"""REST API for scans."""

import csv
import io

from fastapi import APIRouter, Depends, HTTPException, Query, Response
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy.orm import selectinload

from ..constants import (
    CSV_MEDIA_TYPE,
    DEFAULT_OFFSET,
    DEFAULT_PAGE_SIZE,
    DEFAULT_SORT_BY_SCANS,
    DEFAULT_SORT_DIR,
    MAX_PAGE_SIZE,
)
from ..db.engine import get_session
from ..db.models import Scan
from ..db.queries import build_scan_list_query, get_dashboard_stats
from ..schemas import ScanDetailOut, ScanListResponse, StatsResponse, serialize_finding

router = APIRouter(prefix="/api/v1/scans", tags=["scans"])


@router.get("", response_model=ScanListResponse)
async def list_scans(
    limit: int = Query(DEFAULT_PAGE_SIZE, le=MAX_PAGE_SIZE),
    offset: int = Query(DEFAULT_OFFSET, ge=0),
    flagged: bool | None = Query(None),
    search: str | None = Query(None),
    status: str | None = Query(None),
    repository: str | None = Query(None),
    sort_by: str = Query(DEFAULT_SORT_BY_SCANS),
    sort_dir: str = Query(DEFAULT_SORT_DIR),
    session: AsyncSession = Depends(get_session),
) -> dict:
    q, count_q = build_scan_list_query(
        flagged=flagged,
        status=status,
        repository=repository,
        search=search,
        sort_by=sort_by,
        sort_dir=sort_dir,
        limit=limit,
        offset=offset,
    )
    scans = (await session.execute(q)).scalars().all()
    total = await session.scalar(count_q)

    return {
        "total": total,
        "limit": limit,
        "offset": offset,
        "scans": [
            {
                "id": s.id,
                "package_name": s.package_name,
                "package_version": s.package_version,
                "ecosystem": s.ecosystem,
                "repository": s.repository,
                "status": s.status,
                "total_findings": s.total_findings,
                "flagged": s.flagged,
                "started_at": s.started_at.isoformat() if s.started_at else None,
                "finished_at": s.finished_at.isoformat() if s.finished_at else None,
                "error_message": s.error_message,
            }
            for s in scans
        ],
    }


@router.get("/export")
async def export_scans_csv(
    flagged: bool | None = Query(None),
    search: str | None = Query(None),
    status: str | None = Query(None),
    session: AsyncSession = Depends(get_session),
) -> Response:
    q, _count_q = build_scan_list_query(
        flagged=flagged,
        status=status,
        search=search,
        sort_by=DEFAULT_SORT_BY_SCANS,
        sort_dir=DEFAULT_SORT_DIR,
        limit=MAX_PAGE_SIZE,
        offset=0,
    )
    scans = (await session.execute(q)).scalars().all()

    output = io.StringIO()
    writer = csv.writer(output)
    writer.writerow(
        [
            "id",
            "package_name",
            "package_version",
            "ecosystem",
            "repository",
            "status",
            "total_findings",
            "flagged",
            "started_at",
            "finished_at",
            "error_message",
            "sha256",
        ]
    )
    for s in scans:
        writer.writerow(
            [
                s.id,
                s.package_name,
                s.package_version,
                s.ecosystem,
                s.repository,
                s.status,
                s.total_findings,
                s.flagged,
                s.started_at.isoformat() if s.started_at else "",
                s.finished_at.isoformat() if s.finished_at else "",
                s.error_message or "",
                s.sha256 or "",
            ]
        )

    return Response(
        content=output.getvalue(),
        media_type=CSV_MEDIA_TYPE,
        headers={"Content-Disposition": "attachment; filename=scans_export.csv"},
    )


@router.get("/stats", response_model=StatsResponse)
async def scan_stats(session: AsyncSession = Depends(get_session)) -> dict:
    dashboard = await get_dashboard_stats(session)
    latest = dashboard["latest_flagged"]
    return {
        "total_scans": dashboard["total_scans"],
        "flagged_scans": dashboard["flagged_scans"],
        "recent_flagged": dashboard["recent_flagged"],
        "total_findings": dashboard["total_findings"],
        "top_rules": dashboard["top_rules"],
        "latest_scan_at": (
            latest[0].started_at.isoformat() if latest and latest[0].started_at else None
        ),
    }


@router.get("/{scan_id}", response_model=ScanDetailOut)
async def get_scan(scan_id: int, session: AsyncSession = Depends(get_session)) -> dict:
    scan = await session.scalar(
        select(Scan).where(Scan.id == scan_id).options(selectinload(Scan.findings))
    )
    if not scan:
        raise HTTPException(status_code=404, detail="Scan not found")
    return {
        "id": scan.id,
        "package_name": scan.package_name,
        "package_version": scan.package_version,
        "ecosystem": scan.ecosystem,
        "repository": scan.repository,
        "nexus_asset_url": scan.nexus_asset_url,
        "sha256": scan.sha256,
        "status": scan.status,
        "total_findings": scan.total_findings,
        "flagged": scan.flagged,
        "started_at": scan.started_at.isoformat() if scan.started_at else None,
        "finished_at": scan.finished_at.isoformat() if scan.finished_at else None,
        "error_message": scan.error_message,
        "initiator": scan.initiator,
        "source_ip": scan.source_ip,
        "findings": [serialize_finding(f) for f in scan.findings],
    }