#!/usr/bin/env python3
"""Validate commit messages for devx.

Rules:
- On feature branches: conventional commits ONLY, must NOT include <PREFIX>-N prefix.
- On master branch: must follow '<task-id>: <conventional commit>' pattern,
  e.g. 'DEVX-24: fix: resolve timeout'.

The task ID prefix is configurable via the ``DEVX_TASK_PREFIX`` environment
variable (default: ``DEVX``). Projects consuming devx (e.g., GRM) set
their own prefix (e.g., ``GRM``) so the validator enforces the correct
task ID format for each project.
"""

import re
import subprocess  # nosec B404
import sys

import click

from devx.config import CONVENTIONAL_RE, TASK_PREFIX
from devx.i18n import _

MASTER_TASK_ID_RE = re.compile(rf"^{TASK_PREFIX}-\d+:")


def get_latest_commit_msg() -> str:
    """Get the latest commit message from git."""
    result = subprocess.run(  # nosec
        ["git", "log", "-1", "--format=%B"],
        capture_output=True,
        text=True,
        check=True,
    )
    return result.stdout.strip()


def first_line(text: str) -> str:
    return text.split("\n")[0]


def get_branch() -> str:
    try:
        result = subprocess.run(  # nosec
            ["git", "symbolic-ref", "--short", "HEAD"],
            capture_output=True,
            text=True,
            check=True,
        )
        return result.stdout.strip()
    except subprocess.CalledProcessError:
        return ""


@click.command()
@click.argument("commit_msg_file", required=False)
@click.option("--branch", default=None, help="Override branch detection (for CI use).")
@click.option(
    "--git",
    "from_git",
    is_flag=True,
    default=False,
    help="Read commit message from git log instead of a file.",
)
def main(commit_msg_file: str | None, branch: str | None, from_git: bool) -> None:
    if from_git:
        msg = get_latest_commit_msg()
    elif commit_msg_file:
        if commit_msg_file == "-":
            msg = sys.stdin.read().strip()
        else:
            with open(commit_msg_file) as f:
                msg = f.read().strip()
    else:
        raise click.ClickException(_("Provide a commit message file or use --git."))

    if branch is None:
        branch = get_branch()
    subject = first_line(msg)

    if branch == "master":
        if not MASTER_TASK_ID_RE.match(subject):
            raise click.ClickException(
                _(
                    "Oops! Master branch commits must start with a task ID.\n"
                    "  Expected: {prefix}-N: <conventional commit message>\n"
                    "  Got:      {subject}",
                    prefix=TASK_PREFIX,
                    subject=subject,
                )
            )
        remainder = MASTER_TASK_ID_RE.sub("", subject).strip()
        if not CONVENTIONAL_RE.match(remainder):
            raise click.ClickException(
                _(
                    "Oops! Master branch commit must follow conventional format after task ID.\n"
                    "  Expected: {prefix}-N: <type>: <description>\n"
                    "  Got:      {subject}",
                    prefix=TASK_PREFIX,
                    subject=subject,
                )
            )
        return

    if MASTER_TASK_ID_RE.match(subject):
        raise click.ClickException(
            _(
                "Oops! Do not include task ID ({prefix}-N) in feature branch commits.\n"
                "  The task ID will be added automatically on merge via CI.",
                prefix=TASK_PREFIX,
            )
        )

    if not CONVENTIONAL_RE.match(subject):
        raise click.ClickException(
            _(
                "Oops! Commit message must follow conventional commit format.\n"
                "  Expected: <type>: <description>\n"
                "  Got:      {subject}\n"
                "  Allowed types: feat, fix, chore, docs, style, refactor,\n"
                "                 perf, test, ci, build, revert, BREAKING CHANGE",
                subject=subject,
            )
        )


if __name__ == "__main__":  # pragma: no cover
    main()