"""Utility functions for the release tool."""

import argparse
import collections.abc
import fnmatch
import os
import pathlib
import re

from packaging.version import parse as parse_version

from dev.release.git import Git

REPO_URL = "https://github.com/bazel-contrib/rules_python"


def semver_type(value):
    """Argparse type validator for semantic versions."""
    if not re.match(r"^\d+\.\d+\.\d+(rc\d+)?$", value):
        raise argparse.ArgumentTypeError(
            f"'{value}' is not a valid semantic version (X.Y.Z or X.Y.ZrcN)"
        )
    return value


_EXCLUDE_PATTERNS = [
    "./.agents/*",
    "./.git/*",
    "./.github/*",
    "./.bazelci/*",
    "./.bcr/*",
    "./bazel-*/*",
    "./CONTRIBUTING.md",
    "./RELEASING.md",
    "./dev/release/*",
    "./tests/tools/private/release/*",
]


def is_excluded_version_placeholder_path(path: pathlib.Path | str) -> bool:
    """Checks if a path matches any version placeholder exclusion patterns."""
    path_str = str(path)
    if not path_str.startswith("./") and not path_str.startswith("/"):
        path_str = f"./{path_str}"
    return any(fnmatch.fnmatch(path_str, pattern) for pattern in _EXCLUDE_PATTERNS)


def _iter_version_placeholder_files() -> collections.abc.Iterator[pathlib.Path]:
    for root, dirs, files in os.walk(".", topdown=True):
        # Filter directories in-place
        dirs[:] = [
            d
            for d in dirs
            if not is_excluded_version_placeholder_path(os.path.join(root, d))
        ]

        for filename in files:
            filepath = pathlib.Path(root) / filename
            if is_excluded_version_placeholder_path(filepath):
                continue

            yield filepath


def get_latest_version(git=None):
    """Gets the latest version from git tags."""
    if git is None:
        git = Git(os.getcwd())
    tags = git.get_tags()
    versions = [
        (tag, parse_version(tag))
        for tag in tags
        if re.match(r"^\d+\.\d+\.\d+(rc\d+)?$", tag.strip())
    ]
    if not versions:
        raise RuntimeError("No git tags found matching X.Y.Z or X.Y.ZrcN format.")

    versions.sort(key=lambda v: v[1])
    latest_tag, latest_version = versions[-1]

    if latest_version.is_prerelease:
        raise ValueError(f"The latest version is a pre-release version: {latest_tag}")

    stable_versions = [tag for tag, version in versions if not version.is_prerelease]
    if not stable_versions:
        raise ValueError("No stable git tags found matching X.Y.Z format.")

    return stable_versions[-1]


def get_latest_rc_tag(version, remote=None, git=None):
    """Queries git tags and returns the highest RC tag for the version."""
    if git is None:
        git = Git(os.getcwd())
    if remote:
        tags = git.get_remote_tags(remote)
    else:
        tags = git.get_tags()
    pattern = rf"^{re.escape(version)}-rc\d+$"
    rc_tags = [tag.strip() for tag in tags if re.match(pattern, tag.strip())]
    if not rc_tags:
        return None
    rc_tags.sort(key=parse_version)
    return rc_tags[-1]


def should_increment_minor():
    """Checks if the minor version should be incremented."""
    for filepath in _iter_version_placeholder_files():
        try:
            with open(filepath, "r") as f:
                content = f.read()
        except (IOError, UnicodeDecodeError):
            continue

        if "VERSION_NEXT_FEATURE" in content:
            return True
    return False


def determine_next_version(branch_name=None, git=None, is_patch=False):
    """Determines the next version based on git tags and the current branch."""
    if git is None:
        git = Git(os.getcwd())
    if branch_name is None:
        branch_name = git.get_current_branch()

    if branch_name:
        release_match = re.match(r"^release/(\d+)\.(\d+)$", branch_name)
        if release_match:
            branch_major = int(release_match.group(1))
            branch_minor = int(release_match.group(2))
            print(
                f"Detected release branch: {branch_name} (targeting"
                f" {branch_major}.{branch_minor}.x)"
            )

            tags = git.get_tags()
            matching_patches = []
            for tag in tags:
                tag = tag.strip()
                m = re.match(rf"^{branch_major}\.{branch_minor}\.(\d+)$", tag)
                if m:
                    matching_patches.append(int(m.group(1)))

            if matching_patches:
                latest_patch = max(matching_patches)
                next_version = f"{branch_major}.{branch_minor}.{latest_patch + 1}"
                print(
                    f"Latest tag on this branch is"
                    f" {branch_major}.{branch_minor}.{latest_patch}. Next"
                    f" version: {next_version}"
                )
                return next_version
            else:
                next_version = f"{branch_major}.{branch_minor}.0"
                print(
                    f"No stable tags found for {branch_major}.{branch_minor}.x."
                    f" Next version: {next_version}"
                )
                return next_version

    latest_version = get_latest_version(git=git)
    major, minor, patch = [int(n) for n in latest_version.split(".")]

    if not is_patch and should_increment_minor():
        return f"{major}.{minor + 1}.0"
    else:
        return f"{major}.{minor}.{patch + 1}"


def replace_version_next_in_files(
    filepaths: collections.abc.Iterable[pathlib.Path], version: str
) -> list[pathlib.Path]:
    """Replaces VERSION_NEXT_* placeholders with version in the specified files.

    Args:
        filepaths: An iterable of pathlib.Path objects to process.
        version: The release version string to replace placeholders with.

    Returns:
        List of pathlib.Path objects for files that were modified.
    """
    modified: list[pathlib.Path] = []
    for path in filepaths:
        if is_excluded_version_placeholder_path(path):
            continue
        try:
            content = path.read_text(encoding="utf-8")
        except (IOError, UnicodeDecodeError):
            continue

        if "VERSION_NEXT_FEATURE" in content or "VERSION_NEXT_PATCH" in content:
            new_content = content.replace("VERSION_NEXT_FEATURE", version)
            new_content = new_content.replace("VERSION_NEXT_PATCH", version)
            path.write_text(new_content, encoding="utf-8")
            modified.append(path)
    return modified


def replace_version_next(version: str) -> list[pathlib.Path]:
    """Replaces all VERSION_NEXT_* placeholders with the new version.

    Args:
        version: The release version string to replace placeholders with.

    Returns:
        List of pathlib.Path objects for files that were modified.
    """
    return replace_version_next_in_files(_iter_version_placeholder_files(), version)


def parse_pr_list(value: str) -> list[str]:
    """Parses a comma or space separated list of PR references.

    PR references can be numbers (optionally prefixed with '#') or URLs.
    """
    if not value:
        return []
    # Split by space and/or comma
    return [p for p in re.split(r"[\s,]+", value.strip()) if p]


def set_github_output(name: str, value: str) -> None:
    """Sets a GitHub Actions output parameter if GITHUB_OUTPUT is set."""
    if github_output := os.environ.get("GITHUB_OUTPUT"):
        with open(github_output, "a", encoding="utf-8") as f:
            f.write(f"{name}={value}\n")


def format_exception(e: BaseException) -> str:
    """Formats an exception to a string, including any attached PEP 678 notes."""
    msg = str(e)
    notes = getattr(e, "__notes__", None)
    if not notes:
        return msg
    return "\n".join(filter(None, [msg] + [str(note) for note in notes]))