#!/usr/bin/env python3

# TODO setup webserver user disk quota

import tempfile
import uuid
from functools import wraps
from os import path
import os
import sqlite3

from flask import Flask, url_for, redirect, session, make_response, render_template, request, send_file, abort, flash
from flask_wtf import FlaskForm
from flask_wtf.file import FileField, FileRequired
from wtforms.fields import RadioField
from wtforms.validators import DataRequired
from werkzeug.utils import secure_filename

from job_queue import JobQueue

app = Flask(__name__, static_url_path='/static')
app.config.from_envvar('GERBOWEB_SETTINGS')

class UploadForm(FlaskForm):
    upload_file = FileField(validators=[DataRequired()])

class OverlayForm(UploadForm):
    upload_file = FileField(validators=[FileRequired()])
    side = RadioField('Side', choices=[('top', 'Top'), ('bottom', 'Bottom')],
            default=lambda: session.get('side_selected', session.get('last_download')))

class ResetForm(FlaskForm):
    pass

job_queue = JobQueue(app.config['JOB_QUEUE_DB'])

def tempfile_path(namespace):
    """ Return a path for a per-session temporary file identified by the given namespace. Create the session tempfile
    dir if necessary. The application tempfile dir is controlled via the upload_path config value and not managed by
    this function. """
    if not path.isdir(app.config['UPLOAD_PATH']):
        os.mkdir(app.config['UPLOAD_PATH'])
    sess_tmp = path.join(app.config['UPLOAD_PATH'], session['session_id'])
    if not path.isdir(sess_tmp):
        os.mkdir(sess_tmp)

    return path.join(sess_tmp, namespace)

def require_session_id(fun):
    @wraps(fun)
    def wrapper(*args, **kwargs):
        if 'session_id' not in session:
            session['session_id'] = str(uuid.uuid4())
        return fun(*args, **kwargs)
    return wrapper

@app.route('/')
@require_session_id
def index():
    forms = {
            'gerber_form': UploadForm(),
            'overlay_form': OverlayForm(),
            'reset_form': ResetForm() }

    for job_type in ('vector_job', 'render_job'):
        if job_type in session:
            job = job_queue[session[job_type]]
            if job.finished:
                if job.result != 0:
                    flash(f'Error processing gerber files', 'success') # FIXME make this an error, add CSS
                del session[job_type]

    r = make_response(render_template('index.html',
            has_renders = path.isfile(tempfile_path('gerber.zip')),
            has_output = path.isfile(tempfile_path('overlay.png')),
             **forms))
    if 'vector_job' in session or 'render_job' in session:
        r.headers.set('refresh', '10')
    return r

# NOTES about the gerber and overlay file upload routines
#  * The maximum upload size is limited by the MAX_CONTENT_LENGTH config setting.
#  * The uploaded files are deleted after a while by systemd tmpfiles.d
# TODO: validate this setting applies *after* gzip transport compression

def vectorize():
    if 'vector_job' in session:
        job_queue[session['vector_job']].abort()
    session['vector_job'] = job_queue.enqueue('vector',
            client=request.remote_addr,
            session_id=session['session_id'],
            side=session['side_selected'])

def render():
    if 'render_job' in session:
        job_queue[session['render_job']].abort()
    session['render_job'] = job_queue.enqueue('render',
            session_id=session['session_id'],
            client=request.remote_addr)

@app.route('/upload/gerber', methods=['POST'])
@require_session_id
def upload_gerber():
    upload_form = UploadForm()
    if upload_form.validate_on_submit():
        f = upload_form.upload_file.data
        f.save(tempfile_path('gerber.zip'))
        session['filename'] = secure_filename(f.filename) # Cache filename for later download

        render()
        if path.isfile(tempfile_path('overlay.png')): # Re-vectorize when gerbers change
            vectorize()

        flash(f'Gerber file successfully uploaded.', 'success')
    return redirect(url_for('index'))

@app.route('/upload/overlay', methods=['POST'])
@require_session_id
def upload_overlay():
    upload_form = OverlayForm()
    if upload_form.validate_on_submit():
        # FIXME raise error when no side selected
        f = upload_form.upload_file.data
        f.save(tempfile_path('overlay.png'))
        session['side_selected'] = upload_form.side.data

        vectorize()

        flash(f'Overlay file successfully uploaded.', 'success')
    return redirect(url_for('index'))

@app.route('/render/preview/<side>')
def render_preview(side):
    if not side in ('top', 'bottom'):
        return abort(400, 'side must be either "top" or "bottom"')
    return send_file(tempfile_path(f'render_{side}.small.png'))

@app.route('/render/download/<side>')
def render_download(side):
    if not side in ('top', 'bottom'):
        return abort(400, 'side must be either "top" or "bottom"')

    session['last_download'] = side
    return send_file(tempfile_path(f'render_{side}.png'),
            mimetype='image/png',
            as_attachment=True,
            attachment_filename=f'{path.splitext(session["filename"])[0]}_render_{side}.png')

@app.route('/output/download')
def output_download():
    return send_file(tempfile_path('gerber_out.zip'),
            mimetype='application/zip',
            as_attachment=True,
            attachment_filename=f'{path.splitext(session["filename"])[0]}_with_artwork.zip')

@app.route('/session_reset', methods=['POST'])
@require_session_id
def session_reset():
    if 'render_job' in session:
        job_queue[session['render_job']].abort()
    if 'vector_job' in session:
        job_queue[session['vector_job']].abort()
    session.clear()
    flash('Session reset', 'success');
    return redirect(url_for('index'))