"""Step type registry — pluggable step_type metadata.

Each pipeline can define its own step_types. The registry tracks:
- handler function (already in handler.py)
- metadata: display_name, category, is_interactive, form_schema, on_timeout

Built-in interactive types: human_task, approval_gate
"""

import logging
from typing import Dict, Optional

logger = logging.getLogger("pipeline.step_registry")

# step_type -> metadata dict
_REGISTRY: Dict[str, dict] = {}

# Built-in interactive step types
BUILTIN_INTERACTIVE = {
    "human_task": {
        "display_name": "人工任务",
        "category": "interactive",
        "is_interactive": True,
        "description": "需要人工填写表单或执行操作后继续",
    },
    "approval_gate": {
        "display_name": "审批关卡",
        "category": "interactive",
        "is_interactive": True,
        "description": "需要审批人通过后继续，可驳回",
    },
}


def register_step_type(step_type: str, metadata: dict):
    """Register a step type with metadata.

    Args:
        step_type: unique key matching pipeline_steps.step_type
        metadata: dict with keys:
            - display_name (str): 显示名称
            - category (str): 分类 (media/llm/interactive/devops/...)
            - is_interactive (bool): 是否需要人工介入, default False
            - description (str): 描述
            - form_schema (dict): 人工任务表单JSON Schema (可选)
            - on_timeout (str): 超时策略 skip/escalate/fail (可选)
            - timeout_hours (int): 超时小时数 (可选)
    """
    existing = _REGISTRY.get(step_type, {})
    existing.update(metadata)
    _REGISTRY[step_type] = existing
    logger.info(f"Registered step_type: {step_type} (interactive={metadata.get('is_interactive', False)})")


def get_step_type(step_type: str) -> Optional[dict]:
    """Get step type metadata. Returns None if not registered."""
    return _REGISTRY.get(step_type)


def is_interactive(step_type: str) -> bool:
    """Check if a step type requires human interaction."""
    meta = _REGISTRY.get(step_type, {})
    return meta.get("is_interactive", False)


def list_step_types() -> Dict[str, dict]:
    """List all registered step types with metadata."""
    return dict(_REGISTRY)


def unregister_step_type(step_type: str):
    """Remove a step type from registry."""
    removed = _REGISTRY.pop(step_type, None)
    if removed:
        logger.info(f"Unregistered step_type: {step_type}")


def load_builtin_types():
    """Load built-in interactive step types."""
    for st, meta in BUILTIN_INTERACTIVE.items():
        register_step_type(st, meta)