#!/usr/bin/env python3
"""
Student Management System
==========================
Terminal CRUD application for STUDENT / GUARDIAN / ATTENDANCE, backed by
MySQL on 10.10.0.160:3306 (student_db).

On startup this:
  1. Connects to the MySQL server.
  2. Verifies (or creates) the student_db database.
  3. Verifies (or creates) the STUDENT, GUARDIAN and ATTENDANCE tables.
  4. Launches an interactive terminal menu for CRUD operations.

Run:
	python3 main.py
"""

import sys

import mysql.connector

import crud
import db
from ui_helpers import (
	clear_hint,
	pause,
	print_table,
	prompt_attendance_status,
	prompt_date,
	prompt_guid,
	prompt_int,
	prompt_phone,
	prompt_str,
)


# ============================================================ GUARDIAN UI ==

def menu_guardians(conn):
	while True:
		clear_hint()
		print("GUARDIAN MANAGEMENT")
		print("  1. List all guardians")
		print("  2. View a guardian")
		print("  3. Add a guardian")
		print("  4. Update a guardian")
		print("  5. Delete a guardian")
		print("  0. Back to main menu")
		choice = input("\nChoice: ").strip()

		try:
			if choice == "1":
				print()
				print_table(crud.list_guardians(conn))
				pause()
			elif choice == "2":
				guid = prompt_guid()
				row = crud.get_guardian(conn, guid)
				print()
				print_table([row] if row else [])
				pause()
			elif choice == "3":
				add_guardian(conn)
			elif choice == "4":
				update_guardian(conn)
			elif choice == "5":
				delete_guardian(conn)
			elif choice == "0":
				return
			else:
				print("  Invalid choice.")
		except crud.CrudError as e:
			print(f"\n  [ERROR] {e}")
			pause()


def add_guardian(conn):
	print("\n-- Add Guardian --")
	guid = prompt_guid()
	gname = prompt_str("Guardian name", max_len=20)
	gphone = prompt_phone()
	gaddress = prompt_str("Guardian address", max_len=30)
	crud.create_guardian(conn, guid, gname, gphone, gaddress)
	print(f"  [OK] Guardian {guid} added.")
	pause()


def update_guardian(conn):
	print("\n-- Update Guardian --")
	guid = prompt_guid()
	existing = crud.get_guardian(conn, guid)
	if not existing:
		print("  No guardian found with that GUID.")
		pause()
		return
	print(f"  Current: {existing}")
	print("  (Press Enter to leave a field unchanged)")
	gname = prompt_str("New name", max_len=20, allow_blank_skip=True)
	gphone_raw = input("New phone (10 digits, blank = unchanged, 'clear' = remove): ").strip()
	gphone = existing["GPhone"]
	if gphone_raw.lower() == "clear":
		gphone = None
	elif gphone_raw:
		gphone = prompt_phone_validate(gphone_raw)
		if gphone is None:
			print("  Invalid phone — update aborted for that field.")
			gphone = existing["GPhone"]
	gaddress = prompt_str("New address", max_len=30, allow_blank_skip=True)

	crud.update_guardian(conn, guid, gname=gname, gphone=gphone, gaddress=gaddress)
	print("  [OK] Guardian updated.")
	pause()


def prompt_phone_validate(raw):
	import re
	return raw if re.match(r"^\d{10}$", raw) else None


def delete_guardian(conn):
	print("\n-- Delete Guardian --")
	guid = prompt_guid()
	confirm = input(f"  Type 'yes' to confirm deleting guardian {guid}: ").strip().lower()
	if confirm != "yes":
		print("  Cancelled.")
		pause()
		return
	rows = crud.delete_guardian(conn, guid)
	if rows:
		print("  [OK] Guardian deleted.")
	else:
		print("  No guardian found with that GUID.")
	pause()


# ============================================================= STUDENT UI ==

def menu_students(conn):
	while True:
		clear_hint()
		print("STUDENT MANAGEMENT")
		print("  1. List all students")
		print("  2. View a student")
		print("  3. Add a student")
		print("  4. Update a student")
		print("  5. Delete a student")
		print("  0. Back to main menu")
		choice = input("\nChoice: ").strip()

		try:
			if choice == "1":
				print()
				print_table(crud.list_students(conn))
				pause()
			elif choice == "2":
				roll = prompt_int("Roll number", max_digits=3)
				row = crud.get_student(conn, roll)
				print()
				print_table([row] if row else [])
				pause()
			elif choice == "3":
				add_student(conn)
			elif choice == "4":
				update_student(conn)
			elif choice == "5":
				delete_student(conn)
			elif choice == "0":
				return
			else:
				print("  Invalid choice.")
		except crud.CrudError as e:
			print(f"\n  [ERROR] {e}")
			pause()


