProcessEvent(context.Background(), hook, payload)
	assert.Error(t, err, "URL verification should return special error")
	assert.Contains(t, err.Error(), "slack_url_verification")
	assert.Contains(t, err.Error(), "test_challenge_token_123")
}

func TestSlackEventProcessor_MessageEvent(t *testing.T) {
	signer := security.NewWebhookSignatureService(security.DefaultWebhookSignatureConfig())
	proc := NewSlackEventProcessor(nil, nil, signer)
	hook := &model.IntegrationHook{ID: 2, HookType: model.HookTypeSlack, Status: model.HookStatusActive}

	payload := map[string]interface{}{
		"event": map[string]interface{}{
			"type":    "message",
			"user":    "U12345",
			"channel": "C67890",
			"text":    "Hello from Slack!",
			"ts":      "1234567890.123456",
		},
	}

	err := proc.ProcessEvent(context.Background(), hook, payload)
	assert.NoError(t, err, "Valid Slack message event should process successfully")
}

func TestSlackEventProcessor_EmptyMessage(t *testing.T) {
	signer := security.NewWebhookSignatureService(security.DefaultWebhookSignatureConfig())
	proc := NewSlackEventProcessor(nil, nil, signer)
	hook := &model.IntegrationHook{ID: 3, HookType: model.HookTypeSlack, Status: model.HookStatusActive}

	payload := map[string]interface{}{
		"event": map[string]interface{}{
			"type":    "message",
			"user":    "U12345",
			"channel": "C67890",
			"text":    "",
		},
	}

	err := proc.ProcessEvent(context.Background(), hook, payload)
	assert.Error(t, err, "Empty Slack message should be rejected")
	assert.Contains(t, err.Error(), "empty")
}

func TestSlackEventProcessor_MissingEventField(t *testing.T) {
	signer := security.NewWebhookSignatureService(security.DefaultWebhookSignatureConfig())
	proc := NewSlackEventProcessor(nil, nil, signer)
	hook := &model.IntegrationHook{ID: 4, HookType: model.HookTypeSlack, Status: model.HookStatusActive}

	payload := map[string]interface{}{
		"type": "event_callback",
	}

	err := proc.ProcessEvent(context.Background(), hook, payload)
	assert.Error(t, err, "Payload without 'event' field should be rejected")
	assert.Contains(t, err.Error(), "missing 'event' field")
}

func TestSlackEventProcessor_ChannelJoinLeave(t *testing.T) {
	signer := security.NewWebhookSignatureService(security.DefaultWebhookSignatureConfig())
	proc := NewSlackEventProcessor(nil, nil, signer)
	hook := &model.IntegrationHook{ID: 5, HookType: model.HookTypeSlack, Status: model.HookStatusActive}

	for _, eventType := range []string{"channel_join", "channel_leave"} {
		payload := map[string]interface{}{
			"event": map[string]interface{}{
				"type": eventType,
			},
		}
		err := proc.ProcessEvent(context.Background(), hook, payload)
		assert.NoError(t, err, "Channel join/leave events should be accepted (no action needed)")
	}
}

func TestSlackEventProcessor_UnsupportedEventType(t *testing.T) {
	signer := security.NewWebhookSignatureService(security.DefaultWebhookSignatureConfig())
	proc := NewSlackEventProcessor(nil, nil, signer)
	hook := &model.IntegrationHook{ID: 6, HookType: model.HookTypeSlack, Status: model.HookStatusActive}

	payload := map[string]interface{}{
		"event": map[string]interface{}{
			"type": "reaction_added",
		},
	}

	err := proc.ProcessEvent(context.Background(), hook, payload)
	assert.NoError(t, err, "Unsupported Slack events should be silently accepted")
}

