package main

import (
	"database/sql"
	"fmt"
)

var ClimateDb *sql.DB

func InitDb() error {
	db, err := sql.Open("mysql", "admin:sekna123jk@tcp(127.0.0.1:3306)/climate")
	if err != nil {
		fmt.Println("error connecting to database")
		return err
	}
	ClimateDb = db
	return nil
}

func CloseDb() {
	if ClimateDb != nil {
		err := ClimateDb.Close()
		if err != nil {
			fmt.Println("error closing database: " + err.Error())
		}
	}
}

func writeSnapshotToDb(snapshotSub *SnapshotSubmission) error {
	query := fmt.Sprintf("INSERT INTO `snapshots` (`temp`, `humidity`, `co2`, `time`, `id`) VALUES (%v, %v, %v, '%v', NULL);",
		snapshotSub.Temp,
		snapshotSub.Humidity,
		snapshotSub.Co2,
		snapshotSub.Timestamp)
	_, err := ClimateDb.Query(query)
	if err != nil {
		return err
	}
	return nil
}

func getSnapshotRecordsFromDb(rowCount int) ([]*SnapshotRecord, error) {
	snapshots := make([]*SnapshotRecord, rowCount)
	query := fmt.Sprintf("SELECT `%s`, `%s`, `%s`, `%s`, `%s` FROM `snapshots` ORDER BY `id` DESC LIMIT %v;",
		"id",
		"temp",
		"humidity",
		"co2",
		"time",
		rowCount,
	)
	rows, err := ClimateDb.Query(query)
	if err != nil {
		return nil, err
	}
	for i := 0; rows.Next(); i++ {
		var snapshotRecord SnapshotRecord
		err = rows.Scan(
			&snapshotRecord.Id,
			&snapshotRecord.Temp,
			&snapshotRecord.Humidity,
			&snapshotRecord.Co2,
			&snapshotRecord.Timestamp,
		)
		if err != nil {
			return nil, err
		}
		snapshots[i] = &snapshotRecord
	}
	return snapshots, nil
}