load("@bazel_skylib//rules:copy_file.bzl", "copy_file")
load("@rules_cc//cc:defs.bzl", "cc_library")

_ZLIB_HEADERS = [
    "crc32.h",
    "deflate.h",
    "gzguts.h",
    "inffast.h",
    "inffixed.h",
    "inflate.h",
    "inftrees.h",
    "trees.h",
    "zconf.h",
    "zlib.h",
    "zutil.h",
]

# In order to limit the damage from the `includes` propagation
# via `:zlib`, copy the public headers to a subdirectory and
# expose those.
_ZLIB_HEADER_PREFIX = "zlib/include"

_ZLIB_PREFIXED_HEADERS = ["{}/{}".format(_ZLIB_HEADER_PREFIX, hdr) for hdr in _ZLIB_HEADERS]

[
    copy_file(
        name = "{}.copy".format(hdr),
        src = hdr,
        out = "{}/{}".format(_ZLIB_HEADER_PREFIX, hdr),
    )
    for hdr in _ZLIB_HEADERS
]

_COMMON_COPTS = [
    "-Wno-deprecated-non-prototype",
    "-Wno-unused-variable",
    "-Wno-implicit-function-declaration",
]

cc_library(
    name = "zlib",
    srcs = [
        "adler32.c",
        "compress.c",
        "crc32.c",
        "deflate.c",
        "gzclose.c",
        "gzlib.c",
        "gzread.c",
        "gzwrite.c",
        "infback.c",
        "inffast.c",
        "inflate.c",
        "inftrees.c",
        "trees.c",
        "uncompr.c",
        "zutil.c",
        # Include the un-prefixed headers in srcs to work
        # around the fact that zlib isn't consistent in its
        # choice of <> or "" delimiter when including itself.
    ] + _ZLIB_HEADERS,
    hdrs = _ZLIB_PREFIXED_HEADERS,
    copts = select({
        "@platforms//os:linux": [
            # Required for opt builds to avoid
            # `libzlib.a(crc32.o): requires unsupported dynamic reloc 11; recompile with -fPIC`
            "-fPIC",
            # Silence all warnings
            "-w",
        ] + _COMMON_COPTS,
        "@platforms//os:windows": [],
        "//conditions:default": _COMMON_COPTS,
    }),
    includes = ["zlib/include/"],
    visibility = ["//visibility:public"],
)