package login

import (
	"crypto/md5"
	"encoding/binary"
	"fmt"
	"log"
	"strings"
	"sync"
	"time"

	"eq2emu/internal/common/opcodes"
	"eq2emu/internal/packets"
	"eq2emu/internal/udp"
)

// ClientState represents the current state of a login client
type ClientState int

const (
	ClientStateNew ClientState = iota
	ClientStateAuthenticating
	ClientStateAuthenticated
	ClientStateCharacterSelect
	ClientStateDisconnected
)

// String returns the string representation of the client state
func (cs ClientState) String() string {
	switch cs {
	case ClientStateNew:
		return "New"
	case ClientStateAuthenticating:
		return "Authenticating"
	case ClientStateAuthenticated:
		return "Authenticated"
	case ClientStateCharacterSelect:
		return "CharacterSelect"
	case ClientStateDisconnected:
		return "Disconnected"
	default:
		return "Unknown"
	}
}

// Client represents a connected login client
type Client struct {
	connection *udp.Connection
	database   *LoginDB
	
	// Client information
	accountID    int32
	accountName  string
	accountEmail string
	accessLevel  int16
	
	// Authentication data
	loginKey     string
	sessionKey   string
	ipAddress    string
	
	// Client state
	state          ClientState
	clientVersion  uint16
	protocolVersion uint16
	
	// Character data
	characters []CharacterInfo
	
	// Timing
	connectTime    time.Time
	lastActivity   time.Time
	
	// Synchronization
	mu sync.RWMutex
}

// CharacterInfo represents character information for the character select screen
type CharacterInfo struct {
	ID           int32  `json:"id"`
	AccountID    int32  `json:"account_id"`
	Name         string `json:"name"`
	Race         int8   `json:"race"`
	Class        int8   `json:"class"`
	Gender       int8   `json:"gender"`
	Level        int16  `json:"level"`
	Zone         int32  `json:"zone"`
	ZoneInstance int32  `json:"zone_instance"`
	ServerID     int16  `json:"server_id"`
	LastPlayed   int64  `json:"last_played"`
	CreatedDate  int64  `json:"created_date"`
	DeletedDate  int64  `json:"deleted_date"`
	
	// Appearance data
	ModelType        int16   `json:"model_type"`
	SogaModelType    int16   `json:"soga_model_type"`
	HeadType         int16   `json:"head_type"`
	SogaHeadType     int16   `json:"soga_head_type"`
	WingType         int16   `json:"wing_type"`
	ChestType        int16   `json:"chest_type"`
	LegsType         int16   `json:"legs_type"`
	SogaChestType    int16   `json:"soga_chest_type"`
	SogaLegsType     int16   `json:"soga_legs_type"`
	HairType         int16   `json:"hair_type"`
	FacialHairType   int16   `json:"facial_hair_type"`
	SogaHairType     int16   `json:"soga_hair_type"`
	SogaFacialHairType int16 `json:"soga_facial_hair_type"`
	
	// Colors
	HairTypeColor      int16 `json:"hair_type_color"`
	HairTypeHighlight  int16 `json:"hair_type_highlight"`
	HairColor1         int16 `json:"hair_color1"`
	HairColor2         int16 `json:"hair_color2"`
	HairHighlight      int16 `json:"hair_highlight"`
	EyeColor1          int16 `json:"eye_color1"`
	EyeColor2          int16 `json:"eye_color2"`
	SkinColor          int16 `json:"skin_color"`
	
	// Soga colors
	SogaHairTypeColor     int16 `json:"soga_hair_type_color"`
	SogaHairTypeHighlight int16 `json:"soga_hair_type_highlight"`
	SogaHairColor1        int16 `json:"soga_hair_color1"`
	SogaHairColor2        int16 `json:"soga_hair_color2"`
	SogaHairHighlight     int16 `json:"soga_hair_highlight"`
	SogaEyeColor1         int16 `json:"soga_eye_color1"`
	SogaEyeColor2         int16 `json:"soga_eye_color2"`
	SogaSkinColor         int16 `json:"soga_skin_color"`
	
	// Additional data
	CurrentLanguage int8 `json:"current_language"`
	ChosenLanguage  int8 `json:"chosen_language"`
}

