package main

import (
	"database/sql"
	"errors"
	"log"
	"os"
	"time"
)

type Memo struct {
	ID      int64  `json:"id"`
	Time    string `json:"time"`
	Message string `json:"message"`
}

func openOrCreateDb(name string) *sql.DB {
	new := false
	if _, err := os.Stat(name); errors.Is(err, os.ErrNotExist) {
		log.Println("memos db does not exist, creating.")
		new = true
	}
	db, err := sql.Open("sqlite3", name)
	if err != nil {
		log.Fatal(err)
	}
	if new {
		_, err = db.Exec(`create table memos (
			ID integer primary key autoincrement,
			time text not null,
			Message text not null
	   )`)
		if err != nil {
			log.Fatal(err)
		}
	}
	return db
}

func insertMemo(db *sql.DB, message string) int64 {
	tx, err := db.Begin()
	if err != nil {
		log.Fatal(err)
	}

	stmt, err := tx.Prepare("insert into memos (time, Message) values (?, ?)")
	if err != nil {
		log.Fatal(err)
	}
	defer stmt.Close()

	timeStr := time.Now().Format(time.RFC3339)
	row, err := stmt.Exec(timeStr, message)
	if err != nil {
		log.Fatal(err)
	}

	err = tx.Commit()
	if err != nil {
		log.Fatal(err)
	}

	id, err := row.LastInsertId()
	if err != nil {
		log.Fatal(err)
	}

	return id
}

func getMemos(db *sql.DB) []Memo {
	rows, err := db.Query("select * from memos order by id desc")
	if err != nil {
		log.Fatal(err)
	}
	defer rows.Close()
	var memos []Memo
	for rows.Next() {
		var memo Memo
		err = rows.Scan(&memo.ID, &memo.Time, &memo.Message)
		if err != nil {
			log.Fatal(err)
		}
		memos = append(memos, memo)
	}
	err = rows.Err()
	if err != nil {
		log.Fatal(err)
	}
	return memos
}