# Portions Copyright (c) Facebook, Inc. and its affiliates.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2.

# hgweb/wsgicgi.py - CGI->WSGI translator
#
# Copyright 2006 Eric Hopper <hopper@omnifarious.org>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
#
# This was originally copied from the public domain code at
# http://www.python.org/dev/peps/pep-0333/#the-server-gateway-side

from __future__ import absolute_import

from .. import encoding, util
from . import common


def launch(application):
    util.setbinary(util.stdin)
    util.setbinary(util.stdout)

    environ = dict(encoding.environ.items())
    environ.setdefault(r"PATH_INFO", "")
    if environ.get(r"SERVER_SOFTWARE", r"").startswith(r"Microsoft-IIS"):
        # IIS includes script_name in PATH_INFO
        scriptname = environ[r"SCRIPT_NAME"]
        if environ[r"PATH_INFO"].startswith(scriptname):
            environ[r"PATH_INFO"] = environ[r"PATH_INFO"][len(scriptname) :]

    stdin = util.stdin
    if environ.get(r"HTTP_EXPECT", r"").lower() == r"100-continue":
        stdin = common.continuereader(stdin, util.stdout.write)

    environ[r"wsgi.input"] = stdin
    environ[r"wsgi.errors"] = util.stderr
    environ[r"wsgi.version"] = (1, 0)
    environ[r"wsgi.multithread"] = False
    environ[r"wsgi.multiprocess"] = True
    environ[r"wsgi.run_once"] = True

    if environ.get(r"HTTPS", r"off").lower() in (r"on", r"1", r"yes"):
        environ[r"wsgi.url_scheme"] = r"https"
    else:
        environ[r"wsgi.url_scheme"] = r"http"

    headers_set = []
    headers_sent = []
    out = util.stdout

    def write(data):
        if not headers_set:
            raise AssertionError("write() before start_response()")

        elif not headers_sent:
            # Before the first output, send the stored headers
            status, response_headers = headers_sent[:] = headers_set
            out.write("Status: %s\r\n" % status)
            for header in response_headers:
                out.write("%s: %s\r\n" % header)
            out.write("\r\n")

        out.write(data)
        out.flush()

    def start_response(status, response_headers, exc_info=None):
        if exc_info:
            try:
                if headers_sent:
                    # Re-raise original exception if headers sent
                    raise exc_info[0](exc_info[1], exc_info[2])
            finally:
                exc_info = None  # avoid dangling circular ref
        elif headers_set:
            raise AssertionError("Headers already set!")

        headers_set[:] = [status, response_headers]
        return write

    content = application(environ, start_response)
    try:
        for chunk in content:
            write(chunk)
        if not headers_sent:
            write("")  # send headers now if body was empty
    finally:
        getattr(content, "close", lambda: None)()