from __future__ import annotations

import re
from collections.abc import Iterable

from gitea_codex_bot.types import ParsedCommand

PREFIX_RE = re.compile(r"^@([^\s]+)\s+(.+)$", re.IGNORECASE | re.DOTALL)
HELP_ALIASES = {"-h", "--help", "help"}
SUPPORTED_COMMANDS = {"review", "explain", "fix", "ignore", "rerun"}


def parse_command(body: str, aliases: Iterable[str] | None = None) -> ParsedCommand | None:
    stripped = body.strip()
    match = PREFIX_RE.match(stripped)
    if not match:
        return None
    command_alias = match.group(1).lstrip("@").lower()
    allowed_aliases = {alias.lstrip("@").lower() for alias in (aliases or {"codex"})}
    if command_alias not in allowed_aliases:
        return None

    remainder = match.group(2).strip()
    if not remainder:
        return None
    parts = remainder.split(maxsplit=1)
    raw_name = parts[0].lower()
    rest = parts[1].strip() if len(parts) > 1 else ""
    if raw_name in HELP_ALIASES:
        return ParsedCommand(name="help", raw=stripped, arguments=[token for token in rest.split() if token])
    if raw_name not in SUPPORTED_COMMANDS:
        return None
    name = raw_name
    tokens = [token for token in rest.split() if token]

    parsed = ParsedCommand(name=name, raw=stripped, arguments=tokens)
    if name == "review":
        if "--full" in tokens:
            parsed.full = True
            parsed.mode = "full"
            parsed.mode_explicit = True
        for mode in ("security", "performance", "tests"):
            if mode in tokens:
                parsed.mode = mode
                parsed.mode_explicit = True
                break
    elif name == "fix":
        parsed.branch_fix = "--branch" in tokens
    return parsed