package bouquins

import (
	"database/sql"
	"errors"
	"fmt"
	"log"
)

const (
	STMT_PAGE   = " LIMIT ? OFFSET ?"
	STMT_BOOKS0 = `SELECT books.id AS id,title,series_index,name as series_name,series.id AS series_id 
    FROM books LEFT OUTER JOIN books_series_link ON books.id = books_series_link.book 
    LEFT OUTER JOIN series ON series.id = books_series_link.series `
	STMT_BOOKS_TAGS0 = `SELECT name, books_tags_link.book as book FROM tags, books_tags_link 
    WHERE tags.id = books_tags_link.tag AND books_tags_link.book IN ( SELECT id FROM books `
	STMT_BOOKS_AUTHORS0 = `SELECT authors.id, authors.name, books_authors_link.book as book 
    FROM authors, books_authors_link WHERE books_authors_link.author = authors.id 
    AND books_authors_link.book IN ( SELECT id FROM books `
	STMT_WHERE        = " WHERE "
	STMT_SEARCH_TERM  = " books.sort like ? "
	STMT_BOOL_AND     = " AND "
	STMT_BOOL_OR      = " OR "
	STMT_SEARCH_ORDER = " ORDER BY books.sort"

	STMT_BOOKS_COUNT = "SELECT count(id) FROM books"
	STMT_BOOK        = `SELECT books.id AS id,title, series_index, series.name AS series_name, series.id AS series_id, 
    strftime('%s', timestamp), strftime('%Y', pubdate), isbn,lccn,path,uuid,has_cover, 
    languages.lang_code, publishers.name AS pubname FROM books 
    LEFT OUTER JOIN books_languages_link ON books_languages_link.book = books.id 
    LEFT OUTER JOIN languages ON languages.id = books_languages_link.lang_code 
    LEFT OUTER JOIN data ON data.book = books.id 
    LEFT OUTER JOIN books_series_link ON books.id = books_series_link.book 
    LEFT OUTER JOIN series ON series.id = books_series_link.series 
    LEFT OUTER JOIN books_publishers_link ON books.id = books_publishers_link.book 
    LEFT OUTER JOIN publishers ON publishers.id = books_publishers_link.publisher 
    WHERE books.id = ?`
	STMT_BOOK_TAGS    = "SELECT name FROM tags, books_tags_link WHERE tags.id = books_tags_link.tag AND books_tags_link.book = ?"
	STMT_BOOK_AUTHORS = `SELECT authors.id, authors.name, books_authors_link.book as book 
    FROM authors, books_authors_link WHERE books_authors_link.author = authors.id 
    AND books_authors_link.book = ?`
	STMT_BOOK_DATA                = "SELECT data.name, data.format, data.uncompressed_size FROM data WHERE data.book = ?"
	STMT_BOOKS_ID_ASC             = STMT_BOOKS0 + " ORDER BY id" + STMT_PAGE
	STMT_BOOKS_ID_DESC            = STMT_BOOKS0 + "ORDER BY id DESC" + STMT_PAGE
	STMT_BOOKS_TITLE_ASC          = STMT_BOOKS0 + "ORDER BY books.sort" + STMT_PAGE
	STMT_BOOKS_TITLE_DESC         = STMT_BOOKS0 + "ORDER BY books.sort DESC" + STMT_PAGE
	STMT_BOOKS_TAGS_ID_ASC        = STMT_BOOKS_TAGS0 + "ORDER BY id" + STMT_PAGE + ")"
	STMT_BOOKS_TAGS_ID_DESC       = STMT_BOOKS_TAGS0 + "ORDER BY id DESC" + STMT_PAGE + ")"
	STMT_BOOKS_TAGS_TITLE_ASC     = STMT_BOOKS_TAGS0 + "ORDER BY books.sort" + STMT_PAGE + ")"
	STMT_BOOKS_TAGS_TITLE_DESC    = STMT_BOOKS_TAGS0 + "ORDER BY books.sort DESC" + STMT_PAGE + ")"
	STMT_BOOKS_AUTHORS_ID_ASC     = STMT_BOOKS_AUTHORS0 + "ORDER BY id" + STMT_PAGE + ")"
	STMT_BOOKS_AUTHORS_ID_DESC    = STMT_BOOKS_AUTHORS0 + "ORDER BY id DESC" + STMT_PAGE + ")"
	STMT_BOOKS_AUTHORS_TITLE_ASC  = STMT_BOOKS_AUTHORS0 + "ORDER BY books.sort" + STMT_PAGE + ")"
	STMT_BOOKS_AUTHORS_TITLE_DESC = STMT_BOOKS_AUTHORS0 + "ORDER BY books.sort DESC" + STMT_PAGE + ")"

