import boto3
import json
import uuid
import time
import hashlib
import urllib
from boto3.dynamodb.conditions import Key
from string import Template

dynamodb_client = boto3.client('dynamodb')

def lambda_handler(event, context):
  try:
    return run(event)
  except Exception as e:
    return page(repr(e))


def run(event):
  path = event.get('path', '')

  if path == '/':
    return main_handle(event)
  elif path == '/register':
    return page(template('register.html', {'title': 'Регистрация'}))
  elif path == '/registerHandle':
    return register_handle(event)
  elif path == '/login':
    return page(template('login.html', {'title': 'Вход'}))
  elif path == '/loginHandle':
    return login_handle(event)
  elif path == '/profile':
    return profile_handle(event)
  elif path == '/logout':
    return logout_handle(event)
  elif path == '/gifts':
    return gifts_handle(event)
  elif path == '/friends':
    return friends_handle(event)
  elif path == '/test':
    return page(repr(event))
  else:
    return page(template('404.html', {'title': 'Страница не найдена!'}))


def page(html='', status_code=200):
  return {
    'statusCode': status_code,
    'headers': {
      'Content-Type': 'text/html',
    },
    'body': html
  }


def with_cookie(response, cookie):
  response['headers']['Set-Cookie'] = str(cookie) + '; Path=/'
  return response


def get_html(page_name, params={}):
  html_top = read_file('html/header.html')
  html_mid = read_file('html/' + page_name)
  html_bot = read_file('html/footer.html')
  html = html_top + html_mid + html_bot
  return html


def template(page_name, params={}):
  s = get_html(page_name)
  if params:
    t = Template(s)
    s = t.safe_substitute(params)
  return s


def read_file(file_name):
  file = open(file_name,'r')
  html = file.read()
  file.close()
  return html


def redirect(url):
  return {
    'statusCode': 302,
    'headers': {
      'Location': url
    },
    'body': ''
  }


def register_handle(event):
  get_params = event.get('queryStringParameters')

  login = get_params.get('login')
  email = get_params.get('email')
  password = get_params.get('password')
  name = get_params.get('name')
  surname = get_params.get('surname')

  if login and email and password and name and surname:
    same_user = find_user(login)
    if same_user:
      return page(template('error.html', {
        'error': 'Такой логин уже занят.',
        'backLink': '<a href="/default/register">Вернуться назад</a>'
      }))
    else:
      response = dynamodb_client.put_item(
        TableName='users',
        Item={
          'login': {
            'S': login,
          },
          'email': {
            'S': email,
          },
          'password': {
            'S': hash_password(password),
          },
          'name': {
            'S': name,
          },
          'surname': {
            'S': surname,
          },
          'friends': {
            'L': [],
          },
          'wantedGifts': {
            'L': [],
          },
        }
      )
      auth_token = make_auth(login)
      return with_cookie(redirect('/default/gifts'), 'auth='+auth_token)
  else:
    return page(template('error.html', {
      'error': 'Введенные данные некорректны!',
      'backLink': '<a href="/default/register">Вернуться назад</a>'
    }))


def login_handle(event):
  get_params = event.get('queryStringParameters')

  login = get_params.get('login')
  password = get_params.get('password')

  auth_token = None

  if login and password:
    user = find_user(login)
    if user:
      real_password_hash = user.get('password').get('S')
      if real_password_hash == hash_password(password):
        auth_token = make_auth(login)

  if auth_token:
    return with_cookie(redirect('/default/profile'), 'auth='+auth_token)
  else:
    return page(template('error.html', {
      'error': 'Пользователь с такими данными не найден или данные введены неверно',
      'backLink': '<a href="/default/login">Вернуться назад</a>'
    }))


def make_auth(login):
  new_token = str(uuid.uuid4().hex)
  response = dynamodb_client.put_item(
    TableName='auths',
    Item={
      'token': {
        'S': new_token,
      },
      'login': {
        'S': login,
      },
      'login_time': {
        'S': str(time.time()),
      },
    }
  )
  return new_token


def find_user(login):
  response = dynamodb_client.get_item(
    TableName='users',
    Key={'login': {'S': login}}
  )
  item = response.get('Item')
  return item


def get_auth_token(event):
  auth_token = None
  headers = event.get('headers')
  cookie_header = headers.get('cookie')
  if (cookie_header):
    cookies = cookie_header.split('; ')
    for ck in cookies:
      ind = ck.index('=')
      ckName = ck[0:ind]
      ckVal = ck[ind+1:]
      if ckName == 'auth' and ckVal:
        auth_token = str(ckVal)
  return auth_token


def get_auth_user(event):
  auth_user = None
  auth_token = get_auth_token(event)
  if auth_token:
    response = dynamodb_client.get_item(
      TableName='auths',
      Key={'token': {'S': auth_token}}
    )
    item = response.get('Item')
    if item:
      auth_user = item.get('login').get('S')
  return auth_user


def profile_handle(event):
  login = get_auth_user(event)
  if not login:
    return redirect('/default/')

  get_params = event.get('queryStringParameters')
  userid = None
  if get_params:
    userid = get_params.get('id')

  if userid:
    user = find_user(userid)
    if not user:
      return redirect('/default/404')

    name = user.get('name').get('S')
    surname = user.get('surname').get('S')
    email = user.get('email').get('S')
    return page(template('other_profile.html', {
      'title': 'Профиль',
      'name': name,
      'surname': surname,
      'email': email,
      'login': userid,
    }))
  else:
    user = find_user(login)
    if not user:
      return redirect('/default/')

    name = user.get('name').get('S')
    surname = user.get('surname').get('S')
    email = user.get('email').get('S')
    friends_html = ''
    gifts_html = ''

    return page(template('my_profile.html', {
      'title': 'Профиль',
      'name': name,
      'surname': surname,
      'email': email,
      'login': login,
      'friends_html': friends_html,
      'gifts_html': gifts_html,
      'profile_url_encoded': urllib.parse.quote(make_profile_link(login)),
    }))


def make_profile_link(login):
  return 'https://adfx152135.execute-api.us-east-1.amazonaws.com/default/profile?id='+str(login)


def logout_handle(event):
  token = get_auth_token(event)
  if token:
    dynamodb_client.delete_item(
      TableName='auths',
      Key={'token': {'S': token}}
    )
  return with_cookie(redirect('/default/'), 'auth=')


def main_handle(event):
  login = get_auth_user(event)
  if login:
    return redirect('/default/profile')
  else:
    return page(template('index.html', {'title': 'Главная страница'}))


def md5(s):
  return hashlib.md5(s.encode('utf-8')).hexdigest()


def hash_password(passwd):
  s = passwd + '_z04a02b14c'
  hash = md5(s)
  return hash


def gifts_handle(event):
  return page(template('gifts.html'))


def friends_handle(event):
  return page('<h2>Friends</h2>')


def get_gifts(event):
  pass