# Copyright Sage Vaillancourt 2021

import json
import os
import subprocess
import threading
import urllib.parse

from flask import Blueprint, render_template, request, make_response, session, redirect, jsonify, Response, current_app
from wtforms import Form, SelectField, StringField, TextAreaField, validators
from email_validator import validate_email, EmailNotValidError

from app import db, email
from app.pdf_builder import CLData

writing_blueprint = Blueprint('writing', __name__)


class CLForm(Form):
    def __init__(self, form: dict[str, str] = None, email_address: str = None, **kwargs):
        super().__init__(form, **kwargs)
        if email_address:
            user = db.get_user(email_address)
            letters = db.get_user_letters(user.id)
            self.letterName.choices = letter_choices(letters)

    letterName = SelectField(
        'Select Template:',
        [validators.optional()],
        choices=[(1, 'LETTER TITLE')]
    )

    username = StringField(
        'Your Name:',
        [validators.Length(min=4, max=99)],
        default="Sage"
    )
    company = StringField(
        'Company:',
        [validators.Length(min=2, max=99)],
        default="BananaCorp"
    )
    jobAndPronoun = StringField(
        'Job and Pronoun (a/an):',
        [validators.Length(min=4, max=99)],
        default="a banana stocker"
    )
    skillTypes = StringField(
        'Skill Type:',
        [validators.Length(min=2, max=99)],
        default="practical"
    )
    mySkills = StringField(
        'My Skills:',
        [validators.Length(min=2, max=99)],
        default="stocking bananas"
    )

    closingText = TextAreaField(
        'Closing Text:',
        [validators.Length(min=2, max=99)],
        default="I look forward to hearing from you"
    )

    body = TextAreaField(
        'Body:',
        [validators.Length(min=4, max=9999)],
        default=(
            "My name is {\\username}. I'm excited for the opportunity to work as "
            "{\\jobAndPronoun} with your company.  I think with my {\\skillTypes} knowledge "
            "of {\\mySkills}, there's a lot I could contribute to your team.\n\n"

            "I am passionate about what I do, and I believe we would work well together.\n\n"

            "Thank you for your consideration."
        )
    )

    def to_cl_data(self) -> CLData:
        return CLData(
            selectedLetter=int(self.letterName.data or '1') - 1,
            username=self.username.data,
            company=self.company.data,
            jobAndPronoun=self.jobAndPronoun.data,
            skillTypes=self.skillTypes.data,
            mySkills=self.mySkills.data,
            closingText=self.closingText.data,
            body=self.body.data,
        )


def render_index(
        form: CLForm = CLForm(),
        error: str = None,
        status: int = 200,
        letter_errors: list[str] = None
) -> Response:
    return make_response(
        render_template(
            'writing.jinja2',
            form=form,
            username=session.get('username'),
            error=error,
            letter_errors=letter_errors,
        ), status)


@writing_blueprint.route('/login', methods=['POST'])
def login() -> Response | str:
    username = request.form['login']
    if db.login(username, request.form['password']):
        session['username'] = username
        return redirect('/')

    return render_index(error="Invalid username or password", status=401)


@writing_blueprint.route('/test_error', methods=['GET'])
def error_test() -> Response:
    raise Exception("Test error")


@writing_blueprint.route('/create_account', methods=['GET'])
def create_account_redirect() -> Response:
    return redirect('/')


@writing_blueprint.route('/create_account', methods=['POST'])
def create_account() -> Response:
    email_address = request.form['login']
    password = request.form['password']

    if password != request.form['confirm-password']:
        return render_index(error="Passwords did not match!", status=400)
    password_len = len(password)
    if password_len < 8 or password_len > 64:
        return render_index(error="Password must be between 8 and 64 characters", status=400)

    try:
        validate_email(email_address, check_deliverability=True)
    except EmailNotValidError as e:
        return render_index(error=str(e), status=400)

    if db.get_user(email_address):
        return render_index(error="A user with that email already exists!", status=400)

    db.add_user(email_address, password)
    session['username'] = email_address
    return redirect('/')


@writing_blueprint.route('/logout', methods=['POST', 'GET'])
def logout() -> Response:
    session.pop('username', None)
    return redirect('/')


FREE_TIER_TEMPLATES = 2


@writing_blueprint.route('/add_letter')
def add_letter() -> Response:
    email_address = session.get('username')
    if not email_address:
        return render_index()
    user = db.get_user(email_address)

    existing_letter_count = len(db.get_user_letters(user.id))
    if user.in_free_tier() and existing_letter_count >= FREE_TIER_TEMPLATES:
        return redirect('/?error=template_limit')
    new_letter_name = f'Letter{existing_letter_count + 1}'
    default_form_json = jsonify(CLForm().to_cl_data()).get_data(True)
    db.add_letter(user.id, new_letter_name, default_form_json)
    return redirect(f'/?letter_name={new_letter_name}')


def letter_choices(letters: list[db.Letter]) -> list[(int, str)]:
    return [(i + 1, letter.title) for i, letter in enumerate(letters)]


