"""
This script processes the output from the C preprocessor and extracts all
qstr. Each qstr is transformed into a qstr definition of the form 'Q(...)'.

This script works with Python 2.6, 2.7, 3.3 and 3.4.
"""

from __future__ import print_function

import re
import sys
import io
import os

# Python 2/3 compatibility:
#   - iterating through bytes is different
#   - codepoint2name lives in a different module
import platform

if platform.python_version_tuple()[0] == "2":
    bytes_cons = lambda val, enc=None: bytearray(val)
    from htmlentitydefs import name2codepoint
elif platform.python_version_tuple()[0] == "3":
    bytes_cons = bytes
    from html.entities import name2codepoint

    unichr = chr
# end compatibility code

# Blocklist of qstrings that are specially handled in further
# processing and should be ignored
QSTRING_BLOCK_LIST = set(["NULL", "number_of"])

# add some custom names to map characters that aren't in HTML
name2codepoint["hyphen"] = ord("-")
name2codepoint["space"] = ord(" ")
name2codepoint["squot"] = ord("'")
name2codepoint["comma"] = ord(",")
name2codepoint["dot"] = ord(".")
name2codepoint["colon"] = ord(":")
name2codepoint["semicolon"] = ord(";")
name2codepoint["slash"] = ord("/")
name2codepoint["percent"] = ord("%")
name2codepoint["hash"] = ord("#")
name2codepoint["paren_open"] = ord("(")
name2codepoint["paren_close"] = ord(")")
name2codepoint["bracket_open"] = ord("[")
name2codepoint["bracket_close"] = ord("]")
name2codepoint["brace_open"] = ord("{")
name2codepoint["brace_close"] = ord("}")
name2codepoint["star"] = ord("*")
name2codepoint["bang"] = ord("!")
name2codepoint["backslash"] = ord("\\")
name2codepoint["plus"] = ord("+")
name2codepoint["dollar"] = ord("$")
name2codepoint["equals"] = ord("=")
name2codepoint["question"] = ord("?")
name2codepoint["at_sign"] = ord("@")
name2codepoint["caret"] = ord("^")
name2codepoint["pipe"] = ord("|")
name2codepoint["tilde"] = ord("~")

# These are just vexing!
del name2codepoint["and"]
del name2codepoint["or"]


def write_out(fname, output):
    if output:
        for m, r in [("/", "__"), ("\\", "__"), (":", "@"), ("..", "@@")]:
            fname = fname.replace(m, r)
        with open(args.output_dir + "/" + fname + ".qstr", "w") as f:
            f.write("\n".join(output) + "\n")


def qstr_unescape(qstr):
    for name in name2codepoint:
        if "__" + name + "__" in qstr:
            continue
        if "_" + name + "_" in qstr:
            qstr = qstr.replace("_" + name + "_", str(unichr(name2codepoint[name])))
    return qstr


def process_file(f):
    re_line = re.compile(r"#[line]*\s(\d+)\s\"([^\"]+)\"")
    re_qstr = re.compile(r"MP_QSTR_[_a-zA-Z0-9]+")
    re_translate = re.compile(r"translate\(\"((?:(?=(\\?))\2.)*?)\"\)")
    output = []
    last_fname = None
    lineno = 0
    for line in f:
        if line.isspace():
            continue
        # match gcc-like output (# n "file") and msvc-like output (#line n "file")
        if line.startswith(("# ", "#line")):
            m = re_line.match(line)
            assert m is not None
            # print(m.groups())
            lineno = int(m.group(1))
            fname = m.group(2)
            if not fname.endswith(".c"):
                continue
            if fname != last_fname:
                write_out(last_fname, output)
                output = []
                last_fname = fname
            continue
        for match in re_qstr.findall(line):
            name = match.replace("MP_QSTR_", "")
            if name not in QSTRING_BLOCK_LIST:
                output.append("Q(" + qstr_unescape(name) + ")")
        for match in re_translate.findall(line):
            output.append('TRANSLATE("' + match[0] + '")')
        lineno += 1

    write_out(last_fname, output)
    return ""


def cat_together():
    import glob
    import hashlib

    hasher = hashlib.md5()
    all_lines = []
    outf = open(args.output_dir + "/out", "wb")
    for fname in glob.glob(args.output_dir + "/*.qstr"):
        with open(fname, "rb") as f:
            lines = f.readlines()
            all_lines += lines
    all_lines.sort()
    all_lines = b"\n".join(all_lines)
    outf.write(all_lines)
    outf.close()
    hasher.update(all_lines)
    new_hash = hasher.hexdigest()
    # print(new_hash)
    old_hash = None
    try:
        with open(args.output_file + ".hash") as f:
            old_hash = f.read()
    except IOError:
        pass
    if old_hash != new_hash:
        print("QSTR updated")
        try:
            # rename below might fail if file exists
            os.remove(args.output_file)
        except:
            pass
        os.rename(args.output_dir + "/out", args.output_file)
        with open(args.output_file + ".hash", "w") as f:
            f.write(new_hash)
    else:
        print("QSTR not updated")


if __name__ == "__main__":
    if len(sys.argv) != 5:
        print("usage: %s command input_filename output_dir output_file" % sys.argv[0])
        sys.exit(2)

    class Args:
        pass

    args = Args()
    args.command = sys.argv[1]
    args.input_filename = sys.argv[2]
    args.output_dir = sys.argv[3]
    args.output_file = sys.argv[4]

    try:
        os.makedirs(args.output_dir)
    except OSError:
        pass

    if args.command == "split":
        with io.open(args.input_filename, encoding="utf-8") as infile:
            process_file(infile)

    if args.command == "cat":
        cat_together()