package parser

import (
	"eq2emu/internal/common"
	"reflect"
	"testing"
)

type BasicPacket struct {
	Channel     uint8  `eq2:"int8"`
	Count       uint16 `eq2:"int16"`
	MessageType uint8  `eq2:"int8,if=Channel==1"`
}

type ArrayPacket struct {
	ItemCount uint16            `eq2:"int16"`
	Items     []ItemDescription `eq2:"array,arraysize=ItemCount"`
}

type ItemDescription struct {
	InfoHeader WS_ExamineInfoHeader `eq2:"substruct"`
	Info       BaseItemDescription  `eq2:"substruct"`
	ItemType   uint8                `eq2:"int8"`
}

type WS_ExamineInfoHeader struct {
	Unknown1 uint32 `eq2:"int32"`
	Unknown2 uint16 `eq2:"int16"`
}

type BaseItemDescription struct {
	Name     common.EQ2String16 `eq2:"string16"`
	Category common.EQ2String8  `eq2:"string8"`
}

type ConditionalPacket struct {
	HasRewards   uint8       `eq2:"int8"`
	RewardData   *RewardInfo `eq2:"substruct,ifvariableset=HasRewards"`
	CompleteFlag uint8       `eq2:"int8"`
	ClassicSound uint8       `eq2:"int8,ifvariableset=CompleteFlag"`
}

type RewardInfo struct {
	RewardType uint8  `eq2:"int8"`
	Amount     uint32 `eq2:"int32"`
}

type OversizedPacket struct {
	LargeDataCount uint16 `eq2:"int16"`
	LargeData      []byte `eq2:"char,len=LargeDataCount,maxsize=10,skipoversized"`
}

type TypeSwitchPacket struct {
	StatType  uint8 `eq2:"int8"`
	StatValue any   `eq2:"int32,type2=float,type2criteria=StatType!=6"`
}

type FlagPacket struct {
	Equipment []common.EQ2EquipmentItem `eq2:"equipment,len=2,ifflag=has_equipment"`
	Colors    []common.EQ2Color         `eq2:"color,len=3,ifflagnotset=no_colors"`
}

type ComplexPacket struct {
	GroupCount uint8   `eq2:"int8"`
	Groups     []Group `eq2:"array,arraysize=GroupCount"`
}

type Group struct {
	MemberCount uint16   `eq2:"int16"`
	Members     []Member `eq2:"array,arraysize=MemberCount"`
}

type Member struct {
	Name  common.EQ2String16 `eq2:"string16"`
	Level uint8              `eq2:"int8"`
	Class uint8              `eq2:"int8"`
}

// Version-specific structs
type PacketV1 struct {
	Field1 uint8  `eq2:"int8"`
	Field2 uint16 `eq2:"int16"`
}

type PacketV2 struct {
	Field1   uint8  `eq2:"int8"`
	Field2   uint16 `eq2:"int16"`
	NewField uint32 `eq2:"int32"`
}

func TestBasicParsing(t *testing.T) {
	// Basic packet: Channel=1, Count=100, MessageType=5
	data := []byte{0x01, 0x64, 0x00, 0x05}
	parser := NewParser(data)

	var packet BasicPacket
	err := parser.ParseStruct(&packet)
	if err != nil {
		t.Fatalf("Parse error: %v", err)
	}

	if packet.Channel != 1 {
		t.Errorf("Expected Channel=1, got %d", packet.Channel)
	}
	if packet.Count != 100 {
		t.Errorf("Expected Count=100, got %d", packet.Count)
	}
	if packet.MessageType != 5 {
		t.Errorf("Expected MessageType=5, got %d", packet.MessageType)
	}
}

func TestConditionalSkip(t *testing.T) {
	// Channel=2 (not 1), so MessageType should be skipped
	data := []byte{0x02, 0x64, 0x00}
	parser := NewParser(data)

