#!/usr/bin/env python3
"Creates a static site for redacted.life"

import argparse
from collections import UserList
from datetime import datetime
import json
import os
import os.path as path
import re
import subprocess
import shutil
import sys

import jinja2
import markdown
from mutagen.mp3 import MP3


def gen_name(date, slug):
    "Returns to file name"
    return date.strftime("%Y-%m-%d-") + slug


def seconds_to_str(seconds):
    "Convert seconds to a string of hh:mm:ss"
    seconds = int(seconds)
    return f"{seconds // 3600:02}:{(seconds % 3600) // 60:02}:{seconds % 60:02}"


class EpisodeList(UserList):
    "Represents list of episodes"
    def __init__(self, url, data, output, template, archives):
        super().__init__(data)
        self.url = url
        self.output = output
        self.template = template
        self.archives = archives

    def sort(self, *_args, **_kwargs):
        "Sorts the EpisodeList"
        super().sort(key=lambda x: x.date, reverse=False)

    def generate_thumbnails(self):
        "Generates thumbnails for all the videos"
        if not path.isdir(self.output + "assets"):
            os.mkdir(self.output + "assets")
        if not path.isdir(self.output + "assets/thumbnails"):
            os.mkdir(self.output + "assets/thumbnails")
        for episode in self.data:
            location = (self.output + "assets/thumbnails/" +
                        gen_name(episode.date, episode.slug) + ".jpg")
            episode.store_thumbnail(location)

    def generate_rss(self, header):
        "Generates the RSS Feed"
        with open(self.output + "feed_mp3.rss", "w") as mp3, \
                open(self.output + "feed_ogg.rss", "w") as ogg:
            # pylint: disable = invalid-name
            for s, ext in ((mp3, "mp3"), (ogg, "ogg")):
                s.write(header)
                for ep in self.data:
                    s.write("<item>")
                    s.write("\n")
                    # Title
                    s.write(f"<title><![CDATA[{ep.title}]]></title>")
                    s.write("\n")
                    # Description
                    s.write("<description><![CDATA["
                            f"{ep.config['description']}]]></description>")
                    s.write("\n")
                    # Date
                    datestring = ep.date.strftime(
                        '%a, %d %b, %Y %H:%M:%Sz GMT'
                    )
                    s.write(f"<pubDate>{datestring}</pubDate>")
                    s.write("\n")
                    # iTunes: explicit, author, subtitle, keywords
                    s.write(f"<itunes:explicit>{ep.config['explicit']}"
                            "</itunes:explicit>")
                    s.write("\n")
                    s.write(
                        f"<itunes:author><![CDATA[{ep.config['author']}]]>"
                        "</itunes:author>"
                    )
                    s.write("\n")
                    s.write(
                        "<itunes:subtitle><![CDATA["
                        f"{ep.config['subtitle']}]]></itunes:subtitle>"
                    )
                    s.write("\n")
                    s.write(
                        f"<itunes:keywords>{','.join(ep.config['tags'])}"
                        "</itunes:keywords>"
                    )
                    s.write("\n")
                    s.write(f"<itunes:duration>{seconds_to_str(len(ep))}"
                            "</itunes:duration>")
                    s.write("\n")
                    # Content (show_notes)
                    s.write(
                        f"<content:encoded><![CDATA[{ep.show_notes}]]>"
                        "</content:encoded>"
                    )
                    s.write("\n")
                    # GUID
                    s.write(
                        f"<guid isPermaLink=\"true\">{self.url}{ep.slug}"
                        ".html</guid>"
                    )
                    s.write("\n")
                    # Enclosure
                    audio = f'{self.url}assets/music/{ep.slug}.{ext}'
                    size = path.getsize(f"{ep.audio}.{ext}")
                    s.write(
                        f'<enclosure url="{audio}" type="audio/{ext}" '
                        f'length="{size}" />'
                    )
                    s.write("\n")
                    # Categories
                    for tag in ep.config["tags"]:
                        s.write(f"<category><![CDATA[{tag}]]></category>")
                        s.write("\n")
                    s.write("</item>")
                    s.write("\n")
                s.write("</channel>")
                s.write("\n")
                s.write("</rss>")

    def generate_archives(self):
        "Generates archives page"
        with open(self.output + "archives.html", "w") as file:
            episodes = [{
                "slug": gen_name(i.date, i.slug) + ".html",
                "title": i.title
            } for i in self.data[::-1]]
            file.write(self.archives.render(episodes=episodes,
                                            title="Archives"))

    def generate_site(self, root):
        "Generates the entire site"
        # Generate CSS from SCSS
        subprocess.run(["sass", "--update", f"{root}scss:{root}assets/css"],
                       check=True)
        # Copy the existing assets
        shutil.copytree(root + "assets", self.output + "assets",
                        dirs_exist_ok=True)
        # Create the required directories
        paths = [
            "assets",
            "assets/audio",
            "assets/videos",
        ]
        for directory in paths:
            if not path.isdir(self.output + directory):
                os.mkdir(self.output + directory)

