"""
FastAPI app for the FIPI scraper service.
"""

from __future__ import annotations

from datetime import datetime
import logging
import os
from pathlib import Path
import re
import ssl
from typing import Dict, List, Optional
from urllib.parse import parse_qs, urlparse

from bs4 import BeautifulSoup
from dotenv import load_dotenv
from fastapi import BackgroundTasks, FastAPI, HTTPException
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import JSONResponse
import httpx

from models import (
    CheckAnswerRequest,
    CheckAnswerResponse,
    ErrorResponse,
    HealthResponse,
    ScrapeRequest,
    ScrapeResponse,
    StatsResponse,
    TaskResponse,
)
from scraper import FIPIScraper

BASE_DIR = Path(__file__).resolve().parent
load_dotenv(BASE_DIR / ".env")

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

SUPABASE_AVAILABLE = False
SupabaseClient = None

try:
    from supabase_client import SupabaseClient

    SUPABASE_AVAILABLE = True
except ImportError as exc:
    logger.warning("Supabase client import failed: %s", exc)
except Exception as exc:  # pragma: no cover - startup guard
    logger.warning("Supabase client init failed: %s", exc)


app = FastAPI(
    title="AI Scraper FIPI",
    description="Collects, stores and validates FIPI tasks.",
    version="1.1.1-proof-20260317",
)

app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

scraper: Optional[FIPIScraper] = None
supabase_client: Optional[SupabaseClient] = None
last_auto_refresh_at: Optional[datetime] = None
refresh_in_progress = False


@app.on_event("startup")
async def startup_event() -> None:
    global scraper, supabase_client

    scraper = FIPIScraper(base_url=os.getenv("FIPI_BASE_URL", "https://fipi.ru"))
    logger.info("FIPIScraper initialized")

    if not SUPABASE_AVAILABLE:
        logger.info("Supabase disabled")
        return

    supabase_url = os.getenv("SUPABASE_URL")
    supabase_key = os.getenv("SUPABASE_SERVICE_KEY")
    if not supabase_url or not supabase_key:
        logger.warning("SUPABASE_URL or SUPABASE_SERVICE_KEY missing")
        return

    try:
        client = SupabaseClient(url=supabase_url, key=supabase_key)
        if await client.is_available():
            supabase_client = client
            logger.info("Supabase client connected")
        else:
            logger.error("Supabase is unavailable")
    except Exception as exc:  # pragma: no cover - startup guard
        logger.error("Supabase startup error: %s", exc)


def _require_supabase() -> SupabaseClient:
    if not supabase_client:
        raise HTTPException(status_code=503, detail="Supabase is not configured")
    return supabase_client


def _require_scraper() -> FIPIScraper:
    if not scraper:
        raise HTTPException(status_code=503, detail="Scraper is not configured")
    return scraper


def _can_check_answer(task: Dict) -> bool:
    if task.get("source_kind") == "dynamic_bank" and task.get("task_guid"):
        return True

    source_url = task.get("source_url", "")
    parsed = urlparse(source_url)
    query = parse_qs(parsed.query)
    project_guid = (query.get("proj") or [None])[0]
    question_id = (query.get("qid") or [None])[0]

    return parsed.path.endswith("/questions.php") and bool(project_guid and (question_id or task.get("task_guid")))


def _serialize_task(task: Dict) -> Dict:
    payload = dict(task)
    payload["can_check_answer"] = _can_check_answer(task)
    return payload


async def _persist_tasks(tasks: List[Dict]) -> Dict[str, int]:
    client = _require_supabase()
    saved = 0
    duplicates = 0
    for task in tasks:
        result = await client.insert_task(task)
        if result:
            saved += 1
        else:
            duplicates += 1
    return {"saved": saved, "duplicates": duplicates}


async def _collect_tasks(subject: str = "russian", *, include_official_archives: bool = True) -> List[Dict]:
    service = _require_scraper()
    if include_official_archives:
        return await service.scrape_tasks(subject=subject, include_official_archives=True)
    return await service.scrape_dynamic_bank(subject=subject)


