"""
Router Reports – Dashboard e Reportistica (Fase 7).

Endpoint:
  GET  /reports/summary          – KPI + serie storica + breakdown caselle
  GET  /reports/export           – export CSV o PDF

Permessi:
  - Tutti gli utenti autenticati possono accedere.
  - Admin e super_admin: vedono tutto il tenant.
  - Operator/Supervisor/Readonly: vedono solo le caselle su cui hanno can_read.
"""

import uuid
from datetime import datetime
from typing import Optional

from fastapi import APIRouter, Query
from fastapi.responses import Response

from app.dependencies import CurrentUser, DB
from app.schemas.reports import ReportSummaryResponse
from app.services.report_service import ReportService

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


async def _get_visible_ids(user, db) -> Optional[list[uuid.UUID]]:
    """Restituisce None per admin (nessun filtro), lista per non-admin."""
    if user.is_admin:
        return None
    from app.services.permission_service import PermissionService
    svc = PermissionService(db)
    return await svc.get_visible_mailboxes(user)


# ─── GET /reports/summary ─────────────────────────────────────────────────────

@router.get("/summary", response_model=ReportSummaryResponse)
async def get_report_summary(
    current_user: CurrentUser,
    db: DB,
    days: int = Query(7, ge=1, le=365, description="Periodo in giorni per la serie storica"),
) -> ReportSummaryResponse:
    """
    Restituisce il riepilogo completo per la dashboard:
    - KPI (PEC ricevute/inviate oggi, anomalie, tasso consegna, ...)
    - Serie storica giornaliera per il grafico a barre
    - Distribuzione stati outbound per il grafico a torta
    - Statistiche per casella
    """
    visible = await _get_visible_ids(current_user, db)
    svc = ReportService(db)
    return await svc.get_summary(
        tenant_id=current_user.tenant_id,
        period_days=days,
        visible_mailbox_ids=visible,
    )


# ─── GET /reports/export ──────────────────────────────────────────────────────

@router.get("/export")
async def export_report(
    current_user: CurrentUser,
    db: DB,
    format: str = Query("csv", pattern="^(csv|pdf)$", description="Formato: csv o pdf"),
    date_from: Optional[datetime] = Query(None, description="Data inizio (ISO 8601)"),
    date_to: Optional[datetime] = Query(None, description="Data fine (ISO 8601)"),
    mailbox_id: Optional[uuid.UUID] = Query(None, description="Filtra per casella specifica"),
) -> Response:
    """
    Esporta i dati in formato CSV o PDF.

    - CSV: lista completa dei messaggi del periodo con tutti i metadati.
    - PDF: riepilogo KPI + tabella caselle (generato con reportlab).
    """
    visible = await _get_visible_ids(current_user, db)
    svc = ReportService(db)

    now_str = datetime.now().strftime("%Y%m%d_%H%M%S")

    if format == "csv":
        data = await svc.export_csv(
            tenant_id=current_user.tenant_id,
            date_from=date_from,
            date_to=date_to,
            mailbox_id=mailbox_id,
            visible_mailbox_ids=visible,
        )
        return Response(
            content=data,
            media_type="text/csv; charset=utf-8-sig",
            headers={
                "Content-Disposition": f'attachment; filename="pechub_report_{now_str}.csv"',
                "Content-Length": str(len(data)),
            },
        )

    # PDF
    data = await svc.export_pdf(
        tenant_id=current_user.tenant_id,
        date_from=date_from,
        date_to=date_to,
        visible_mailbox_ids=visible,
    )
    return Response(
        content=data,
        media_type="application/pdf",
        headers={
            "Content-Disposition": f'attachment; filename="pechub_report_{now_str}.pdf"',
            "Content-Length": str(len(data)),
        },
    )