#!/usr/bin/env python3

import os
import time
import sys
import requests
import json
import re

from lxml import etree

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

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

def usage_download():
    print("mangadex.py download <url> <download_dir>")
    print("examples:")
    print("  mangadex.py download \"https://mangadex.org/title/7139/one-punch-man\" /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):
    with requests.get(url, stream=True) as response:
        if not response.ok:
            return False
        with open(save_path, "wb") as file:
            for chunk in response.iter_content(chunk_size=8192):
                if chunk:
                    file.write(chunk)
    return True

def title_url_extract_manga_id(url):
    result = re.search("mangadex.org/title/([0-9]+)/", url)
    if result and len(result.groups()) > 0:
        return result.groups()[0]

# TODO: Support pagination. Currently only the n latest chapters are listed,
# but going through all pages might be too slow for large manga like naruto
def list_chapters(url, chapter_list_input):
    manga_id = title_url_extract_manga_id(url)
    if not manga_id:
        print("Failed to extract manga id from url: %s. Note: url is expected to be in this format: mangadex.org/title/<number>/..." % url)
        exit(2)

    response = requests.get(url)
    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)

    lang = "1" # english

    tree = etree.HTML(response.text)
    chapters = []
    prev_chapter_number = None
    for element in tree.xpath("//div[@data-manga-id='%s']" % manga_id):
        chapter_lang = element.attrib.get("data-lang")
        if chapter_lang != lang:
            continue
        chapter_id = element.attrib.get("data-id")
        chapter_url = "https://mangadex.org/chapter/%s" % chapter_id
        chapter_title = element.attrib.get("data-title") # optional
        chapter_number = element.attrib.get("data-chapter")
        if prev_chapter_number and chapter_number == prev_chapter_number:
            continue
        prev_chapter_number = chapter_number
        chapter_name = "Ch. %s" % chapter_number
        if chapter_title:
            chapter_name += " - %s" % chapter_title
        if chapter_title.lower().replace(" ", "") in seen_titles or chapter_url in seen_urls:
            break
        chapters.append({ "name": chapter_name, "url": chapter_url })
    print(json.dumps(chapters))

def chapter_url_extract_manga_id(url):
    result = re.search("mangadex.org/chapter/([0-9]+)", url)
    if result and len(result.groups()) > 0:
        return result.groups()[0]

def download_chapter(url, download_dir):
    request_url = url
    manga_id = chapter_url_extract_manga_id(url)
    if not manga_id:
        print("Failed to extract manga id from url: %s. Note: url is expected to be in this format: mangadex.org/chapter/<number>" % url)
        exit(2)

    url = "https://mangadex.org/api/?id=%s&server=null&type=chapter" % manga_id

    response = requests.get(url)
    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(request_url)

    img_number = 1
    json_response = response.json()
    status = json_response["status"]
    if status != "OK":
        print("Expected server response OK, got %s" % status)
        exit(2)

    chapter_hash = json_response["hash"]
    for image_name in json_response["page_array"]:
        image_url = "https://mangadex.org/data/%s/%s" % (chapter_hash, image_name)
        ext = image_url[image_url.rfind("."):]
        image_name = str(img_number) + ext
        image_path = os.path.join(download_dir, image_name)
        print("Downloading {} to {}".format(image_url, image_path))
        if not download_file(image_url, image_path):
            print("Failed to download image: %s" % image_url)
            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()