async def _refresh_tasks(subject: str = "russian", *, include_official_archives: bool = True) -> Dict[str, int]:
    scraped_tasks = await _collect_tasks(
        subject=subject,
        include_official_archives=include_official_archives,
    )
    persisted = await _persist_tasks(scraped_tasks)
    return {
        "scraped": len(scraped_tasks),
        "saved": persisted["saved"],
        "duplicates": persisted["duplicates"],
    }


def _needs_task_refresh(tasks: List[Dict]) -> bool:
    if not tasks:
        return True

    dynamic_count = sum(1 for task in tasks if task.get("source_kind") == "dynamic_bank")
    checkable_count = sum(1 for task in tasks if _can_check_answer(task))
    minimum_total = max(10, int(os.getenv("SCRAPER_MIN_READY_TASKS", "40")))

    if dynamic_count == 0 or checkable_count == 0:
        return True

    return len(tasks) < minimum_total


def _needs_dynamic_bank_refresh(tasks: List[Dict]) -> bool:
    if not tasks:
        return True

    dynamic_count = sum(1 for task in tasks if task.get("source_kind") == "dynamic_bank")
    checkable_count = sum(1 for task in tasks if _can_check_answer(task))
    return dynamic_count == 0 or checkable_count == 0


def _is_refresh_running() -> bool:
    return refresh_in_progress


async def _run_refresh(subject: str = "russian", include_official_archives: bool = True) -> None:
    global refresh_in_progress

    try:
        refresh_in_progress = True
        refreshed = await _refresh_tasks(
            subject=subject,
            include_official_archives=include_official_archives,
        )
        logger.info(
            "Background refresh finished: scraped=%s saved=%s duplicates=%s include_archives=%s",
            refreshed["scraped"],
            refreshed["saved"],
            refreshed["duplicates"],
            include_official_archives,
        )
    except Exception as exc:  # pragma: no cover - background guard
        logger.error("Background refresh failed: %s", exc)
    finally:
        refresh_in_progress = False


def _schedule_refresh(
    background_tasks: BackgroundTasks,
    subject: str = "russian",
    *,
    include_official_archives: bool = True,
) -> bool:
    global last_auto_refresh_at

    if _is_refresh_running():
        return False

    last_auto_refresh_at = datetime.utcnow()
    background_tasks.add_task(_run_refresh, subject, include_official_archives)
    return True


async def _ensure_tasks_available(background_tasks: BackgroundTasks, subject: str = "russian") -> List[Dict]:
    global last_auto_refresh_at

    client = _require_supabase()
    existing = await client.get_all_tasks()
    if existing and not _needs_task_refresh(existing):
        return existing

    if not existing:
        logger.info("Tasks table is empty, running initial dynamic scrape")
        last_auto_refresh_at = datetime.utcnow()
        await _refresh_tasks(subject=subject, include_official_archives=False)
        refreshed = await client.get_all_tasks()
        if refreshed and _schedule_refresh(background_tasks, subject, include_official_archives=True):
            logger.info("Scheduled full refresh after initial dynamic scrape")
        return refreshed or existing

    if _needs_dynamic_bank_refresh(existing):
        if _is_refresh_running():
            logger.info("Dynamic bank refresh is already running, returning existing tasks")
            return existing

        if _schedule_refresh(background_tasks, subject, include_official_archives=False):
            logger.info("Tasks are missing dynamic/checkable entries, scheduled targeted dynamic refresh")
        else:
            logger.info("Unable to schedule targeted dynamic refresh, returning existing tasks")
        return existing

    cooldown_minutes = max(1, int(os.getenv("SCRAPER_AUTO_REFRESH_COOLDOWN_MINUTES", "30")))
    if last_auto_refresh_at and (datetime.utcnow() - last_auto_refresh_at).total_seconds() < cooldown_minutes * 60:
        logger.info("Skipping auto refresh because cooldown is active")
        return existing

    if _schedule_refresh(background_tasks, subject, include_official_archives=True):
        logger.info("Existing tasks are stale or incomplete, scheduled background refresh")
    else:
        logger.info("Refresh is already running, returning existing tasks")

    return existing


def _normalize_answer(answer: str) -> str:
    return re.sub(r"\s+", "", answer.strip()).upper()


