#!/usr/bin/env python3
import asyncio
import collections
import http.client
import json
import re
import shlex
import socket
import sys
import time


HOST = 'web.archive.org'


def make_connection():
	return http.client.HTTPSConnection(HOST, timeout = 60)


def fetch(url, tries, connection):
	for i in range(tries):
		try:
			print(f'GET {url}', file = sys.stderr)
			connection.request('GET', url)
			r = connection.getresponse()
			status = r.status
			print(f'{status} {url}', file = sys.stderr)
			if status == 302 and r.getheader('Location') in ('https://web.archive.org/429.html', '/429.html'):
				# The CDX API is (was?) stupid and doesn't return 429s directly...
				status = 429
			if status == 429:
				print('Exceeded rate limit, waiting...', file = sys.stderr)
				time.sleep(30)
				raise RuntimeError(f'Rate-limited on {url}')
			if status != 200:
				raise RuntimeError(f'Could not fetch {url}')
			data = r.read()
			print(f'Read {len(data)} bytes from {url}', file = sys.stderr)
			o = json.loads(data)
			break
		except (RuntimeError, TimeoutError, socket.timeout, ConnectionError, http.client.HTTPException, json.JSONDecodeError) as e:
			# socket.timeout is an alias of TimeoutError from Python 3.10 but still needs to be caught explicitly for older versions
			print(f'Error retrieving {url}: {type(e).__module__}.{type(e).__name__} {e!s}', file = sys.stderr)
			connection.close()
			connection = make_connection()
			if i == tries - 1:
				raise
	return url, status, o, connection


async def wait_first_and_print(tasks):
	if not tasks:
		return
	task = tasks.popleft()
	url, code, o, connection = await task
	if not o:
		print(f'Completed processing page {task._ia_cdx_page} (0 results)', file = sys.stderr)
		return task._ia_cdx_page, connection
	fields = o[0]
	assert all(len(v) == len(fields) for v in o[1:]), 'got unexpected response format'
	for row in o[1:]:
		print(json.dumps(dict(zip(fields, row))))
	print(f'Completed processing page {task._ia_cdx_page} ({len(o) - 1} results)', file = sys.stderr)
	return task._ia_cdx_page, connection


async def main(query, concurrency = 1, tries = 1, startPage = None, numPages = None):
	assert (startPage is None) == (numPages is None)
	connections = collections.deque()
	for i in range(concurrency):
		connections.append(make_connection())
	baseUrl = f'/cdx/search/cdx?{query}'
	if startPage is None:
		url = f'{baseUrl}&showNumPages=true'
		connection = connections.popleft()
		_, _, numPages, connection = fetch(url, tries, connection)
		numPages = int(numPages)
		connections.append(connection)
		startPage = 0
		print(f'{numPages} pages', file = sys.stderr)

	loop = asyncio.get_running_loop()
	tasks = collections.deque()
	lastGoodPage = -1
	try:
		try:
			for page in range(startPage, numPages):
				while len(tasks) >= concurrency:
					lastGoodPage, connection = await wait_first_and_print(tasks)
					connections.append(connection)
				url = f'{baseUrl}&output=json&page={page}'
				connection = connections.popleft()
				task = loop.run_in_executor(None, fetch, url, tries, connection)
				task._ia_cdx_page = page
				tasks.append(task)
			while len(tasks) > 0:
				lastGoodPage, connection = await wait_first_and_print(tasks)
				connections.append(connection)
		except:
			# It isn't possible to actually cancel a task running in a thread, so need to await them and discard any additional errors that occur.
			for task in tasks:
				try:
					_, _, _, connection = await task
				except:
					pass
				else:
					connections.append(connection)
			for connection in connections:
				connection.close()
			raise
	except (RuntimeError, json.JSONDecodeError, AssertionError):
		concurrencyS = f'--concurrency {concurrency} ' if concurrency != 1 else ''
		triesS = f'--tries {tries} ' if tries != 1 else ''
		print(f'To resume this search from where it crashed, run: ia-cdx-search {concurrencyS}{triesS}--page {lastGoodPage + 1} --numpages {numPages} {shlex.quote(query)}', file = sys.stderr)
		raise
	except (BrokenPipeError, KeyboardInterrupt):
		pass


def usage():
	print('Usage: ia-cdx-search [--concurrency N] [--tries N] [--page N --numpages N] QUERY', file = sys.stderr)
	print('Please refer to https://github.com/internetarchive/wayback/tree/master/wayback-cdx-server for the relevant query parameters', file = sys.stderr)
	print('The output, limit, resumeKey, showResumeKey, page, and showNumPages parameters must not be included.', file = sys.stderr)
	print('To resume a search that failed for some reason, provide the page number and number of pages through the second argument instead.', file = sys.stderr)
	print('Output is produces in JSONL format with one line per CDX entry.', file = sys.stderr)
	print('', file = sys.stderr)
	print('Examples:', file = sys.stderr)
	print(" - Subdomains: ia-cdx-search 'url=example.org&collapse=urlkey&fl=original&matchType=domain&filter=original:^https?://[^/]*example\.org(?::[0-9]*)?/'", file = sys.stderr)
	print('   Note that this will only find subdomains whose homepages are in the Wayback Machine. To discover all known subdomains, remove the filter and then extract the domains from the results.', file = sys.stderr)
	print(" - Subdirectories: ia-cdex-search 'url=example.org&collapse=urlkey&fl=original&matchType=domain&filter=original:^https?://[^/]*example\.org(?::[0-9]*)?/[^/]*/'", file = sys.stderr)
	print('   The same caveat applies. The directory must have been retrieved directly without an additional trailing path or query string.', file = sys.stderr)
	sys.exit(1)


args = sys.argv[1:]
if not args or args[0].lower() in ('-h', '--help'):
	usage()
kwargs = {}
while args[0].startswith('--'):
	if args[0] == '--concurrency':
		kwargs['concurrency'] = int(args[1])
		args = args[2:]
	elif args[0] == '--tries':
		kwargs['tries'] = int(args[1])
		args = args[2:]
	elif args[0] == '--page' and args[2].lower() == '--numpages':
		kwargs['startPage'] = int(args[1])
		kwargs['numPages'] = int(args[3])
		args = args[4:]
	else:
		break
if len(args) != 1 or re.search(r'(^|&)(output|limit|resumekey|showresumekey|page|shownumpages)=', args[0], re.IGNORECASE):
	usage()
query = args[0]
asyncio.run(main(query, **kwargs))