	DEF_LIM = 10

	BOOKS         QueryType = iota
	BOOKS_TAGS    QueryType = iota
	BOOKS_AUTHORS QueryType = iota
	BOOK          QueryType = iota
	BOOK_TAGS     QueryType = iota
	BOOK_DATA     QueryType = iota
	BOOKS_COUNT   QueryType = iota
)

var QUERIES = map[Query]string{
	Query{BOOKS, true, true}:           STMT_BOOKS_TITLE_DESC,
	Query{BOOKS, true, false}:          STMT_BOOKS_TITLE_ASC,
	Query{BOOKS, false, true}:          STMT_BOOKS_ID_DESC,
	Query{BOOKS, false, false}:         STMT_BOOKS_ID_ASC,
	Query{BOOKS_TAGS, true, true}:      STMT_BOOKS_TAGS_TITLE_DESC,
	Query{BOOKS_TAGS, true, false}:     STMT_BOOKS_TAGS_TITLE_ASC,
	Query{BOOKS_TAGS, false, true}:     STMT_BOOKS_TAGS_ID_DESC,
	Query{BOOKS_TAGS, false, false}:    STMT_BOOKS_TAGS_ID_ASC,
	Query{BOOKS_AUTHORS, true, true}:   STMT_BOOKS_AUTHORS_TITLE_DESC,
	Query{BOOKS_AUTHORS, true, false}:  STMT_BOOKS_AUTHORS_TITLE_ASC,
	Query{BOOKS_AUTHORS, false, true}:  STMT_BOOKS_AUTHORS_ID_DESC,
	Query{BOOKS_AUTHORS, false, false}: STMT_BOOKS_AUTHORS_ID_ASC,
	Query{BOOK, false, false}:          STMT_BOOK,
	Query{BOOK_TAGS, false, false}:     STMT_BOOK_TAGS,
	Query{BOOK_DATA, false, false}:     STMT_BOOK_DATA,
	Query{BOOKS_COUNT, false, false}:   STMT_BOOKS_COUNT,
}
var STMTS = make(map[Query]*sql.Stmt)

type QueryType uint
type Query struct {
	Type  QueryType
	Title bool
	Desc  bool
}

// PREPARED STATEMENTS //
func (app *Bouquins) PrepareAll() error {
	errcount := 0
	for q, v := range QUERIES {
		stmt, err := app.DB.Prepare(v)
		if err != nil {
			log.Println(err, v)
			errcount++
		}
		STMTS[q] = stmt
	}
	if errcount > 0 {
		return errors.New(fmt.Sprintf("%d errors on queries, see logs", errcount))
	}
	return nil
}

// prepared statement with sort on books
func (app *Bouquins) psSortBooks(qt QueryType, sort, order string) (*sql.Stmt, error) {
	q := Query{qt, sort == "title", order == "desc"}
	query := QUERIES[q]
	log.Println(query)
	stmt := STMTS[q]
	if stmt == nil {
		log.Println("Missing statement for ", q)
		var err error
		stmt, err = app.DB.Prepare(query)
		if err != nil {
			return nil, err
		}
	}
	return stmt, nil
}

// prepared statement without sort
func (app *Bouquins) ps(qt QueryType) (*sql.Stmt, error) {
	return app.psSortBooks(qt, "", "")
}

// MERGE SUB QUERIES //
func assignAuthorsTagsBooks(books []*BookAdv, authors map[int64][]*Author, tags map[int64][]string) {
	for _, b := range books {
		b.Authors = authors[b.Id]
		b.Tags = tags[b.Id]
	}
}

// SUB QUERIES //

func (app *Bouquins) queryBooks(limit, offset int, sort, order string) ([]*BookAdv, error) {
	books := make([]*BookAdv, 0, limit)
	stmt, err := app.psSortBooks(BOOKS, sort, order)
	if err != nil {
		return nil, err
	}
	rows, err := stmt.Query(limit, offset)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	for rows.Next() {
		book := new(BookAdv)
		var series_name sql.NullString
		var series_id sql.NullInt64
		if err := rows.Scan(&book.Id, &book.Title, &book.SeriesIndex, &series_name, &series_id); err != nil {
			return nil, err
		}
		if series_name.Valid && series_id.Valid {
			book.Series = &Series{
				series_id.Int64,
				series_name.String,
			}
		}
		books = append(books, book)
	}
	if err := rows.Err(); err != nil {
		return nil, err
	}
	return books, nil
}

func (app *Bouquins) queryBooksAuthors(limit, offset int, sort, order string) (map[int64][]*Author, error) {
	authors := make(map[int64][]*Author)
	stmt, err := app.psSortBooks(BOOKS_AUTHORS, sort, order)
	if err != nil {
		return nil, err
	}
	rows, err := stmt.Query(limit, offset)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	for rows.Next() {
		author := new(Author)
		var book int64
		if err := rows.Scan(&author.Id, &author.Name, &book); err != nil {
			return nil, err
		}
		if authors[book] == nil {
			authors[book] = append(make([]*Author, 0), author)
		} else {
			authors[book] = append(authors[book], author)
		}
	}
	if err := rows.Err(); err != nil {
		return nil, err
	}
	return authors, nil
}