async def _resolve_task_guid(task: Dict) -> Optional[str]:
    if task.get("task_guid"):
        return task["task_guid"]

    source_url = task.get("source_url", "")
    if not _can_check_answer(task):
        return None

    html = await _require_scraper().fetch_page(source_url)
    if not html:
        return None

    soup = BeautifulSoup(html, "lxml")
    guid_input = soup.select_one("form[id^='checkform'] input[name='guid']")
    return guid_input.get("value") if guid_input and guid_input.get("value") else None


async def _check_task_answer(task: Dict, answer: str) -> CheckAnswerResponse:
    if not _can_check_answer(task):
        raise HTTPException(status_code=400, detail="This task does not support answer checking")

    normalized = _normalize_answer(answer)
    if not normalized:
        raise HTTPException(status_code=400, detail="Answer is empty")

    parsed = urlparse(task["source_url"])
    query = parse_qs(parsed.query)
    project_guid = (query.get("proj") or [None])[0]
    task_guid = await _resolve_task_guid(task)

    if not project_guid or not task_guid:
        raise HTTPException(status_code=500, detail="Unable to resolve FIPI task metadata")

    solve_url = f"{parsed.scheme}://{parsed.netloc}{parsed.path.rsplit('/', 1)[0]}/solve.php"
    ssl_context = ssl.create_default_context()
    ssl_context.check_hostname = False
    ssl_context.verify_mode = ssl.CERT_NONE

    async with httpx.AsyncClient(
        headers=_require_scraper().headers,
        timeout=45.0,
        verify=ssl_context,
        follow_redirects=True,
        trust_env=False,
    ) as client:
        page_response = await client.get(task["source_url"])
        page_response.raise_for_status()
        response = await client.post(
            solve_url,
            data={
                "guid": task_guid,
                "answer": normalized,
                "ajax": "1",
                "proj": project_guid,
            },
            headers={"Referer": task["source_url"]},
        )
        response.raise_for_status()

    if not response:
        raise HTTPException(status_code=502, detail="FIPI answer check failed")

    status_code = response.text.strip()
    status_map = {
        "0": ("not_solved", False, "Не решено"),
        "1": ("solved", True, "Решено"),
        "2": ("incorrect", False, "Неверно"),
        "3": ("correct", True, "Верно"),
    }
    if status_code not in status_map:
        raise HTTPException(status_code=502, detail=f"Unexpected FIPI response: {status_code}")

    status_label, is_correct, message = status_map[status_code]
    return CheckAnswerResponse(
        success=True,
        is_correct=is_correct,
        status_code=status_label,
        status_label=message,
        submitted_answer=answer,
        normalized_answer=normalized,
        message=message,
    )


@app.get("/api/health", response_model=HealthResponse)
async def health_check() -> HealthResponse:
    services = {
        "api": True,
        "scraper": scraper is not None,
        "supabase": False,
    }

    if supabase_client:
        try:
            services["supabase"] = await supabase_client.is_available()
        except Exception:
            services["supabase"] = False

    all_critical_ok = services["api"] and services["scraper"]
    if all_critical_ok and all(services.values()):
        status = "healthy"
    elif all_critical_ok:
        status = "degraded"
    else:
        status = "unhealthy"

    return HealthResponse(status=status, timestamp=datetime.utcnow(), services=services)


@app.get("/api/tasks", response_model=List[TaskResponse])
async def get_all_tasks(background_tasks: BackgroundTasks) -> List[TaskResponse]:
    tasks = await _ensure_tasks_available(background_tasks)
    return [TaskResponse(**_serialize_task(task)) for task in tasks]


@app.get("/api/tasks/latest", response_model=List[TaskResponse])
async def get_latest_tasks(limit: int = 10) -> List[TaskResponse]:
    tasks = await _require_supabase().get_latest_tasks(limit=limit)
    return [TaskResponse(**_serialize_task(task)) for task in tasks]


@app.get("/api/tasks/{task_id}", response_model=TaskResponse)
async def get_task(task_id: int) -> TaskResponse:
    task = await _require_supabase().get_task_by_id(task_id)
    if not task:
        raise HTTPException(status_code=404, detail="Task not found")
    return TaskResponse(**_serialize_task(task))


