"""
Skill system — each skill is a piece of domain knowledge or a capability
that can be attached to an agent to shape its behavior and system prompt.

A Skill is a lightweight object with:
- name            : short identifier (e.g. "media_info")
- description     : human-readable summary
- prompt_fragment : extra text injected into the agent's system prompt
- tools           : OpenAI function-calling tool definitions (list of dicts)
- execute         : async callable to run a tool → ToolResult
"""

from dataclasses import dataclass, field
from typing import Any, Awaitable, Callable, Dict, List, Optional
from src.config import get_config  # re-export so every skill can use it


# ---------------------------------------------------------------------------
# ToolResult — every skill executor must return this
# ---------------------------------------------------------------------------
@dataclass
class ToolResult:
    """Result of executing a tool.
    - success: True if the API returned 2xx and the action completed.
    - content: The message to feed back to the LLM (will be shown to the user).
    """
    content: str
    success: bool = True

    @classmethod
    def ok(cls, content: str) -> "ToolResult":
        return cls(content=content, success=True)

    @classmethod
    def fail(cls, content: str) -> "ToolResult":
        return cls(content=content, success=False)


# Type alias for a tool executor
ToolExecutor = Callable[[str, dict], Awaitable[ToolResult]]


@dataclass
class Skill:
    name: str
    description: str
    prompt_fragment: str = ""
    tools: List[Dict[str, Any]] = field(default_factory=list)
    execute: Optional[ToolExecutor] = None
    requires_auth: List[str] = field(default_factory=list)


# ---------------------------------------------------------------------------
# Global skill registry — populated at startup / import time
# ---------------------------------------------------------------------------
_skill_registry: Dict[str, Skill] = {}


def register(skill: Skill) -> None:
    """Register a skill so agents can look it up by name."""
    _skill_registry[skill.name] = skill


def get(name: str) -> Skill | None:
    """Return a registered skill by name, or None."""
    return _skill_registry.get(name)


def list_all() -> Dict[str, Skill]:
    """Return a shallow copy of the registry."""
    return dict(_skill_registry)


def get_combined_prompt(skill_names: list[str], base_prompt: str = "") -> str:
    """Build a system prompt from a base prompt + requested skill fragments."""
    parts = [base_prompt] if base_prompt else []
    for name in skill_names:
        s = get(name)
        if s and s.prompt_fragment:
            parts.append(s.prompt_fragment)
    return "\n\n".join(parts)


def get_all_tools(skill_names: list[str]) -> List[Dict[str, Any]]:
    """Collect all OpenAI tool definitions across the requested skills."""
    tools: List[Dict[str, Any]] = []
    seen: set[str] = set()
    for name in skill_names:
        s = get(name)
        if s:
            for t in s.tools:
                fn_name = t.get("function", {}).get("name", "")
                if fn_name and fn_name not in seen:
                    seen.add(fn_name)
                    tools.append(t)
    return tools


async def execute_tool(
    skill_names: list[str], tool_name: str, args: dict,
    discord_user_id: int | None = None,
) -> ToolResult | None:
    """Find the skill that owns *tool_name* and run its executor.
    
    If *discord_user_id* is provided, also checks whether the owning skill
    requires authentication for any services.  If auth is missing, returns
    a friendly ToolResult.fail(...) telling the user how to log in.
    
    Only logs failures to the console — successful calls are silent.
    """
    import logging
    logger = logging.getLogger("skills")

    for name in skill_names:
        s = get(name)
        if s and s.execute:
            for t in s.tools:
                if t.get("function", {}).get("name") == tool_name:
                    # --- Auth gate ---
                    if s.requires_auth and discord_user_id is not None:
                        from core import auth_store
                        from auth import get_auth_service
                        missing: list[str] = []
                        for svc in s.requires_auth:
                            if not auth_store.is_authenticated(discord_user_id, svc):
                                missing.append(svc)
                        if missing:
                            svc_displays = ", ".join(
                                (get_auth_service(m) and get_auth_service(m).display_name) or m
                                for m in missing
                            )
                            return ToolResult.fail(
                                f"You need to log in to {svc_displays} first. "
                                + " ".join(f"Send `/login {m}` in a DM to get started." for m in missing)
                            )
                    # --- End auth gate ---
                    try:
                        result = await s.execute(tool_name, args)
                        if not result.success:
                            logger.warning(
                                "⚠️  TOOL FAILED: %s | args=%s → %s",
                                tool_name, args, result.content[:300],
                            )
                        return result
                    except Exception as exc:
                        logger.exception(
                            "💥 TOOL CRASH: %s | args=%s", tool_name, args
                        )
                        return ToolResult.fail(
                            f"Tool '{tool_name}' crashed unexpectedly: {exc}"
                        )

    logger.warning("⚠️  TOOL NOT FOUND: %s (skills=%s)", tool_name, skill_names)
    return None