#!/usr/bin/python3

import sys, getopt, subprocess, re

def usage(out):
    out.write("usage: gpgrep PATTERN FILENAME\n")

opts, args = getopt.getopt(sys.argv[1:], "h")
for o, a in opts:
    if o == "-h":
        usage(sys.stdout)
        sys.exit(0)
if len(args) < 2:
    usage(sys.stderr)
    sys.exit(1)

try:
    pattern = re.compile(args[0], re.IGNORECASE)
except Exception as exc:
    sys.stderr.write("gpgrep: %s: %s\n" % (args[0], exc))
    sys.exit(1)
try:
    efp = open(args[1], "r")
except OSError as exc:
    sys.stderr.write("gpgrep: %s: %s\n" % (args[1], exc.strerror))
    sys.exit(1)
with efp, subprocess.Popen(["gpg", "--quiet", "--decrypt", "--armor"], stdin=efp, stdout=subprocess.PIPE, universal_newlines=True) as gpg:
    try:
        for line in gpg.stdout:
            line = line.rstrip()
            if len(line) > 0 and not line[0].isspace() and pattern.search(line):
                sys.stdout.write("%s\n" % (line))
                for line in gpg.stdout:
                    line = line.rstrip()
                    if line == "" or not line[0].isspace():
                        break
                    sys.stdout.write("%s\n" % (line))
                sys.exit(0)
        sys.exit(1)
    finally:
        gpg.stdout.close()
        if gpg.wait() != 0:
            sys.stderr.write("gpgrep: gpg failed\n")
            sys.exit(1)