@app.post("/api/tasks/{task_id}/check-answer", response_model=CheckAnswerResponse)
async def check_task_answer(task_id: int, request: CheckAnswerRequest) -> CheckAnswerResponse:
    task = await _require_supabase().get_task_by_id(task_id)
    if not task:
        raise HTTPException(status_code=404, detail="Task not found")
    return await _check_task_answer(task, request.answer)


@app.get("/api/tasks/type/{task_type}", response_model=List[TaskResponse])
async def get_tasks_by_type(task_type: str) -> List[TaskResponse]:
    tasks = await _require_supabase().get_tasks_by_type(task_type)
    return [TaskResponse(**_serialize_task(task)) for task in tasks]


@app.get("/api/tasks/search", response_model=List[TaskResponse])
async def search_tasks(q: str) -> List[TaskResponse]:
    tasks = await _require_supabase().search_tasks(q)
    return [TaskResponse(**_serialize_task(task)) for task in tasks]


@app.post("/api/scrape", response_model=ScrapeResponse)
async def scrape_tasks(request: ScrapeRequest) -> ScrapeResponse:
    client = _require_supabase()
    service = _require_scraper()

    try:
        tasks_scraped = 0
        tasks_saved = 0
        duplicates_skipped = 0

        if request.urls:
            for url in request.urls:
                html = await service.fetch_page(url)
                task = service.parse_task_page(html, url) if html else None
                if not task:
                    continue
                tasks_scraped += 1
                result = await client.insert_task(task)
                if result:
                    tasks_saved += 1
                else:
                    duplicates_skipped += 1
        elif request.query:
            tasks = await service.search_tasks(request.query)
            tasks_scraped = len(tasks)
            persisted = await _persist_tasks(tasks)
            tasks_saved = persisted["saved"]
            duplicates_skipped = persisted["duplicates"]
        else:
            if request.full_refresh:
                tasks = await service.scrape_tasks(
                    subject=request.subject or "russian",
                    include_official_archives=True,
                )
            else:
                tasks = await service.scrape_dynamic_bank(subject=request.subject or "russian")
            tasks_scraped = len(tasks)
            persisted = await _persist_tasks(tasks)
            tasks_saved = persisted["saved"]
            duplicates_skipped = persisted["duplicates"]

        return ScrapeResponse(
            success=True,
            tasks_scraped=tasks_scraped,
            tasks_saved=tasks_saved,
            duplicates_skipped=duplicates_skipped,
            message=(
                f"Processed {tasks_scraped} tasks. "
                f"Saved: {tasks_saved}, duplicates: {duplicates_skipped}"
            ),
        )
    except HTTPException:
        raise
    except Exception as exc:  # pragma: no cover - endpoint guard
        logger.error("Scrape error: %s", exc)
        raise HTTPException(status_code=500, detail=f"Scrape error: {exc}")


@app.get("/api/stats", response_model=StatsResponse)
async def get_stats() -> StatsResponse:
    client = _require_supabase()
    stats = await client.get_stats()
    latest = await client.get_latest_tasks(limit=1)
    last_scrape = latest[0].get("scraped_at") if latest else None
    return StatsResponse(
        total_tasks=stats.get("total", 0),
        by_type=stats.get("by_type", {}),
        last_scrape=last_scrape,
    )


@app.get("/", tags=["root"])
async def root() -> Dict[str, str]:
    return {
        "message": "AI Scraper FIPI API proof-20260317",
        "version": "1.1.1-proof-20260317",
        "docs": "/docs",
    }


@app.exception_handler(Exception)
async def global_exception_handler(request, exc) -> JSONResponse:
    logger.error("Unhandled exception: %s", exc)
    payload = ErrorResponse(
        error="Internal Server Error",
        detail=str(exc),
        timestamp=datetime.utcnow(),
    )
    return JSONResponse(status_code=500, content=payload.model_dump(mode="json"))


if __name__ == "__main__":
    import uvicorn

    uvicorn.run(app, host="0.0.0.0", port=8000)