package main

import (
	"encoding/json"
)

type book struct {
	ID        int      `json:"id"`
	Platform  string   `json:"platform"`
	ReaderURL string   `json:"readerUrl"`
	Title     string   `json:"title"`
	Authors   []string `json:"authors"`
}

type library struct {
	db *database
}

type newLibraryOptions struct {
	db *database
}

func newLibrary(options newLibraryOptions) *library {
	return &library{options.db}
}

func (lib *library) add(b book) error {
	authors, err := json.Marshal(b.Authors)
	if err != nil {
		return err
	}

	_, err = lib.db.Exec(`
	insert into books(
		platform_id,
		reader_url,
		title,
		authors)
	values((select id from platforms where name = $1), $2, $3, $4)
	on conflict(reader_url)
		do update set title = excluded.title, authors = excluded.authors
`,

		b.Platform,
		b.ReaderURL,
		b.Title,
		authors,
	)

	return err
}

func (lib *library) delete(id string) error {
	_, err := lib.db.Exec(`delete from books where id = $1`, id)

	return err
}

func (lib *library) get(readerURLOrBookID string) (*book, error) {
	row := lib.db.QueryRow(`
	select
		books.id,
		platforms.name,
		books.reader_url,
		books.title,
		books.authors
	from books
	left join platforms
	on books.platform_id = platforms.id
	where books.reader_url = $1 or books.id = $1
`,
		readerURLOrBookID,
	)

	var (
		b       book
		authors []byte
	)

	err := row.Scan(
		&b.ID,
		&b.Platform,
		&b.ReaderURL,
		&b.Title,
		&authors,
	)

	if err != nil {
		return nil, err
	}

	err = json.Unmarshal(authors, &b.Authors)

	return &b, err
}

func (lib *library) getBooks() (*[]book, error) {
	rows, err := lib.db.Query(`
	select
		books.id,
		platforms.name,
		books.reader_url,
		books.title,
		books.authors
	from books
	left join platforms
	on books.platform_id = platforms.id
`)

	if err != nil {
		return nil, err
	}

	bs := &[]book{}

	for rows.Next() {
		var (
			b       book
			authors []byte
		)

		if err := rows.Scan(
			&b.ID,
			&b.Platform,
			&b.ReaderURL,
			&b.Title,
			&authors,
		); err != nil {
			return nil, err
		}

		if err = json.Unmarshal(authors, &b.Authors); err != nil {
			return nil, err
		}

		*bs = append(*bs, b)
	}

	return bs, err
}