import secrets, jwt
from datetime import datetime, timedelta, timezone

from flask import Blueprint, request, jsonify, current_app
from flask_mail import Mail, Message
from tinydb import Query

from api.error_codes import MISSING_FIELDS, EMAIL_EXISTS, MISSING_TOKEN, INVALID_TOKEN, TOKEN_TIMESTAMP_MISSING, \
    TOKEN_EXPIRED, ALREADY_VERIFIED, MISSING_EMAIL, USER_NOT_FOUND, MISSING_EMAIL_OR_PASSWORD, INVALID_CREDENTIALS, \
    NOT_VERIFIED
from db.db import users_db

auth_api = Blueprint('auth_api', __name__)
UserQuery = Query()
mail = Mail()
TOKEN_EXPIRY_MINUTES = 60*4

SECRET_KEY = "your-secret-key"  # Use a secure key in production
#SECRET_KEY = os.environ.get('SECRET_KEY')

def send_verification_email(to_email, token):
    verify_url = f"{current_app.config['FRONTEND_URL']}/auth/verify?token={token}"
    msg = Message(
        subject="Verify your account",
        recipients=[to_email],
        body=f"Click to verify your account: {verify_url}",
        sender=current_app.config['MAIL_DEFAULT_SENDER']
    )
    mail.send(msg)

@auth_api.route('/signup', methods=['POST'])
def signup():
    data = request.get_json()
    required_fields = ['first_name', 'last_name', 'email', 'password']
    if not all(field in data for field in required_fields):
        return jsonify({'error': 'Missing required fields', 'code': MISSING_FIELDS}), 400

    if users_db.search(UserQuery.email == data['email']):
        return jsonify({'error': 'Email already exists', 'code': EMAIL_EXISTS}), 400

    token = secrets.token_urlsafe(32)
    now_iso = datetime.utcnow().isoformat()
    users_db.insert({
        'first_name': data['first_name'],
        'last_name': data['last_name'],
        'email': data['email'],
        'password': data['password'],  # Hash in production!
        'verified': False,
        'verify_token': token,
        'verify_token_created': now_iso
    })
    send_verification_email(data['email'], token)
    return jsonify({'message': 'User created, verification email sent'}), 201

@auth_api.route('/verify', methods=['GET'])
def verify():
    token = request.args.get('token')
    status = 'success'
    reason = ''
    code = ''

    if not token:
        status = 'error'
        reason = 'Missing token'
        code = MISSING_TOKEN
    else:
        user = users_db.get(Query().verify_token == token)
        if not user:
            status = 'error'
            reason = 'Invalid token'
            code = INVALID_TOKEN
        else:
            created_str = user.get('verify_token_created')
            if not created_str:
                status = 'error'
                reason = 'Token timestamp missing'
                code = TOKEN_TIMESTAMP_MISSING
            else:
                created_dt = datetime.fromisoformat(created_str).replace(tzinfo=timezone.utc)
                if datetime.now(timezone.utc) - created_dt > timedelta(minutes=TOKEN_EXPIRY_MINUTES):
                    status = 'error'
                    reason = 'Token expired'
                    code = TOKEN_EXPIRED
                else:
                    users_db.update({'verified': True, 'verify_token': None, 'verify_token_created': None}, Query().verify_token == token)

    http_status = 200 if status == 'success' else 400
    return jsonify({'status': status, 'reason': reason, 'code': code}), http_status

@auth_api.route('/resend-verify', methods=['POST'])
def resend_verify():
    data = request.get_json()
    email = data.get('email')
    if not email:
        return jsonify({'error': 'Missing email', 'code': MISSING_EMAIL}), 400

    user = users_db.get(UserQuery.email == email)
    if not user:
        return jsonify({'error': 'User not found', 'code': USER_NOT_FOUND}), 404

    if user.get('verified'):
        return jsonify({'error': 'Account already verified', 'code': ALREADY_VERIFIED}), 400

    token = secrets.token_urlsafe(32)
    now_iso = datetime.utcnow().isoformat()
    users_db.update({
        'verify_token': token,
        'verify_token_created': now_iso
    }, UserQuery.email == email)
    send_verification_email(email, token)
    return jsonify({'message': 'Verification email resent'}), 200


@auth_api.route('/login', methods=['POST'])
def login():
    data = request.get_json()
    email = data.get('email')
    password = data.get('password')
    if not email or not password:
        return jsonify({'error': 'Missing email or password', 'code': MISSING_EMAIL_OR_PASSWORD}), 400

    user = users_db.get(UserQuery.email == email)
    if not user or user.get('password') != password:
        return jsonify({'error': 'Invalid credentials', 'code': INVALID_CREDENTIALS}), 401

    if not user.get('verified'):
        return jsonify({'error': 'This account has not verified', 'code': NOT_VERIFIED}), 403

    payload = {
        'email': email,
        'exp': datetime.utcnow() + timedelta(hours=24*7)
    }
    token = jwt.encode(payload, SECRET_KEY, algorithm='HS256')

    resp = jsonify({'message': 'Login successful'})
    resp.set_cookie('token', token, httponly=True, secure=True, samesite='Strict')
    return resp, 200

@auth_api.route('/me', methods=['GET'])
def me():
    token = request.cookies.get('token')
    if not token:
        return jsonify({'error': 'Missing token', 'code': MISSING_TOKEN}), 401

    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=['HS256'])
        email = payload.get('email')
        user = users_db.get(UserQuery.email == email)
        if not user:
            return jsonify({'error': 'User not found', 'code': USER_NOT_FOUND}), 404
        return jsonify({
            'email': user['email'],
            'first_name': user['first_name'],
            'last_name': user['last_name'],
            'verified': user['verified']
        }), 200
    except jwt.ExpiredSignatureError:
        return jsonify({'error': 'Token expired', 'code': TOKEN_EXPIRED}), 401
    except jwt.InvalidTokenError:
        return jsonify({'error': 'Invalid token', 'code': INVALID_TOKEN}), 401

@auth_api.route('/logout', methods=['POST'])
def logout():
    resp = jsonify({'message': 'Logged out'})
    resp.set_cookie('token', '', expires=0, httponly=True, secure=True, samesite='Strict')
    return resp, 200