package decoder

import (
	"context"
	"testing"
	"time"

	"github.com/AFASystems/presence/internal/pkg/common/appcontext"
	"github.com/AFASystems/presence/internal/pkg/model"
)

func TestEventLoop_RawMessageProcessing(t *testing.T) {
	// Setup
	appState := appcontext.NewAppState()
	mockWriter := &MockKafkaWriter{Messages: []kafka.Message{}}
	parserRegistry := &model.ParserRegistry{}

	chRaw := make(chan model.BeaconAdvertisement, 10)
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	// Create a test message
	msg := model.BeaconAdvertisement{
		ID:   "test-beacon",
		Data: "020106",
	}

	// Simulate event loop processing
	go func() {
		for {
			select {
			case <-ctx.Done():
				return
			case m := <-chRaw:
				processIncoming(m, appState, mockWriter, parserRegistry)
			}
		}
	}()

	// Send message
	chRaw <- msg

	// Give it time to process
	time.Sleep(100 * time.Millisecond)

	// Cancel context
	cancel()

	// Verify message was processed (even if no parser matched, processIncoming was called)
	// We just verify no panic occurred
}

func TestEventLoop_ParserRegistryUpdates(t *testing.T) {
	// Setup
	appState := appcontext.NewAppState()
	parserRegistry := &model.ParserRegistry{}

	chParser := make(chan model.KafkaParser, 10)

	// Test ADD operation
	addMsg := model.KafkaParser{
		ID:   "add",
		Name: "new-parser",
		Config: model.Config{
			Name:   "new-parser",
			Prefix: "02",
			Length: 2,
		},
	}

	chParser <- addMsg

	// Simulate event loop handling
	select {
	case msg := <-chParser:
		switch msg.ID {
		case "add":
			config := msg.Config
			parserRegistry.Register(config.Name, config)
		case "delete":
			parserRegistry.Unregister(msg.Name)
		case "update":
			config := msg.Config
			parserRegistry.Register(config.Name, config)
		}
	case <-time.After(1 * time.Second):
		t.Fatal("Timeout waiting for parser message")
	}

	// Verify parser was added
	if len(parserRegistry.ParserList) != 1 {
		t.Errorf("Expected 1 parser after add, got %d", len(parserRegistry.ParserList))
	}

	// Test DELETE operation
	deleteMsg := model.KafkaParser{
		ID:   "delete",
		Name: "new-parser",
	}

	chParser <- deleteMsg

	select {
	case msg := <-chParser:
		switch msg.ID {
		case "add":
			config := msg.Config
			parserRegistry.Register(config.Name, config)
		case "delete":
			parserRegistry.Unregister(msg.Name)
		case "update":
			config := msg.Config
			parserRegistry.Register(config.Name, config)
		}
	case <-time.After(1 * time.Second):
		t.Fatal("Timeout waiting for parser message")
	}

	// Verify parser was deleted
	if len(parserRegistry.ParserList) != 0 {
		t.Errorf("Expected 0 parsers after delete, got %d", len(parserRegistry.ParserList))
	}
}

func TestEventLoop_UpdateParser(t *testing.T) {
	// Setup
	appState := appcontext.NewAppState()
	parserRegistry := &model.ParserRegistry{}

	// Add initial parser
	parserRegistry.Register("test-parser", model.Config{
		Name:   "test-parser",
		Prefix: "02",
		Length: 2,
	})

	chParser := make(chan model.KafkaParser, 10)

	// Test UPDATE operation
	updateMsg := model.KafkaParser{
		ID:   "update",
		Name: "test-parser",
		Config: model.Config{
			Name:   "test-parser",
			Prefix: "03",
			Length: 3,
		},
	}

	chParser <- updateMsg

	// Simulate event loop handling
	select {
	case msg := <-chParser:
		switch msg.ID {
		case "add":
			config := msg.Config
			parserRegistry.Register(config.Name, config)
		case "delete":
			parserRegistry.Unregister(msg.Name)
		case "update":
			config := msg.Config
			parserRegistry.Register(config.Name, config)
		}
	case <-time.After(1 * time.Second):
		t.Fatal("Timeout waiting for parser message")
	}

	// Verify parser still exists (was updated, not deleted)
	if len(parserRegistry.ParserList) != 1 {
		t.Errorf("Expected 1 parser after update, got %d", len(parserRegistry.ParserList))
	}

	if _, exists := parserRegistry.ParserList["test-parser"]; !exists {
		t.Error("Parser should still exist after update")
	}
}

func TestEventLoop_MultipleParserOperations(t *testing.T) {
	// Setup
	appState := appcontext.NewAppState()
	parserRegistry := &model.ParserRegistry{}

	chParser := make(chan model.KafkaParser, 10)

