// Package config provides configuration management for Kiro API Proxy.
//
// This package handles persistent storage and retrieval of:
//   - Account credentials and authentication tokens
//   - Server settings (port, host, API keys)
//   - Usage statistics and metrics
//   - Thinking mode configuration for AI responses
//
// All configuration is stored in a JSON file with thread-safe access
// via read-write mutex protection.
package config

import (
	"crypto/rand"
	"encoding/json"
	"fmt"
	"os"
	"runtime"
	"sync"
)

// GenerateMachineId generates a UUID v4 format machine identifier.
// This ID is used to uniquely identify the proxy instance in Kiro API requests,
// helping with request tracking and rate limiting on the server side.
func GenerateMachineId() string {
	bytes := make([]byte, 16)
	rand.Read(bytes)
	bytes[6] = (bytes[6] & 0x0f) | 0x40 // 版本 4
	bytes[8] = (bytes[8] & 0x3f) | 0x80 // 变体
	return fmt.Sprintf("%08x-%04x-%04x-%04x-%012x",
		bytes[0:4], bytes[4:6], bytes[6:8], bytes[8:10], bytes[10:16])
}

// Account represents a Kiro API account with authentication credentials and usage statistics.
type Account struct {
	// Basic identification
	ID       string `json:"id"`                 // Unique account identifier (UUID)
	Email    string `json:"email,omitempty"`    // User email address
	UserId   string `json:"userId,omitempty"`   // Kiro user ID
	Nickname string `json:"nickname,omitempty"` // Display name for admin panel

	// Authentication credentials
	AccessToken  string `json:"accessToken"`            // OAuth access token for API calls
	RefreshToken string `json:"refreshToken"`           // OAuth refresh token for token renewal
	ClientID     string `json:"clientId,omitempty"`     // OIDC client ID (for IdC auth)
	ClientSecret string `json:"clientSecret,omitempty"` // OIDC client secret (for IdC auth)
	AuthMethod   string `json:"authMethod"`             // Authentication method: "idc" (AWS IdC) or "social" (GitHub/Google)
	Provider     string `json:"provider,omitempty"`     // Identity provider name (e.g., "BuilderId", "GitHub")
	Region       string `json:"region"`                 // AWS region for OIDC endpoints
	StartUrl     string `json:"startUrl,omitempty"`     // AWS SSO start URL
	ExpiresAt    int64  `json:"expiresAt,omitempty"`    // Token expiration timestamp (Unix seconds)
	MachineId    string `json:"machineId,omitempty"`    // UUID machine identifier for request tracking

	// Priority weight for load balancing (higher = more requests)
	Weight int `json:"weight,omitempty"` // 0 or 1 = normal, 2+ = higher priority

	// Account status
	Enabled   bool   `json:"enabled"`             // Whether account is active in the pool
	BanStatus string `json:"banStatus,omitempty"` // Ban status: "ACTIVE", "BANNED", "SUSPENDED"
	BanReason string `json:"banReason,omitempty"` // Reason for ban/suspension
	BanTime   int64  `json:"banTime,omitempty"`   // Timestamp when ban was detected

	// Subscription information
	SubscriptionType  string `json:"subscriptionType,omitempty"`  // Tier: FREE, PRO, PRO_PLUS, or POWER
	SubscriptionTitle string `json:"subscriptionTitle,omitempty"` // Human-readable subscription name
	DaysRemaining     int    `json:"daysRemaining,omitempty"`     // Days until subscription expires

	// Usage tracking
	UsageCurrent  float64 `json:"usageCurrent,omitempty"`  // Current period usage (credits)
	UsageLimit    float64 `json:"usageLimit,omitempty"`    // Maximum allowed usage per period
	UsagePercent  float64 `json:"usagePercent,omitempty"`  // Usage percentage (0.0-1.0)
	NextResetDate string  `json:"nextResetDate,omitempty"` // Date when usage resets (YYYY-MM-DD)
	LastRefresh   int64   `json:"lastRefresh,omitempty"`   // Last info refresh timestamp

	// Trial usage tracking
	TrialUsageCurrent float64 `json:"trialUsageCurrent,omitempty"` // Trial quota current usage
	TrialUsageLimit   float64 `json:"trialUsageLimit,omitempty"`   // Trial quota total limit
	TrialUsagePercent float64 `json:"trialUsagePercent,omitempty"` // Trial quota usage percentage (0.0-1.0)
	TrialStatus       string  `json:"trialStatus,omitempty"`       // Trial status: ACTIVE, EXPIRED, NONE
	TrialExpiresAt    int64   `json:"trialExpiresAt,omitempty"`    // Trial expiration timestamp (Unix seconds)