// NewClient creates a new login client
func NewClient(conn *udp.Connection, db *LoginDB) *Client {
	now := time.Now()
	
	client := &Client{
		connection:    conn,
		database:      db,
		state:         ClientStateNew,
		connectTime:   now,
		lastActivity:  now,
		ipAddress:     conn.GetClientAddr().String(),
		characters:    make([]CharacterInfo, 0),
	}
	
	return client
}

// HandlePacket processes an incoming packet from the client
func (c *Client) HandlePacket(data []byte) error {
	c.mu.Lock()
	defer c.mu.Unlock()
	
	c.lastActivity = time.Now()
	
	if len(data) < 2 {
		return fmt.Errorf("packet too short")
	}
	
	// Extract opcode
	opcode := binary.LittleEndian.Uint16(data[:2])
	payload := data[2:]
	
	log.Printf("Client %s: Received opcode 0x%04x, size %d", c.ipAddress, opcode, len(payload))
	
	switch opcode {
	case opcodes.OpLoginRequestMsg:
		return c.handleLoginRequest(payload)
	case opcodes.OpAllCharactersDescRequestMsg:
		return c.handleCharacterSelectRequest(payload)
	case opcodes.OpPlayCharacterRequestMsg:
		return c.handlePlayCharacterRequest(payload)
	case opcodes.OpDeleteCharacterRequestMsg:
		return c.handleDeleteCharacterRequest(payload)
	case opcodes.OpCreateCharacterRequestMsg:
		return c.handleCreateCharacterRequest(payload)
	default:
		log.Printf("Client %s: Unknown opcode 0x%04x", c.ipAddress, opcode)
		return nil
	}
}

// handleLoginRequest processes a login request from the client
func (c *Client) handleLoginRequest(payload []byte) error {
	if c.state != ClientStateNew {
		return fmt.Errorf("invalid state for login request: %s", c.state)
	}
	
	// Parse the packet using the proper packet system
	clientVersion := uint32(562) // Assume version 562 for now
	data, err := packets.ParsePacketFields(payload, "LoginRequest", clientVersion)
	if err != nil {
		return fmt.Errorf("failed to parse login request: %w", err)
	}
	
	// Extract fields based on the XML definition
	accessCode := getStringField(data, "accesscode")
	unknown1 := getStringField(data, "unknown1") 
	username := getStringField(data, "username")
	password := getStringField(data, "password")
	
	log.Printf("Login request - Username: %s, Access: %s, Unknown: %s", 
		username, accessCode, unknown1)
	
	c.state = ClientStateAuthenticating
	
	// Authenticate user
	return c.authenticateUser(username, password)
}

// Helper function to safely extract string fields from packet data
func getStringField(data map[string]any, field string) string {
	if val, ok := data[field]; ok {
		if str, ok := val.(string); ok {
			return str
		}
	}
	return ""
}

// authenticateUser authenticates the user credentials
func (c *Client) authenticateUser(username, password string) error {
	username = strings.TrimSpace(strings.Trim(username, "\x00"))
	
	// Hash the password (MD5 for EQ2 compatibility)
	hasher := md5.New()
	hasher.Write([]byte(password))
	hashedPassword := fmt.Sprintf("%x", hasher.Sum(nil))
	
	// Query database for account
	account, err := c.database.GetLoginAccount(username, hashedPassword)
	if err != nil {
		log.Printf("Authentication failed for %s: %v", username, err)
		return c.sendLoginReply(0, "Invalid username or password")
	}
	
	// Check account status
	if account.Status != "Active" {
		log.Printf("Account %s is not active: %s", username, account.Status)
		return c.sendLoginReply(0, "Account is suspended")
	}
	
	// Store account information
	c.accountID = account.ID
	c.accountName = account.Username
	c.accountEmail = account.Email
	c.accessLevel = account.AccessLevel
	c.state = ClientStateAuthenticated
	
	log.Printf("User %s (ID: %d) authenticated successfully", username, account.ID)
	
	// Generate session key
	c.sessionKey = c.generateSessionKey()
	
	// Update last login
	c.database.UpdateLastLogin(c.accountID, c.ipAddress)
	
