package config

import (
	"fmt"
	"os"
	"strconv"
	"time"
)

type Config struct {
	// llama.cpp server
	LlamaCppURL  string
	Model        string
	SystemPrompt string
	Temperature  float64
	TopP         float64
	MaxTokens    int
	ContextSize  int

	// SQLite
	DBPath      string
	CompanionDB string

	// Matrix
	MatrixEnabled    bool
	MatrixHomeserver string
	MatrixUser       string
	MatrixToken      string

	// Scheduler
	SchedulerInterval time.Duration
	AutoDiary         bool
	DiaryHour         int

	// Memory
	MemoryTopK     int
	MemoryMinScore float64

	// Chat template
	ChatTemplate string

	// Embedding
	EmbeddingModel string

	// Personality
	TraitChangeMaxDaily   float64
	TraitChangeMaxMonthly float64

	// Logging
	LogLevel string

	// API
	APIEnabled bool
	APIPort    string
}

func Load() *Config {
	return &Config{
		LlamaCppURL:  getEnv("LLAMACPP_URL", "http://localhost:8080"),
		Model:        getEnv("MODEL_NAME", ""),
		SystemPrompt: getEnv("SYSTEM_PROMPT", "You are Diva, a curious and thoughtful AI companion."),
		Temperature:  getEnvFloat("TEMPERATURE", 0.85),
		TopP:         getEnvFloat("TOP_P", 0.9),
		MaxTokens:    getEnvInt("MAX_TOKENS", 2048),
		ContextSize:  getEnvInt("CONTEXT_SIZE", 8192),

		DBPath:      getEnv("DB_PATH", "./data/divacode.db"),
		CompanionDB: getEnv("COMPANION_DB_PATH", "./data/companion.db"),

		MatrixEnabled:    getEnvBool("MATRIX_ENABLED", false),
		MatrixHomeserver: getEnv("MATRIX_HOMESERVER", ""),
		MatrixUser:       getEnv("MATRIX_USER", ""),
		MatrixToken:      getEnv("MATRIX_TOKEN", ""),

		SchedulerInterval: getEnvDuration("SCHEDULER_INTERVAL", 15*time.Minute),
		AutoDiary:         getEnvBool("AUTO_DIARY", true),
		DiaryHour:         getEnvInt("DIARY_HOUR", 23),

		MemoryTopK:     getEnvInt("MEMORY_TOP_K", 5),
		MemoryMinScore: getEnvFloat("MEMORY_MIN_SCORE", 0.6),

		ChatTemplate: getEnv("CHAT_TEMPLATE", "chatml"),

		EmbeddingModel: getEnv("EMBEDDING_MODEL", ""),

		TraitChangeMaxDaily:   getEnvFloat("TRAIT_CHANGE_MAX_DAILY", 0.005),
		TraitChangeMaxMonthly: getEnvFloat("TRAIT_CHANGE_MAX_MONTHLY", 0.05),

		LogLevel: getEnv("LOG_LEVEL", "INFO"),

		APIEnabled: getEnvBool("API_ENABLED", false),
		APIPort:    getEnv("API_PORT", "8080"),
	}
}

func (c *Config) Validate() error {
	if c.LlamaCppURL == "" {
		return fmt.Errorf("LLAMACPP_URL is required")
	}
	if c.DBPath == "" {
		return fmt.Errorf("DB_PATH is required")
	}
	if c.CompanionDB == "" {
		return fmt.Errorf("COMPANION_DB_PATH is required")
	}
	if c.SystemPrompt == "" {
		return fmt.Errorf("SYSTEM_PROMPT is required")
	}
	if c.DiaryHour < 0 || c.DiaryHour > 23 {
		return fmt.Errorf("DIARY_HOUR must be 0-23")
	}
	switch c.ChatTemplate {
	case "chatml", "llama3", "none":
	default:
		return fmt.Errorf("CHAT_TEMPLATE must be chatml, llama3, or none")
	}
	return nil
}

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

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

func getEnvFloat(key string, fallback float64) float64 {
	if v := os.Getenv(key); v != "" {
		if f, err := strconv.ParseFloat(v, 64); err == nil {
			return f
		}
	}
	return fallback
}

func getEnvBool(key string, fallback bool) bool {
	if v := os.Getenv(key); v != "" {
		if b, err := strconv.ParseBool(v); err == nil {
			return b
		}
	}
	return fallback
}

func getEnvDuration(key string, fallback time.Duration) time.Duration {
	if v := os.Getenv(key); v != "" {
		if d, err := time.ParseDuration(v); err == nil {
			return d
		}
	}
	return fallback
}