import os
import re
import mimetypes
from os.path import isdir, abspath, exists, split
from flask import Flask, render_template, abort, send_file, safe_join
from PIL import Image
from jinja2 import contextfilter, FileSystemLoader

app = Flask('gallery')
app.config.from_pyfile('gallery.cfg')

app.jinja_loader = FileSystemLoader(app.config['TEMPLATE_DIR'])

picmime = re.compile(app.config['MIME'])
base = app.config['DIRECTORY']
thumb = app.config['THUMB_DIR']
thsize = app.config['THUMB_SIZE']

def is_image(path):
    return picmime.match(mimetypes.guess_type(path)[0] or 'NOPE')

def relurl(ctx, tgt):
    return safe_join(ctx['path'], tgt)

@app.template_filter('gallery')
@contextfilter
def url_gallery(ctx, tgt):
    return safe_join('/', relurl(ctx, tgt))

@app.template_filter('picture')
@contextfilter
def url_picture(ctx, tgt):
    return safe_join('/pictures', relurl(ctx, tgt))

@app.template_filter('thumb')
@contextfilter
def url_thumb(ctx, tgt):
    return safe_join('/thumb', relurl(ctx, tgt))

@app.route('/pictures/<path:tgt>')
def send_pic(tgt):
    path = safe_join(base, tgt)
    if is_image(path):
        return send_file(path)
    else:
        abort(403)

def ensure_dir(path):
    try:
        os.makedirs(split(path)[0])
    except OSError as e:
        if e.errno == 17:
            pass
        else:
            raise

@app.route('/thumb/<path:tgt>')
def send_thumb(tgt):
    orig_path = safe_join(base, tgt)
    if not is_image(orig_path):
        abort(403)
    thumb_path = safe_join(thumb, tgt)
    if not exists(thumb_path) or \
        os.stat(thumb_path).st_mtime < os.stat(orig_path).st_mtime:
        ensure_dir(thumb_path)
        image = Image.open(orig_path)
        sz = image.size
        scale = min(float(b) / a for a,b in zip(sz, thsize))
        scale = min(scale, 1)
        image.resize(list(map(int, (scale * sz[0], scale * sz[1]))), Image.ANTIALIAS).save(thumb_path)
    return send_file(thumb_path)

@app.route('/')
@app.route('/<path:tgt>')
def view(tgt=''):
    try:
        path = abspath(safe_join(base, tgt))
        names = [s for s in sorted(os.listdir(path))]
        dirs = [f for f in names if isdir(safe_join(path,f))]
        pics = list(filter(is_image, names))
        return render_template('main.html', dirs=dirs, pics=pics, path=tgt,
                parent = '/' + os.path.split(tgt)[0])
    except OSError as e:
        if e.errno == 2:
            abort(404)


if __name__ == '__main__':
    app.run('::', 8080, debug=True)