	// Runtime statistics (updated during operation)
	RequestCount int     `json:"requestCount,omitempty"` // Total requests processed
	ErrorCount   int     `json:"errorCount,omitempty"`   // Total errors encountered
	LastUsed     int64   `json:"lastUsed,omitempty"`     // Last request timestamp
	TotalTokens  int     `json:"totalTokens,omitempty"`  // Cumulative tokens processed
	TotalCredits float64 `json:"totalCredits,omitempty"` // Cumulative credits consumed
}

// Config represents the global application configuration.
type Config struct {
	// Server settings
	Password      string    `json:"password"`         // Admin panel password
	Port          int       `json:"port"`             // HTTP server port (default: 8080)
	Host          string    `json:"host"`             // HTTP server bind address (default: 0.0.0.0)
	ApiKey        string    `json:"apiKey,omitempty"` // API key for client authentication
	RequireApiKey bool      `json:"requireApiKey"`    // Whether to enforce API key validation
	KiroVersion   string    `json:"kiroVersion,omitempty"`
	SystemVersion string    `json:"systemVersion,omitempty"`
	NodeVersion   string    `json:"nodeVersion,omitempty"`
	Accounts      []Account `json:"accounts"` // Registered Kiro accounts

	// Thinking mode configuration for extended reasoning output
	ThinkingSuffix       string `json:"thinkingSuffix,omitempty"`       // Model suffix to trigger thinking mode (default: "-thinking")
	OpenAIThinkingFormat string `json:"openaiThinkingFormat,omitempty"` // OpenAI output format: "reasoning_content", "thinking", or "think"
	ClaudeThinkingFormat string `json:"claudeThinkingFormat,omitempty"` // Claude output format: "reasoning_content", "thinking", or "think"

	// Endpoint configuration: "auto", "codewhisperer", or "amazonq"
	PreferredEndpoint string `json:"preferredEndpoint,omitempty"`

	// Global statistics (persisted across restarts)
	TotalRequests   int     `json:"totalRequests,omitempty"`   // Total API requests received
	SuccessRequests int     `json:"successRequests,omitempty"` // Successful requests count
	FailedRequests  int     `json:"failedRequests,omitempty"`  // Failed requests count
	TotalTokens     int     `json:"totalTokens,omitempty"`     // Total tokens processed
	TotalCredits    float64 `json:"totalCredits,omitempty"`    // Total credits consumed
}

// AccountInfo contains account metadata retrieved from Kiro API.
// Used for updating subscription and usage information.
type AccountInfo struct {
	Email             string
	UserId            string
	SubscriptionType  string
	SubscriptionTitle string
	DaysRemaining     int
	UsageCurrent      float64
	UsageLimit        float64
	UsagePercent      float64
	NextResetDate     string
	LastRefresh       int64
	TrialUsageCurrent float64
	TrialUsageLimit   float64
	TrialUsagePercent float64
	TrialStatus       string
	TrialExpiresAt    int64
}

// Version 当前版本号
const Version = "1.0.4"

var (
	cfg     *Config
	cfgLock sync.RWMutex
	cfgPath string
)

// Init initializes the configuration system with the specified file path.
// If the file doesn't exist, a default configuration is created.
func Init(path string) error {
	cfgPath = path
	return Load()
}

func Load() error {
	cfgLock.Lock()
	defer cfgLock.Unlock()

	data, err := os.ReadFile(cfgPath)
	if err != nil {
		if os.IsNotExist(err) {
			// Create default configuration.
			// Binds to 0.0.0.0 by default for Docker/container compatibility.
			cfg = &Config{
				Password:      "changeme",
				Port:          8080,
				Host:          "0.0.0.0",
				RequireApiKey: false,
				Accounts:      []Account{},
			}
			return Save()
		}
		return err
	}

	var c Config
	if err := json.Unmarshal(data, &c); err != nil {
		return err
	}
	cfg = &c
	return nil
}

// Save persists the current configuration to the JSON file.
// Uses indented formatting for human readability.
func Save() error {
	data, err := json.MarshalIndent(cfg, "", "  ")
	if err != nil {
		return err
	}
	return os.WriteFile(cfgPath, data, 0600)
}