	var packet BasicPacket
	err := parser.ParseStruct(&packet)
	if err != nil {
		t.Fatalf("Parse error: %v", err)
	}

	if packet.Channel != 2 {
		t.Errorf("Expected Channel=2, got %d", packet.Channel)
	}
	if packet.MessageType != 0 {
		t.Errorf("Expected MessageType=0 (skipped), got %d", packet.MessageType)
	}
}

func TestArrayParsing(t *testing.T) {
	// ItemCount=2, then 2 items
	data := []byte{
		0x02, 0x00, // ItemCount = 2
		// Item 1
		0x01, 0x00, 0x00, 0x00, // InfoHeader.Unknown1 = 1
		0x02, 0x00, // InfoHeader.Unknown2 = 2
		0x04, 0x00, 't', 'e', 's', 't', // Name: "test"
		0x03, 'c', 'a', 't', // Category: "cat"
		0x05, // ItemType = 5
		// Item 2
		0x03, 0x00, 0x00, 0x00, // InfoHeader.Unknown1 = 3
		0x04, 0x00, // InfoHeader.Unknown2 = 4
		0x05, 0x00, 'i', 't', 'e', 'm', '2', // Name: "item2"
		0x04, 't', 'y', 'p', 'e', // Category: "type"
		0x06, // ItemType = 6
	}

	parser := NewParser(data)
	var packet ArrayPacket
	err := parser.ParseStruct(&packet)
	if err != nil {
		t.Fatalf("Parse error: %v", err)
	}

	if packet.ItemCount != 2 {
		t.Errorf("Expected ItemCount=2, got %d", packet.ItemCount)
	}
	if len(packet.Items) != 2 {
		t.Errorf("Expected 2 items, got %d", len(packet.Items))
	}

	if packet.Items[0].Info.Name.Data != "test" {
		t.Errorf("Expected first item name 'test', got '%s'", packet.Items[0].Info.Name.Data)
	}
	if packet.Items[1].ItemType != 6 {
		t.Errorf("Expected second item type 6, got %d", packet.Items[1].ItemType)
	}
}

func TestConditionalFields(t *testing.T) {
	// HasRewards=1, RewardData present, CompleteFlag=1, ClassicSound present
	data := []byte{
		0x01,                   // HasRewards = 1
		0x02,                   // RewardType = 2
		0x64, 0x00, 0x00, 0x00, // Amount = 100
		0x01, // CompleteFlag = 1
		0x05, // ClassicSound = 5
	}

	parser := NewParser(data)
	var packet ConditionalPacket
	err := parser.ParseStruct(&packet)
	if err != nil {
		t.Fatalf("Parse error: %v", err)
	}

	if packet.HasRewards != 1 {
		t.Errorf("Expected HasRewards=1, got %d", packet.HasRewards)
	}
	if packet.RewardData == nil {
		t.Error("Expected RewardData to be present")
	} else {
		if packet.RewardData.RewardType != 2 {
			t.Errorf("Expected RewardType=2, got %d", packet.RewardData.RewardType)
		}
		if packet.RewardData.Amount != 100 {
			t.Errorf("Expected Amount=100, got %d", packet.RewardData.Amount)
		}
	}
	if packet.ClassicSound != 5 {
		t.Errorf("Expected ClassicSound=5, got %d", packet.ClassicSound)
	}
}

func TestOversizedHandling(t *testing.T) {
	// LargeDataCount=15 (exceeds maxsize=10), should be truncated
	data := []byte{
		0x0F, 0x00, // LargeDataCount = 15
		0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A,
		0x0B, 0x0C, 0x0D, 0x0E, 0x0F, // 15 bytes of data
	}

	parser := NewParser(data)
	var packet OversizedPacket
	err := parser.ParseStruct(&packet)
	if err != nil {
		t.Fatalf("Parse error: %v", err)
	}

