from __future__ import annotations

import csv
import io
from datetime import datetime

from fastapi import APIRouter, Depends, Query
from fastapi.responses import StreamingResponse
from sqlalchemy import String, cast, func, select
from sqlalchemy.ext.asyncio import AsyncSession

from app.dependencies import get_db_session, require_admin
from app.models.intercept_log import InterceptLog
from app.schemas.log import InterceptLogItem, LogListResponse

router = APIRouter(prefix="/admin/api/logs", tags=["logs"], dependencies=[Depends(require_admin)])


def apply_log_filters(
    statement,
    token: str | None,
    attempt_ip: str | None,
    start_time: datetime | None,
    end_time: datetime | None,
):
    if token:
        statement = statement.where(InterceptLog.token_display.ilike(f"%{token}%"))
    if attempt_ip:
        statement = statement.where(cast(InterceptLog.attempt_ip, String).ilike(f"%{attempt_ip}%"))
    if start_time:
        statement = statement.where(InterceptLog.intercepted_at >= start_time)
    if end_time:
        statement = statement.where(InterceptLog.intercepted_at <= end_time)
    return statement


def to_log_item(item: InterceptLog) -> InterceptLogItem:
    return InterceptLogItem(
        id=item.id,
        token_display=item.token_display,
        bound_ip=str(item.bound_ip),
        attempt_ip=str(item.attempt_ip),
        alerted=item.alerted,
        intercepted_at=item.intercepted_at,
    )


def write_log_csv(buffer: io.StringIO, logs: list[InterceptLog]) -> None:
    writer = csv.writer(buffer)
    writer.writerow(["id", "token_display", "bound_ip", "attempt_ip", "alerted", "intercepted_at"])
    for item in logs:
        writer.writerow(
            [
                item.id,
                item.token_display,
                str(item.bound_ip),
                str(item.attempt_ip),
                item.alerted,
                item.intercepted_at.isoformat(),
            ]
        )


@router.get("", response_model=LogListResponse)
async def list_logs(
    page: int = Query(default=1, ge=1),
    page_size: int = Query(default=20, ge=1, le=200),
    token: str | None = Query(default=None),
    attempt_ip: str | None = Query(default=None),
    start_time: datetime | None = Query(default=None),
    end_time: datetime | None = Query(default=None),
    session: AsyncSession = Depends(get_db_session),
) -> LogListResponse:
    statement = apply_log_filters(select(InterceptLog), token, attempt_ip, start_time, end_time)
    total_result = await session.execute(select(func.count()).select_from(statement.subquery()))
    total = int(total_result.scalar_one())
    logs = (
        await session.scalars(
            statement.order_by(InterceptLog.intercepted_at.desc()).offset((page - 1) * page_size).limit(page_size)
        )
    ).all()

    return LogListResponse(
        items=[to_log_item(item) for item in logs],
        total=total,
        page=page,
        page_size=page_size,
    )


@router.get("/export")
async def export_logs(
    token: str | None = Query(default=None),
    attempt_ip: str | None = Query(default=None),
    start_time: datetime | None = Query(default=None),
    end_time: datetime | None = Query(default=None),
    session: AsyncSession = Depends(get_db_session),
):
    statement = apply_log_filters(select(InterceptLog), token, attempt_ip, start_time, end_time).order_by(
        InterceptLog.intercepted_at.desc()
    )
    logs = (await session.scalars(statement)).all()

    buffer = io.StringIO()
    write_log_csv(buffer, logs)

    filename = f"sentinel-logs-{datetime.utcnow().strftime('%Y%m%d%H%M%S')}.csv"
    return StreamingResponse(
        iter([buffer.getvalue()]),
        media_type="text/csv",
        headers={"Content-Disposition": f'attachment; filename="{filename}"'},
    )