package main

import (
	"database/sql"
	"sync"
	"time"

	_ "github.com/mattn/go-sqlite3"
	en "github.com/number571/go-peer/encoding"
	lc "github.com/number571/go-peer/local"
)

type DB struct {
	ptr *sql.DB
	mtx sync.Mutex
}

func NewDB(filename string) *DB {
	db, err := sql.Open("sqlite3", filename)
	if err != nil {
		return nil
	}
	_, err = db.Exec(`
PRAGMA secure_delete=ON;
CREATE TABLE IF NOT EXISTS emails (
	id      INTEGER,
	recv    VARCHAR(255),
	hash    VARCHAR(255) UNIQUE,
	data    TEXT,
	addtime DATETIME DEFAULT CURRENT_TIMESTAMP,
	PRIMARY KEY(id)
);
`)
	if err != nil {
		return nil
	}
	return &DB{
		ptr: db,
	}
}

func (db *DB) SetEmail(recv string, pack lc.Message) error {
	db.mtx.Lock()
	defer db.mtx.Unlock()
	_, err := db.ptr.Exec(
		"INSERT INTO emails (recv, hash, data) VALUES ($1, $2, $3)",
		recv,
		en.Base64Encode(pack.Body.Hash),
		string(pack.Serialize()),
	)
	return err
}

func (db *DB) GetEmail(id int, recv string) string {
	db.mtx.Lock()
	defer db.mtx.Unlock()
	var data string
	row := db.ptr.QueryRow(
		"SELECT data FROM emails WHERE recv=$1 ORDER BY id LIMIT 1 OFFSET $2",
		recv,
		id-1,
	)
	row.Scan(&data)
	return data
}

func (db *DB) DelEmailsByTime(t time.Duration) error {
	db.mtx.Lock()
	defer db.mtx.Unlock()
	_, err := db.ptr.Exec(
		"DELETE FROM emails WHERE addtime < datetime('now', '-' || $1 || ' seconds')",
		uint64(t)/1000000000, // seconds
	)
	return err
}

func (db *DB) Size(recv string) int {
	db.mtx.Lock()
	defer db.mtx.Unlock()
	var data int
	row := db.ptr.QueryRow(
		"SELECT COUNT(*) FROM emails WHERE recv=$1",
		recv,
	)
	row.Scan(&data)
	return data
}