	if packet.LargeDataCount != 15 {
		t.Errorf("Expected LargeDataCount=15, got %d", packet.LargeDataCount)
	}
	if len(packet.LargeData) != 10 {
		t.Errorf("Expected LargeData length=10 (truncated), got %d", len(packet.LargeData))
	}
}

func TestTypeSwitching(t *testing.T) {
	// StatType=3 (not 6), so StatValue should be parsed as float
	data := []byte{
		0x03,                   // StatType = 3
		0x00, 0x00, 0x80, 0x3F, // float32: 1.0
	}

	parser := NewParser(data)
	var packet TypeSwitchPacket
	err := parser.ParseStruct(&packet)
	if err != nil {
		t.Fatalf("Parse error: %v", err)
	}

	if packet.StatType != 3 {
		t.Errorf("Expected StatType=3, got %d", packet.StatType)
	}

	// Should be parsed as float32 since StatType != 6
	floatVal, ok := packet.StatValue.(float32)
	if !ok {
		t.Errorf("Expected StatValue to be float32, got %T", packet.StatValue)
	} else if floatVal != 1.0 {
		t.Errorf("Expected StatValue=1.0, got %f", floatVal)
	}
}

func TestFlagBasedConditionals(t *testing.T) {
	// Equipment data (2 items)
	data := []byte{
		// Equipment item 1
		0x01, 0x00, // Type = 1
		0xFF, 0x00, 0x00, // Color: Red=255, Green=0, Blue=0
		0x00, 0xFF, 0x00, // Highlight: Red=0, Green=255, Blue=0
		// Equipment item 2
		0x02, 0x00, // Type = 2
		0x00, 0x00, 0xFF, // Color: Red=0, Green=0, Blue=255
		0xFF, 0xFF, 0x00, // Highlight: Red=255, Green=255, Blue=0
		// Colors (3 items)
		0x80, 0x80, 0x80, // Color 1: Gray
		0x40, 0x40, 0x40, // Color 2: Dark gray
		0xC0, 0xC0, 0xC0, // Color 3: Light gray
	}

	parser := NewParser(data)
	parser.SetFlag("has_equipment", true)
	// no_colors flag is not set, so colors should be parsed

	var packet FlagPacket
	err := parser.ParseStruct(&packet)
	if err != nil {
		t.Fatalf("Parse error: %v", err)
	}

	if len(packet.Equipment) != 2 {
		t.Errorf("Expected 2 equipment items, got %d", len(packet.Equipment))
	}
	if len(packet.Colors) != 3 {
		t.Errorf("Expected 3 colors, got %d", len(packet.Colors))
	}

	if packet.Equipment[0].Type != 1 {
		t.Errorf("Expected first equipment type 1, got %d", packet.Equipment[0].Type)
	}
	if packet.Colors[0].Red != 0x80 {
		t.Errorf("Expected first color red=128, got %d", packet.Colors[0].Red)
	}
}

func TestComplexNestedArrays(t *testing.T) {
	// GroupCount=1, Group has MemberCount=2
	data := []byte{
		0x01,       // GroupCount = 1
		0x02, 0x00, // MemberCount = 2
		// Member 1
		0x05, 0x00, 'A', 'l', 'i', 'c', 'e', // Name: "Alice"
		0x0A, // Level = 10
		0x01, // Class = 1
		// Member 2
		0x03, 0x00, 'B', 'o', 'b', // Name: "Bob"
		0x0F, // Level = 15
		0x02, // Class = 2
	}

	parser := NewParser(data)
	var packet ComplexPacket
	err := parser.ParseStruct(&packet)
	if err != nil {
		t.Fatalf("Parse error: %v", err)
	}

	if packet.GroupCount != 1 {
		t.Errorf("Expected GroupCount=1, got %d", packet.GroupCount)
	}
	if len(packet.Groups) != 1 {
		t.Errorf("Expected 1 group, got %d", len(packet.Groups))
	}
	if len(packet.Groups[0].Members) != 2 {
		t.Errorf("Expected 2 members, got %d", len(packet.Groups[0].Members))
	}

	if packet.Groups[0].Members[0].Name.Data != "Alice" {
		t.Errorf("Expected first member 'Alice', got '%s'", packet.Groups[0].Members[0].Name.Data)
	}
	if packet.Groups[0].Members[1].Level != 15 {
		t.Errorf("Expected second member level 15, got %d", packet.Groups[0].Members[1].Level)
	}
}

func TestVersionRegistry(t *testing.T) {
	registry := NewVersionRegistry()