	// Send successful login reply
	return c.sendLoginReply(1, "Welcome to EverQuest II")
}

// sendLoginReply sends a login reply to the client
func (c *Client) sendLoginReply(success int8, message string) error {
	// Build login reply using the packet system
	clientVersion := uint32(562) // TODO: Track actual client version
	
	data := map[string]any{
		"login_response": success,
		"unknown": message,
	}
	
	if success == 1 {
		data["account_id"] = c.accountID
		// Add other required fields for successful login
		data["parental_control_flag"] = uint8(0)
		data["parental_control_timer"] = uint32(0)
		
		// TODO: Add more fields as needed based on client version
	}
	
	packet, err := packets.BuildPacket("LoginReplyMsg", data, clientVersion, 0)
	if err != nil {
		return fmt.Errorf("failed to build login reply packet: %w", err)
	}
	
	// Send the packet
	appPacket := &udp.ApplicationPacket{
		Data: packet,
	}
	c.connection.SendPacket(appPacket)
	
	// If login successful, send character list
	if success == 1 {
		if err := c.loadCharacters(); err != nil {
			log.Printf("Failed to load characters: %v", err)
		}
		return c.sendCharacterList()
	}
	
	return nil
}

// loadCharacters loads the character list for this account
func (c *Client) loadCharacters() error {
	characters, err := c.database.GetCharacters(c.accountID)
	if err != nil {
		return fmt.Errorf("failed to load characters: %w", err)
	}
	
	c.characters = make([]CharacterInfo, len(characters))
	for i, char := range characters {
		c.characters[i] = CharacterInfo{
			ID:          char.ID,
			AccountID:   char.AccountID,
			Name:        strings.TrimSpace(strings.Trim(char.Name, "\x00")),
			Race:        char.Race,
			Class:       char.Class,
			Gender:      char.Gender,
			Level:       char.Level,
			Zone:        char.Zone,
			ServerID:    char.ServerID,
			LastPlayed:  char.LastPlayed,
			CreatedDate: char.CreatedDate,
		}
	}
	
	return nil
}


// handleCharacterSelectRequest handles character selection
func (c *Client) handleCharacterSelectRequest(payload []byte) error {
	if c.state != ClientStateAuthenticated {
		return fmt.Errorf("invalid state for character select: %s", c.state)
	}
	
	c.state = ClientStateCharacterSelect
	
	// Send character list
	if err := c.loadCharacters(); err != nil {
		return fmt.Errorf("failed to load characters: %w", err)
	}
	
	return c.sendCharacterList()
}

// sendCharacterList sends the character list to the client
func (c *Client) sendCharacterList() error {
	// For now, send character profiles individually using CharSelectProfile packet
	// In the real implementation, this would be sent as part of LoginReplyMsg
	
	for _, char := range c.characters {
		data := map[string]any{
			"version":       uint32(562),
			"charid":        uint32(char.ID),
			"server_id":     uint32(char.ServerID),
			"name":          char.Name,
			"unknown":       uint8(0),
			"race":          uint8(char.Race),
			"class":         uint8(char.Class), 
			"gender":        uint8(char.Gender),
			"level":         uint32(char.Level),
			"zone":          "Qeynos Harbor", // TODO: Get actual zone name
			"unknown1":      uint32(0),
			"unknown2":      uint32(0),
			"created_date":  uint32(char.CreatedDate),
			"last_played":   uint32(char.LastPlayed),
			"unknown3":      uint32(0),
			"unknown4":      uint32(0),
			"zonename2":     "Qeynos Harbor",
			"zonedesc":      "The Harbor District",
			"unknown5":      uint32(0),
			"server_name":   "EQ2Go Server",
			"account_id":    uint32(c.accountID),
		}
		
