package config

import (
	"fmt"

	"github.com/joho/godotenv"
	"github.com/spf13/viper"

	"git.georgsen.dk/hwlab/internal/ai"
)

type Config struct {
	Host     string `mapstructure:"host"`
	Port     int    `mapstructure:"port"`
	LogLevel string `mapstructure:"log_level"`

	NetBoxURL            string `mapstructure:"netbox_url"`
	NetBoxToken          string `mapstructure:"netbox_token"`
	NetBoxTimeoutSeconds int    `mapstructure:"netbox_timeout_seconds"`

	DragonflyURL            string `mapstructure:"dragonfly_url"`
	WAQRetryIntervalSeconds int    `mapstructure:"waq_retry_interval_seconds"`
	WAQMaxAttempts          int    `mapstructure:"waq_max_attempts"`

	QualityGateConfidenceThreshold float64 `mapstructure:"quality_gate_confidence_threshold"`

	AI ai.AIConfig `mapstructure:"ai"`
}

func Load() (*Config, error) {
	// Load .env file if present (ignore error — .env is optional in production)
	_ = godotenv.Load()

	v := viper.New()

	// Set defaults
	v.SetDefault("host", "0.0.0.0")
	v.SetDefault("port", 8080)
	v.SetDefault("log_level", "info")
	v.SetDefault("netbox_timeout_seconds", 10)
	v.SetDefault("waq_retry_interval_seconds", 30)
	v.SetDefault("waq_max_attempts", 5)
	v.SetDefault("quality_gate_confidence_threshold", 0.75)

	// AI tier defaults
	v.SetDefault("ai.tier1.base_url", "http://localhost:8000/v1")
	v.SetDefault("ai.tier1.api_key", "local")
	v.SetDefault("ai.tier1.model", "gemma-4-e4b")
	v.SetDefault("ai.tier1.timeout_seconds", 30)
	v.SetDefault("ai.tier2.base_url", "https://openrouter.ai/api/v1")
	v.SetDefault("ai.tier2.api_key", "")
	v.SetDefault("ai.tier2.model", "google/gemma-3-27b-it")
	v.SetDefault("ai.tier2.timeout_seconds", 60)
	v.SetDefault("ai.confidence_threshold", 0.75)
	v.SetDefault("ai.quick_add_enabled", false)
	v.SetDefault("ai.quick_add_threshold", 0.90)

	// Config file
	v.SetConfigName("config")
	v.SetConfigType("json")
	v.AddConfigPath(".")
	v.AddConfigPath("/etc/hwlab")

	// Environment variables: HWLAB_PORT -> port, HWLAB_NETBOX_URL -> netbox_url, etc.
	v.SetEnvPrefix("HWLAB")
	v.AutomaticEnv()

	// Explicit bindings ensure AutomaticEnv works correctly with mapstructure v2 unmarshalling.
	_ = v.BindEnv("host", "HWLAB_HOST")
	_ = v.BindEnv("port", "HWLAB_PORT")
	_ = v.BindEnv("log_level", "HWLAB_LOG_LEVEL")
	_ = v.BindEnv("netbox_url", "HWLAB_NETBOX_URL")
	_ = v.BindEnv("netbox_token", "HWLAB_NETBOX_TOKEN")
	_ = v.BindEnv("netbox_timeout_seconds", "HWLAB_NETBOX_TIMEOUT_SECONDS")
	_ = v.BindEnv("dragonfly_url", "HWLAB_DRAGONFLY_URL")
	_ = v.BindEnv("waq_retry_interval_seconds", "HWLAB_WAQ_RETRY_INTERVAL_SECONDS")
	_ = v.BindEnv("waq_max_attempts", "HWLAB_WAQ_MAX_ATTEMPTS")
	_ = v.BindEnv("quality_gate_confidence_threshold", "HWLAB_QUALITY_GATE_CONFIDENCE_THRESHOLD")

	// AI env bindings
	_ = v.BindEnv("ai.tier1.base_url", "HWLAB_AI_TIER1_BASE_URL")
	_ = v.BindEnv("ai.tier1.api_key", "HWLAB_AI_TIER1_API_KEY")
	_ = v.BindEnv("ai.tier1.model", "HWLAB_AI_TIER1_MODEL")
	_ = v.BindEnv("ai.tier2.base_url", "HWLAB_AI_TIER2_BASE_URL")
	_ = v.BindEnv("ai.tier2.api_key", "HWLAB_AI_TIER2_API_KEY")
	_ = v.BindEnv("ai.tier2.model", "HWLAB_AI_TIER2_MODEL")
	_ = v.BindEnv("ai.confidence_threshold", "HWLAB_AI_CONFIDENCE_THRESHOLD")
	_ = v.BindEnv("ai.quick_add_enabled", "HWLAB_AI_QUICK_ADD_ENABLED")

	// Read primary config file (non-fatal if missing)
	if err := v.ReadInConfig(); err != nil {
		if _, ok := err.(viper.ConfigFileNotFoundError); !ok {
			return nil, fmt.Errorf("config file: %w", err)
		}
	}

	// Optionally merge ai_config.json as an override (separate viper instance to avoid
	// conflicts with the primary config file name).
	v2 := viper.New()
	v2.SetConfigName("ai_config")
	v2.SetConfigType("json")
	v2.AddConfigPath(".")
	v2.AddConfigPath("/etc/hwlab")
	if err := v2.ReadInConfig(); err == nil {
		// ai_config.json present — merge AI section into main viper
		if err := v.MergeConfigMap(v2.AllSettings()); err != nil {
			return nil, fmt.Errorf("merge ai_config: %w", err)
		}
	}

	var cfg Config
	if err := v.Unmarshal(&cfg); err != nil {
		return nil, fmt.Errorf("unmarshal config: %w", err)
	}

	return &cfg, nil
}