	// Register different versions
	registry.RegisterStruct("TestPacket", "1.0", reflect.TypeOf(PacketV1{}))
	registry.RegisterStruct("TestPacket", "2.0", reflect.TypeOf(PacketV2{}))

	// Test version 1.0
	data1 := []byte{0x01, 0x64, 0x00} // Field1=1, Field2=100
	parser1 := NewParser(data1)

	result1, err := parser1.ParseWithVersion(registry, "TestPacket", "1.0")
	if err != nil {
		t.Fatalf("Parse v1.0 error: %v", err)
	}

	v1Packet, ok := result1.(PacketV1)
	if !ok {
		t.Fatal("Expected PacketV1 type")
	}
	if v1Packet.Field1 != 1 || v1Packet.Field2 != 100 {
		t.Errorf("V1 packet values incorrect: Field1=%d, Field2=%d", v1Packet.Field1, v1Packet.Field2)
	}

	// Test version 2.0
	data2 := []byte{0x02, 0xC8, 0x00, 0x90, 0x01, 0x00, 0x00} // Field1=2, Field2=200, NewField=400
	parser2 := NewParser(data2)

	result2, err := parser2.ParseWithVersion(registry, "TestPacket", "2.0")
	if err != nil {
		t.Fatalf("Parse v2.0 error: %v", err)
	}

	v2Packet, ok := result2.(PacketV2)
	if !ok {
		t.Fatal("Expected PacketV2 type")
	}
	if v2Packet.Field1 != 2 || v2Packet.Field2 != 200 || v2Packet.NewField != 400 {
		t.Errorf("V2 packet values incorrect: Field1=%d, Field2=%d, NewField=%d",
			v2Packet.Field1, v2Packet.Field2, v2Packet.NewField)
	}
}

func TestVersionFallback(t *testing.T) {
	registry := NewVersionRegistry()
	registry.RegisterStruct("TestPacket", "1.0", reflect.TypeOf(PacketV1{}))
	registry.RegisterStruct("TestPacket", "2.0", reflect.TypeOf(PacketV2{}))

	// Request version 1.5 (doesn't exist), should fall back to 1.0
	data := []byte{0x01, 0x64, 0x00}
	parser := NewParser(data)

	result, err := parser.ParseWithVersion(registry, "TestPacket", "1.5")
	if err != nil {
		t.Fatalf("Parse with fallback error: %v", err)
	}

	// Should get v1.0 (nearest lower version)
	_, ok := result.(PacketV1)
	if !ok {
		t.Error("Expected fallback to PacketV1")
	}
}

func TestParserPosition(t *testing.T) {
	data := []byte{0x01, 0x02, 0x03, 0x04}
	parser := NewParser(data)

	if parser.Offset() != 0 {
		t.Errorf("Initial offset should be 0, got %d", parser.Offset())
	}

	parser.readUint8() // Read one byte
	if parser.Offset() != 1 {
		t.Errorf("After reading 1 byte, offset should be 1, got %d", parser.Offset())
	}

	if parser.Remaining() != 3 {
		t.Errorf("After reading 1 byte, remaining should be 3, got %d", parser.Remaining())
	}

	parser.SetOffset(2)
	if parser.Offset() != 2 {
		t.Errorf("After SetOffset(2), offset should be 2, got %d", parser.Offset())
	}
}