def add_student(conn):
	print("\n-- Add Student --")
	roll = prompt_int("Roll number (max 3 digits)", max_digits=3)
	sname = prompt_str("Student name", max_len=20)
	dob = prompt_date("Date of birth")
	print("  (Guardian must already exist — add them first via Guardian Management if needed)")
	guid = prompt_guid()
	crud.create_student(conn, roll, sname, dob, guid)
	print(f"  [OK] Student {roll} added.")
	pause()


def update_student(conn):
	print("\n-- Update Student --")
	roll = prompt_int("Roll number", max_digits=3)
	existing = crud.get_student(conn, roll)
	if not existing:
		print("  No student found with that roll number.")
		pause()
		return
	print(f"  Current: {existing}")
	print("  (Press Enter to leave a field unchanged)")
	sname = prompt_str("New name", max_len=20, allow_blank_skip=True)
	dob = prompt_date("New date of birth", allow_blank_skip=True)
	guid = prompt_guid("New guardian GUID", allow_blank_skip=True)

	crud.update_student(conn, roll, sname=sname, sdateofbirth=dob, guid=guid)
	print("  [OK] Student updated.")
	pause()


def delete_student(conn):
	print("\n-- Delete Student --")
	roll = prompt_int("Roll number", max_digits=3)
	confirm = input(f"  Type 'yes' to confirm deleting student {roll} "
					 f"(also deletes their attendance records): ").strip().lower()
	if confirm != "yes":
		print("  Cancelled.")
		pause()
		return
	rows = crud.delete_student(conn, roll)
	if rows:
		print("  [OK] Student deleted.")
	else:
		print("  No student found with that roll number.")
	pause()


# =========================================================== ATTENDANCE UI ==

def menu_attendance(conn):
	while True:
		clear_hint()
		print("ATTENDANCE MANAGEMENT")
		print("  1. Mark / update attendance for a student")
		print("  2. View attendance by date")
		print("  3. View attendance history for a student")
		print("  4. Delete an attendance record")
		print("  0. Back to main menu")
		choice = input("\nChoice: ").strip()

		try:
			if choice == "1":
				mark_attendance(conn)
			elif choice == "2":
				d = prompt_date("Date")
				print()
				print_table(crud.list_attendance_by_date(conn, d))
				pause()
			elif choice == "3":
				roll = prompt_int("Roll number", max_digits=3)
				print()
				print_table(crud.list_attendance_by_student(conn, roll))
				pause()
			elif choice == "4":
				delete_attendance(conn)
			elif choice == "0":
				return
			else:
				print("  Invalid choice.")
		except crud.CrudError as e:
			print(f"\n  [ERROR] {e}")
			pause()


def mark_attendance(conn):
	print("\n-- Mark Attendance --")
	roll = prompt_int("Roll number", max_digits=3)
	if not crud.get_student(conn, roll):
		print("  No student found with that roll number.")
		pause()
		return
	d = prompt_date("Date")
	status = prompt_attendance_status()
	result = crud.mark_attendance(conn, d, roll, status)
	print(f"  [OK] Attendance {result} for student {roll} on {d}: {status}")
	pause()


def delete_attendance(conn):
	print("\n-- Delete Attendance Record --")
	roll = prompt_int("Roll number", max_digits=3)
	d = prompt_date("Date")
	confirm = input("  Type 'yes' to confirm: ").strip().lower()
	if confirm != "yes":
		print("  Cancelled.")
		pause()
		return
	rows = crud.delete_attendance(conn, d, roll)
	if rows:
		print("  [OK] Attendance record deleted.")
	else:
		print("  No matching attendance record found.")
	pause()


# ================================================================ MAIN ====

def main_menu(conn):
	while True:
		clear_hint()
		print("STUDENT MANAGEMENT SYSTEM")
		print("  1. Guardian management")
		print("  2. Student management")
		print("  3. Attendance management")
		print("  0. Exit")
		choice = input("\nChoice: ").strip()

		if choice == "1":
			menu_guardians(conn)
		elif choice == "2":
			menu_students(conn)
		elif choice == "3":
			menu_attendance(conn)
		elif choice == "0":
			print("\nGoodbye!")
			return
		else:
			print("  Invalid choice.")


def main():
	print("=" * 60)
	print(" STUDENT MANAGEMENT SYSTEM - Startup")
	print("=" * 60)

	conn = db.get_connection()

	print("\nAll checks passed. Starting application...\n")
	try:
		main_menu(conn)
	except KeyboardInterrupt:
		print("\n\nInterrupted. Exiting.")
	except mysql.connector.Error as e:
		print(f"\n[ERROR] Lost database connection: {e}")
		sys.exit(1)
	finally:
		conn.close()


if __name__ == "__main__":
	main()