package config

import (
	"log/slog"
	"os"
	"strconv"
	"time"
)

type Config struct {
	// Server
	LlamalinkEnv string
	LlamalinkHost string
	LlamalinkPort int

	// Database
	DatabaseURL         string
	DatabaseMaxOpenConns int
	DatabaseMaxIdleConns int
	DatabaseConnMaxLifetime int // seconds

	// Llama server management
	ManageLlamaServer bool
	LlamaServerBin    string
	LlamaServerHost   string
	LlamaServerPort   int
	LlamaServerStartupTimeout int // seconds
	LlamaServerStopTimeout    int // seconds
	ModelSwapCooldown        int // seconds

	// Rate limiting
	RateLimitPerMinute int
	RateLimitStorage   string // "memory" or "redis"

	// Auth
	AdminUsername string
	AdminPassword string
	JWTSecret    []byte
	AdminSessionTTL int // seconds

	// Logging
	LogLevel  string
	LogFormat string // "json" or "text"
}

func Load() *Config {
	c := &Config{
		LlamalinkEnv:              getEnv("LLAMALINK_ENV", "development"),
		LlamalinkHost:             getEnv("LLAMALINK_HOST", "0.0.0.0"),
		LlamalinkPort:             intEnv("LLAMALINK_PORT", 8000),
		DatabaseURL:               getEnv("DATABASE_URL", "sqlite:///./llamalink.db"),
		DatabaseMaxOpenConns:      intEnv("DATABASE_MAX_OPEN_CONNS", 25),
		DatabaseMaxIdleConns:       intEnv("DATABASE_MAX_IDLE_CONNS", 5),
		DatabaseConnMaxLifetime:    intEnv("DATABASE_CONN_MAX_LIFETIME", 300),
		ManageLlamaServer:         boolEnv("MANAGE_LLAMA_SERVER", true),
		LlamaServerBin:            getEnv("LLAMA_SERVER_BIN", "/usr/local/bin/llama-server"),
		LlamaServerHost:           getEnv("LLAMA_SERVER_HOST", "127.0.0.1"),
		LlamaServerPort:           intEnv("LLAMA_SERVER_PORT", 8080),
		LlamaServerStartupTimeout: intEnv("LLAMA_SERVER_STARTUP_TIMEOUT", 120),
		LlamaServerStopTimeout:    intEnv("LLAMA_SERVER_STOP_TIMEOUT", 10),
		ModelSwapCooldown:         intEnv("MODEL_SWAP_COOLDOWN", 2),
		RateLimitPerMinute:        intEnv("RATE_LIMIT_PER_MINUTE", 60),
		RateLimitStorage:          getEnv("RATE_LIMIT_STORAGE", "memory"),
		AdminUsername:             getEnv("ADMIN_USERNAME", "admin"),
		AdminPassword:             getEnv("ADMIN_PASSWORD", ""),
		AdminSessionTTL:           intEnv("ADMIN_SESSION_TTL", 86400),
		LogLevel:                  getEnv("LOG_LEVEL", "info"),
		LogFormat:                 getEnv("LOG_FORMAT", "json"),
	}

	secretKey := getEnv("LLAMALINK_SECRET_KEY", "change-me-in-production")
	if secretKey == "change-me-in-production" {
		slog.Warn("LLAMALINK_SECRET_KEY is using the default value — set a secure random string in production")
	}
	c.JWTSecret = []byte(secretKey)

	return c
}

func (c *Config) LlamaServerURL() string {
	return "http://" + c.LlamaServerHost + ":" + strconv.Itoa(c.LlamaServerPort)
}

func (c *Config) LlamaServerStartupTimeoutDuration() time.Duration {
	return time.Duration(c.LlamaServerStartupTimeout) * time.Second
}

func (c *Config) LlamaServerStopTimeoutDuration() time.Duration {
	return time.Duration(c.LlamaServerStopTimeout) * time.Second
}

func (c *Config) ModelSwapCooldownDuration() time.Duration {
	return time.Duration(c.ModelSwapCooldown) * time.Second
}

func (c *Config) Logger() *slog.Logger {
	var level slog.Level
	switch c.LogLevel {
	case "debug":
		level = slog.LevelDebug
	case "warn":
		level = slog.LevelWarn
	case "error":
		level = slog.LevelError
	default:
		level = slog.LevelInfo
	}

	opts := &slog.HandlerOptions{
		Level: level,
	}

	var handler slog.Handler
	if c.LogFormat == "text" {
		handler = slog.NewTextHandler(os.Stdout, opts)
	} else {
		handler = slog.NewJSONHandler(os.Stdout, opts)
	}

	return slog.New(handler)
}

func getEnv(key, defaultValue string) string {
	if v := os.Getenv(key); v != "" {
		return v
	}
	return defaultValue
}

func intEnv(key string, defaultValue int) int {
	if v := os.Getenv(key); v != "" {
		if i, err := strconv.Atoi(v); err == nil {
			return i
		}
	}
	return defaultValue
}

func boolEnv(key string, defaultValue bool) bool {
	if v := os.Getenv(key); v != "" {
		if v == "true" || v == "1" || v == "yes" {
			return true
		}
		if v == "false" || v == "0" || v == "no" {
			return false
		}
	}
	return defaultValue
}