"""CLI handlers for ``hermes migrate ...``.

Currently exposes only ``hermes migrate xai`` — diagnoses and (with --apply)
rewrites references to xAI models retired on May 15, 2026.
"""
from __future__ import annotations

import sys
from pathlib import Path
from typing import Any

from hermes_cli.colors import Colors, color
from hermes_cli.config import load_config


def cmd_migrate(args: Any) -> int:
    """Dispatcher for ``hermes migrate <subtype>``."""
    sub = getattr(args, "migrate_type", None)
    if sub == "xai":
        return cmd_migrate_xai(args)

    print("usage: hermes migrate xai [--apply] [--no-backup]", file=sys.stderr)
    return 2


def cmd_migrate_xai(args: Any) -> int:
    """Run xAI May-15 model migration in dry-run or apply mode."""
    from hermes_cli.xai_retirement import (
        MIGRATION_GUIDE_URL,
        RETIREMENT_DATE,
        apply_migration,
        find_retired_xai_refs,
        format_issue,
    )

    apply = bool(getattr(args, "apply", False))
    no_backup = bool(getattr(args, "no_backup", False))

    config = load_config()
    issues = find_retired_xai_refs(config)

    print()
    print(color(
        f"◆ xAI Model Retirement Migration ({RETIREMENT_DATE})",
        Colors.CYAN, Colors.BOLD,
    ))
    print()

    if not issues:
        print(f"  {color('✓', Colors.GREEN)} No retired xAI models in config — nothing to migrate.")
        return 0

    print(f"  Found {len(issues)} retired xAI model reference(s):")
    print()
    for issue in issues:
        print(f"    {color('⚠', Colors.YELLOW)} {format_issue(issue)}")
    print()
    print(f"    {color('→', Colors.CYAN)} Migration guide: {MIGRATION_GUIDE_URL}")
    print()

    config_path = _resolve_config_path()

    if not apply:
        print(color("Dry-run mode — no changes written.", Colors.DIM))
        print(color(
            "Re-run with `hermes migrate xai --apply` to rewrite "
            f"{config_path} in-place (backup created automatically).",
            Colors.DIM,
        ))
        return 0

    if not config_path or not config_path.exists():
        print(
            f"  {color('✗', Colors.RED)} Could not locate config.yaml "
            f"(looked at: {config_path})",
            file=sys.stderr,
        )
        return 1

    try:
        result = apply_migration(
            config_path=config_path,
            issues=issues,
            backup=not no_backup,
        )
    except Exception as exc:
        print(
            f"  {color('✗', Colors.RED)} Migration failed: {exc}",
            file=sys.stderr,
        )
        return 1

    if not result.config_changed:
        print(f"  {color('⚠', Colors.YELLOW)} No changes written.")
        return 0

    if result.backup_path is not None:
        print(f"  {color('✓', Colors.GREEN)} Backup: {result.backup_path}")
    print(
        f"  {color('✓', Colors.GREEN)} Updated {len(result.issues_resolved)} "
        f"slot(s) in {result.file_path}"
    )
    print()
    print(color(
        "Run `hermes doctor` to confirm no retired xAI models remain.",
        Colors.DIM,
    ))
    return 0


def _resolve_config_path() -> Path:
    """Best-effort: locate the active config.yaml on disk."""
    from hermes_cli.config import get_hermes_home

    return get_hermes_home() / "config.yaml"
