from flask import Flask, url_for, render_template, abort
import os
import json
from app.config import PANDOC_LINK, PANDOC_PATH, WHITELIST_PATH
from app.hash_manager import hash_file_sha512
import subprocess

app = Flask(__name__)


@app.context_processor
def override_url_for():
    return dict(url_for=dated_url_for)


#TODO: make instead of datetime hash of commit


def dated_url_for(endpoint, **values):
    if endpoint == 'static':
        filename = values.get('filename', None)
        if filename:
            file_path = os.path.join(app.root_path, endpoint, filename)
            values['q'] = int(os.stat(file_path).st_mtime)
    return url_for(endpoint, **values)


def render_page(page):
    path = f'{PANDOC_PATH}/{page}'
    whitelist = WHITELIST_PATH
    with open(whitelist, 'r') as f:
        if page not in f.readlines():
            raise Exception("Page doesn't exist!")
    if not os.path.exists(f'{path}'):
        raise Exception("Page doesn't exist!")
    in_filename = f'{path}/main.md'
    out_filename = f'{path}/render.html'
    os.system(f'pandoc {in_filename} --to html --mathjax --output {out_filename}')
    print('Creating lock file')
    os.system(f'echo {hash_file_sha512(in_filename)} > {out_filename}.lock')


@app.route(f'/{PANDOC_LINK}/<page>')
def get_pandoc_page(page):
    path = f'{PANDOC_PATH}/{page}'
    whitelist = WHITELIST_PATH
    with open(whitelist, 'r') as f:
        if page not in f.readlines():
            return 'This page does not exist'
    if not os.path.exists(f'{path}'):
        # TODO: Add 404 handler
        return 'This page does not exist'
    with open(f'{path}/config.json') as f:
        data = json.loads(f.read())
    if not os.path.exists(f'{path}/render.html') or not os.path.exists(f'{path}/render.html.lock'):
        print('Rendered page or lockfile for {page} does not exist! Rendering {page}')
        render_page(page)
    else:
        with open(f'{path}/render.html.lock', 'r') as f:
            rendered_hash = f.read().strip()
        current_hash = hash_file_sha512(f'{path}/main.md')
        if rendered_hash != current_hash:
            print(f'CURRENT: {current_hash}, RENDERED: {rendered_hash}')
            print('Integrity test failed, rendering {page}!')
            render_page(page)
    template = data['template']
    with open(f'{path}/render.html', 'r') as f:
        inserted = f.read()
    return render_template(template, markdown=inserted)


@app.route('/')
def index():
    return render_template('index.html')