from flask import Flask, render_template, request, redirect, url_for, flash
from flask_sqlalchemy import SQLAlchemy
from flask_bootstrap import Bootstrap
from config import Config
from models import db, Author, Book, Loan
from datetime import date, datetime

def create_app():
    app = Flask(__name__)
    app.config.from_object(Config)
    bootstrap = Bootstrap(app)
    db.init_app(app)
    
    with app.app_context():
        # Initialize the database here
        db.create_all()

    @app.context_processor
    def inject_bootstrap():
        return dict(bootstrap=bootstrap)

    @app.route('/')
    def index():
        return render_template('index.html')

    @app.route('/authors')
    def authors():
        all_authors = Author.query.all()
        return render_template('author.html', authors=all_authors)

    @app.route('/books')
    def books():
        db.session.expire_all()
        all_books = Book.query.all()
        all_authors = Author.query.all()
        return render_template('book.html', books=all_books, authors=all_authors)

    @app.route('/loans')
    def loans():
        all_loans = Loan.query.all()
        available_books = Book.query.filter(~Book.loans.any()).all()
        today = date.today().strftime('%Y-%m-%d')
        return render_template('loan.html', 
                             loans=all_loans, 
                             available_books=available_books,
                             today=today)

    @app.route('/add_author', methods=['POST'])
    def add_author():
        new_author = Author(name=request.form['name'])
        db.session.add(new_author)
        db.session.commit()
        return redirect(url_for('authors'))

    @app.route('/add_book', methods=['POST'])
    def add_book():
        try:
            new_book = Book(
                title=request.form['title'],
                published_date=request.form['published_date'],
                author_id=request.form['author_id']
            )
            print("new_book: ", new_book)
            db.session.add(new_book)
            db.session.commit()
            db.session.refresh(new_book)
            flash('图书添加成功！', 'success')
        except ValueError as e:
            print(e)
            flash('日期格式无效！', 'danger')
        except Exception as e:
            print(e)
            flash('添加图书失败！', 'danger')
            db.session.rollback()
        
        return redirect(url_for('books'))

    @app.route('/add_loan', methods=['POST'])
    def add_loan():
        new_loan = Loan(
            user_name=request.form['user_name'],
            loan_date=datetime.strptime(request.form['loan_date'], '%Y-%m-%d').date()
        )
        book = Book.query.get(request.form['book_id'])
        if book:
            new_loan.books.append(book)
            db.session.add(new_loan)
            db.session.commit()
        return redirect(url_for('loans'))

    @app.route('/return_loan/<int:loan_id>', methods=['POST'])
    def return_loan(loan_id):
        loan = Loan.query.get_or_404(loan_id)
        loan.return_date = date.today()
        db.session.commit()
        return redirect(url_for('loans'))

    return app

if __name__ == '__main__':
    app = create_app()
    SERVER_PORT=9999
    app.run(host='0.0.0.0', port=SERVER_PORT, debug=True)