@writing_blueprint.route('/', methods=['GET'])
def index_get() -> Response:
    email_address = session.get('username')
    if not email_address:
        return render_index()

    form = CLForm()
    user = db.get_user(email_address)
    letters = db.get_user_letters(user.id)
    letter_names = letter_choices(letters)
    if len(letter_names) == 0:
        return render_index()
    form.letterName.choices = letter_names

    form.letterName.data = 1
    selected_letter = request.args.get('letter_name')
    error = None
    if request.args.get('error') == 'template_limit':
        error = f'A maximum of {FREE_TIER_TEMPLATES} templates are available to each user.'

    if selected_letter:
        for i, letter in enumerate(letters):
            if letter.title == selected_letter:
                form.letterName.data = i + 1
                break

    # TODO: Load this data more dynamically
    # I.e. use a dictionary instead of explicitly-defined fields
    data = json.loads(letters[form.letterName.data - 1].contents)

    # Ensures default value is set
    form.letterName.process_data(form.letterName.data)

    form.company.data = data['company']
    form.body.data = data['body']
    form.closingText.data = data['closingText']
    form.jobAndPronoun.data = data['jobAndPronoun']
    form.mySkills.data = data['mySkills']
    form.skillTypes.data = data['skillTypes']
    form.username.data = data['username']

    return render_index(form=form, error=error)


@writing_blueprint.route('/reset', methods=['POST', 'GET'])
def reset_password() -> Response | str:
    if request.method == 'POST':
        email_address = request.form.get('login')
        existing_reset_id = request.form.get('reset_id')
        if email_address:
            reset_id = db.initiate_password_reset(email_address)
            if reset_id:
                if not email.send_password_reset(email_address, 'https://undercover.cafe/reset?id=' + str(reset_id)):
                    return render_index(error="Failed to send reset email. Please try again later.", status=500)
        elif existing_reset_id:
            new_password = request.form['password']
            if not db.complete_reset(existing_reset_id, new_password):
                return render_index(error="Password reset failed. Your reset link may have expired.", status=500)
            # TODO: Log in?

        return redirect('/')

    query_reset_id = request.args.get('id')
    # TODO: Add password validation
    return f'''
        <form formaction="/reset" method="post">
            <p><input type=hidden name=reset_id value="{query_reset_id}"></p>
            <label>New Password:</label>
            <p><input type=password name=password></p>
            <p><input type=submit value="Save Password"></p>
        </form>
    '''


@writing_blueprint.route('/dbtest', methods=['GET'])
def db_test_get() -> Response:
    response = make_response(db.get_user_letters(1)[0].contents, 200)
    response.mimetype = "text/plain"
    return response


@writing_blueprint.route('/update', methods=['POST'])
def update_get() -> Response:
    expected_token = os.environ['GITLAB_HOOK_TOKEN']
    given_token = request.headers['X-Gitlab-Token']
    event_type = request.headers['X-Gitlab-Event']

    if expected_token == given_token and event_type == "Push Hook":
        print("Update notification received.")
        response = make_response("", 200)
        response.mimetype = "text/plain"
        threading.Timer(5, git_update, []).start()
        return response
    else:
        return make_response("", 404)


def git_update() -> None:
    script = os.environ['UPDATE_SCRIPT_PATH']
    if not script:
        return
    subprocess.Popen(['bash', '-c', "test -f " + script + " && " + script])


@writing_blueprint.route('/status', methods=['GET'])
def status_page() -> Response:
    status_message = f"Currently running on '{os.environ.get('UNDERCOVER_SERVER_NAME')}' server"
    git_commands = 'git log -1 --pretty=%B; git rev-parse --short HEAD'
    current_git_hash = subprocess.check_output([git_commands], shell=True, universal_newlines=True)
    return make_response(render_template('error.jinja2', status=200, error_text=status_message, extra_text='Latest commit: ' + current_git_hash), 200)


@writing_blueprint.route('/', methods=['POST'])
def generate_pdf() -> Response:
    email_address = session.get('username')
    form = CLForm(request.form, email_address=email_address)
    if not form.validate():
        return render_index(form=form)

    data = form.to_cl_data()

    if email_address:
        user = db.get_user(email_address)
        letters = db.get_user_letters(user.id)
        letter_json = jsonify(data).get_data(True)
        if len(letters) == 0:
            db.add_letter(user.id, 'Letter1', letter_json)
        else:
            letter = letters[data.selectedLetter]
            # TODO: Support title editing
            db.edit_letter(letter.id, letter.title, letter_json)

    try:
        resp = data.generate_pdf()
    except ValueError as e:
        resp = render_index(form=form, letter_errors=e.args[0])

    # Save entered data as cookies on user's machine
    for pair in data.get_pairs():
        resp.set_cookie(pair[0], urllib.parse.quote(pair[1]))

    return resp