        # Render episodes and copy data
        for episode in self.data:
            html = f"{self.output}{gen_name(episode.date, episode.slug)}.html"
            thumbnail = ("assets/thumbnails/" +
                         gen_name(episode.date, episode.slug) + ".jpg")
            video = (self.output + "assets/videos/" +
                     gen_name(episode.date, episode.slug) + ".mp4")
            audio = (self.output + "assets/audio/" +
                     gen_name(episode.date, episode.slug) + ".mp3")
            shutil.copy2(episode.video, video)
            shutil.copy2(episode.audio + ".mp3", audio)
            shutil.copy2(episode.audio + ".ogg", audio)
            with open(html, "w") as file:
                file.write(episode.render(self.template, thumbnail))

        last = self.data[-1]
        last_name = f"{self.output}{gen_name(last.date, last.slug)}.html"
        shutil.copy2(last_name, self.output + "index.html")


class Episode:
    "Represents one episode of podcast"
    def __init__(self, date, slug, title, show_notes, video_src, audio_src, config):
        self.date = date
        self.slug = slug
        self.title = title
        self.show_notes = markdown.markdown(show_notes)
        self.video = video_src
        self.audio = audio_src
        self.config = config
        self.length = MP3(audio_src + ".mp3").info.length

    def render(self, template, thumbnail_src):
        "Renders the Episode with the given template"
        return template.render(
            title=self.title,
            show_notes=jinja2.Markup(self.show_notes),
            thumbnail_src=thumbnail_src,
            video_src=f"assets/videos/{path.basename(self.video)}"
        )

    def store_thumbnail(self, location):
        "Stores the thumbnail for given image at path"
        args = ["ffmpeg", "-i", self.video, "-ss", "00:00:01.000", "-vframes",
                "1", location]
        subprocess.run(args, check=False)

    def __len__(self):
        return int(self.length)


def parse_args():
    "Parses arguments"
    parser = argparse.ArgumentParser()
    parser.add_argument("input_dir", help="Input directory")
    parser.add_argument("output_dir", help="Output directory")
    parser.add_argument("url", help="Base URL of website")
    args = parser.parse_args()
    input_dir = args.input_dir.rstrip("/") + "/"
    output_dir = args.output_dir.rstrip("/") + "/"
    url = args.url.rstrip("/") + "/"
    return input_dir, output_dir, url


class ParseError(ValueError):
    "Error raised while parsing a file"


def parse_file(file, array_keys=("tags")):
    "Parses a file"
    config = {}
    kv_re = re.compile(r"(?P<key>\w+):\s*(?P<value>.*)")
    while line := file.readline():
        if line.rstrip("\n") == "---":
            break
        if line.strip() == "":
            continue
        if match := kv_re.match(line):
            if match.group("key").strip().lower() in array_keys:
                config[match.group("key")] = [i.strip() for i in
                                              match.group("value").split(",")]
            else:
                config[match.group("key")] = match.group("value").strip()
        else:
            raise ParseError(f"Invalid line {line}")

    return (config, file.read())


def main(args):
    "Main method"
    root = path.dirname(sys.argv[0]).rstrip("/") + "/"
    input_dir, output_dir, url = args

    # Input validation
    paths = [
        input_dir,
        input_dir + "md",
        input_dir + "videos",
        input_dir + "audio",
    ]
    if not all(path.isdir((fail := i)) for i in paths):
        print(f"Invalid Input. {fail} is not a directory.", file=sys.stderr)
        return 1

    if not path.isdir(output_dir):
        os.mkdir(output_dir)

    env = jinja2.Environment(
        loader=jinja2.FileSystemLoader(root),
        autoescape=jinja2.select_autoescape("html")
    )

    podcast = EpisodeList(
        url,
        [],
        output_dir,
        env.get_template("index.html"),
        env.get_template("archives.html")
    )

    split = re.compile(r"((?P<date>\d{4}-[01]?\d-[0123]?\d)-(?P<slug>.*).md)")
    for file in os.listdir(input_dir + "md"):
        match = split.match(file)
        if not match:
            print(f"Invalid filename: {file}", file=sys.stderr)
            continue
        date = datetime.strptime(match.group("date"), "%Y-%M-%d")
        slug = match.group("slug")
        with open(input_dir + "md/" + file) as episode:
            try:
                config, show_notes = parse_file(episode)
            except ParseError as err:
                print(f"Error while parsing file: {file}")
                print(err)
                return 2
        podcast.append(
            Episode(
                date,
                slug,
                config["title"],
                show_notes,
                input_dir + "videos/" + gen_name(date, slug) + ".mp4",
                input_dir + "audio/" + gen_name(date, slug),
                config
            )
        )

    with open(input_dir + "subscribe.json") as subscribe, \
            open(output_dir + "subscribe.html", "w") as html:
        html.write(env.get_template("subscribe.html").render(
            subscribtions=json.load(subscribe)
        ))

    with open(input_dir + "donate.json") as donate, \
            open(output_dir + "donate.html", "w") as html:
        html.write(env.get_template("donate.html").render(
            donations=json.load(donate)
        ))

    podcast.sort()
    podcast.generate_thumbnails()
    podcast.generate_archives()
    with open(input_dir + "header.rss") as header:
        podcast.generate_rss(header.read())
    podcast.generate_site(root)
    shutil.copytree(input_dir + "overrides", output_dir, dirs_exist_ok=True)
    return 0


if __name__ == "__main__":
    sys.exit(main(parse_args()))