#!/usr/bin/env python3

import os
import time
import sys
import requests
import json

from lxml import etree

headers = {
    'User-Agent': "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.163 Safari/537.36"
}

def usage():
    print("mangatown.py command")
    print("commands:")
    print("  download")
    print("  list")
    exit(1)

def usage_list():
    print("mangatown.py list <url>")
    exit(1)

def usage_download():
    print("mangatown.py download <url> <download_dir>")
    print("examples:")
    print("  mangatown.py download \"https://www.mangatown.com/manga/naruto/v63/c700.2/\" /home/adam/Manga/MangaName")
    print("")
    print("Note: The manga directory has to exist.")
    exit(1)

if len(sys.argv) < 2:
    usage()

def download_file(url, save_path):
    file_size = 0
    with requests.get(url, headers=headers, stream=True) as response:
        if not response.ok:
            return 0
        with open(save_path, "wb") as file:
            for chunk in response.iter_content(chunk_size=8192):
                if chunk:
                    file.write(chunk)
                    file_size += len(chunk)
    return file_size

def list_chapters(url, chapter_list_input):
    response = requests.get(url, headers=headers)
    if response.status_code != 200:
        print("Failed to list chapters, server responded with status code %d" % response.status_code)
        exit(2)

    seen_titles = set()
    for item in chapter_list_input:
        title = item.get("title")
        if title and len(title) > 0:
            seen_titles.add(title.lower().replace(" ", ""))

    seen_urls = set()
    for item in chapter_list_input:
        url = item.get("url")
        if url and len(url) > 0:
            seen_urls.add(url)

    tree = etree.HTML(response.text)
    chapters = []
    for element in tree.xpath('//ul[@class="chapter_list"]//a'):
        element_text = element.text.strip()
        url = element.attrib.get("href").strip()
        if "/manga/" not in url:
            continue
        url = "https://www.mangatown.com" + url
        if element_text.lower().replace(" ", "") in seen_titles or url in seen_urls:
            break
        chapters.append({ "name": element_text, "url": url })
    print(json.dumps(chapters))

def is_only_num(s):
    for c in s:
        if c < '0' or c > '9':
            return False
    return True

def download_chapter(url, download_dir):
    response = requests.get(url, headers=headers)
    if response.status_code != 200:
        print("Failed to list chapter images, server responded with status code %d" % response.status_code)
        exit(2)

    in_progress_filepath = os.path.join(download_dir, ".in_progress")
    with open(in_progress_filepath, "w") as file:
        file.write(url)

    img_number = 1
    while True:
        full_url = url + str(img_number) + ".html"
        response = requests.get(full_url, headers=headers)
        if response.status_code != 200:
            break

        tree = etree.HTML(response.text)
        for image_source in tree.xpath('//div[@id="viewer"]//img/@src'):
            if "/store/manga/" not in image_source:
                continue
            if len(image_source) >= 2:
                image_source = image_source[2:]
            image_source = "https://" + image_source
            image_name = str(img_number) + ".jpg"
            image_path = os.path.join(download_dir, image_name)
            print("Downloading {} to {}".format(image_source, image_path))
            if not download_file(image_source, image_path):
                print("Failed to download image: %s" % image_source)
                os.remove(in_progress_filepath)
                exit(2)
            img_number += 1
    
    if img_number == 1:
        print("Failed to find images for chapter")
        os.remove(in_progress_filepath)
        exit(2)

    with open(os.path.join(download_dir, ".finished"), "w") as file:
        file.write("1")

    os.remove(in_progress_filepath)

command = sys.argv[1]
if command == "list":
    if len(sys.argv) < 3:
        usage_list()
    
    url = sys.argv[2]
    chapter_list_input = sys.stdin.read()
    if len(chapter_list_input) == 0:
        chapter_list_input = []
    else:
        chapter_list_input = json.loads(chapter_list_input)
    list_chapters(url, chapter_list_input)
elif command == "download":
    if len(sys.argv) < 4:
        usage_download()
    url = sys.argv[2]
    download_dir = sys.argv[3]
    download_chapter(url, download_dir)
else:
    usage()