package main

import (
	"bufio"
	"fmt"
	"log"
	"os"

	"github.com/boltdb/bolt"
)

const usage = "bdb <(w)rite|(r)ead> <db>"
const queued = "queued"

func main() {
	log.SetFlags(log.Lshortfile)
	if len(os.Args) != 3 {
		fmt.Fprintf(os.Stderr, "%s\n", usage)
		os.Exit(1)
	}

	switch os.Args[1] {
	case "write", "read", "w", "r":
	default:
		fmt.Fprintf(os.Stderr, "%s\n", usage)
		os.Exit(1)
	}

	db, err := bolt.Open(os.Args[2], 0600, nil)
	if err != nil {
		panic(err)
	}
	defer db.Close()

	switch os.Args[1] {
	case "write", "w":
		err = db.Update(func(tx *bolt.Tx) error {
			_, err := tx.CreateBucketIfNotExists([]byte(queued))
			if err != nil {
				return err
			}
			return nil
		})
		if err != nil {
			panic(err)
		}
		err := db.Update(func(tx *bolt.Tx) error {
			s := bufio.NewScanner(os.Stdin)
			b := tx.Bucket([]byte(queued))
			for s.Scan() {
				err := b.Put(s.Bytes(), s.Bytes())
				if err != nil {
					return err
				}
			}
			return s.Err()
		})
		if err != nil {
			panic(err)
		}
	case "read", "r":
		err = db.Update(func(tx *bolt.Tx) error {
			_, err := tx.CreateBucketIfNotExists([]byte(queued))
			if err != nil {
				return err
			}
			return nil
		})
		if err != nil {
			panic(err)
		}
		db.View(func(tx *bolt.Tx) error {
			b := tx.Bucket([]byte(queued))
			c := b.Cursor()

			for k, v := c.First(); k != nil; k, v = c.Next() {
				fmt.Printf("key=%s, value=%s\n", k, v)
			}

			return nil
		})
	}
}