package sqlite

import (
	"database/sql"
	"delayed.link/storage"
	"encoding/json"
	"errors"
	"github.com/google/uuid"
	_ "github.com/mattn/go-sqlite3"
	"github.com/spf13/pflag"
	"log"
)

var (
	dbFile = pflag.StringP("dbfile", "d", "delayedlink.db", "")
)

type SqliteStorage struct {
	*sql.DB
}

func (s *SqliteStorage) Close() error {
	return s.DB.Close()
}

func (s *SqliteStorage) Save(item storage.Link) (uuid.UUID, error) {
	stmt, err := s.Prepare("INSERT INTO links VALUES (?, ?)")
	if err != nil {
		return storage.Null, err
	}
	id := uuid.New()
	item.Id = id
	obj, err := item.Serialize()
	if err != nil {
		return storage.Null, err
	}
	_, err = stmt.Exec(id, obj)
	if err != nil {
		return storage.Null, err
	}
	return id, nil
}

const insertStatement = `SELECT (obj) FROM links WHERE id = ? LIMIT 1`

func (s *SqliteStorage) Load(key uuid.UUID) (*storage.Link, error) {
	stmt, err := s.DB.Prepare(insertStatement)
	if err != nil {
		return nil, err
	}
	rows, err := stmt.Query(key.String())
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var link *storage.Link
	var data []byte
	if !rows.Next() {
		return nil, storage.NotFoundError
	}
	err = rows.Scan(&data)
	if err != nil {
		return nil, err
	}
	err = json.Unmarshal(data, &link)
	if err != nil {
		return nil, err
	}

	return link, nil
}

const creation_sql = `CREATE TABLE IF NOT EXISTS links (
    id UUID PRIMARY KEY,
    obj JSONB NOT NULL
);`

func New() *SqliteStorage {
	db, err := sql.Open("sqlite3", *dbFile)
	if err != nil {
		log.Panic(err)
	}

	_, err = db.Exec(creation_sql)
	if err != nil {
		panic(err)
	}

	return &SqliteStorage{
		db,
	}
}

const deleteQuery = `DELETE FROM links WHERE id = ?`

var NotFoundError = errors.New("entry not found")

func (s *SqliteStorage) Delete(item storage.Link) error {
	stmt, err := s.DB.Prepare(deleteQuery)
	if err != nil {
		return err
	}
	res, err := stmt.Exec(item.Id)
	if err != nil {
		return err
	}
	if aff, err := res.RowsAffected(); aff < 1 || err != nil {
		if err == nil {
			return NotFoundError
		}
		return err
	}
	return nil
}

const updateQuery = `UPDATE links SET obj = ? WHERE id = ?`

func (s *SqliteStorage) Update(item storage.Link) error {
	stmt, err := s.DB.Prepare(updateQuery)
	if err != nil {
		return err
	}
	obj, err := item.Serialize()
	if err != nil {
		return err
	}
	_, err = stmt.Exec(item.Id, obj)
	if err != nil {
		return err
	}
	return nil
}