// --- Shopify Processor Tests ---

func TestShopifyEventProcessor_OrderCreate(t *testing.T) {
	signer := security.NewWebhookSignatureService(security.DefaultWebhookSignatureConfig())
	proc := NewShopifyEventProcessor(nil, signer)
	hook := &model.IntegrationHook{ID: 10, HookType: model.HookTypeShopify, Status: model.HookStatusActive}

	for _, topic := range []string{"orders/create", "orders/updated", "orders/paid"} {
		payload := map[string]interface{}{
			"_shopify_topic": topic,
			"id":             float64(12345),
			"email":          "customer@example.com",
		}
		err := proc.ProcessEvent(context.Background(), hook, payload)
		assert.NoError(t, err, "Shopify %s should process successfully", topic)
	}
}

func TestShopifyEventProcessor_CustomerCreate(t *testing.T) {
	signer := security.NewWebhookSignatureService(security.DefaultWebhookSignatureConfig())
	proc := NewShopifyEventProcessor(nil, signer)
	hook := &model.IntegrationHook{ID: 11, HookType: model.HookTypeShopify, Status: model.HookStatusActive}

	payload := map[string]interface{}{
		"_shopify_topic": "customers/create",
		"id":             float64(67890),
		"email":          "newcustomer@example.com",
	}

	err := proc.ProcessEvent(context.Background(), hook, payload)
	assert.NoError(t, err)
}

func TestShopifyEventProcessor_UnsupportedTopic(t *testing.T) {
	signer := security.NewWebhookSignatureService(security.DefaultWebhookSignatureConfig())
	proc := NewShopifyEventProcessor(nil, signer)
	hook := &model.IntegrationHook{ID: 12, HookType: model.HookTypeShopify, Status: model.HookStatusActive}

	payload := map[string]interface{}{
		"_shopify_topic": "products/create",
	}

	err := proc.ProcessEvent(context.Background(), hook, payload)
	assert.NoError(t, err, "Unsupported Shopify topics should be silently accepted")
}

// --- Linear Processor Tests ---

func TestLinearEventProcessor_IssueEvent(t *testing.T) {
	signer := security.NewWebhookSignatureService(security.DefaultWebhookSignatureConfig())
	proc := NewLinearEventProcessor(nil, signer)
	hook := &model.IntegrationHook{ID: 20, HookType: model.HookTypeLinear, Status: model.HookStatusActive}

	payload := map[string]interface{}{
		"action": "create",
		"data": map[string]interface{}{
			"entityType": "Issue",
			"id":         "abc-123",
			"title":      "Bug report: login fails",
		},
	}

	err := proc.ProcessEvent(context.Background(), hook, payload)
	assert.NoError(t, err)
}

func TestLinearEventProcessor_CommentEvent(t *testing.T) {
	signer := security.NewWebhookSignatureService(security.DefaultWebhookSignatureConfig())
	proc := NewLinearEventProcessor(nil, signer)
	hook := &model.IntegrationHook{ID: 21, HookType: model.HookTypeLinear, Status: model.HookStatusActive}

	payload := map[string]interface{}{
		"action": "create",
		"data": map[string]interface{}{
			"entityType": "Comment",
			"id":         "comment-456",
			"body":       "This is a comment",
		},
	}

	err := proc.ProcessEvent(context.Background(), hook, payload)
	assert.NoError(t, err)
}

func TestLinearEventProcessor_MissingDataField(t *testing.T) {
	signer := security.NewWebhookSignatureService(security.DefaultWebhookSignatureConfig())
	proc := NewLinearEventProcessor(nil, signer)
	hook := &model.IntegrationHook{ID: 22, HookType: model.HookTypeLinear, Status: model.HookStatusActive}

	payload := map[string]interface{}{
		"action": "create",
	}

	err := proc.ProcessEvent(context.Background(), hook, payload)
	assert.Error(t, err, "Linear payload without 'data' should be rejected")
	assert.Contains(t, err.Error(), "missing 'data' field")
}

