#! /usr/bin/env python3

RE_EXEC = "./re"

test_suite = [
    # basics
    ("search", r"abc", "abcdef"),
    ("search", r"cde", "abcdef"),
    ("search", r"abc*", "abdef"),
    ("search", r"abc*", "abcccdef"),
    ("search", r"abc+", "abdef"),
    ("search", r"abc+", "abcccdef"),

    # match
    ("match", r"abc", "abcdef"),
    ("match", r"abc*", "abdef"),

    # search vs match distinction
    ("match", r"a*", "baa"),
    ("search", r"a*", "baa"),

    # nested group matching
    ("match", r"(([0-9]*)([a-z]*)[0-9]*)", "1234hello567"),
    ("match", r"([0-9]*)(([a-z]*)([0-9]*))", "1234hello567"),

    # non-capturing groups
    ("match", r"(([0-9]*)(?:[a-z]*)[0-9]*)", "1234hello568"),
    ("match", r"(?:[0-9]*)(([a-z]*)(?:[0-9]*))", "1234hello568"),
    ("match", r"([0-9]*)(?:([a-z]*)(?:[0-9]*))", "1234hello568"),
    ("match", r"(?:)", "1234hello568"),
    ("match", r"1?:", "1:"),

    # named character classes
    ("match", r"\d+", "123abc456"),
    ("match", r"\s+", " \t123abc456"),
    ("match", r"\w+", "123abc_456 abc"),
    ("match", r"(\w+)\s+(\w+)", "ABC \t123hello456 abc"),
    ("match", r"(\S+)\s+(\D+)", "ABC \thello abc456 abc"),
    ("match", r"(([0-9]*)([a-z]*)\d*)", "123hello456"),

    # classes
    ("match", r"[a]*", "a"),
    ("search", r"([yab]*)(e*)([cd])", "xyac"),
    ("search", r"([yab]*)(e*)([^y]?)$", "xyac"),
    ("match", r"[-]*", "--"),
    ("match", r"[-a]*", "-a-b"),
    ("match", r"[-ab]*", "-a-b"),
    ("match", r"[-a-c]*", "-a-b-d-"),
    ("match", r"[a-]*", "-a-b"),
    ("match", r"[ab-]*", "-a-b"),
    ("match", r"[a-c-]*", "-a-b-d-"),

    # escaped metacharacters
    ("match", r"(\?:)", ":"),
    ("match", r"\(?:", "(:"),

    # non-greedy
    ("match", r"a(b??)(b*)c", "abbc"),
    ("match", r"a(b+?)(b*)c", "abbbc"),
    ("match", r"a(b*?)(b*)c", "abbbbc"),

    # greedy
    ("match", r"a(b?)(b*)c", "abbc"),
    ("match", r"a(b+)(b*)c", "abbbc"),
    ("match", r"a(b*)(b*)c", "abbbbc"),

    # errors
    ("search", r"?", ""),
    ("search", r"*", ""),
    ("search", r"+", ""),
    ("search", r"[", ""),
    ("search", r"(", ""),
    ("search", r")", ""),
    ("search", "\\", ""),
    ("search", "|+", ""),
    ("search", "|*", ""),
    ("search", "|?", ""),
    ("search", "^*", ""),
    ("search", "$*", ""),
    ("search", "a*+", ""),
    ("search", "a*?", ""),
    ("search", "a**", ""),
]

import re
import sre_constants
import subprocess
from collections import OrderedDict

def parse_result(string, res):
    name, rest = res.split(b" ", 1)
    if rest == b"-no match-":
        return name, None
    if rest == b"REGEX ERROR":
        return name, rest
    assert rest.startswith(b"match ")
    rest = rest[6:]
    tuples = [eval(t) for t in rest.split()]
    matches = tuple(string[t[0]:t[1]] for t in tuples)
    return name, matches

def fit_str(string, width):
    if len(string) <= width:
        return string
    else:
        return string[:width - 2] + ".."

def main():
    engine_stats = OrderedDict()
    for kind, regex, string in test_suite:
        # run Python re to get correct result
        try:
            if kind == "match":
                py_res = re.match(regex, string)
            else:
                py_res = re.search(regex, string)
            if py_res is not None:
                py_res = (py_res.group(0),) + py_res.groups()
        except sre_constants.error:
            py_res = b"REGEX ERROR"

        # run our code
        try:
            args = (["-m"] if kind == "match" else []) + [regex, string]
            re_res = subprocess.check_output([RE_EXEC]+args, stderr=subprocess.STDOUT)
            re_res = re_res.split(b'\n')[1:-1] # split lines, remove first and last
        except subprocess.CalledProcessError as e:
            if e.returncode == 2 and e.output == b"fatal error: Error in regexp\n":
                re_res = [b"recursive REGEX ERROR", b"recursiveloop REGEX ERROR", b"backtrack REGEX ERROR", b"thompson REGEX ERROR", b"pike REGEX ERROR"]
            else:
                raise

        # check result of each engine
        for engine in re_res:
            engine_name, re_res = parse_result(string, engine)
            try:
                stats = engine_stats[engine_name]
            except KeyError:
                engine_stats[engine_name] = stats = [0, 0]

            # Thompson algo offers just boolean match/no match status
            py_res_cur = py_res
            re_res_cur = re_res
            if engine_name == b"thompson":
                if py_res is not None:
                    py_res_cur = True
                if re_res is not None:
                    re_res_cur = True

            if py_res_cur == re_res_cur:
                print("pass ", end="")
                stats[0] += 1
            else:
                print("FAIL ", end="")
                stats[1] += 1

        print("%s %-25s %-20s" % (kind[0], fit_str(regex, 25), fit_str(string, 20)))

    print("Ran %d tests, results:" % len(test_suite))
    for name, stats in engine_stats.items():
        print("%15s %2d pass %2d fail" % (str(name, encoding='utf8'), stats[0], stats[1]))

if __name__ == "__main__":
    main()