package database

import (
	"database/sql"
	"errors"
	"log"

	"gopkg.in/guregu/null.v4"
)

type OS struct {
	ID           int         `json:"id"`
	Distribution null.String `json:"distribution"`
	Version      null.String `json:"version"`
	EndOfSupport null.String `json:"EndOfSupport"`
}

func GetOS(db *sql.DB) ([]OS, error) {
	var oses []OS
	rows, err := db.Query("SELECT * FROM dashboard_os")
	if err != nil {
		log.Println("Error querying list of OS", err)
	}
	defer func(rows *sql.Rows) {
		err := rows.Close()
		if err != nil {

		}
	}(rows)

	for rows.Next() {
		var os OS
		err := rows.Scan(&os.ID, &os.Distribution, &os.Version, &os.EndOfSupport)
		if err != nil {
			log.Println("Error building list", err)
		}
		oses = append(oses, os)
	}
	return oses, err
}

func GetOSbyID(db *sql.DB, id int64) (OS, error) {
	var os OS
	if err := db.QueryRow("SELECT * FROM dashboard_os where id = ?", id).Scan(&os.ID, &os.Distribution, &os.Version, &os.EndOfSupport); err != nil {
		if errors.Is(err, sql.ErrNoRows) {
			return os, nil
		}
		log.Println("Error getting OS by ID", err)
	}
	return os, nil
}

func GetDistributionList(db *sql.DB) ([]null.String, error) {
	var list []null.String
	rows, err := db.Query("SELECT DISTINCT distribution FROM dashboard_os")
	if err != nil {
		log.Println("Error getting distribution list", err)
	}
	for rows.Next() {
		var os OS
		err := rows.Scan(&os.Distribution)
		if err != nil {
			log.Println("Error building distribution list", err)
		}
		list = append(list, os.Distribution)
	}
	return list, nil
}

func GetVersionsByDistributionList(db *sql.DB, d string) ([]null.String, error) {
	var list []null.String
	rows, err := db.Query("SELECT DISTINCT version FROM dashboard_os where distribution = ?", d)
	if err != nil {
		log.Println("Error getting distribution list", err)
	}
	for rows.Next() {
		var os OS
		err := rows.Scan(&os.Distribution)
		if err != nil {
			log.Println("Error building distribution list", err)
		}
		list = append(list, os.Distribution)
	}
	return list, nil
}

func checkIfOsExists(os OS, db *sql.DB) bool {
	row := db.QueryRow("Select distribution, version from dashboard_os where distribution = ? and version = ?", os.Distribution, os.Version)
	err := row.Scan(&os.Distribution, &os.Version)
	if !errors.Is(err, sql.ErrNoRows) {
		log.Println("OS exists")
		return true
	}
	return false
}

func CreateOS(os OS, db *sql.DB) error {
	if checkIfOsExists(os, db) {
		log.Println("OS already exists")
		return nil
	}
	q, err := db.Prepare("INSERT INTO `dashboard_os` (`distribution`,`version`,`end_of_support`) VALUES (?,?,?)")
	if err != nil {
		log.Println("Error creating query", err)
		return err
	}
	_, err = q.Exec(&os.Distribution, &os.Version, &os.EndOfSupport)
	if err != nil {
		log.Println("Error inserting OS", err)
		return err
	}
	return nil
}

func DeleteOS(os OS, db *sql.DB) (int, error) {
	if !checkIfOsExists(os, db) {
		log.Println("OS does not exist, nothing to delete")
		return 404, nil
	}
	q, err := db.Prepare("DELETE FROM dashboard_os WHERE distribution = ? AND version = ?")
	if err != nil {
		log.Println("Error deleting OS", err)
		return 500, err
	}
	_, err = q.Exec(&os.Distribution, &os.Version)
	if err != nil {
		log.Println("Error deleting OS", err)
		return 500, err
	}
	log.Println("OS deleted")
	return 200, nil
}