import faulthandler
import os
import re
from types import SimpleNamespace

import sanitizers
import cffi

SELF_DIR = os.path.dirname(os.path.abspath(__file__))

TOPLEVEL = os.path.abspath(SELF_DIR + "/../../../../") + "/"

PREDEFINITIONS = """
typedef ... regex_t;
/*
 * While pycparser supports __int128, cffi does not.  Provide these
 * fake definitions for __[u]int128_t; they look the same to the ABI
 * (in as much as there is an ABI for this extension).
 */
typedef struct {
	uint64_t lo;
	uint64_t hi;
} __uint128_t;
typedef struct {
	uint64_t lo;
	int64_t hi;
} __int128_t;
"""

REPLACEMENTS = {
    r"STAILQ_HEAD\s*\(\s*(\w*)\s*,\s*(\w+)\s*\)": r"struct \1 { struct \2 *stqh_first; struct \2 **stqh_last; }",
    r"STAILQ_ENTRY\s*\(\s*(\w+)\s*\)": r"struct { struct \1 *stqe_next; }",
}


PUBLIC_HEADERS = [
    # ...
]

INTERNAL_HEADERS = [
    # ...
]

STRIPPED_PREFIXES = [
    "crdb_",
    "CRDB_",
]

FFI = cffi.FFI()


def read_stripped_header(path):
    """Returns the contents of a header file without preprocessor directives."""
    ret = ""
    in_directive = False
    with open(path) as f:
        for line in f:
            if in_directive or re.match(r"^\s*#", line):
                in_directive = line.endswith("\\\n")
            else:
                in_directive = False
                for pattern, repl in REPLACEMENTS.items():
                    line = re.sub(pattern, repl, line)
                ret += line
    return ret


FFI.cdef(PREDEFINITIONS)

for header in PUBLIC_HEADERS:
    FFI.cdef(read_stripped_header(TOPLEVEL + "src/crdb/include/" + header))

for header in INTERNAL_HEADERS:
    FFI.cdef(read_stripped_header(TOPLEVEL + "src/crdb/include/crdb/" + header))


if sanitizers.ENABLED:
    C = FFI.dlopen(TOPLEVEL + "_build_asan/crdb/libcrdb.so")
else:
    C = FFI.dlopen(TOPLEVEL + "_build/crdb/libcrdb.so")


def _strip_prefixes(lib):
    """Returns a namespace with every symbol in `lib` resolved eagerly,
    and with aliases stripped of the `crdb_` prefix (and other entries
    in STRIPPED_PREFIXES).
    """
    ret = SimpleNamespace()
    symbols = dir(lib)
    for symbol in symbols:
        # This is where we would wrap with BTS hooks.
        fn = sanitizers.wrap_with_tracking(getattr(lib, symbol))
        setattr(ret, symbol, fn)
        for prefix in STRIPPED_PREFIXES:
            if symbol.startswith(prefix):
                suffix = symbol[len(prefix) :]
                assert (
                    suffix not in symbols
                ), "Name collision when stripping %s from %s." % (prefix, symbol,)
                setattr(ret, suffix, fn)
                break
    return ret


C = _strip_prefixes(C)


def _init_crdb():
    error = FFI.new("crdb_error_t *")
    assert C.init(FFI.NULL, error), "crdb_init: %s %i" % (
        FFI.string(error.message),
        error.error,
    )


FFI.init_once(_init_crdb, "init_crdb")

# Pass in a copy of stderr in case anyone plays redirection tricks.
faulthandler.enable(os.dup(2))