#!/usr/bin/env python
# coding: utf-8
# # Bibliothek
#!pip install PyMySQL


import pprint
import json
import pymysql.cursors
from fastapi import FastAPI, HTTPException, Request
from fastapi.responses import JSONResponse, HTMLResponse
import time
from dbutils.pooled_db import PooledDB
import os
import logging
from fastapi.templating import Jinja2Templates

AUSLEIHE_TABLE = os.environ.get('AUSLEIHE_TABLE', 'ausleihe_test')
PAGE_TITLE = os.environ.get('PAGE_TITLE', 'Murmel Bibliothek TEST')

# Create a connection pool
db_config = {
    'host': os.environ['MURMEL_DB_HOST'],
    'user': os.environ['MURMEL_DB_USER'],
    'password': os.environ['MURMEL_DB_PASSWORD'],
    'database': 'murmel',
    'cursorclass': pymysql.cursors.DictCursor
}

pool = PooledDB(pymysql, maxconnections=5, **db_config)

app = FastAPI()
LOG = logging.getLogger('uvicorn.error')

def execute_query(sql, params=None, max_retries=3, retry_delay=1):
    LOG.debug("executing query " + sql + "with params" + str(params))
    for attempt in range(max_retries):
        try:
            connection = pool.connection()
            with connection.cursor() as cursor:
                cursor.execute(sql, params or ())
                result = cursor.fetchall()
            connection.commit()
            return result
        except pymysql.OperationalError as e:
            if attempt == max_retries - 1:
                raise HTTPException(status_code=500, detail="Database connection error")
            time.sleep(retry_delay)
        finally:
            if 'connection' in locals():
                connection.close()

templates = Jinja2Templates(directory=".")

@app.get("/groups")
def get_groups():
    sql = "SELECT Gruppe, idGruppe FROM `gruppe` WHERE aktuell is True ORDER BY idGruppe ASC;"
    return execute_query(sql)

@app.get("/students/{idGruppe}")
def get_students(idGruppe):
    if idGruppe == 'all':
        sql = """
        SELECT DISTINCT concat(`ki`.`Vorname`,' ',`ki`.`Nachnamen`) AS `Kind`, `ki`.`idKind` AS `idKind`
        FROM `kind` `ki`
        JOIN `kind_x_gruppe_x_schuljahr` `kgs` ON `ki`.`idKind` = `kgs`.`x_kind`
        JOIN `schuljahr` `sch` ON `sch`.`idschuljahr` = `kgs`.`x_schuljahr`
        WHERE `sch`.`aktuell` = 1
        ORDER BY 1
        """
        return execute_query(sql)
    else:
        sql = """
        SELECT concat(`ki`.`Vorname`,' ',`ki`.`Nachnamen`) AS `Kind`, `ki`.`idKind` AS `idKind`
        FROM `kind` `ki`
        JOIN `kind_x_gruppe_x_schuljahr` `kgs` ON `ki`.`idKind` = `kgs`.`x_kind`
        JOIN `schuljahr` `sch` ON `sch`.`idschuljahr` = `kgs`.`x_schuljahr`
        JOIN `gruppe` `gr` ON `gr`.`idGruppe` = `kgs`.`x_gruppe`
        WHERE `sch`.`aktuell` = 1 AND (`gr`.`Gruppe` = %s OR `gr`.`idGruppe` = %s)
        ORDER BY 1
        """
        return execute_query(sql, (idGruppe, idGruppe))

@app.get("/return/{idBuch}")
def rueckgabe(idBuch, grund='rueckgabe'):
    """
    Updates the database to mark a book as returned.

    Parameters:
    - idBuch (int): The ID of the book to be returned.
    - grund (str): The reason for the return (default: 'rueckgabe').

    Returns:
    - dict: Information about the return, including the students who had the book.
    """
    sql = f"""
    SELECT a.`idBuch`, a.`idKind`, a.`ausleihe`, a.`rueckgabe`, a.`rueckGrund`,
           CONCAT(k.`Vorname`, ' ', k.`Nachnamen`) AS student_name
    FROM `{AUSLEIHE_TABLE}` a
    JOIN `kind` k ON a.`idKind` = k.`idKind`
    WHERE a.`idBuch` = %s AND a.`rueckgabe` is NULL;
    """
    result = execute_query(sql, (idBuch,))
    if len(result) == 0:
        return {"success": False, "message": "Buch nicht gefunden oder bereits zurückgegeben"}
    
    # return the book
    sql = f"UPDATE `{AUSLEIHE_TABLE}` SET `rueckgabe` = NOW(), `rueckGrund` = %s WHERE `idBuch` = %s AND `rueckgabe` is NULL;"
    execute_query(sql, (grund, idBuch))
    
    student_names = [row['student_name'] for row in result]
    students_str = ", ".join(student_names)
    
    return {
        "success": True,
        "message": f"Buch zurückgegeben von: {students_str}",
        "student_names": student_names
    }

@app.get("/borrow/{idBuch}/{idKind}")
def ausleihe(idBuch, idKind):
    """
    Performs a book loan operation by inserting a new record into 'ausleihe_test' or the table defined by the AUSLEIHE_TABLE environment variable.

    Parameters:
    - idBuch (int): The ID of the book being loaned.
    - idKind (int): The ID of the child borrowing the book.

    Returns:
    - dict: A dictionary containing the result of the borrowing operation.
    """
    try:
        rueckgabe_result = rueckgabe(idBuch, grund="neu-ausleihe")
        
        message = "Buch erfolgreich ausgeliehen"
        if rueckgabe_result.get("success", False):
            # Get the name of the previous borrower
            prev_borrower_id = rueckgabe_result["student_names"][0]
            sql = "SELECT CONCAT(Vorname, ' ', Nachnamen) AS full_name FROM kind WHERE idKind = %s;"
            prev_borrower_name = execute_query(sql, (prev_borrower_id,))[0]['full_name']
            message += f". Zuvor ausgeliehen von {prev_borrower_name}"
        
        # Insert new borrowing record
        sql = f"INSERT INTO `{AUSLEIHE_TABLE}` (`idBuch`, `idKind`, `ausleihe`) VALUES (%s, %s, NOW());"
        execute_query(sql, (idBuch, idKind))
        
        return {"success": True, "message": message}
    except Exception as e:
        LOG.error(f"Error in ausleihe: {str(e)}")
        return {"success": False, "message": f"Fehler beim Ausleihen des Buches: {str(e)}"}

@app.get("/borrowed/{idKind}")
def ausgeliehen(idKind):
    """
    Retrieves the books that are currently borrowed by a specific child.

    Args:
        idKind (int): The ID of the child.

    Returns:
        list: A list of tuples containing the book ID and the borrowing date for each book that is currently borrowed by the child.
    """
    sql = f"SELECT `idBuch`, `ausleihe` FROM `{AUSLEIHE_TABLE}` WHERE `idKind` = %s AND `rueckgabe` IS NULL;"
    result = execute_query(sql, (idKind,))
    #pprint.pprint(result)
    return result

@app.get("/", response_class=HTMLResponse)
async def read_root(request: Request):
    return templates.TemplateResponse("index.html", {"request": request, "page_title": PAGE_TITLE})

# run the app
if __name__ == '__main__':
    import uvicorn
    uvicorn.run(app, host='localhost', port=5000)

# %%