#!/usr/bin/python3
import logging
import sys
import re
import os
import json
import shutil

sys.path.append(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
from setup_support import SetupApp, Config

PYTHON_DATA_SCRIPT = """
import json
from sysconfig import get_config_vars, get_path, get_path_names
if "platinclude" in get_path_names():
    plat_include_key = "platinclude"
else:
    plat_include_key = "include"
result = {'config_vars': get_config_vars(),
          'python_inc': get_path("include"),
          'python_inc_plat': get_path(plat_include_key),
          'prefix': get_path("data")}
print(json.dumps(result))
"""


def fetch_python_config(config):
    logging.info("Fetch Python information...")
    python_output = config.run(
        config.data["python_exec"], "-c", PYTHON_DATA_SCRIPT, grab=True
    )
    python_data = json.loads(python_output)
    config_vars = python_data["config_vars"]
    python_version = config_vars["VERSION"]
    python_ldversion = config_vars.get("LDVERSION", python_version)
    logging.info("  %-24s %s", "Python version:", python_version)

    # Current python location
    current_prefix = python_data["prefix"]

    # Fetch prefix during the build process. Some paths of interest might
    # still reference a location used during the Python build process.
    build_prefix = (
        [sys.prefix]
        + re.findall(r"'--prefix=([^']+)'", config_vars.get("CONFIG_ARGS", ""))
    )[-1]

    def relocate(path):
        if os.path.isabs(path):
            rel_path = os.path.relpath(path, build_prefix)
            if not rel_path.startswith(os.pardir):
                # If the input path is relative to the original build
                # directory, replace build prefix by the current one.
                return os.path.join(current_prefix, rel_path)
            else:
                # Otherwise, return it unchanged
                return path
        else:
            # The input path is relative so assume it's relative to the current
            # python prefix.
            return os.path.join(current_prefix, path)

    # Retrieve cflags, and linker flags
    static_dir = relocate(config_vars.get("LIBPL", "libs"))
    logging.info("  %-24s %s", "Static dir", static_dir)

    shared_dir = relocate(config_vars.get("LIBDIR", "."))
    logging.info("  %-24s %s", "Shared dir", shared_dir)

    # Add first relocated include dirs followed by non-relocated version.
    # Indeed, when using venv and maybe virtualenv, includes are not copied.
    cflags = "-I" + relocate(python_data["python_inc"])
    if python_data["python_inc"] != python_data["python_inc_plat"]:
        cflags += " -I" + relocate(python_data["python_inc_plat"])
        cflags += " -I" + python_data["python_inc_plat"]
    cflags += " -I" + python_data["python_inc"]

    logging.info("  %-24s %s", "CFLAGS", cflags)

    if python_version.startswith("3"):
        # In python 3.x MODLIBS seems to drag in too many libraries
        python_libs = [
            config_vars[v]
            for v in ("LIBS", "SYSLIBS")
            if v in config_vars and config_vars[v]
        ]
    else:
        python_libs = [
            config_vars[v]
            for v in ("LIBS", "SYSLIBS", "MODLIBS")
            if v in config_vars and config_vars[v]
        ]
    python_libs = " ".join(python_libs)

    python_shared_libs = "-L%s -lpython%s %s" % (
        shared_dir,
        python_ldversion,
        python_libs,
    )
    python_static_libs = python_libs
    libpython_a = os.path.join(
        static_dir, config_vars.get("LIBRARY", "libpython%s.a" % python_version)
    )

    if os.path.isfile(libpython_a):
        config.set_data("GNATCOLL_PYTHON_STATIC_LIB", libpython_a, sub="gprbuild")
    else:
        logging.info("static python library not found")

    if sys.platform.startswith("linux"):
        # On Linux platform, even when linking with the static libpython,
        # symbols not used by the application itself should be exported so
        # that shared library present in Python can use the Python C API.
        python_static_libs += " -export-dynamic"
        python_shared_libs += " -export-dynamic"

    logging.info("  %-24s %s", "Shared linker flags", python_shared_libs)
    logging.info("  %-24s %s", "Static linker flags", python_static_libs)

