package eq2net

import (
	"fmt"
	"sync"
)

// VersionRange represents a client version range mapped to an opcode version
type VersionRange struct {
	MinVersion   uint16 // version_range1 in database
	MaxVersion   uint16 // version_range2 in database
	OpcodeVersion uint16 // The opcode version for this range (usually MinVersion)
}

// OpcodeVersionMap maps version ranges for opcode lookups
// This replaces the C++ EQOpcodeVersions map<int16, int16>
type OpcodeVersionMap map[uint16]uint16 // Key: version_range1, Value: version_range2

// GetOpcodeVersion returns the opcode version for a given client version
// This is a direct port of the C++ GetOpcodeVersion function
func GetOpcodeVersion(clientVersion uint16, versionMap OpcodeVersionMap) uint16 {
	ret := clientVersion
	
	// Iterate through version ranges to find a match
	for minVersion, maxVersion := range versionMap {
		if clientVersion >= minVersion && clientVersion <= maxVersion {
			ret = minVersion
			break
		}
	}
	
	return ret
}

// EmuOpcode represents an emulator-side opcode
type EmuOpcode uint16

// Common emulator opcodes - these match the C++ emu_opcodes.h
const (
	OP_Unknown           EmuOpcode = 0x0000
	OP_LoginRequestMsg   EmuOpcode = 0x0001
	OP_LoginByNumRequestMsg EmuOpcode = 0x0002
	OP_WSLoginRequestMsg EmuOpcode = 0x0003
	OP_ESLoginRequestMsg EmuOpcode = 0x0004
	OP_LoginReplyMsg     EmuOpcode = 0x0005
	OP_WSStatusReplyMsg  EmuOpcode = 0x0006
	OP_WorldListMsg      EmuOpcode = 0x0007
	OP_WorldStatusMsg    EmuOpcode = 0x0008
	OP_DeleteCharacterRequestMsg EmuOpcode = 0x0009
	OP_DeleteCharacterReplyMsg   EmuOpcode = 0x000A
	OP_CreateCharacterRequestMsg EmuOpcode = 0x000B
	OP_CreateCharacterReplyMsg   EmuOpcode = 0x000C
	OP_PlayCharacterRequestMsg   EmuOpcode = 0x000D
	OP_PlayCharacterReplyMsg     EmuOpcode = 0x000E
	OP_ServerListRequestMsg      EmuOpcode = 0x000F
	OP_ServerListReplyMsg        EmuOpcode = 0x0010
	OP_CharacterListRequestMsg   EmuOpcode = 0x0011
	OP_CharacterListReplyMsg     EmuOpcode = 0x0012
	// Add more opcodes as needed
)

// OpcodeNames maps emulator opcodes to their string names
// This matches the C++ OpcodeNames array
var OpcodeNames = map[EmuOpcode]string{
	OP_Unknown:           "OP_Unknown",
	OP_LoginRequestMsg:   "OP_LoginRequestMsg",
	OP_LoginByNumRequestMsg: "OP_LoginByNumRequestMsg",
	OP_WSLoginRequestMsg: "OP_WSLoginRequestMsg",
	OP_ESLoginRequestMsg: "OP_ESLoginRequestMsg",
	OP_LoginReplyMsg:     "OP_LoginReplyMsg",
	OP_WSStatusReplyMsg:  "OP_WSStatusReplyMsg",
	OP_WorldListMsg:      "OP_WorldListMsg",
	OP_WorldStatusMsg:    "OP_WorldStatusMsg",
	OP_DeleteCharacterRequestMsg: "OP_DeleteCharacterRequestMsg",
	OP_DeleteCharacterReplyMsg:   "OP_DeleteCharacterReplyMsg",
	OP_CreateCharacterRequestMsg: "OP_CreateCharacterRequestMsg",
	OP_CreateCharacterReplyMsg:   "OP_CreateCharacterReplyMsg",
	OP_PlayCharacterRequestMsg:   "OP_PlayCharacterRequestMsg",
	OP_PlayCharacterReplyMsg:     "OP_PlayCharacterReplyMsg",
	OP_ServerListRequestMsg:      "OP_ServerListRequestMsg",
	OP_ServerListReplyMsg:        "OP_ServerListReplyMsg",
	OP_CharacterListRequestMsg:   "OP_CharacterListRequestMsg",
	OP_CharacterListReplyMsg:     "OP_CharacterListReplyMsg",
}

// RegularOpcodeManager manages opcode mappings for a specific version
// This is equivalent to the C++ RegularOpcodeManager class
type RegularOpcodeManager struct {
	version      uint16
	emuToEQ      map[EmuOpcode]uint16
	eqToEmu      map[uint16]EmuOpcode
	mu           sync.RWMutex
}

// NewRegularOpcodeManager creates a new opcode manager
func NewRegularOpcodeManager(version uint16) *RegularOpcodeManager {
	return &RegularOpcodeManager{
		version: version,
		emuToEQ: make(map[EmuOpcode]uint16),
		eqToEmu: make(map[uint16]EmuOpcode),
	}
}

// LoadOpcodes loads opcode mappings from a map
// Input format matches database: map[opcode_name]opcode_value
func (om *RegularOpcodeManager) LoadOpcodes(opcodes map[string]uint16) bool {
	om.mu.Lock()
	defer om.mu.Unlock()
	
	// Clear existing mappings
	om.emuToEQ = make(map[EmuOpcode]uint16)
	om.eqToEmu = make(map[uint16]EmuOpcode)
	
