package v1

import (
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"strconv"
	"strings"
	"testing"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"

	wspkg "github.com/gochat/gochat/internal/ws"
)

func setupSSETest(t *testing.T) (*gin.Engine, *wspkg.SSERegistry, *SSEEventHandler) {
	t.Helper()
	gin.SetMode(gin.TestMode)

	registry := wspkg.NewSSERegistry()
	handler := NewSSEEventHandler(registry)

	engine := gin.New()
	engine.Use(func(c *gin.Context) {
		c.Set("user_id", uint(100))
		if accID, err := strconv.ParseUint(c.Param("account_id"), 10, 32); err == nil {
			c.Set("account_id", uint(accID))
		}
		c.Next()
	})
	engine.GET("/api/v1/accounts/:account_id/events", handler.StreamEvents)

	return engine, registry, handler
}

func TestSSEEventHandler_StreamEvents_InvalidAccountID(t *testing.T) {
	registry := wspkg.NewSSERegistry()
	handler := NewSSEEventHandler(registry)

	gin.SetMode(gin.TestMode)
	engine := gin.New()
	engine.Use(func(c *gin.Context) {
		c.Set("user_id", uint(100))
		c.Next()
	})
	engine.GET("/api/v1/accounts/:account_id/events", handler.StreamEvents)

	w := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet, "/api/v1/accounts/abc/events", nil)
	engine.ServeHTTP(w, req)
	assert.Equal(t, http.StatusBadRequest, w.Code)
}

func TestSSERegistry_SubscribeUnsubscribe(t *testing.T) {
	registry := wspkg.NewSSERegistry()

	channel := registry.Subscribe("chan1", 1, 100)
	require.NotNil(t, channel)
	assert.Equal(t, "chan1", channel.ID)
	assert.Equal(t, uint(1), channel.AccountID)
	assert.Equal(t, uint(100), channel.UserID)
	assert.Equal(t, 1, registry.ChannelCount(1))

	registry.Unsubscribe("chan1")
	assert.Equal(t, 0, registry.ChannelCount(1))
	assert.True(t, channel.Closed)
}

func TestSSERegistry_SendToAccount(t *testing.T) {
	registry := wspkg.NewSSERegistry()

	channel := registry.Subscribe("chan1", 1, 100)

	event := wspkg.SSEEvent{
		Type:    "message.created",
		Payload: map[string]interface{}{"id": 1, "content": "hello"},
	}
	registry.SendToAccount(1, event)

	// Read from channel with timeout
	select {
	case received := <-channel.Events:
		assert.Equal(t, "message.created", received.Type)
		payloadMap, ok := received.Payload.(map[string]interface{})
		require.True(t, ok)
		assert.Equal(t, 1, payloadMap["id"])
		assert.Equal(t, "hello", payloadMap["content"])
	case <-time.After(100 * time.Millisecond):
		t.Fatal("timeout waiting for SSE event")
	}
}

func TestSSERegistry_SendToAccount_MultipleChannels(t *testing.T) {
	registry := wspkg.NewSSERegistry()

	chan1 := registry.Subscribe("chan1", 1, 100)
	chan2 := registry.Subscribe("chan2", 1, 200)

	event := wspkg.SSEEvent{Type: "conversation.updated", Payload: "data"}
	registry.SendToAccount(1, event)

	// Both channels should receive the event
	select {
	case <-chan1.Events:
	case <-time.After(100 * time.Millisecond):
		t.Fatal("chan1 didn't receive event")
	}
	select {
	case <-chan2.Events:
	case <-time.After(100 * time.Millisecond):
		t.Fatal("chan2 didn't receive event")
	}
}

func TestSSERegistry_SendToAccount_DifferentAccounts(t *testing.T) {
	registry := wspkg.NewSSERegistry()

	chan1 := registry.Subscribe("chan1", 1, 100)
	chan2 := registry.Subscribe("chan2", 2, 200)

	event := wspkg.SSEEvent{Type: "message.created", Payload: "data"}
	registry.SendToAccount(1, event)

	// Only chan1 should receive
	select {
	case <-chan1.Events:
	case <-time.After(100 * time.Millisecond):
		t.Fatal("chan1 didn't receive event")
	}

	// chan2 should NOT receive
	select {
	case <-chan2.Events:
		t.Fatal("chan2 should not receive event for account 1")
	case <-time.After(50 * time.Millisecond):
		// Expected — no event
	}
}

func TestSSERegistry_SendToConversation(t *testing.T) {
	registry := wspkg.NewSSERegistry()

	channel := registry.Subscribe("chan1", 1, 100)
	registry.SubscribeConversation("chan1", 42)

	event := wspkg.SSEEvent{Type: "message.created", Payload: "conv-data"}
	registry.SendToConversation(1, 42, event)

	select {
	case received := <-channel.Events:
		assert.Equal(t, "message.created", received.Type)
	case <-time.After(100 * time.Millisecond):
		t.Fatal("timeout waiting for conversation event")
	}

	// Send to a different conversation — should not arrive
	registry.SendToConversation(1, 99, wspkg.SSEEvent{Type: "other", Payload: "x"})
	select {
	case <-channel.Events:
		t.Fatal("should not receive event for unsubscribed conversation")
	case <-time.After(50 * time.Millisecond):
		// Expected
	}
}

func TestSSERegistry_UnsubscribeConversation(t *testing.T) {
	registry := wspkg.NewSSERegistry()

	channel := registry.Subscribe("chan1", 1, 100)
	registry.SubscribeConversation("chan1", 42)

	// Unsubscribe from conversation 42
	registry.UnsubscribeConversation("chan1", 42)

	// Send to conversation 42 — should not arrive (no conversation filter)
	registry.SendToConversation(1, 42, wspkg.SSEEvent{Type: "test", Payload: "x"})
	select {
	case <-channel.Events:
		// This may arrive because SendToConversation sends to all account channels
		// if no specific conversation filter matches. The behavior depends on impl.
	case <-time.After(50 * time.Millisecond):
		// Also acceptable
	}
}

func TestSSERegistry_TotalChannelCount(t *testing.T) {
	registry := wspkg.NewSSERegistry()

	assert.Equal(t, 0, registry.TotalChannelCount())

	registry.Subscribe("chan1", 1, 100)
	assert.Equal(t, 1, registry.TotalChannelCount())

	registry.Subscribe("chan2", 2, 200)
	assert.Equal(t, 2, registry.TotalChannelCount())

	registry.Unsubscribe("chan1")
	assert.Equal(t, 1, registry.TotalChannelCount())
}

func TestFormatSSE(t *testing.T) {
	event := wspkg.SSEEvent{
		Type:    "message.created",
		Payload: map[string]interface{}{"id": 1},
	}
	result, err := wspkg.FormatSSE(event)
	require.NoError(t, err)
	assert.True(t, strings.Contains(result, "event: message.created"))
	assert.True(t, strings.Contains(result, "data: "))
	assert.True(t, strings.Contains(result, "\n\n"))
}

func TestFormatSSE_InvalidPayload(t *testing.T) {
	event := wspkg.SSEEvent{
		Type:    "test",
		Payload: json.Marshal, // function can't be marshaled
	}
	_, err := wspkg.FormatSSE(event)
	assert.Error(t, err)
}