package main

import (
	"database/sql"
	"encoding/json"
	"log"
	"os"
	"time"

	mqtt "github.com/eclipse/paho.mqtt.golang"
	_ "github.com/lib/pq"
)

type Payload struct {
	T   string `json:"t"`
	Dt1 int    `json:"dt1"`
	Dt2 int    `json:"dt2"`
	Rt1 int    `json:"rt1"`
	Rt2 int    `json:"rt2"`
	D   int    `json:"d"`
	R   int    `json:"r"`
	F   int    `json:"f"`
	Fl  int    `json:"fl"`
	G   int    `json:"g"`
	V1  int    `json:"v1"`
	V2  int    `json:"v2"`
	V3  int    `json:"v3"`
	C1  int    `json:"c1"`
	C2  int    `json:"c2"`
	C3  int    `json:"c3"`
	D1  int    `json:"d1"`
	D2  int    `json:"d2"`
	D3  int    `json:"d3"`
	R1  int    `json:"r1"`
	R2  int    `json:"r2"`
	R3  int    `json:"r3"`
}

var db *sql.DB

func main() {
	// Load environment variables from .env file if it exists
	// err := godotenv.Load()
	// if err != nil {
	// 	log.Println("Error loading .env file:", err)
	// }

	// Connect to PostgreSQL
	pgConnStr := os.Getenv("PG_DB")
	db, err = sql.Open("postgres", pgConnStr)
	if err != nil {
		log.Fatal(err)
	}
	defer db.Close()

	// Enable TimescaleDB
	_, err = db.Exec(`
		CREATE EXTENSION IF NOT EXISTS timescaledb;
	`)
	if err != nil {
		log.Fatal("Error creating TimescaleDB extension:", err)
	}

	// Create table if not exists
	_, err = db.Exec(`
		CREATE TABLE IF NOT EXISTS p1 (
			timestamp TIMESTAMPTZ,
			delivered_tariff1 INT,
			delivered_tariff2 INT,
			returned_tariff1 INT,
			returned_tariff2 INT,
			delivery_all INT,
			returning_all INT,
			failures INT,
			long_failures INT,
			gas INT,
			voltage_l1 INT,
			voltage_l2 INT,
			voltage_l3 INT,
			current_l1 INT,
			current_l2 INT,
			current_l3 INT,
			delivery_l1 INT,
			delivery_l2 INT,
			delivery_l3 INT,
			returning_l1 INT,
			returning_l2 INT,
			returning_l3 INT
			);
		SELECT create_hypertable('p1', 'timestamp', if_not_exists => TRUE);
	`)
	if err != nil {
		log.Fatal("Error creating table:", err)
	}

	// Initialize MQTT options
	opts := mqtt.NewClientOptions()
	opts.AddBroker(os.Getenv("MQTT_BROKER"))
	opts.SetUsername(os.Getenv("MQTT_USERNAME"))
	opts.SetPassword(os.Getenv("MQTT_PASSWORD"))

	// Connect to MQTT broker
	client := mqtt.NewClient(opts)
	if token := client.Connect(); token.Wait() && token.Error() != nil {
		log.Fatal(token.Error())
	}

	// Subscribe to MQTT topic
	topic := os.Getenv("MQTT_TOPIC")
	if token := client.Subscribe(topic, 0, mqttMessageHandler); token.Wait() && token.Error() != nil {
		log.Fatal(token.Error())
	}

	// Keep the program running
	select {}
}

func mqttMessageHandler(client mqtt.Client, msg mqtt.Message) {
	// Parse JSON payload
	var payload Payload
	err := json.Unmarshal(msg.Payload(), &payload)
	if err != nil {
		log.Println("Error parsing MQTT payload:", err)
		return
	}

	// Parse timestamp to time.Time
	timestamp, err := parseTimestamp(payload.T)
	if err != nil {
		log.Println("Error parsing timestamp:", err)
		return
	}

	// Insert data into PostgreSQL
	err = insertData(timestamp, payload)
	if err != nil {
		log.Println("Error inserting data into PostgreSQL:", err)
	}
}

func parseTimestamp(t string) (time.Time, error) {

	// Extract values from timestamp string
	year, month, day := 2000+int(t[0]-'0')*10+int(t[1]-'0'), time.Month(int(t[2]-'0')*10+int(t[3]-'0')), int(t[4]-'0')*10+int(t[5]-'0')
	hour, min, sec := int(t[6]-'0')*10+int(t[7]-'0'), int(t[8]-'0')*10+int(t[9]-'0'), int(t[10]-'0')*10+int(t[11]-'0')

	// Load location for "Europe/Amsterdam" time zone
	loc, err := time.LoadLocation("Europe/Amsterdam")
	if err != nil {
		return time.Time{}, err
	}

	// Create and return the timestamp
	return time.Date(year, month, day, hour, min, sec, 0, loc), nil

}

func insertData(timestamp time.Time, payload Payload) error {
	// Prepare SQL statement
	stmt := `
		INSERT INTO p1 (
			timestamp, delivered_tariff1, delivered_tariff2, returned_tariff1, returned_tariff2,
			delivery_all, returning_all, failures, long_failures, gas,
			voltage_l1, voltage_l2, voltage_l3,
			current_l1, current_l2, current_l3,
			delivery_l1, delivery_l2, delivery_l3,
			returning_l1, returning_l2, returning_l3
		) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, $14, $15, $16, $17, $18, $19, $20, $21, $22)
	`
	_, err := db.Exec(
		stmt,
		timestamp,
		payload.Dt1, payload.Dt2,
		payload.Rt1, payload.Rt2,
		payload.D, payload.R,
		payload.F, payload.Fl,
		payload.G,
		payload.V1, payload.V2, payload.V3,
		payload.C1, payload.C2, payload.C3,
		payload.D1, payload.D2, payload.D3,
		payload.R1, payload.R2, payload.R3,
	)
	return err
}