	// Build bidirectional mappings
	for name, eqOpcode := range opcodes {
		// Find the emulator opcode by name
		var emuOpcode EmuOpcode = OP_Unknown
		for emu, opcName := range OpcodeNames {
			if opcName == name {
				emuOpcode = emu
				break
			}
		}
		
		if emuOpcode != OP_Unknown {
			om.emuToEQ[emuOpcode] = eqOpcode
			om.eqToEmu[eqOpcode] = emuOpcode
		}
	}
	
	return true
}

// EmuToEQ converts an emulator opcode to EQ network opcode
func (om *RegularOpcodeManager) EmuToEQ(emu EmuOpcode) uint16 {
	om.mu.RLock()
	defer om.mu.RUnlock()
	
	if eq, exists := om.emuToEQ[emu]; exists {
		return eq
	}
	return 0xCDCD // Invalid opcode marker (matches C++)
}

// EQToEmu converts an EQ network opcode to emulator opcode
func (om *RegularOpcodeManager) EQToEmu(eq uint16) EmuOpcode {
	om.mu.RLock()
	defer om.mu.RUnlock()
	
	if emu, exists := om.eqToEmu[eq]; exists {
		return emu
	}
	return OP_Unknown
}

// EmuToName returns the name of an emulator opcode
func (om *RegularOpcodeManager) EmuToName(emu EmuOpcode) string {
	if name, exists := OpcodeNames[emu]; exists {
		return name
	}
	return "OP_Unknown"
}

// EQToName returns the name of an EQ network opcode
func (om *RegularOpcodeManager) EQToName(eq uint16) string {
	emu := om.EQToEmu(eq)
	return om.EmuToName(emu)
}

// NameSearch finds an emulator opcode by name
func NameSearch(name string) EmuOpcode {
	for opcode, opcName := range OpcodeNames {
		if opcName == name {
			return opcode
		}
	}
	return OP_Unknown
}

// EQOpcodeManager is the global opcode manager map
// Maps opcode version to manager instance
// This replaces the C++ map<int16, OpcodeManager*> EQOpcodeManager
type EQOpcodeManagerMap map[uint16]*RegularOpcodeManager

// NewEQOpcodeManager creates and initializes the global opcode manager
func NewEQOpcodeManager() EQOpcodeManagerMap {
	return make(EQOpcodeManagerMap)
}

// LoadFromDatabase simulates loading opcodes from database results
// This would be called by your application after querying the database
func (m EQOpcodeManagerMap) LoadFromDatabase(versions OpcodeVersionMap, opcodesByVersion map[uint16]map[string]uint16) error {
	// For each version range, create an opcode manager
	for minVersion := range versions {
		manager := NewRegularOpcodeManager(minVersion)
		
		// Load opcodes for this version
		if opcodes, exists := opcodesByVersion[minVersion]; exists {
			if !manager.LoadOpcodes(opcodes) {
				return fmt.Errorf("failed to load opcodes for version %d", minVersion)
			}
		} else {
			return fmt.Errorf("no opcodes found for version %d", minVersion)
		}
		
		m[minVersion] = manager
	}
	
	return nil
}

// GetManagerForClient returns the appropriate opcode manager for a client version
func (m EQOpcodeManagerMap) GetManagerForClient(clientVersion uint16, versionMap OpcodeVersionMap) *RegularOpcodeManager {
	opcodeVersion := GetOpcodeVersion(clientVersion, versionMap)
	return m[opcodeVersion]
}

// Example helper functions for database integration
// These would be implemented by the application using this library

// LoadVersionsFromDB would execute: 
// SELECT DISTINCT version_range1, version_range2 FROM opcodes
func LoadVersionsFromDB() OpcodeVersionMap {
	// This is just an example - actual implementation would query the database
	return OpcodeVersionMap{
		1: 546,      // Version range 1-546 uses opcode version 1
		547: 889,    // Version range 547-889 uses opcode version 547
		890: 1027,   // etc.
		1028: 1048,
		1049: 1095,
		1096: 1184,
		1185: 1197,
		1198: 1207,
		1208: 1211,
		1212: 9999,
	}
}

// LoadOpcodesFromDB would execute:
// SELECT name, opcode FROM opcodes WHERE ? BETWEEN version_range1 AND version_range2
func LoadOpcodesFromDB(version uint16) map[string]uint16 {
	// This is just an example - actual implementation would query the database
	return map[string]uint16{
		"OP_LoginRequestMsg": 0x00B3,
		"OP_LoginReplyMsg":   0x00B6,
		// ... etc
	}
}

// InitializeOpcodeSystem shows how to initialize the opcode system
// This would be called during server startup
func InitializeOpcodeSystem() (EQOpcodeManagerMap, OpcodeVersionMap, error) {
	// Load version ranges from database
	versions := LoadVersionsFromDB()
	
	// Create the global opcode manager
	opcodeManager := NewEQOpcodeManager()
	
	// Load opcodes for each version
	opcodesByVersion := make(map[uint16]map[string]uint16)
	for minVersion := range versions {
		opcodes := LoadOpcodesFromDB(minVersion)
		opcodesByVersion[minVersion] = opcodes
	}
	
	// Initialize the manager
	if err := opcodeManager.LoadFromDatabase(versions, opcodesByVersion); err != nil {
		return nil, nil, err
	}
	
	return opcodeManager, versions, nil
}