#!/usr/bin/env python
from __future__ import print_function

# Copyright (c) 2014 Justus Winter <4winter@informatik.uni-hamburg.de>
#
# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

import difflib
import logging as log
import os
import re
import subprocess
import string
import sys

log.basicConfig(format='%(levelname)s:%(message)s', level=log.DEBUG)

base_path = os.path.dirname (os.path.dirname (os.path.abspath (sys.argv[0])))
template_path = os.path.join (base_path, "share", "portseal")
state_path = os.path.abspath (".portseal")
portseal_h = os.path.join (base_path, "libportseal", "portseal.h")
portseal_L = os.path.join (base_path, "libportseal")

def pkg_config (pkg, what):
    return subprocess.check_output (["pkg-config", "--"+what, pkg]).strip ()

ldflags = "-L{0} -Wl,-rpath={0} -lportseal -ldl {1} {2} {3}".format (
    portseal_L,
    pkg_config ("liburcu", "libs"),
    pkg_config ("liburcu-cds", "libs"),
    pkg_config ("liburcu-mb", "libs"),
)

def template (x):
    return os.path.join (template_path, x)

def state (x):
    return os.path.join (state_path, x)

def make_state_dir ():
    if not os.path.exists (state_path):
        os.mkdir (state_path)

def is_patched ():
    return os.path.exists (state ("portseal.patch"))

def template_apply (name, mapping, sink=None, **overlay):
    log.debug ("applying template {0}".format (name))
    with open (template (name)) as source:
        t = source.read ()

    m = mapping.copy ()
    m.update (overlay)
    for key, value in sorted (m.items (),
                              cmp=lambda a, b: cmp (len (a[0]), len (b[0])),
                              reverse=True):
        t = t.replace (key, value)

    if sink:
        sink.write (t)
    else:
        with open (state (name), "w") as sink:
            sink.write (t)

def spatch (cocci):
    includes = list ()
    for i in (args.I or ["/usr/include"]):
        includes.extend (("-I", i))

    c = ["spatch",
         "--no-loops",
         "--no-gotos",
         "--smpl-spacing",
         "--include-headers",
         "--sp-file", cocci,
         "-dir", ".",
    ] + includes
    log.debug ("executing {0}".format (c))

    return subprocess.check_output (c)

def do_wrap_hack(s, r = False):
    wraphack = 'PORTSEAL_WRAP_HACK'
    if r:
        wraphack += '_R'

    def walk (s, i, direction, p):
        while p != 0:
            if s[i] == "(":
                p += 1
            elif s[i] == ")":
                p -= 1
            i += direction
        return i

    def skip_ws (s, i, direction):
        while 0 < i < len (s) - 1:
            if string.strip (s[i]):
                break
            i += direction
        return i

    def skip_nws (s, i, direction):
        while 0 < i < len (s) - 1:
            if not string.strip (s[i]):
                break
            i += direction
        return i

    while wraphack in s:
        i = s.index(wraphack)
        start = skip_nws (s, skip_ws (s, walk (s, i, -1, -1), -1), -1)
        id_start = skip_ws (s, i + len (wraphack), 1)
        id_end = walk (s, id_start + 1, 1, 1)
        ident = s[id_start:id_end]
        end = walk (s, id_end, 1, 1)
        s = "{0} PORTSEAL_WRAP{1}({2}{3}, {4}){5}".format (
            s[:start],
            "_R" if r else "",
            s[start:i],
            s[id_start:end],
            ident,
            s[end:])

    return s

def patch (args):
    if is_patched ():
        return

    make_state_dir ()

    mapping = dict ()
    with open (state ("portseal.cocci"), "w") as sink:
        template_apply ("portseal.cocci", mapping, sink)

    cocci_patch = spatch (state ("portseal.cocci"))

    patches = list ()
    patches.append (cocci_patch)

    # add include to every file the cocci patch touched
    for l in cocci_patch.split ("\n"):
        if not l.startswith ("--- a/"):
            continue
        patches.append (make_patch (
            l[6:],
            lambda a: "#include \"{0}\"\n#line 1\n{1}".format (portseal_h, a)))

    ldflags_re = re.compile (r"^(\s*LDFLAGS\s*=.*)(\\?)$", re.M)
    for dirpath, dirs, files in os.walk("."):
        if dirpath.endswith (".portseal"):
            continue
        for f in filter (lambda f: "Make" in f, files):
            patches.append (
                make_patch (
                    os.path.join (dirpath, f),
                    lambda m:
                        ldflags_re.sub (r"\1 {0} \2".format (ldflags), m, 0)))

    with open(state ("portseal.patch"), "w") as h:
        h.write ("\n".join (patches))

    subprocess.check_call (
        ["patch", "-p1"],
        stdin=open (state ("portseal.patch")),
    )

    # wraphack
    wraphack_patches = list ()
    for dirpath, dirs, files in os.walk("."):
        if dirpath.endswith (".portseal"):
            continue

        #continue

        for f in filter (lambda f: f[-2:] in ('.c', '.h'), files):
            try:
                wraphack_patches.append (
                    make_patch (
                        os.path.join (dirpath, f),
                        lambda m: do_wrap_hack (do_wrap_hack (m, True))))
            except IOError:
                pass

    with open(state ("wraphack.patch"), "w") as h:
        h.write ("\n".join (wraphack_patches))

    subprocess.check_call (
        ["patch", "-p1"],
        stdin=open (state ("wraphack.patch")),
    )


def make_patch (filename, mutator):
    a = open (filename).read ()
    b = mutator (a)
    p = os.path.join ("a", filename)
    def split(x):
        return [l+"\n" for l in x.split ("\n")]
    return "".join (difflib.unified_diff (split (a),
                                          split (b),
                                          fromfile=p,
                                          tofile=p))
def unpatch (args):
    if not is_patched ():
        return

    subprocess.check_call (
        ["patch", "-p1", "-R"],
        stdin=open (state ("wraphack.patch")),
    )

    subprocess.check_call (
        ["patch", "-p1", "-R"],
        stdin=open (state ("portseal.patch")),
    )

    os.remove (state ("portseal.patch"))

import argparse

parser = argparse.ArgumentParser()
subparsers = parser.add_subparsers(title='subcommands',
                                   description='valid subcommands',
                                   help='additional help')

parser_patch = subparsers.add_parser('patch')
parser_patch.set_defaults(func=patch)
parser_patch.add_argument('-I', metavar='DIR', action="append",
                          help='add include directory')

parser_unpatch = subparsers.add_parser('unpatch')
parser_unpatch.set_defaults(func=unpatch)

args = parser.parse_args()
sys.exit(args.func(args))