// SetPassword updates the admin password.
// Primarily used for environment variable override in containerized deployments.
func SetPassword(password string) {
	cfgLock.Lock()
	defer cfgLock.Unlock()
	cfg.Password = password
}

func Get() *Config {
	cfgLock.RLock()
	defer cfgLock.RUnlock()
	return cfg
}

func GetPassword() string {
	cfgLock.RLock()
	defer cfgLock.RUnlock()
	return cfg.Password
}

func GetPort() int {
	cfgLock.RLock()
	defer cfgLock.RUnlock()
	if cfg.Port == 0 {
		return 8080
	}
	return cfg.Port
}

func GetHost() string {
	cfgLock.RLock()
	defer cfgLock.RUnlock()
	if cfg.Host == "" {
		return "127.0.0.1"
	}
	return cfg.Host
}

func GetAccounts() []Account {
	cfgLock.RLock()
	defer cfgLock.RUnlock()
	accounts := make([]Account, len(cfg.Accounts))
	copy(accounts, cfg.Accounts)
	return accounts
}

func GetEnabledAccounts() []Account {
	cfgLock.RLock()
	defer cfgLock.RUnlock()
	var accounts []Account
	for _, a := range cfg.Accounts {
		if a.Enabled {
			accounts = append(accounts, a)
		}
	}
	return accounts
}

func AddAccount(account Account) error {
	cfgLock.Lock()
	defer cfgLock.Unlock()
	cfg.Accounts = append(cfg.Accounts, account)
	return Save()
}

func UpdateAccount(id string, account Account) error {
	cfgLock.Lock()
	defer cfgLock.Unlock()
	for i, a := range cfg.Accounts {
		if a.ID == id {
			cfg.Accounts[i] = account
			return Save()
		}
	}
	return nil
}

func DeleteAccount(id string) error {
	cfgLock.Lock()
	defer cfgLock.Unlock()
	for i, a := range cfg.Accounts {
		if a.ID == id {
			cfg.Accounts = append(cfg.Accounts[:i], cfg.Accounts[i+1:]...)
			return Save()
		}
	}
	return nil
}

func UpdateAccountToken(id, accessToken, refreshToken string, expiresAt int64) error {
	cfgLock.Lock()
	defer cfgLock.Unlock()
	for i, a := range cfg.Accounts {
		if a.ID == id {
			cfg.Accounts[i].AccessToken = accessToken
			if refreshToken != "" {
				cfg.Accounts[i].RefreshToken = refreshToken
			}
			cfg.Accounts[i].ExpiresAt = expiresAt
			return Save()
		}
	}
	return nil
}

func GetApiKey() string {
	cfgLock.RLock()
	defer cfgLock.RUnlock()
	return cfg.ApiKey
}

func IsApiKeyRequired() bool {
	cfgLock.RLock()
	defer cfgLock.RUnlock()
	return cfg.RequireApiKey
}

func UpdateSettings(apiKey string, requireApiKey bool, password string) error {
	cfgLock.Lock()
	defer cfgLock.Unlock()
	cfg.ApiKey = apiKey
	cfg.RequireApiKey = requireApiKey
	if password != "" {
		cfg.Password = password
	}
	return Save()
}

func UpdateStats(totalReq, successReq, failedReq, totalTokens int, totalCredits float64) error {
	cfgLock.Lock()
	defer cfgLock.Unlock()
	cfg.TotalRequests = totalReq
	cfg.SuccessRequests = successReq
	cfg.FailedRequests = failedReq
	cfg.TotalTokens = totalTokens
	cfg.TotalCredits = totalCredits
	return Save()
}

func GetStats() (int, int, int, int, float64) {
	cfgLock.RLock()
	defer cfgLock.RUnlock()
	return cfg.TotalRequests, cfg.SuccessRequests, cfg.FailedRequests, cfg.TotalTokens, cfg.TotalCredits
}

func UpdateAccountStats(id string, requestCount, errorCount, totalTokens int, totalCredits float64, lastUsed int64) error {
	cfgLock.Lock()
	defer cfgLock.Unlock()
	for i, a := range cfg.Accounts {
		if a.ID == id {
			cfg.Accounts[i].RequestCount = requestCount
			cfg.Accounts[i].ErrorCount = errorCount
			cfg.Accounts[i].TotalTokens = totalTokens
			cfg.Accounts[i].TotalCredits = totalCredits
			cfg.Accounts[i].LastUsed = lastUsed
			return Save()
		}
	}
	return nil
}