		// Add appearance data with defaults for now
		// TODO: Load actual character appearance data
		
		clientVersion := uint32(562)
		packet, err := packets.BuildPacket("CharSelectProfile", data, clientVersion, 0)
		if err != nil {
			log.Printf("Failed to build character profile packet: %v", err)
			continue
		}
		
		appPacket := &udp.ApplicationPacket{
			Data: packet,
		}
		c.connection.SendPacket(appPacket)
	}
	
	return nil
}

// handlePlayCharacterRequest handles play character request
func (c *Client) handlePlayCharacterRequest(payload []byte) error {
	if c.state != ClientStateCharacterSelect && c.state != ClientStateAuthenticated {
		return fmt.Errorf("invalid state for play character: %s", c.state)
	}
	
	if len(payload) < 8 {
		return fmt.Errorf("play character packet too short")
	}
	
	characterID := binary.LittleEndian.Uint32(payload[:4])
	serverID := binary.LittleEndian.Uint16(payload[4:6])
	
	log.Printf("Play character request - Character: %d, Server: %d", characterID, serverID)
	
	// Find character
	var character *CharacterInfo
	for i := range c.characters {
		if c.characters[i].ID == int32(characterID) {
			character = &c.characters[i]
			break
		}
	}
	
	if character == nil {
		return fmt.Errorf("character %d not found", characterID)
	}
	
	// TODO: Forward to world server
	return c.sendPlayCharacterReply(character, "127.0.0.1", 9000)
}

// sendPlayCharacterReply sends play character reply to client
func (c *Client) sendPlayCharacterReply(character *CharacterInfo, worldIP string, worldPort int) error {
	data := map[string]any{
		"response":    uint8(1), // Success
		"server":      worldIP,
		"port":        uint16(worldPort),
		"account_id":  uint32(c.accountID),
		"access_code": uint32(12345), // TODO: Generate proper access code
	}
	
	clientVersion := uint32(562)
	packet, err := packets.BuildPacket("PlayResponse", data, clientVersion, 0)
	if err != nil {
		return fmt.Errorf("failed to build play response packet: %w", err)
	}
	
	appPacket := &udp.ApplicationPacket{
		Data: packet,
	}
	c.connection.SendPacket(appPacket)
	return nil
}

// handleDeleteCharacterRequest handles character deletion
func (c *Client) handleDeleteCharacterRequest(payload []byte) error {
	// TODO: Implement character deletion
	return nil
}

// handleCreateCharacterRequest handles character creation
func (c *Client) handleCreateCharacterRequest(payload []byte) error {
	// TODO: Implement character creation
	return nil
}

// generateSessionKey generates a unique session key for this client
func (c *Client) generateSessionKey() string {
	now := time.Now()
	data := fmt.Sprintf("%d-%s-%d", c.accountID, c.ipAddress, now.Unix())
	
	hasher := md5.New()
	hasher.Write([]byte(data))
	
	return fmt.Sprintf("%x", hasher.Sum(nil))
}

// Disconnect disconnects the client
func (c *Client) Disconnect(reason string) {
	c.mu.Lock()
	defer c.mu.Unlock()
	
	if c.state == ClientStateDisconnected {
		return
	}
	
	log.Printf("Disconnecting client %s: %s", c.ipAddress, reason)
	
	c.state = ClientStateDisconnected
	if c.connection != nil {
		c.connection.Close()
	}
}

// GetState returns the current client state (thread-safe)
func (c *Client) GetState() ClientState {
	c.mu.RLock()
	defer c.mu.RUnlock()
	return c.state
}

// GetAccountID returns the account ID (thread-safe)
func (c *Client) GetAccountID() int32 {
	c.mu.RLock()
	defer c.mu.RUnlock()
	return c.accountID
}

// GetAccountName returns the account name (thread-safe)
func (c *Client) GetAccountName() string {
	c.mu.RLock()
	defer c.mu.RUnlock()
	return c.accountName
}

// GetIPAddress returns the client IP address
func (c *Client) GetIPAddress() string {
	return c.ipAddress
}

// GetConnection returns the UDP connection
func (c *Client) GetConnection() *udp.Connection {
	return c.connection
}

// GetConnectTime returns when the client connected
func (c *Client) GetConnectTime() time.Time {
	return c.connectTime
}

// GetLastActivity returns the last activity time
func (c *Client) GetLastActivity() time.Time {
	c.mu.RLock()
	defer c.mu.RUnlock()
	return c.lastActivity
}

// IsTimedOut returns whether the client has timed out
func (c *Client) IsTimedOut(timeout time.Duration) bool {
	c.mu.RLock()
	defer c.mu.RUnlock()
	return time.Since(c.lastActivity) > timeout
}