    # User does not have the choice between linking with static libpython
    # and shared libpython. If --enable-shared or --enable-framework was
    # passed to Python's configure during Python build, then we should
    # link with the shared libpython, otherwise with the static one.
    # Indeed otherwise some C modules might not work as expected or even
    # crash. On Windows always link with shared version of libpython
    # (if the static is present, this is just an indirection to the shared)
    if (
        "--enable-shared" in config_vars.get("CONFIG_ARGS", "")
        or "--enable-framework" in config_vars.get("CONFIG_ARGS", "")
        or sys.platform.startswith("win")
    ):
        logging.info("Force link to shared python library")
        config.set_data("GNATCOLL_PYTHON_LIBS", python_shared_libs, sub="gprbuild")
        config.set_data("GNATCOLL_LIBPYTHON_KIND", "shared", sub="gprbuild")
    else:
        logging.info("Force link to static python library")
        config.set_data("GNATCOLL_PYTHON_LIBS", python_static_libs, sub="gprbuild")
        config.set_data("GNATCOLL_LIBPYTHON_KIND", "static", sub="gprbuild")
    config.set_data("GNATCOLL_PYTHON_CFLAGS", cflags, sub="gprbuild")


class GNATCollPython(SetupApp):
    name = "gnatcoll_python"
    project = "gnatcoll_python.gpr"
    description = "GNATColl Python bindings"

    def create(self):
        super(GNATCollPython, self).create()
        self.build_cmd.add_argument(
            "--python-exec",
            help="set python executable location",
            metavar="PATH",
            default=sys.executable,
        )
        self.build_cmd.add_argument(
            "--debug",
            help="build project in debug mode",
            action="store_true",
            default=False,
        )

    def update_config(self, config, args):
        # Fetch python information
        config.set_data("python_exec", args.python_exec)
        fetch_python_config(config)

        logging.info(
            "%-26s %s", "Libraries kind", ", ".join(config.data["library_types"])
        )

        # Set library version
        with open(
            os.path.join(config.source_dir, "..", "version_information"), "r"
        ) as fd:
            version = fd.read().strip()
        config.set_data("GNATCOLL_VERSION", version, sub="gprbuild")
        logging.info("%-26s %s", "Version", version)

        # Set build mode
        config.set_data("BUILD", "DEBUG" if args.debug else "PROD", sub="gprbuild")
        logging.info("%-26s %s", "Build mode", config.data["gprbuild"]["BUILD"])

        # Set GNATCOLL_OS
        if "darwin" in config.data["canonical_target"]:
            gnatcoll_os = "osx"
        elif "windows" in config.data["canonical_target"]:
            gnatcoll_os = "windows"
        else:
            # Assume this is an Unix system
            gnatcoll_os = "unix"
        config.set_data("GNATCOLL_OS", gnatcoll_os, sub="gprbuild")

    def variants(self, config, cmd):
        result = []
        for library_type in config.data["library_types"]:
            gpr_vars = {
                "LIBRARY_TYPE": library_type,
                "XMLADA_BUILD": library_type,
                "GPR_BUILD": library_type,
            }
            if cmd == "install":
                result.append(
                    (
                        ["--build-name=%s" % library_type, "--build-var=LIBRARY_TYPE"],
                        gpr_vars,
                    )
                )
            else:
                result.append(([], gpr_vars))
        return result

    def install(self, args):
        config = Config()
        has_static_python = "GNATCOLL_PYTHON_STATIC_LIB" in config.data["gprbuild"]

        if not has_static_python:
            super(GNATCollPython, self).install(args)
        else:
            python_la = config.data["gprbuild"]["GNATCOLL_PYTHON_STATIC_LIB"]
            prefix = args.prefix
            if prefix is None:
                prefix = config.data["prefix"]
            rel_target = os.path.join(
                "..", "..", "lib", "gnatcoll_python.static", os.path.basename(python_la)
            )
            abs_target = os.path.join(
                prefix, "lib", "gnatcoll_python.static", os.path.basename(python_la)
            )

            shutil.copy(config.json_cache, config.json_cache + ".backup")
            try:
                # Temporary change the configuration to set a relative path to the
                # static Python library.
                config.set_data(
                    "GNATCOLL_PYTHON_STATIC_LIB", rel_target, sub="gprbuild"
                )
                config.save_data()

                # Perform the installation
                super(GNATCollPython, self).install(args)

                # Copy over the libpython*.a
                logging.info("Copy static libpython into target lib")
                if not os.path.isdir(os.path.dirname(abs_target)):
                    os.mkdir(abs_target)
                result = shutil.copy(python_la, abs_target)
                logging.info(f"Python static lib in {result}")
            finally:
                # Restore the configuration cache
                shutil.copy(config.json_cache + ".backup", config.json_cache)
                os.unlink(config.json_cache + ".backup")


if __name__ == "__main__":
    app = GNATCollPython()
    sys.exit(app.run())