// --- Notion Processor Tests ---

func TestNotionEventProcessor_BasicEvent(t *testing.T) {
	signer := security.NewWebhookSignatureService(security.DefaultWebhookSignatureConfig())
	proc := NewNotionEventProcessor(nil, signer)
	hook := &model.IntegrationHook{ID: 30, HookType: model.HookTypeNotion, Status: model.HookStatusActive}

	payload := map[string]interface{}{
		"type": "page.created",
	}

	err := proc.ProcessEvent(context.Background(), hook, payload)
	assert.NoError(t, err)
}

// --- Generic Webhook Processor Tests ---

func TestGenericWebhookProcessor_BasicEvent(t *testing.T) {
	signer := security.NewWebhookSignatureService(security.DefaultWebhookSignatureConfig())
	proc := NewGenericWebhookProcessor(nil, signer)
	hook := &model.IntegrationHook{ID: 40, HookType: model.HookTypeWebhook, Status: model.HookStatusActive, AccessToken: "test_secret_unique_webhook_001"}

	payload := map[string]interface{}{
		"event": "custom_event",
		"data":  "some data",
	}

	err := proc.ProcessEvent(context.Background(), hook, payload)
	assert.NoError(t, err)
}

// --- ParseWebhookPayload Tests ---

func TestParseWebhookPayload_ValidJSON(t *testing.T) {
	body := []byte(`{"type":"message","text":"hello","user":"U123"}`)
	payload, err := ParseWebhookPayload(body)
	require.NoError(t, err)
	assert.Equal(t, "message", payload["type"])
	assert.Equal(t, "hello", payload["text"])
}

func TestParseWebhookPayload_InvalidJSON(t *testing.T) {
	body := []byte(`{invalid json}`)
	payload, err := ParseWebhookPayload(body)
	assert.Error(t, err)
	assert.Nil(t, payload)
}

func TestParseWebhookPayload_EmptyBody(t *testing.T) {
	body := []byte(``)
	payload, err := ParseWebhookPayload(body)
	assert.Error(t, err)
	assert.Nil(t, payload)
}

// --- Signature Verification Integration Tests ---
// These tests verify that the VerifySignature method correctly integrates
// with the WebhookSignatureService for each channel type.

func TestSlackEventProcessor_VerifySignature_InvalidSignature(t *testing.T) {
	signer := security.NewWebhookSignatureService(security.DefaultWebhookSignatureConfig())
	proc := NewSlackEventProcessor(nil, nil, signer)

	hook := &model.IntegrationHook{ID: 1, AccessToken: "slack_secret_token_123_unique"}
	body := []byte(`{"type":"event_callback","event":{"type":"message"}}`)

	r := httptest.NewRequest("POST", "/webhooks/slack", bytes.NewReader(body))
	r.Header.Set("X-Slack-Signature", "v0=invalid_signature_hash")
	r.Header.Set("X-Slack-Request-Timestamp", "1234567890")

	err := proc.VerifySignature(r, body, hook)
	assert.Error(t, err, "Invalid Slack signature should be rejected")
}

func TestShopifyEventProcessor_VerifySignature_InvalidSignature(t *testing.T) {
	signer := security.NewWebhookSignatureService(security.DefaultWebhookSignatureConfig())
	proc := NewShopifyEventProcessor(nil, signer)

	hook := &model.IntegrationHook{ID: 2, AccessToken: "shopify_shared_secret_unique_456"}
	body := []byte(`{"id":12345,"email":"test@example.com"}`)

	r := httptest.NewRequest("POST", "/webhooks/shopify", bytes.NewReader(body))
	r.Header.Set("X-Shopify-Hmac-Sha256", "invalid_base64_signature")

	err := proc.VerifySignature(r, body, hook)
	assert.Error(t, err, "Invalid Shopify signature should be rejected")
}

func TestLinearEventProcessor_VerifySignature_InvalidSignature(t *testing.T) {
	signer := security.NewWebhookSignatureService(security.DefaultWebhookSignatureConfig())
	proc := NewLinearEventProcessor(nil, signer)