	// Send multiple operations
	operations := []model.KafkaParser{
		{ID: "add", Name: "parser-1", Config: model.Config{Name: "parser-1", Prefix: "02", Length: 2}},
		{ID: "add", Name: "parser-2", Config: model.Config{Name: "parser-2", Prefix: "03", Length: 3}},
		{ID: "add", Name: "parser-3", Config: model.Config{Name: "parser-3", Prefix: "04", Length: 4}},
		{ID: "delete", Name: "parser-2"},
		{ID: "update", Name: "parser-1", Config: model.Config{Name: "parser-1", Prefix: "05", Length: 5}},
	}

	for _, op := range operations {
		chParser <- op
	}

	// Process all operations
	for i := 0; i < len(operations); i++ {
		select {
		case msg := <-chParser:
			switch msg.ID {
			case "add":
				config := msg.Config
				parserRegistry.Register(config.Name, config)
			case "delete":
				parserRegistry.Unregister(msg.Name)
			case "update":
				config := msg.Config
				parserRegistry.Register(config.Name, config)
			}
		case <-time.After(1 * time.Second):
			t.Fatalf("Timeout processing operation %d", i)
		}
	}

	// Verify final state
	if len(parserRegistry.ParserList) != 2 {
		t.Errorf("Expected 2 parsers after all operations, got %d", len(parserRegistry.ParserList))
	}

	// parser-1 should exist (updated)
	if _, exists := parserRegistry.ParserList["parser-1"]; !exists {
		t.Error("parser-1 should exist")
	}

	// parser-2 should not exist (deleted)
	if _, exists := parserRegistry.ParserList["parser-2"]; exists {
		t.Error("parser-2 should not exist")
	}

	// parser-3 should exist (added)
	if _, exists := parserRegistry.ParserList["parser-3"]; !exists {
		t.Error("parser-3 should exist")
	}
}

func TestEventLoop_ContextCancellation(t *testing.T) {
	// Setup
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	chRaw := make(chan model.BeaconAdvertisement, 10)
	chParser := make(chan model.KafkaParser, 10)

	// Cancel immediately
	cancel()

	// Verify context is cancelled
	select {
	case <-ctx.Done():
		// Expected - context was cancelled
		return
	case msg := <-chRaw:
		t.Errorf("Should not receive raw messages after context cancellation, got: %+v", msg)
	case msg := <-chParser:
		t.Errorf("Should not receive parser messages after context cancellation, got: %+v", msg)
	case <-time.After(1 * time.Second):
		t.Error("Timeout - context cancellation should have been immediate")
	}
}

func TestEventLoop_ChannelBuffering(t *testing.T) {
	// Setup
	appState := appcontext.NewAppState()
	mockWriter := &MockKafkaWriter{Messages: []kafka.Message{}}
	parserRegistry := &model.ParserRegistry{}

	// Create buffered channels (like in main)
	chRaw := make(chan model.BeaconAdvertisement, 2000)
	chParser := make(chan model.KafkaParser, 200)

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	// Send multiple messages without blocking
	for i := 0; i < 100; i++ {
		msg := model.BeaconAdvertisement{
			ID:   "test-beacon",
			Data: "020106",
		}
		chRaw <- msg
	}

	// Verify all messages are buffered
	if len(chRaw) != 100 {
		t.Errorf("Expected 100 messages in buffer, got %d", len(chRaw))
	}

	// Send parser updates
	for i := 0; i < 10; i++ {
		msg := model.KafkaParser{
			ID:   "add",
			Name: "parser-" + string(rune('A'+i)),
			Config: model.Config{
				Name:   "parser-" + string(rune('A'+i)),
				Prefix: "02",
				Length: 2,
			},
		}
		chParser <- msg
	}

	// Verify all parser messages are buffered
	if len(chParser) != 10 {
		t.Errorf("Expected 10 parser messages in buffer, got %d", len(chParser))
	}

	// Cancel context
	cancel()
}

func TestEventLoop_ParserAndRawChannels(t *testing.T) {
	// Setup
	appState := appcontext.NewAppState()
	mockWriter := &MockKafkaWriter{Messages: []kafka.Message{}}
	parserRegistry := &model.ParserRegistry{}

	chRaw := make(chan model.BeaconAdvertisement, 10)
	chParser := make(chan model.KafkaParser, 10)

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	// Send both raw and parser messages
	rawMsg := model.BeaconAdvertisement{
		ID:   "test-beacon",
		Data: "020106",
	}

	parserMsg := model.KafkaParser{
		ID:   "add",
		Name: "test-parser",
		Config: model.Config{
			Name:   "test-parser",
			Prefix: "02",
			Length: 2,
		},
	}

	chRaw <- rawMsg
	chParser <- parserMsg

	// Process both messages
	processedRaw := false
	processedParser := false

	for i := 0; i < 2; i++ {
		select {
		case <-chRaw:
			processedRaw = true
		case <-chParser:
			processedParser = true
		case <-time.After(1 * time.Second):
			t.Fatal("Timeout waiting for messages")
		}
	}

	if !processedRaw {
		t.Error("Raw message should have been processed")
	}

	if !processedParser {
		t.Error("Parser message should have been processed")
	}

	cancel()
}