package main

import (
	"encoding/json"
	"os"
)

type Config struct {
	SampleRate int           `json:"sample_rate"` // seconds
	AlphaEss   AlphaConf    `json:"alphaess"`
	MQTT       MQTTConf     `json:"mqtt"`
	Charger    ChargerConf  `json:"charger"`
	DB         DBConf       `json:"db"`
}

type ChargerConf struct {
	Host string `json:"host"` // hostname or IP of go-e charger
}

type AlphaConf struct {
	Host    string `json:"host"`
	Port    int    `json:"port"`
	SlaveID uint8  `json:"slave_id"`
}

type MQTTConf struct {
	Broker        string       `json:"broker"`
	BrokerIP      string       `json:"broker_ip"`       // optional scoped IPv6 e.g. fe80::1%eth0
	BrokerTLSName string       `json:"broker_tls_name"` // TLS ServerName when broker_ip is set
	Port          int          `json:"port"`
	ClientID      string       `json:"client_id"`
	TopicPrefix   string       `json:"topic_prefix"`
	CACert        string       `json:"ca_cert"`
	ClientCert    string       `json:"client_cert"`
	ClientKey     string       `json:"client_key"`
	Devices       []DeviceConf `json:"devices"`
}

// DeviceConf describes one SDM630 meter reachable via the MQTT/Modbus bridge.
type DeviceConf struct {
	SlaveAddress int    `json:"slave_address"`
	Name         string `json:"name"`    // used as the 'device' column value in power_meter
	Segment      string `json:"segment"` // MQTT topic segment
}

type DBConf struct {
	DSN string `json:"dsn"` // PostgreSQL connection string
}

func loadConfig(path string) (Config, error) {
	data, err := os.ReadFile(path)
	if err != nil {
		return Config{}, err
	}
	var cfg Config
	return cfg, json.Unmarshal(data, &cfg)
}