from __future__ import annotations

import inspect
import os
import re
import warnings
from pathlib import Path
from typing import Callable

from packaging.version import Version
from pdm.backend.exceptions import ConfigError, PDMWarning, ValidationError
from pdm.backend.hooks.base import Context
from pdm.backend.hooks.version.scm import SCMVersion as SCMVersion
from pdm.backend.hooks.version.scm import (
    default_version_formatter,
    get_version_from_scm,
)
from pdm.backend.utils import evaluate_module_attribute

_fallback_version_warning = (
    "Can't get a valid version from {}, use fallback_version instead."
)


class DynamicVersionBuildHook:
    """Dynamic version implementation.

    Currently supports `file` and `scm` sources.
    """

    supported_sources = ("file", "scm", "call")

    def pdm_build_initialize(self, context: Context) -> None:
        version_config = (
            context.config.data.get("tool", {}).get("pdm", {}).get("version", {})
        )
        metadata = context.config.metadata
        if not version_config or "version" in metadata:
            if metadata.get("version") is None:
                metadata["version"] = "0.0.0"
            try:
                metadata["dynamic"].remove("version")
            except (ValueError, KeyError):
                pass
            return
        if "version" not in metadata.get("dynamic", []):
            raise ValidationError(
                "missing 'version' in project.dynamic",
                "The 'version' field must be present in project.dynamic to "
                "resolve it dynamically",
            )
        source: str = version_config.get("source")
        if not source:
            raise ConfigError("tool.pdm.version.source is required")
        if source not in self.supported_sources:
            warnings.warn(
                f"Invalid version source {source}, must be one of "
                f"{', '.join(self.supported_sources)}",
                PDMWarning,
            )
            return
        options = {k: v for k, v in version_config.items() if k != "source"}
        metadata["version"] = str(
            getattr(self, f"resolve_version_from_{source}")(context, **options)
        )
        metadata["dynamic"].remove("version")

    def resolve_version_from_file(self, context: Context, path: str) -> Version:
        """Resolve version from a file."""
        version_source = context.root / path
        with open(version_source, encoding="utf-8") as fp:
            match = re.search(
                r"^__version__\s*=\s*[\"'](.+?)[\"']\s*(?:#.*)?$", fp.read(), re.M
            )
        if not match:
            raise ConfigError(
                f"Couldn't find version in file {version_source!r}, "
                "it should appear as `__version__ = 'a.b.c'`.",
            )
        return Version(match.group(1))

    def resolve_version_from_scm(
        self,
        context: Context,
        write_to: str | None = None,
        write_template: str = "{}\n",
        tag_regex: str | None = None,
        tag_filter: str | None = None,
        version_format: str | None = None,
        fallback_version: str | None = None,
    ) -> Version:
        if os.environ.get("PDM_BUILD_SCM_VERSION"):
            source = "environment variable"
            version = os.environ["PDM_BUILD_SCM_VERSION"]
        else:
            source = "scm"
            version_formatter: (
                Callable[[SCMVersion, Context], str] | Callable[[SCMVersion], str]
            )
            if version_format is not None:
                version_formatter, _ = evaluate_module_attribute(
                    version_format, context.root
                )
            else:
                version_formatter = default_version_formatter
            scm_version = get_version_from_scm(
                context.root, tag_regex=tag_regex, tag_filter=tag_filter
            )
            if scm_version is None:
                if fallback_version is not None:
                    warnings.warn(_fallback_version_warning.format(source), PDMWarning)
                    version = fallback_version
                else:
                    raise ConfigError(
                        "Cannot find the version from SCM or SCM isn't detected. \n"
                        "You can still specify the version via environment variable "
                        "`PDM_BUILD_SCM_VERSION`, or specify `fallback_version` config."
                    )
            else:
                params = inspect.signature(version_formatter).parameters
                if len(params) > 1:
                    version = version_formatter(scm_version, context)  # type: ignore[call-arg]
                else:
                    version = version_formatter(scm_version)  # type: ignore[call-arg]
        try:
            parsed_version = Version(version)
        except ValueError:
            if fallback_version is not None:
                warnings.warn(_fallback_version_warning.format(source), PDMWarning)
                return Version(fallback_version)
            raise ConfigError(
                f"Invalid version {version}, it must comply with PEP 440. \n"
                "You can still specify the version via environment variable "
                "`PDM_BUILD_SCM_VERSION`, or specify `fallback_version` config."
            )
        self._write_version(context, version, write_to, write_template)
        return parsed_version

    def _write_version(
        self,
        context: Context,
        version: str,
        write_to: str | None = None,
        write_template: str = "{}\n",
    ) -> None:
        """Write the resolved version to the file."""
        if write_to is not None:
            if context.target == "sdist" and context.config.build_config.package_dir:
                write_to = os.path.join(
                    context.config.build_config.package_dir, write_to
                )
            if context.target == "editable":
                target = Path(context.config.build_config.package_dir or ".") / write_to
            else:
                target = context.build_dir / write_to
            if not target.parent.exists():
                target.parent.mkdir(0o700, parents=True)
            with open(target, "w", encoding="utf-8", newline="") as fp:
                fp.write(write_template.format(version))

    def resolve_version_from_call(
        self,
        context: Context,
        getter: str,
        write_to: str | None = None,
        write_template: str = "{}\n",
        fallback_version: str | None = None,
    ) -> Version:
        version_getter, args = evaluate_module_attribute(getter, context.root)
        version = version_getter(*args)
        if version is None:
            if fallback_version is not None:
                warnings.warn(_fallback_version_warning.format("call"), PDMWarning)
                return Version(fallback_version)
            else:
                raise ConfigError(
                    "Cannot get version from the call, you can specify fallback version via `fallback_version` config."
                )
        parsed_version = Version(version)
        self._write_version(context, version, write_to, write_template)
        return parsed_version
