from __future__ import annotations

import json
import re
import time
from concurrent.futures import ThreadPoolExecutor
from pathlib import Path
from typing import Callable

from review_agent.llm import generate_completion
from review_agent.regulatory_info_package.schemas import InstructionExtractResult


FIELD_PATTERNS = {
    "product_name": ("产品名称", r"产品名称[:：\s]*([^\n\r]+)"),
    "storage_condition": ("储存条件", r"(?:储存条件|贮存条件|保存条件)[:：\s]*([^\n\r]+)"),
    "intended_use": ("预期用途", r"预期用途[:：\s]*([^\n\r]+)"),
    "package_specification": ("包装规格", r"(?:包装规格|规格)[:：\s]*([^\n\r]+)"),
    "sample_type": ("样本类型", r"样本类型[:：\s]*([^\n\r]+)"),
    "applicable_instrument": ("适用仪器", r"适用仪器[:：\s]*([^\n\r]+)"),
    "standard_no": ("标准号", r"((?:GB|YY|WS|T/C[A-Z0-9]*)[ /T0-9.\-—]+)"),
}


def extract_fields_by_rules(instruction: InstructionExtractResult) -> dict[str, dict]:
    text = "\n".join([instruction.front_text, *instruction.paragraphs, *instruction.sections.values()])
    results: dict[str, dict] = {}
    for key, (label, pattern) in FIELD_PATTERNS.items():
        section_value = _value_after_label_paragraph(instruction.paragraphs, label)
        if section_value:
            results[key] = {
                "label": label,
                "value": section_value,
                "evidence": f"【{label}】\n{section_value}",
                "confidence": 0.82,
                "source": "rule",
            }
            continue
        match = re.search(pattern, text, flags=re.IGNORECASE)
        if match:
            value = _clean_value(match.group(1))
            if value:
                results[key] = {
                    "label": label,
                    "value": value,
                    "evidence": match.group(0)[:240],
                    "confidence": 0.75,
                    "source": "rule",
                }
    return results


def extract_fields_with_llm(instruction: InstructionExtractResult) -> dict[str, dict]:
    prompt = (
        "请从体外诊断试剂产品说明书中抽取字段，输出 JSON 对象，字段包括 "
        "product_name、storage_condition、intended_use、package_specification、sample_type、applicable_instrument、standard_no。"
        "每个字段值为 {label,value,evidence,confidence}。\n\n"
        + instruction.front_text[:6000]
    )
    raw = generate_completion([{"role": "user", "content": prompt}], temperature=0.0)
    payload = _parse_json_object(raw)
    return {key: value for key, value in payload.items() if isinstance(value, dict)}


def run_llm_extract_with_retry(
    instruction: InstructionExtractResult,
    *,
    llm_extract_func: Callable[[InstructionExtractResult], dict[str, dict]] | None = None,
    sleep_func: Callable[[float], None] = time.sleep,
) -> dict[str, dict]:
    func = llm_extract_func or extract_fields_with_llm
    last_exc: Exception | None = None
    for delay in [0, 1, 2]:
        if delay:
            sleep_func(delay)
        try:
            return func(instruction)
        except Exception as exc:
            last_exc = exc
    if last_exc:
        raise last_exc
    return {}


def run_parallel_extract(
    instruction: InstructionExtractResult,
    *,
    llm_extract_func: Callable[[InstructionExtractResult], dict[str, dict]] | None = None,
) -> dict:
    payload = {"regex_results": {}, "llm_results": {}, "llm_error": ""}
    with ThreadPoolExecutor(max_workers=2) as executor:
        rule_future = executor.submit(extract_fields_by_rules, instruction)
        llm_future = executor.submit(run_llm_extract_with_retry, instruction, llm_extract_func=llm_extract_func)
        payload["regex_results"] = rule_future.result()
        try:
            payload["llm_results"] = llm_future.result()
        except Exception as exc:
            payload["llm_error"] = str(exc)
    return payload


def save_field_extract_result(path: str | Path, payload: dict) -> Path:
    target = Path(path)
    target.parent.mkdir(parents=True, exist_ok=True)
    target.write_text(json.dumps(payload, ensure_ascii=False, indent=2), encoding="utf-8")
    return target


def _clean_value(value: str) -> str:
    cleaned = value.strip()
    if cleaned in {"】", "】】", "】:"}:
        return ""
    return re.split(r"[。；;]", cleaned)[0].strip()


def _value_after_label_paragraph(paragraphs: list[str], label: str) -> str:
    bracketed = {f"【{label}】", f"[{label}]", label}
    for index, text in enumerate(paragraphs):
        stripped = text.strip()
        if stripped in bracketed and index + 1 < len(paragraphs):
            return _clean_value(paragraphs[index + 1])
    return ""


def _parse_json_object(raw: str) -> dict:
    text = (raw or "").strip()
    if text.startswith("```"):
        text = text.strip("`").strip()
        if text.lower().startswith("json"):
            text = text[4:].strip()
    start = text.find("{")
    end = text.rfind("}")
    if start == -1 or end == -1:
        return {}
    return json.loads(text[start : end + 1])