package query

import (
	"regexp"
	"strings"

	"git.artlef.fr/bibliomane/internal/dto"
	"git.artlef.fr/bibliomane/internal/fileutils"
	"git.artlef.fr/bibliomane/internal/model"
	"gorm.io/gorm"
)

func FetchBookGet(db *gorm.DB, userId uint, bookId uint64) (dto.FullBookGet, error) {
	var book dto.FullBookGet
	query := db.Model(&model.Book{})
	selectQueryString := "books.title, authors.name as author, authors.id as author_id, books.isbn, books.inventaire_id, books.open_library_id, books.short_description, books.summary, " +
		"user_books.review, user_books.rating, user_books.read, user_books.want_read, " +
		"DATE(user_books.start_read_date) as start_read_date, " +
		"DATE(user_books.end_read_date) AS end_read_date, " +
		selectStaticFilesPath()
	query = query.Select(selectQueryString)
	query = joinAuthors(query)
	query = query.Joins("left join user_books on (user_books.book_id = books.id and user_books.user_id = ?)", userId)
	query = joinStaticFiles(query)
	query = query.Where("books.id = ?", bookId)
	res := query.First(&book)
	return book, res.Error
}

func FetchReadUserBook(db *gorm.DB, userId uint, limit int, offset int) ([]dto.BookItemGet, error) {
	var books []dto.BookItemGet
	query := fetchReadUserBookQuery(db, userId)
	query = query.Limit(limit)
	query = query.Offset(offset)
	res := query.Find(&books)
	return books, res.Error
}

func FetchReadUserBookCount(db *gorm.DB, userId uint) (int64, error) {
	query := fetchReadUserBookQuery(db, userId)
	var count int64
	res := query.Count(&count)
	return count, res.Error
}

func FetchReadingUserBook(db *gorm.DB, userId uint, limit int, offset int) ([]dto.BookItemGet, error) {
	var books []dto.BookItemGet
	query := fetchReadingUserBookQuery(db, userId)
	query = query.Limit(limit)
	query = query.Offset(offset)
	res := query.Find(&books)
	return books, res.Error
}

func FetchReadingUserBookCount(db *gorm.DB, userId uint) (int64, error) {
	query := fetchReadingUserBookQuery(db, userId)
	var count int64
	res := query.Count(&count)
	return count, res.Error
}

func fetchReadUserBookQuery(db *gorm.DB, userId uint) *gorm.DB {
	query := fetchUserBookGet(db, userId)
	query = query.Where("user_books.read IS TRUE")
	return query
}
func fetchReadingUserBookQuery(db *gorm.DB, userId uint) *gorm.DB {
	query := fetchUserBookGet(db, userId)
	query = query.Where("user_books.start_read_date IS NOT NULL AND (user_books.read IS NULL OR user_books.read IS FALSE)")
	return query
}

func FetchWantReadUserBook(db *gorm.DB, userId uint, limit int, offset int) ([]dto.BookItemGet, error) {
	var books []dto.BookItemGet

	query := fetchWantReadUserBookQuery(db, userId)
	query = query.Limit(limit)
	query = query.Offset(offset)
	res := query.Find(&books)
	return books, res.Error
}

func FetchWantReadUserBookCount(db *gorm.DB, userId uint) (int64, error) {
	query := fetchWantReadUserBookQuery(db, userId)
	var count int64
	res := query.Count(&count)
	return count, res.Error
}

func fetchWantReadUserBookQuery(db *gorm.DB, userId uint) *gorm.DB {
	query := fetchUserBookGet(db, userId)
	query = query.Where("user_books.want_read IS TRUE")
	return query
}

// fetch only books where userbook exists
func fetchUserBookGet(db *gorm.DB, userId uint) *gorm.DB {
	query := db.Model(&model.UserBook{})
	query = query.Select(selectBookItem())
	query = query.Joins("left join books on (books.id = user_books.book_id)")
	query = joinAuthors(query)
	query = joinStaticFiles(query)
	query = query.Where("user_id = ?", userId)
	return query
}

func FetchAllBooks(db *gorm.DB, userId uint, limit int, offset int) ([]dto.BookItemGet, error) {
	var books []dto.BookItemGet
	query := fetchBookQueryBuilder(db, userId)
	query = query.Limit(limit)
	query = query.Offset(offset)
	query = query.Order("books.id DESC")
	res := query.Find(&books)
	return books, res.Error
}

func FetchAllBooksCount(db *gorm.DB, userId uint) (int64, error) {
	var count int64
	query := fetchBookQueryBuilder(db, userId)
	res := query.Count(&count)
	return count, res.Error
}

func FetchBookSearchByAuthorGet(db *gorm.DB, userId uint, authorId uint64, limit int, offset int) ([]dto.BookItemGet, error) {
	var books []dto.BookItemGet
	query := fetchBookSearchByAuthorQuery(db, userId, authorId)
	query = query.Limit(limit)
	query = query.Offset(offset)
	res := query.Find(&books)
	return books, res.Error
}

