import json
import logging
import os

from services.llm import LLMError, send_message_with_model, send_message

logger = logging.getLogger(__name__)

FACTS_MODEL = os.getenv("RPG_FACTS_MODEL", "").strip() or "deepseek/deepseek-chat-v3"

FACTS_SYSTEM = """Extract stable facts from the conversation.
Return ONLY valid JSON (no markdown), as an array of short strings.
Rules:
- Facts must be durable (names, relations, inventory, locations, world rules).
- Do not include ephemeral actions unless they change state.
- Avoid duplicates.
- Keep each fact <= 120 chars.
Example output:
["User name is Alex", "We are in a ruined castle", "NPC Mira distrusts the user"]"""


def merge_facts(existing_json: str, new_facts: list[str], limit: int = 80) -> str:
    try:
        existing = json.loads(existing_json or "[]")
        if not isinstance(existing, list):
            existing = []
    except json.JSONDecodeError:
        existing = []

    seen = {str(x).strip() for x in existing if str(x).strip()}
    merged = [str(x).strip() for x in existing if str(x).strip()]
    for f in new_facts:
        s = str(f).strip()
        if not s or s in seen:
            continue
        seen.add(s)
        merged.append(s)

    if len(merged) > limit:
        merged = merged[-limit:]
    return json.dumps(merged, ensure_ascii=False)


async def extract_facts(context_messages: list[dict]) -> list[str]:
    # Build a compact transcript
    transcript = "\n".join(
        f"{m.get('role')}: {m.get('content','')}".strip()
        for m in context_messages
        if m.get("role") in ("user", "assistant")
    )[-6000:]

    messages = [
        {"role": "system", "content": FACTS_SYSTEM},
        {"role": "user", "content": transcript},
    ]

    try:
        raw = await (
            send_message_with_model(messages, FACTS_MODEL)
            if FACTS_MODEL
            else send_message(messages)
        )
    except LLMError as e:
        logger.warning("extract_facts LLM failed (model=%s): %s", FACTS_MODEL or "SYSTEM", e)
        return []
    except Exception as e:
        logger.warning("extract_facts unexpected error: %s", e)
        return []

    try:
        data = json.loads(raw.strip())
        if isinstance(data, list):
            return [str(x) for x in data][:40]
    except Exception:
        return []
    return []


def facts_to_prompt(facts_json: str, max_items: int = 20) -> str:
    try:
        facts = json.loads(facts_json or "[]")
        if not isinstance(facts, list):
            return ""
    except json.JSONDecodeError:
        return ""
    facts = [str(x).strip() for x in facts if str(x).strip()]
    if not facts:
        return ""
    block = "\n".join(f"- {x}" for x in facts[-max_items:])
    return f"--- Facts (persistent memory) ---\n{block}\n---"