#!/usr/bin/env python3

#!/usr/bin/env python3
"""
Host application of the browser extension PassFF
that wraps around the zx2c4 pass script.
"""

import json
import os
import re
import shlex
import struct
import subprocess
import sys

VERSION = "1.2.4"

###############################################################################
######################## Begin preferences section ############################
###############################################################################
COMMAND = "pass"
COMMAND_ARGS = []
COMMAND_ENV = {
"TREE_CHARSET": "ISO-8859-1",
"PATH": "/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin",
}
CHARSET = "UTF-8"

###############################################################################
######################### End preferences section #############################
###############################################################################

def getMessage():
""" Read a message from stdin and decode it. """
rawLength = sys.stdin.buffer.read(4)
if len(rawLength) == 0:
sys.exit(0)
messageLength = struct.unpack('@I', rawLength)[0]
message = sys.stdin.buffer.read(messageLength).decode("utf-8")
return json.loads(message)

def encodeMessage(messageContent):
""" Encode a message for transmission, given its content. """
encodedContent = json.dumps(messageContent)
encodedLength = struct.pack('@I', len(encodedContent))
return {'length': encodedLength, 'content': encodedContent}

def sendMessage(encodedMessage):
""" Send an encoded message to stdout. """
sys.stdout.buffer.write(encodedMessage['length'])
sys.stdout.write(encodedMessage['content'])
sys.stdout.flush()

def setPassGpgOpts(env, opts_dict):
""" Add arguments to PASSWORD_STORE_GPG_OPTS. """
opts = env.get('PASSWORD_STORE_GPG_OPTS', '')
for opt, value in opts_dict.items():
re_opt = new_opt = opt
if value is not None:
re_opt = rf"{opt}(?:=|\s+)\S*"
new_opt = (
f"{opt}={shlex.quote(value)}"
if opt.startswith("--") else
f"{opt} {shlex.quote(value)}"
)
# If the user's environment sets this opt, remove it.
opts = re.sub(re_opt, '', opts)
opts = f"{new_opt} {opts}"
env['PASSWORD_STORE_GPG_OPTS'] = opts.strip()

if __name__ == "__main__":
# Read message from standard input
receivedMessage = getMessage()
opt_args = []
pos_args = []
std_input = None

if len(receivedMessage) == 0:
opt_args = ["show"]
pos_args = ["/"]
elif receivedMessage[0] == "insert":
opt_args = ["insert", "-m"]
pos_args = [receivedMessage[1]]
std_input = receivedMessage[2]
elif receivedMessage[0] == "generate":
opt_args = ["generate"]
pos_args = [receivedMessage[1], receivedMessage[2]]
if "-n" in receivedMessage[3:]:
opt_args.append("-n")
elif receivedMessage[0] == "grepMetaUrls" and len(receivedMessage) == 2:
opt_args = ["grep", "-iE"]
url_field_names = receivedMessage[1]
pos_args = ["^({}):".format('|'.join(url_field_names))]
elif receivedMessage[0] == "otp" and len(receivedMessage) == 2:
opt_args = ["otp"]
key = receivedMessage[1]
key = "/" + (key[1:] if key[0] == "/" else key)
pos_args = [key]
else:
opt_args = ["show"]
key = receivedMessage[0]
key = "/" + (key[1:] if key[0] == "/" else key)
pos_args = [key]
opt_args += COMMAND_ARGS

# Set up (modified) command environment
env = dict(os.environ)
if "HOME" not in env:
env["HOME"] = os.path.expanduser('~')
for key, val in COMMAND_ENV.items():
env[key] = val
setPassGpgOpts(env, {'--status-fd': '2', '--debug': 'ipc'})

# Set up subprocess params
cmd = [COMMAND] + opt_args + ['--'] + pos_args
proc_params = {
'input': bytes(std_input, CHARSET) if std_input else None,
'stdout': subprocess.PIPE,
'stderr': subprocess.PIPE,
'env': env
}

# Run and communicate with pass script
proc = subprocess.run(cmd, **proc_params)

# Send response
sendMessage(
encodeMessage({
"exitCode": proc.returncode,
"stdout": proc.stdout.decode(CHARSET),
"stderr": proc.stderr.decode(CHARSET),
"version": VERSION
}))