	hook := &model.IntegrationHook{ID: 3, AccessToken: "linear_webhook_secret_unique_789"}
	body := []byte(`{"action":"create","data":{"entityType":"Issue"}}`)

	r := httptest.NewRequest("POST", "/webhooks/linear", bytes.NewReader(body))
	r.Header.Set("X-Linear-Signature", "invalid_hex_signature")

	err := proc.VerifySignature(r, body, hook)
	assert.Error(t, err, "Invalid Linear signature should be rejected")
}

func TestGenericWebhookProcessor_VerifySignature_InvalidSignature(t *testing.T) {
	signer := security.NewWebhookSignatureService(security.DefaultWebhookSignatureConfig())
	proc := NewGenericWebhookProcessor(nil, signer)

	hook := &model.IntegrationHook{ID: 4, AccessToken: "generic_webhook_secret_unique_012"}
	body := []byte(`{"event":"custom_event"}`)

	r := httptest.NewRequest("POST", "/webhooks/generic", bytes.NewReader(body))
	r.Header.Set("X-Webhook-Hmac-Signature", "invalid_hmac_hex")

	err := proc.VerifySignature(r, body, hook)
	assert.Error(t, err, "Invalid generic webhook signature should be rejected")
}

func TestGenericWebhookProcessor_VerifySignature_EmptySecret(t *testing.T) {
	signer := security.NewWebhookSignatureService(security.DefaultWebhookSignatureConfig())
	proc := NewGenericWebhookProcessor(nil, signer)

	hook := &model.IntegrationHook{ID: 5, AccessToken: ""}
	body := []byte(`{"event":"test"}`)

	r := httptest.NewRequest("POST", "/webhooks/generic", bytes.NewReader(body))
	r.Header.Set("X-Webhook-Hmac-Signature", "some_signature")

	err := proc.VerifySignature(r, body, hook)
	assert.Error(t, err, "Empty secret should be rejected")
}

func TestGenericWebhookProcessor_VerifySignature_EmptyPayload(t *testing.T) {
	signer := security.NewWebhookSignatureService(security.DefaultWebhookSignatureConfig())
	proc := NewGenericWebhookProcessor(nil, signer)

	hook := &model.IntegrationHook{ID: 6, AccessToken: "secret_for_empty_payload_test"}
	body := []byte{}

	r := httptest.NewRequest("POST", "/webhooks/generic", bytes.NewReader(body))
	r.Header.Set("X-Webhook-Hmac-Signature", "some_signature")

	err := proc.VerifySignature(r, body, hook)
	assert.Error(t, err, "Empty payload should be rejected")
}

// --- ProcessWebhookEvent Integration Tests (using IntegrationHookService) ---
// These tests verify the full flow: hook lookup → status check → signature verify → event dispatch

func TestProcessWebhookEvent_InactiveHook(t *testing.T) {
	// Inactive hooks should be rejected before signature verification
	signer := security.NewWebhookSignatureService(security.DefaultWebhookSignatureConfig())
	hookRepo := createTestHookRepo(t)
	appRepo := createTestAppRepo(t)
	reg := NewWebhookProcessorRegistry(signer, hookRepo, nil)
	svc := NewIntegrationHookService(hookRepo, appRepo, reg)

	ctx := context.Background()
	hook := &model.IntegrationHook{
		AccountID:   1,
		HookType:    model.HookTypeSlack,
		Status:      model.HookStatusInactive,
		AccessToken: "slack_inactive_hook_secret_unique_001",
	}
	err := hookRepo.Create(ctx, hook)
	require.NoError(t, err)

	body := []byte(`{"type":"url_verification","challenge":"test"}`)
	r := httptest.NewRequest("POST", "/webhooks/slack", bytes.NewReader(body))
	payload := map[string]interface{}{"type": "url_verification", "challenge": "test"}

	err = svc.ProcessWebhookEvent(ctx, hook.ID, payload, r, body)
	assert.Error(t, err, "Inactive hook should be rejected")
	assert.Contains(t, err.Error(), "inactive")
}

