"""Start Claude Code in the myclaude project directory."""

import os
import shutil
import subprocess
import sys
from pathlib import Path

import click
from rich.console import Console

from myclaude.project_root import get_myclaude_project_root

console = Console()
stderr_console = Console(stderr=True)


def _resolve_chat_cwd() -> Path:
    root = get_myclaude_project_root()
    fallback = Path.home() / ".myclaude"
    if root == fallback:
        stderr_console.print(
            "[red]Cannot resolve myclaude project root.[/red] Run from the repo or set "
            "[cyan]MYCLAUDE_PROJECT_ROOT[/cyan].",
        )
        raise SystemExit(1)
    return root


def _parse_cwd_from_args(args: list[str]) -> tuple[str | None, list[str]]:
    """
    Parse --cwd with optional value from args.

    Returns (cwd_value, remaining_args).
    --cwd alone -> cwd_value='.'
    --cwd /path -> cwd_value='/path'
    --cwd .     -> cwd_value='.'
    """
    cwd_value: str | None = None
    remaining: list[str] = []
    skip_next = False

    for i, arg in enumerate(args):
        if skip_next:
            skip_next = False
            continue

        if arg in ("--cwd", "-C"):
            # Check if next arg exists and is not a flag
            if i + 1 < len(args) and not args[i + 1].startswith("-"):
                cwd_value = args[i + 1]
                skip_next = True
            else:
                # --cwd alone, default to current directory
                cwd_value = "."
        elif arg.startswith("--cwd="):
            cwd_value = arg[6:]
        elif arg.startswith("-C="):
            cwd_value = arg[3:]
        elif arg.startswith("-C") and len(arg) > 2:
            # -C/path or -C.
            cwd_value = arg[2:]
        else:
            remaining.append(arg)

    return cwd_value, remaining


@click.command(
    "chat",
    context_settings={
        "ignore_unknown_options": True,
        "allow_extra_args": True,
    },
)
@click.option(
    "--dangerously-skip-permissions",
    is_flag=True,
    default=False,
    help="Forward to claude: bypass permission checks (sandbox / isolated use only).",
)
@click.pass_context
def chat_cmd(ctx: click.Context, dangerously_skip_permissions: bool) -> None:
    """Run `claude` in the myclaude repo so CLAUDE.md and .claude/ apply; extra args pass through.

    \b
    Working directory options:
      --cwd, -C           Use current directory as working directory
      --cwd /path, -C/path  Use specified path as working directory
      (none)              Use myclaude project root (default)
    """
    binary = os.environ.get("CLAUDE_BIN") or shutil.which("claude")
    if not binary:
        stderr_console.print(
            "[red]claude CLI not found in PATH.[/red] Install Claude Code or set "
            "[cyan]CLAUDE_BIN[/cyan].",
        )
        raise SystemExit(127)

    # Parse --cwd from raw args (Click doesn't support optional values natively)
    cwd_value, remaining_args = _parse_cwd_from_args(ctx.args)

    if cwd_value is None:
        chat_cwd = _resolve_chat_cwd()
    else:
        chat_cwd = Path(cwd_value).resolve()
        if not chat_cwd.is_dir():
            stderr_console.print(f"[red]Not a directory:[/red] {cwd_value}")
            raise SystemExit(1)

    cmd: list[str] = [binary]
    if dangerously_skip_permissions:
        cmd.append("--dangerously-skip-permissions")
    cmd.extend(remaining_args)

    proc = subprocess.run(cmd, cwd=str(chat_cwd), check=False)
    raise SystemExit(proc.returncode)