func (app *Bouquins) queryBooksTags(limit, offset int, sort, order string) (map[int64][]string, error) {
	stmt, err := app.psSortBooks(BOOKS_TAGS, sort, order)
	if err != nil {
		return nil, err
	}
	rows, err := stmt.Query(limit, offset)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	tags := make(map[int64][]string)
	for rows.Next() {
		var tag string
		var book int64
		if err := rows.Scan(&tag, &book); err != nil {
			return nil, err
		}
		bookTags := tags[book]
		if bookTags == nil {
			bookTags = make([]string, 0)
			tags[book] = bookTags
		}
		tags[book] = append(bookTags, tag)
	}
	if err := rows.Err(); err != nil {
		return nil, err
	}
	return tags, nil
}
func (app *Bouquins) queryBook(id int64) (*BookFull, error) {
	stmt, err := app.ps(BOOK)
	if err != nil {
		return nil, err
	}
	book := new(BookFull)
	var seriesIdx sql.NullFloat64
	var seriesId, timestamp, pubdate sql.NullInt64
	var seriesName, isbn, lccn, uuid, lang, publisher sql.NullString
	var cover sql.NullBool
	err = stmt.QueryRow(id).Scan(&book.Id, &book.Title, &seriesIdx, &seriesName, &seriesId,
		&timestamp, &pubdate, &isbn, &lccn, &book.Path, &uuid, &cover, &lang, &publisher)
	if err != nil {
		return nil, err
	}
	if seriesId.Valid && seriesName.Valid && seriesIdx.Valid {
		book.SeriesIndex = seriesIdx.Float64
		book.Series = &Series{seriesId.Int64, seriesName.String}
	}
	if timestamp.Valid {
		book.Timestamp = timestamp.Int64
	}
	if pubdate.Valid {
		book.Pubdate = pubdate.Int64
	}
	if isbn.Valid {
		book.Isbn = isbn.String
	}
	if lccn.Valid {
		book.Lccn = lccn.String
	}
	if uuid.Valid {
		book.Uuid = uuid.String
	}
	if lang.Valid {
		book.Lang = lang.String
	}
	if publisher.Valid {
		book.Publisher = publisher.String
	}
	if cover.Valid {
		book.Has_cover = cover.Bool
	}
	return book, nil
}
func (app *Bouquins) queryBookTags(book *BookFull) error {
	stmt, err := app.ps(BOOK_TAGS)
	if err != nil {
		return err
	}
	rows, err := stmt.Query(book.Id)
	if err != nil {
		return err
	}
	defer rows.Close()
	for rows.Next() {
		var tag string
		if err = rows.Scan(&tag); err != nil {
			return err
		}
		book.Tags = append(book.Tags, tag)
	}
	if err := rows.Err(); err != nil {
		return err
	}
	return nil
}
func (app *Bouquins) queryBookData(book *BookFull) error {
	stmt, err := app.ps(BOOK_DATA)
	if err != nil {
		return err
	}
	rows, err := stmt.Query(book.Id)
	if err != nil {
		return err
	}
	defer rows.Close()
	for rows.Next() {
		data := new(BookData)
		if err = rows.Scan(&data.Name, &data.Format, &data.Size); err != nil {
			return err
		}
		book.Data = append(book.Data, data)
	}
	if err := rows.Err(); err != nil {
		return err
	}
	return nil
}
func (app *Bouquins) queryBookAuthors(book *BookFull) error {
	return nil
}

// DB LOADS //

func (app *Bouquins) BookCount() (int64, error) {
	var count int64
	stmt, err := app.ps(BOOKS_COUNT)
	if err != nil {
		return 0, err
	}
	row := stmt.QueryRow()
	err = row.Scan(&count)
	return count, err
}
func (app *Bouquins) SeriesAdv(limit, offset int, sort, order string) ([]*SeriesAdv, error) {
	panic("not implemented")
}
func (app *Bouquins) AuthorsAdv(limit, offset int, sort, order string) ([]*AuthorAdv, error) {
	panic("not implemented")
}

func (app *Bouquins) BookFull(id int64) (*BookFull, error) {
	book, err := app.queryBook(id)
	if err != nil {
		return nil, err
	}
	err = app.queryBookTags(book)
	if err != nil {
		return nil, err
	}
	err = app.queryBookAuthors(book)
	if err != nil {
		return nil, err
	}
	err = app.queryBookData(book)
	if err != nil {
		return nil, err
	}
	return book, nil
}

func (app *Bouquins) BooksAdv(limit, offset int, sort, order string) ([]*BookAdv, error) {
	if limit == 0 {
		limit = DEF_LIM
	}
	books, err := app.queryBooks(limit, offset, sort, order)
	if err != nil {
		return nil, err
	}
	authors, err := app.queryBooksAuthors(limit, offset, sort, order)
	if err != nil {
		return nil, err
	}
	tags, err := app.queryBooksTags(limit, offset, sort, order)
	if err != nil {
		return nil, err
	}
	assignAuthorsTagsBooks(books, authors, tags)
	return books, nil
}