import csv
import io
from pathlib import Path

from fastapi import APIRouter, Depends, File, Form, HTTPException, Query, Request, UploadFile
from fastapi.responses import HTMLResponse, Response
from fastapi.templating import Jinja2Templates

from app.config import get_settings
from app.db import list_leads, stats
from app.frontend import ALLOWED_FILENAMES
from app.security import require_admin

router = APIRouter(prefix="/admin", tags=["admin"])

_TEMPLATES_DIR = Path(__file__).parent / "templates"
templates = Jinja2Templates(directory=str(_TEMPLATES_DIR))


@router.get("/leads.html", response_class=HTMLResponse)
@router.get("/leads", response_class=HTMLResponse)
def admin_leads_html(
    request: Request,
    _user: str = Depends(require_admin),
    limit: int = Query(1000, ge=1, le=10000),
):
    leads = list_leads(limit=limit, offset=0)
    s = stats()
    return templates.TemplateResponse(
        "admin_leads.html",
        {
            "request": request,
            "leads": leads,
            "total": s["total_leads"],
            "total_downloads": s["total_downloads"],
            "top_empresas": s["top_5_empresas"],
            "downloads_por_archivo": s["downloads_por_archivo"],
        },
    )


@router.get("/material-files")
def admin_material_files(_user: str = Depends(require_admin)):
    """Lista los archivos en el directorio material/ con sus tamaños."""
    material_dir = Path(get_settings().material_dir)
    if not material_dir.exists():
        return {"material_dir": str(material_dir), "exists": False, "files": []}
    files = []
    for path in sorted(material_dir.iterdir()):
        if path.is_file():
            size = path.stat().st_size
            files.append({
                "name": path.name,
                "size_bytes": size,
                "size_mb": round(size / (1024 * 1024), 2),
            })
    return {"material_dir": str(material_dir), "exists": True, "files": files}


@router.post("/upload-material")
async def admin_upload_material(
    target_name: str = Form(...),
    file: UploadFile = File(...),
    _user: str = Depends(require_admin),
):
    """Sube un archivo al volumen /app/material/ con un nombre de la whitelist."""
    if target_name not in ALLOWED_FILENAMES:
        raise HTTPException(
            status_code=400,
            detail=f"target_name must be one of {sorted(ALLOWED_FILENAMES)}",
        )
    material_dir = Path(get_settings().material_dir)
    material_dir.mkdir(parents=True, exist_ok=True)
    dest = material_dir / target_name
    content = await file.read()
    dest.write_bytes(content)
    return {
        "saved_as": str(dest),
        "size_bytes": len(content),
        "size_mb": round(len(content) / (1024 * 1024), 2),
        "original_filename": file.filename,
    }


@router.delete("/material-files/{filename}")
def admin_delete_material(filename: str, _user: str = Depends(require_admin)):
    """Borra un archivo del volumen material/."""
    if filename not in ALLOWED_FILENAMES:
        raise HTTPException(status_code=400, detail="filename not in whitelist")
    path = Path(get_settings().material_dir) / filename
    if not path.exists():
        raise HTTPException(status_code=404, detail="file not found")
    path.unlink()
    return {"deleted": filename}


@router.get("/leads.json")
def admin_leads_json(
    _user: str = Depends(require_admin),
    limit: int = Query(100, ge=1, le=1000),
    offset: int = Query(0, ge=0),
):
    return list_leads(limit=limit, offset=offset)


@router.get("/leads.csv")
def admin_leads_csv(_user: str = Depends(require_admin)):
    rows = list_leads(limit=10_000, offset=0)
    buf = io.StringIO()
    if rows:
        writer = csv.DictWriter(buf, fieldnames=list(rows[0].keys()))
        writer.writeheader()
        writer.writerows(rows)
    else:
        buf.write("(no leads)\n")
    payload = "" + buf.getvalue()
    return Response(
        content=payload,
        media_type="text/csv; charset=utf-8",
        headers={"Content-Disposition": 'attachment; filename="leads.csv"'},
    )


@router.get("/stats")
def admin_stats(_user: str = Depends(require_admin)):
    return stats()