import csv
import io
from pathlib import Path

from fastapi import APIRouter, Depends, File, Form, HTTPException, Query, UploadFile
from fastapi.responses import Response

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"])


@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()