from __future__ import annotations

import json
import logging
import os
import shutil
import time
from collections import defaultdict, deque
from pathlib import Path

import pandas as pd
from fastapi import BackgroundTasks, FastAPI, HTTPException, Request
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import FileResponse, JSONResponse
from fastapi.staticfiles import StaticFiles

from web.job_store import JobStore
from web.schemas import JobPreview, JobRequest, JobSummary, JobStatus


REPO_ROOT = Path(__file__).resolve().parents[2]
STATIC_DIR = REPO_ROOT / "web" / "static"
JOBS_DIR = REPO_ROOT / "tmp" / "web_jobs"
LOG_DIR = REPO_ROOT / "logs"
LOG_DIR.mkdir(parents=True, exist_ok=True)

logging.basicConfig(
    level=logging.INFO,
    filename=str(LOG_DIR / "webapp.log"),
    filemode="a",
    format="%(asctime)s %(levelname)s %(message)s",
)
logger = logging.getLogger("equitia.web")

app = FastAPI(title="EQUITIA Web API", version="0.1.0")
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=False,
    allow_methods=["*"],
    allow_headers=["*"],
)
MAX_PENDING_JOBS = int(os.getenv("EQUITIA_MAX_PENDING_JOBS", "20"))
RETENTION_MINUTES = int(os.getenv("EQUITIA_RETENTION_MINUTES", "60"))
job_store = JobStore(JOBS_DIR, max_pendientes=MAX_PENDING_JOBS, retention_minutes=RETENTION_MINUTES)


MAX_BODY_BYTES = 300_000
RATE_LIMIT_WINDOW = 60
RATE_LIMIT_REQUESTS = 30
request_buckets: dict[str, deque[float]] = defaultdict(deque)
blocked_ips: dict[str, float] = {}
BLOCK_SECONDS = 300
MAX_429_BEFORE_BLOCK = 3
rate_limit_hits: dict[str, int] = defaultdict(int)


@app.middleware("http")
async def rate_limit_and_size_guard(request: Request, call_next):
    client_ip = request.client.host if request.client else "unknown"
    now = time.time()

    blocked_until = blocked_ips.get(client_ip)
    if blocked_until and blocked_until > now:
        return JSONResponse(status_code=429, content={"detail": "IP temporalmente bloqueada por exceso de uso."})
    if blocked_until and blocked_until <= now:
        blocked_ips.pop(client_ip, None)
        rate_limit_hits.pop(client_ip, None)

    bucket = request_buckets[client_ip]
    while bucket and now - bucket[0] > RATE_LIMIT_WINDOW:
        bucket.popleft()
    if len(bucket) >= RATE_LIMIT_REQUESTS:
        rate_limit_hits[client_ip] += 1
        if rate_limit_hits[client_ip] >= MAX_429_BEFORE_BLOCK:
            blocked_ips[client_ip] = now + BLOCK_SECONDS
        return JSONResponse(status_code=429, content={"detail": "Rate limit excedido. Inténtalo más tarde."})
    rate_limit_hits[client_ip] = 0
    bucket.append(now)

    content_length = request.headers.get("content-length")
    if content_length and int(content_length) > MAX_BODY_BYTES:
        return JSONResponse(status_code=413, content={"detail": "Payload demasiado grande."})

    return await call_next(request)


@app.get("/api/health")
def health() -> dict[str, str]:
    return {"status": "ok"}


@app.get("/api/schema/plantilla-personalizada")
def obtener_schema_plantilla() -> dict:
    ruta = REPO_ROOT / "config" / "schemas" / "plantilla_general_ejemplo.json"
    if not ruta.exists():
        raise HTTPException(status_code=404, detail="Schema no encontrado.")
    with open(ruta, "r", encoding="utf-8") as f:
        return json.load(f)


@app.post("/api/jobs", response_model=JobSummary)
def crear_job(payload: JobRequest) -> JobSummary:
    try:
        job = job_store.create_job(payload)
        logger.info("Job creado id=%s modo=%s tipo=%s", job.id, payload.modo_evaluacion, payload.tipo_evaluacion)
        return JobSummary(
            id=job.id,
            estado=job.estado,
            creado_en=job.creado_en,
            actualizado_en=job.actualizado_en,
            error=job.error,
        )
    except RuntimeError as exc:
        raise HTTPException(status_code=429, detail=str(exc)) from exc


@app.get("/api/jobs/{job_id}", response_model=JobSummary)
def estado_job(job_id: str) -> JobSummary:
    job = job_store.get_job(job_id)
    if not job:
        raise HTTPException(status_code=404, detail="Job no encontrado.")
    return JobSummary(
        id=job.id,
        estado=job.estado,
        creado_en=job.creado_en,
        actualizado_en=job.actualizado_en,
        error=job.error,
    )


@app.get("/api/jobs/{job_id}/preview", response_model=JobPreview)
def preview_job(job_id: str) -> JobPreview:
    job = job_store.get_job(job_id)
    if not job:
        raise HTTPException(status_code=404, detail="Job no encontrado.")

    resumen = None
    if job.job_dir and (job.job_dir / "resumen.json").exists():
        with open(job.job_dir / "resumen.json", "r", encoding="utf-8") as f:
            resumen = json.load(f)

        resultados_csv = job.job_dir / "graficos" / "resultados.csv"
        if resultados_csv.exists():
            df = pd.read_csv(resultados_csv, sep="|")
            resumen["muestra"] = df.head(10).to_dict(orient="records")

    return JobPreview(id=job.id, estado=job.estado, resumen=resumen)


@app.get("/api/jobs/{job_id}/download")
def descargar_job(job_id: str, background_tasks: BackgroundTasks):
    job = job_store.get_job(job_id)
    if not job:
        raise HTTPException(status_code=404, detail="Job no encontrado.")
    if job.estado != JobStatus.FINALIZADA:
        raise HTTPException(status_code=409, detail="El job no ha finalizado todavía.")
    if not job.job_dir or not job.job_dir.exists():
        raise HTTPException(status_code=404, detail="No se encontraron artefactos para descargar.")

    zip_base = job.job_dir.parent / f"{job.id}_resultados"
    zip_path = Path(shutil.make_archive(str(zip_base), "zip", str(job.job_dir)))

    def _cleanup() -> None:
        try:
            if zip_path.exists():
                zip_path.unlink(missing_ok=True)
            job_store.delete_job_artifacts(job_id)
            logger.info("Artefactos eliminados tras descarga job=%s", job_id)
        except Exception as exc:
            logger.error("Error limpiando artefactos job=%s error=%s", job_id, exc)

    background_tasks.add_task(_cleanup)
    return FileResponse(path=zip_path, filename=f"resultados_{job.id}.zip", media_type="application/zip")


if STATIC_DIR.exists():
    app.mount("/", StaticFiles(directory=str(STATIC_DIR), html=True), name="static")