func FetchBookSearchByAuthorGetCount(db *gorm.DB, userId uint, authorId uint64) (int64, error) {
	var count int64
	query := fetchBookSearchByAuthorQuery(db, userId, authorId)
	res := query.Count(&count)
	return count, res.Error
}

func fetchBookSearchByAuthorQuery(db *gorm.DB, userId uint, authorId uint64) *gorm.DB {
	query := fetchBookQueryBuilder(db, userId)
	return query.Where("authors.id = ?", authorId)
}

func FetchBookSearchGet(db *gorm.DB, userId uint, searchterm string, limit int, offset int) ([]dto.BookItemGet, error) {
	var books []dto.BookItemGet
	query := fetchBookSearchQuery(db, userId, searchterm)
	query = query.Limit(limit)
	query = query.Offset(offset)
	res := query.Find(&books)
	return books, res.Error
}

func FetchBookSearchGetCount(db *gorm.DB, userId uint, searchterm string) (int64, error) {
	query := fetchBookSearchQuery(db, userId, searchterm)
	var count int64
	res := query.Count(&count)
	return count, res.Error
}

func fetchBookSearchQuery(db *gorm.DB, userId uint, searchterm string) *gorm.DB {
	query := fetchBookQueryBuilder(db, userId)
	isIsbn, _ := regexp.Match(`\d{10,13}`, []byte(searchterm))
	if isIsbn {
		query = query.Where("books.isbn = ?", searchterm)
	} else {
		query = query.Where("LOWER(books.title) LIKE ?", "%"+strings.ToLower(searchterm)+"%")
	}

	return query
}

// fetch all books even whithout user books
func fetchBookQueryBuilder(db *gorm.DB, userId uint) *gorm.DB {
	query := db.Model(&model.Book{})
	query = query.Select(selectBookItem())
	query = joinAuthors(query)
	query = query.Joins("left join user_books on (user_books.book_id = books.id and user_books.user_id = ?)", userId)
	query = joinStaticFiles(query)
	return query
}

func selectBookItem() string {
	return "books.id, books.title, authors.name as author, books.short_description as description, books.inventaire_id, user_books.rating, user_books.read, DATE(user_books.start_read_date) as start_read_date, user_books.want_read, " + selectStaticFilesPath()
}

type CollectionsQueryResult struct {
	ID        uint
	UserID    uint
	Name      string
	BookId    uint
	BookTitle string
	CoverPath string
}

type collectionId struct {
	ID uint
}

func FetchAllCollections(db *gorm.DB, userId uint, limit int, offset int) ([]CollectionsQueryResult, error) {
	var collections []CollectionsQueryResult
	var collectionIds []collectionId
	res := fetchCollections(db, userId).Limit(limit).Offset(offset).Order("collections.id DESC").Find(&collectionIds)
	if res.Error != nil {
		return collections, res.Error
	}
	for _, collectionId := range collectionIds {
		//only takes first 5 books
		queryResults, err := FetchCollectionBooks(db, collectionId.ID, 5, 0)
		if err != nil {
			return collections, res.Error
		}
		collections = append(collections, queryResults...)
	}
	return collections, res.Error
}

func FetchCollectionBooks(db *gorm.DB, collectionId uint, limit int, offset int) ([]CollectionsQueryResult, error) {
	var collections []CollectionsQueryResult
	query := fetchCollectionBooksQuery(db, collectionId)
	query = query.Limit(limit)
	query = query.Offset(offset)
	res := query.Find(&collections)
	return collections, res.Error
}

func FetchCollectionBooksCount(db *gorm.DB, collectionId uint) (int64, error) {
	var count int64
	res := fetchCollectionBooksQuery(db, collectionId).Where("book_id IS NOT NULL").Count(&count)
	return count, res.Error
}

func fetchCollectionBooksQuery(db *gorm.DB, collectionId uint) *gorm.DB {
	query := db.Model(&model.Collection{})
	query = query.Select("collections.id, collections.user_id, collections.name, books.id as book_id, books.title as book_title, " + selectStaticFilesPath())
	query = query.Joins("left join collection_books on (collection_books.collection_id = collections.id)")
	query = query.Joins("left join books on (books.id = collection_books.book_id)")
	query = joinStaticFiles(query)
	query = query.Where("collections.id = ?", collectionId)
	return query
}

func FetchAllCollectionsCount(db *gorm.DB, userId uint) (int64, error) {
	var count int64
	res := fetchCollections(db, userId).Count(&count)
	return count, res.Error
}

func fetchCollections(db *gorm.DB, userId uint) *gorm.DB {
	return db.Model(&model.Collection{}).Where("collections.user_id = ?", userId)
}

func selectStaticFilesPath() string {
	return "(CASE COALESCE(static_files.path, '') WHEN '' THEN '' ELSE concat('" + fileutils.GetWsLinkPrefix() + "', static_files.path) END) as CoverPath"
}

func joinAuthors(query *gorm.DB) *gorm.DB {
	return query.Joins("left join authors on (authors.id = books.author_id)")
}

func joinStaticFiles(query *gorm.DB) *gorm.DB {
	return query.Joins("left join static_files on (static_files.id = books.cover_id)")
}