"""A built-in hook to generate setup.py and run the script"""
from __future__ import annotations

import atexit
import pickle
import shutil
import subprocess
import sys
import tempfile
from pathlib import Path
from typing import cast

from pdm.backend.exceptions import BuildError
from pdm.backend.hooks.base import Context

# A minimal template of setup.py, which is used to build extensions
SETUP_FORMAT = """\
# -*- coding: utf-8 -*-
from setuptools import setup

{before}
setup_kwargs = {{
    'name': {name!r},
    'version': {version!r},
    'description': {description!r},
    'url': {url!r},
{extra}
}}
{after}

setup(**setup_kwargs)
"""

HOOK_TEMPLATE = """\
import pickle

context_dump = {context_dump!r}
context = pickle.loads(context_dump)
builder = context.builder
builder.call_hook("pdm_build_update_setup_kwargs", context, setup_kwargs)
"""


def _format_list(data: list[str], indent: int = 4) -> str:
    result = ["["]
    for row in data:
        result.append(" " * indent + repr(row) + ",")
    result.append(" " * (indent - 4) + "]")
    return "\n".join(result)


def _format_dict_list(data: dict[str, list[str]], indent: int = 4) -> str:
    result = ["{"]
    for key, value in data.items():
        result.append(
            " " * indent + repr(key) + ": " + _format_list(value, indent + 4) + ","
        )
    result.append(" " * (indent - 4) + "}")
    return "\n".join(result)


def _recursive_copy_files(src: Path, dest: Path) -> None:
    if src.is_file():
        shutil.copy2(src, dest)
    else:
        dest.mkdir(exist_ok=True)
        for child in src.iterdir():
            _recursive_copy_files(child, dest / child.name)


class SetuptoolsBuildHook:
    """A build hook to run setuptools build command."""

    def pdm_build_hook_enabled(self, context: Context) -> bool:
        return context.target != "sdist" and context.config.build_config.run_setuptools

    def pdm_build_update_files(self, context: Context, files: dict[str, Path]) -> None:
        if context.target == "editable":
            self._build_inplace(context)
        else:
            self._build_lib(context)

    def _build_lib(self, context: Context) -> None:
        build_dir = context.ensure_build_dir()
        setup_py = self.ensure_setup_py(context)
        with tempfile.TemporaryDirectory(prefix="pdm-build-") as temp_dir:
            build_args = [sys.executable, str(setup_py), "build", "-b", temp_dir]
            try:
                subprocess.check_call(build_args)
            except subprocess.CalledProcessError as e:
                raise BuildError(f"Error occurs when running {build_args}:\n{e}")
            lib_dir = next(Path(temp_dir).glob("lib.*"), None)
            if not lib_dir:
                return
            # copy the files under temp_dir/lib.* to context.build_dir
            _recursive_copy_files(lib_dir, build_dir)

    def _build_inplace(self, context: Context) -> None:
        setup_py = self.ensure_setup_py(context)
        build_args = [sys.executable, str(setup_py), "build_ext", "--inplace"]
        try:
            subprocess.check_call(build_args)
        except subprocess.CalledProcessError as e:
            raise BuildError(f"Error occurs when running {build_args}:\n{e}")

    def ensure_setup_py(self, context: Context, clean: bool = True) -> Path:
        """Ensures the requirement has a setup.py ready."""
        # XXX: Currently only handle PDM project, and do nothing if not.

        setup_py_path = context.root.joinpath("setup.py")
        if setup_py_path.is_file():
            return setup_py_path

        setup_py_path.write_text(self.format_setup_py(context), encoding="utf-8")

        # Clean this temp file when process exits
        def cleanup() -> None:
            try:
                setup_py_path.unlink()
            except OSError:
                pass

        if clean:
            atexit.register(cleanup)
        return setup_py_path

    def format_setup_py(self, context: Context) -> str:
        before, extra, after = [], [], []
        meta = context.config.metadata
        kwargs = {
            "name": meta["name"],
            "version": meta.get("version", "0.0.0"),
            "description": meta.get("description", "UNKNOWN"),
            "url": (meta.get("project-urls", {})).get("homepage", ""),
        }

        # Run the pdm_build_update_setup_kwargs hook to update the kwargs
        after.append(HOOK_TEMPLATE.format(context_dump=pickle.dumps(context)))

        package_paths = context.config.convert_package_paths()
        if package_paths["packages"]:
            extra.append(
                "    'packages': {},\n".format(
                    _format_list(cast("list[str]", package_paths["packages"]), 8)
                )
            )
        if package_paths["package_dir"]:
            extra.append(
                "    'package_dir': {!r},\n".format(package_paths["package_dir"])
            )
        if package_paths["package_data"]:
            extra.append(
                "    'package_data': {!r},\n".format(package_paths["package_data"])
            )
        if package_paths["exclude_package_data"]:
            extra.append(
                "    'exclude_package_data': {!r},\n".format(
                    package_paths["exclude_package_data"]
                )
            )

        if meta.get("dependencies"):
            before.append(f"INSTALL_REQUIRES = {_format_list(meta['dependencies'])}\n")
            extra.append("    'install_requires': INSTALL_REQUIRES,\n")
        if meta.get("optional-dependencies"):
            before.append(
                "EXTRAS_REQUIRE = {}\n".format(
                    _format_dict_list(meta["optional-dependencies"])
                )
            )
            extra.append("    'extras_require': EXTRAS_REQUIRE,\n")
        if meta.get("requires-python"):
            extra.append(f"    'python_requires': {meta['requires-python']!r},\n")
        entry_points = meta.entry_points
        if entry_points:
            entry_points_list = {
                group: [f"{k} = {v}" for k, v in values.items()]
                for group, values in entry_points.items()
            }
            before.append(f"ENTRY_POINTS = {_format_dict_list(entry_points_list)}\n")
            extra.append("    'entry_points': ENTRY_POINTS,\n")
        return SETUP_FORMAT.format(
            before="".join(before), after="".join(after), extra="".join(extra), **kwargs
        )