"""Prompt construction for llm-connect delegation (CYA-WP-0008)."""

from __future__ import annotations

import json
from typing import Any

from cya.llm.adapter import AssistanceRequest

_DEFAULT_SYSTEM = """You are cya, a console-native assistant for practical local work from the shell.

Help the user with command-line tasks: repository inspection, file workflows, command
suggestion, command explanation, and local context summarization.

Be concise and practical. When suggesting shell commands, explain risks briefly.
Do not claim to have executed anything — the user runs commands themselves.
Reference the provided context when it is relevant."""


def default_system_prompt() -> str:
    return _DEFAULT_SYSTEM


def build_assistance_prompt(request: AssistanceRequest, *, system_prompt: str | None = None) -> tuple[str, str]:
    """Return (system_prompt, user_prompt) for llm-connect execute_prompt."""
    system = system_prompt or default_system_prompt()
    parts: list[str] = []

    context = request.context or {}
    session_turns = context.get("session_turns")
    if session_turns:
        parts.append("## Recent conversation")
        for turn in session_turns:
            parts.append(f"User: {turn.get('user', '')}")
            parts.append(f"Assistant: {turn.get('assistant', '')}")

    envelope = {k: v for k, v in context.items() if k not in ("session_turns", "memory")}
    if envelope:
        parts.append("## Local context")
        parts.append(_summarize_context(envelope))

    memory = context.get("memory")
    if isinstance(memory, dict) and memory.get("items"):
        parts.append("## Activated memory")
        for item in memory["items"][:8]:
            parts.append(f"- [{item.get('kind', '?')}] {item.get('key', '?')}: {item.get('value', '')}")

    parts.append("## Current request")
    parts.append(request.user_request.strip())

    return system, "\n\n".join(parts)


def _summarize_context(envelope: dict[str, Any]) -> str:
    """Compact, JSON-safe context summary to stay within prompt budget."""
    summary: dict[str, Any] = {}
    if envelope.get("cwd"):
        summary["cwd"] = envelope["cwd"]
    if envelope.get("git"):
        git = envelope["git"]
        summary["git"] = {
            k: git[k]
            for k in ("branch", "status_short", "workdir", "is_repo")
            if k in git
        }
    if envelope.get("top_level"):
        names = [e.get("name") for e in envelope["top_level"][:30] if e.get("name")]
        summary["top_level"] = names
    if envelope.get("env"):
        summary["env"] = envelope["env"]
    if envelope.get("notes"):
        summary["notes"] = envelope["notes"][:5]
    return json.dumps(summary, indent=2, default=str)