func TestProcessWebhookEvent_UnknownHookType(t *testing.T) {
	signer := security.NewWebhookSignatureService(security.DefaultWebhookSignatureConfig())
	hookRepo := createTestHookRepo(t)
	appRepo := createTestAppRepo(t)
	reg := NewWebhookProcessorRegistry(signer, hookRepo, nil)
	svc := NewIntegrationHookService(hookRepo, appRepo, reg)

	ctx := context.Background()
	hook := &model.IntegrationHook{
		AccountID:   1,
		HookType:    model.HookType("unknown_type"),
		Status:      model.HookStatusActive,
		AccessToken: "unknown_hook_secret_unique_002",
	}
	err := hookRepo.Create(ctx, hook)
	require.NoError(t, err)

	body := []byte(`{"event":"test"}`)
	r := httptest.NewRequest("POST", "/webhooks/unknown", bytes.NewReader(body))
	payload := map[string]interface{}{"event": "test"}

	err = svc.ProcessWebhookEvent(ctx, hook.ID, payload, r, body)
	assert.Error(t, err, "Unknown hook type should be rejected")
	assert.Contains(t, err.Error(), "no processor")
}

func TestProcessWebhookEvent_HookNotFound(t *testing.T) {
	signer := security.NewWebhookSignatureService(security.DefaultWebhookSignatureConfig())
	hookRepo := createTestHookRepo(t)
	appRepo := createTestAppRepo(t)
	reg := NewWebhookProcessorRegistry(signer, hookRepo, nil)
	svc := NewIntegrationHookService(hookRepo, appRepo, reg)

	ctx := context.Background()
	body := []byte(`{"event":"test"}`)
	r := httptest.NewRequest("POST", "/webhooks/999999", bytes.NewReader(body))
	payload := map[string]interface{}{"event": "test"}

	err := svc.ProcessWebhookEvent(ctx, 999999, payload, r, body)
	assert.Error(t, err, "Non-existent hook ID should be rejected")
	assert.Contains(t, err.Error(), "not found")
}

// --- Utility function tests ---

func TestPayloadKeys(t *testing.T) {
	m := map[string]interface{}{
		"type":  "message",
		"text":  "hello",
		"user":  "U123",
	}
	keys := payloadKeys(m)
	assert.Len(t, keys, 3)
	assert.Contains(t, keys, "type")
	assert.Contains(t, keys, "text")
	assert.Contains(t, keys, "user")
}

func TestPayloadKeys_Empty(t *testing.T) {
	keys := payloadKeys(map[string]interface{}{})
	assert.Len(t, keys, 0)
}

// --- WebhookDelivery struct tests ---

func TestWebhookDelivery_JSON(t *testing.T) {
	delivery := WebhookDelivery{
		HookID:   1,
		Status:   "success",
		Attempts: 1,
		Payload:  map[string]interface{}{"event": "test"},
	}
	data, err := json.Marshal(delivery)
	require.NoError(t, err)
	assert.Contains(t, string(data), `"hook_id":1`)
	assert.Contains(t, string(data), `"status":"success"`)

	var decoded WebhookDelivery
	err = json.Unmarshal(data, &decoded)
	require.NoError(t, err)
	assert.Equal(t, uint(1), decoded.HookID)
	assert.Equal(t, "success", decoded.Status)
}

// --- Test helpers ---
// NOTE: These use in-memory SQLite DB via the repository layer.
// For the webhook processor tests, most tests don't need a DB (processors
// accept nil repos for logging-only processing). Only the full integration
// tests (ProcessWebhookEvent) need actual repos.

func createTestHookRepo(t *testing.T) *repository.IntegrationHookRepo {
	t.Helper()
	hookRepo, _ := setupIntegrationHookTestDB(t)
	return hookRepo
}

func createTestAppRepo(t *testing.T) *repository.IntegrationAppRepo {
	t.Helper()
	_, appRepo := setupIntegrationHookTestDB(t)
	return appRepo
}