// UpdateAccountInfo updates an account's subscription and usage information.
// Called after refreshing account data from Kiro API.
func UpdateAccountInfo(id string, info AccountInfo) error {
	cfgLock.Lock()
	defer cfgLock.Unlock()
	for i, a := range cfg.Accounts {
		if a.ID == id {
			if info.Email != "" {
				cfg.Accounts[i].Email = info.Email
			}
			if info.UserId != "" {
				cfg.Accounts[i].UserId = info.UserId
			}
			cfg.Accounts[i].SubscriptionType = info.SubscriptionType
			cfg.Accounts[i].SubscriptionTitle = info.SubscriptionTitle
			cfg.Accounts[i].DaysRemaining = info.DaysRemaining
			cfg.Accounts[i].UsageCurrent = info.UsageCurrent
			cfg.Accounts[i].UsageLimit = info.UsageLimit
			cfg.Accounts[i].UsagePercent = info.UsagePercent
			cfg.Accounts[i].NextResetDate = info.NextResetDate
			cfg.Accounts[i].LastRefresh = info.LastRefresh
			cfg.Accounts[i].TrialUsageCurrent = info.TrialUsageCurrent
			cfg.Accounts[i].TrialUsageLimit = info.TrialUsageLimit
			cfg.Accounts[i].TrialUsagePercent = info.TrialUsagePercent
			cfg.Accounts[i].TrialStatus = info.TrialStatus
			cfg.Accounts[i].TrialExpiresAt = info.TrialExpiresAt
			return Save()
		}
	}
	return nil
}

// ThinkingConfig holds settings for AI thinking/reasoning mode.
// When enabled, models output their reasoning process alongside the response.
type ThinkingConfig struct {
	Suffix       string `json:"suffix"`       // Model name suffix that triggers thinking mode
	OpenAIFormat string `json:"openaiFormat"` // Output format for OpenAI-compatible responses
	ClaudeFormat string `json:"claudeFormat"` // Output format for Claude-compatible responses
}

// GetThinkingConfig 获取 thinking 配置
func GetThinkingConfig() ThinkingConfig {
	cfgLock.RLock()
	defer cfgLock.RUnlock()

	suffix := cfg.ThinkingSuffix
	if suffix == "" {
		suffix = "-thinking"
	}
	openaiFormat := cfg.OpenAIThinkingFormat
	if openaiFormat == "" {
		openaiFormat = "reasoning_content"
	}
	claudeFormat := cfg.ClaudeThinkingFormat
	if claudeFormat == "" {
		claudeFormat = "thinking"
	}

	return ThinkingConfig{
		Suffix:       suffix,
		OpenAIFormat: openaiFormat,
		ClaudeFormat: claudeFormat,
	}
}

// UpdateThinkingConfig 更新 thinking 配置
func UpdateThinkingConfig(suffix, openaiFormat, claudeFormat string) error {
	cfgLock.Lock()
	defer cfgLock.Unlock()
	cfg.ThinkingSuffix = suffix
	cfg.OpenAIThinkingFormat = openaiFormat
	cfg.ClaudeThinkingFormat = claudeFormat
	return Save()
}

// GetPreferredEndpoint 获取首选端点配置
func GetPreferredEndpoint() string {
	cfgLock.RLock()
	defer cfgLock.RUnlock()
	if cfg.PreferredEndpoint == "" {
		return "auto"
	}
	return cfg.PreferredEndpoint
}

// UpdatePreferredEndpoint 更新首选端点配置
func UpdatePreferredEndpoint(endpoint string) error {
	cfgLock.Lock()
	defer cfgLock.Unlock()
	cfg.PreferredEndpoint = endpoint
	return Save()
}

type KiroClientConfig struct {
	KiroVersion   string
	SystemVersion string
	NodeVersion   string
}

func GetKiroClientConfig() KiroClientConfig {
	cfgLock.RLock()
	defer cfgLock.RUnlock()

	kiroVersion := "0.11.107"
	if cfg != nil && cfg.KiroVersion != "" {
		kiroVersion = cfg.KiroVersion
	}

	systemVersion := ""
	if cfg != nil {
		systemVersion = cfg.SystemVersion
	}
	if systemVersion == "" {
		systemVersion = defaultSystemVersion()
	}

	nodeVersion := "22.22.0"
	if cfg != nil && cfg.NodeVersion != "" {
		nodeVersion = cfg.NodeVersion
	}

	return KiroClientConfig{
		KiroVersion:   kiroVersion,
		SystemVersion: systemVersion,
		NodeVersion:   nodeVersion,
	}
}

func defaultSystemVersion() string {
	switch runtime.GOOS {
	case "windows":
		return "win32#10.0.22631"
	case "darwin":
		return "darwin#24.6.0"
	default:
		return "linux#6.6.87"
	}
}