"""LLM extraction — primary qwen3-8b via llama-cpp, Tier 2 fallback to
claude-agent-service when qwen confidence is low or JSON unparseable.

Both backends speak the OpenAI-compatible chat-completions API. We
issue a strict JSON-schema prompt and parse the first `choices[0]`
message into `ExtractedExample`. Tier 2 escalation lives in
`extract_with_fallback` (added in Task 8) — primary failure is silent
(returns None) so the orchestrator can choose to escalate or skip.
"""
from __future__ import annotations

import json
import logging
from decimal import Decimal, InvalidOperation
from typing import Any

import httpx
from pydantic import ValidationError

from fire_planner.examples.models import ExtractedExample, RawPost

log = logging.getLogger(__name__)

QWEN_MODEL = "qwen3-8b"
CLAUDE_AGENT_MODEL = "claude-haiku-4-5"
HTTP_TIMEOUT = httpx.Timeout(60.0)

PROMPT_SYSTEM = (
    "You are extracting structured FIRE-example data from a Reddit post. "
    "Output ONLY a single JSON object with these keys (use null when the "
    "post does not say): country, city, portfolio_native (number), "
    "annual_exp_native (number), raw_currency (3-letter ISO), age (int), "
    "family_size (int, default 1 if single), fi_status (one of: "
    "accumulating, coastFIRE, baristaFIRE, leanFIRE, FIRE, fatFIRE, "
    "unknown), is_retired (bool), confidence (0.0-1.0). "
    "DO NOT include any prose or markdown — JSON only."
)


def _user_prompt(post: RawPost) -> str:
    return (
        f"Subreddit: {post.source_sub}\n"
        f"Title: {post.title}\n"
        f"Body:\n{post.body[:4000]}"
    )


async def extract_with_qwen(
    post: RawPost,
    llama_url: str,
    client: httpx.AsyncClient,
) -> ExtractedExample | None:
    """Call qwen3-8b via llama-cpp. Returns None on any failure."""
    return await _call_openai_chat(
        url=llama_url,
        model_name=QWEN_MODEL,
        post=post,
        client=client,
        record_model=QWEN_MODEL,
    )


async def _call_openai_chat(
    *,
    url: str,
    model_name: str,
    post: RawPost,
    client: httpx.AsyncClient,
    record_model: str,
    extra_headers: dict[str, str] | None = None,
) -> ExtractedExample | None:
    body = {
        "model": model_name,
        "messages": [
            {"role": "system", "content": PROMPT_SYSTEM},
            {"role": "user", "content": _user_prompt(post)},
        ],
        "temperature": 0.0,
        "max_tokens": 512,
    }
    try:
        resp = await client.post(
            url,
            json=body,
            timeout=HTTP_TIMEOUT,
            headers=extra_headers,
        )
        resp.raise_for_status()
    except httpx.HTTPError:
        log.warning("LLM call failed for %s via %s", post.reddit_id, url, exc_info=True)
        return None

    try:
        content: str = resp.json()["choices"][0]["message"]["content"]
    except (KeyError, IndexError, ValueError):
        log.warning("Unexpected LLM response shape for %s", post.reddit_id)
        return None

    return _parse_extracted_json(content, record_model)


def _parse_extracted_json(content: str, record_model: str) -> ExtractedExample | None:
    """Tolerant JSON parser — strip fences, parse, validate."""
    cleaned = (
        content.strip()
        .removeprefix("```json")
        .removeprefix("```")
        .removesuffix("```")
        .strip()
    )
    try:
        data: dict[str, Any] = json.loads(cleaned)
    except json.JSONDecodeError:
        log.warning("LLM returned unparseable JSON: %s", cleaned[:200])
        return None

    # Convert numeric fields to Decimal where present.
    for k in ("portfolio_native", "annual_exp_native", "confidence"):
        if data.get(k) is not None:
            try:
                data[k] = Decimal(str(data[k]))
            except InvalidOperation:
                data[k] = None

    data["llm_model"] = record_model
    try:
        return ExtractedExample.model_validate(data)
    except ValidationError:
        log.warning("LLM JSON failed schema validation: %s", cleaned[:200])
        return None


DEFAULT_CONFIDENCE_THRESHOLD = Decimal("0.5")


async def extract_with_claude(
    post: RawPost,
    claude_url: str,
    bearer: str,
    client: httpx.AsyncClient,
) -> ExtractedExample | None:
    """Call claude-agent-service. Returns None on any failure."""
    return await _call_openai_chat(
        url=claude_url,
        model_name=CLAUDE_AGENT_MODEL,
        post=post,
        client=client,
        record_model=CLAUDE_AGENT_MODEL,
        extra_headers={"Authorization": f"Bearer {bearer}"},
    )


async def extract_with_fallback(
    post: RawPost,
    *,
    llama_url: str,
    claude_url: str,
    claude_bearer: str,
    client: httpx.AsyncClient,
    confidence_threshold: Decimal = DEFAULT_CONFIDENCE_THRESHOLD,
) -> ExtractedExample | None:
    """Try qwen first; escalate to claude on failure or low confidence.

    Returns None only when both backends fail (the orchestrator drops
    the post and increments `fire_examples_extract_failed_total`).
    """
    primary = await extract_with_qwen(post, llama_url=llama_url, client=client)
    if primary is not None and primary.confidence >= confidence_threshold:
        return primary
    log.info(
        "Escalating %s to Tier 2 (primary=%s)",
        post.reddit_id,
        "none" if primary is None else f"conf={primary.confidence}",
    )
    secondary = await extract_with_claude(
        post,
        claude_url=claude_url,
        bearer=claude_bearer,
        client=client,
    )
    return secondary or primary