import argparse
import json
import re
import sys
import time
from html.parser import HTMLParser

import requests


OWNER_HREF = re.compile(r"/(?:corporation|alliance)/(\d+)/?")
SYSTEM_AND_DATE = re.compile(r"/(\d+)/(\d+)/?$")


def get_hash(kill):
	"""
	Looks up and returns hash of the *kill* using Zkillboard's API.
	"""
	response = requests.get("https://zkillboard.com/api/killID/{}/".format(kill))
	response.raise_for_status()
	data = response.json()
	if len(data) > 1:
		raise ValueError()
	return data[0]["zkb"]["hash"]


class RelatedParser(HTMLParser):
	"""
	Reads kill IDs and teams from Zkillboard's related kills page.
	"""
	def __init__(self):
		super().__init__()
		self._team = 0
		self._kills = set()
		self._current = None

	def handle_starttag(self, tag, attrs):
		attrs = dict(attrs)

		if tag == "table" and attrs.get("id", "").lower() == "killlist":
			self._team += 1

		if tag == "tr" and attrs.get("class", "").lower() == "killlistrow" and self._team > 0:
			self._flush()
			killid = attrs.get("killid", "")
			self._current = (killid, self._team, None)

		if tag == "a" and self._team > 0 and self._current:
			match = OWNER_HREF.match(attrs.get("href", ""))
			if match:
				self._current = (*self._current[:2], match.group(1))
				self._flush()

	def _flush(self):
		if self._current and all(self._current):
			self._kills.add(self._current)
			self._current = None

	@property
	def kills(self):
		"""
		Returns all kills found by the parser along with their team and the ID of the victim.
		"""
		self._flush()
		return self._kills


def get_related_kills(url):
	response = requests.get(url)
	response.raise_for_status()
	page = response.text
	related = RelatedParser()
	related.feed(page)
	killmails = []
	teams = (set(), set())
	for kill, team, victim in related.kills:
		time.sleep(1.05)  # Zkillboard is very sensitive.
		killmails.append({"id": int(kill), "hash": get_hash(kill)})
		destination = teams[team - 1]
		destination.add(int(victim))
	return {"killmails": killmails, "teams": list(map(list, teams))}


def output_name(args):
	"""
	Generates name of the output file based on the CLI *args*.
	"""
	if args.output:
		return args.output
	match = SYSTEM_AND_DATE.search(args.url)
	if match:
		return "{}_{}.json".format(*match.groups())
	return "a.json"


def main():
	parser = argparse.ArgumentParser()
	parser.add_argument("url")
	parser.add_argument("-o", "--output")
	args = parser.parse_args()
	snapshot = get_related_kills(args.url)
	filename = output_name(args)
	with open(filename, "w") as fd:
		fd.write(json.dumps(snapshot))
		fd.write("\n")


if __name__ == "__main__":
	main()