export def "books add" [
    name: string, # name of the book
    author: string, # name of the book's author
    --finished # mark the book already read - default: false
] {
    let book_id = random uuid
    {
        id: $book_id,
        name: $name,
        author: $author
        finished: ($finished | default false)
    } | into sqlite $env.READINGORDER_DB_PATH -t books

    print $"Added ($name) successfully to list of books."
    books show --id $book_id
}

export def "books show" [
    --id: string, # id of the book, identify using `reading-order books show --explore`
    --explore # show in nushell explorer
] {
    if not ($env.READINGORDER_DB_PATH | path exists) {
        print "List of books is empty. If it shouldn't be empty, check the READINGORDER_DB_PATH environment variable." 
        return
    }
    mut books = open $env.READINGORDER_DB_PATH | get books

    if $id != null {
        $books = $books | where id == $id
    }

    if ($explore) {
        return ($books | explore -p)
    }

    return $books
}

export def "books set-name" [
    id: string, # id of the book, identify using `reading-order books show --explore`
    name: string
] {
    if not ($env.READINGORDER_DB_PATH | path exists) {
        print "List of books is empty. If it shouldn't be empty, check the READINGORDER_DB_PATH environment variable." 
        return
    }
    open $env.READINGORDER_DB_PATH | query db "UPDATE books SET name = ? WHERE id = ?" -p [$name, $id]
    print $"Updated name for book with id ($id) successfully."
    books show --id $id
}

export def "books set-author-name" [
    id: string, # id of the book, identify using `reading-order books show --explore`
    author: string
] {
    if not ($env.READINGORDER_DB_PATH | path exists) {
        print "List of books is empty. If it shouldn't be empty, check the READINGORDER_DB_PATH environment variable." 
        return
    }
    open $env.READINGORDER_DB_PATH | query db "UPDATE books SET author = ? WHERE id = ?" -p [$author, $id]
    print $"Updated author name for book with id ($id) successfully."
    books show --id $id
}

export def "books set-finished" [
    id: string, # id of the book, identify using `reading-order books show --explore`
    finished: bool = true,
] {
    if not ($env.READINGORDER_DB_PATH | path exists) {
        print "List of books is empty. If it shouldn't be empty, check the READINGORDER_DB_PATH environment variable." 
        return
    }
    open $env.READINGORDER_DB_PATH | query db "UPDATE books SET finished = ? WHERE id = ?" -p [$finished, $id]
    print $"Updated finished status for book with id ($id) successfully."
    books show --id $id
}

# Add a reading order
export def add [
    book1_id: string, # id of the book to be read before book 2, identify using `reading-order books show --explore`
    book2_id: string, # id of the book to be read after book 1, identify using `reading-order books show --explore`
] {
    let reading_order_id = random uuid
    {
        id: $reading_order_id,
        book1: $book1_id,
        book2: $book2_id,
    } | into sqlite $env.READINGORDER_DB_PATH

    print $"Added reading order successfully."
    show --id $reading_order_id
}

export def show [
    --id: string, # id of the book, identify using `reading-order books show --explore`
    --explore # show in nushell explorer
] {
    if not ($env.READINGORDER_DB_PATH | path exists) {
        print "List of books is empty. If it shouldn't be empty, check the READINGORDER_DB_PATH environment variable." 
        return
    }

    mut reading_orders = open $env.READINGORDER_DB_PATH | get main

    if $id != null {
        return ($reading_orders | where id == $id)
    }

    if ($explore) {
        return ($reading_orders | explore -p) 
    }

    return $reading_orders
}

export def read-next [] {
    if not ($env.READINGORDER_DB_PATH | path exists) {
        print "List of books is empty. If it shouldn't be empty, check the READINGORDER_DB_PATH environment variable." 
        return
    }

    let reading_orders = open $env.READINGORDER_DB_PATH | get main
    mut books = open $env.READINGORDER_DB_PATH | get books | where { |book| 
       if $book.finished == 1 {
          return false
       }

       
       for order in $reading_orders {
          if $order.book2 != $book.id {
            continue
          }
          let book_to_read_before = books show --id $order.book1
          if $book_to_read_before.finished != 1 {
            return false
          }
       }
       return true

    }
    return $books
}