"""REST API for packages (distinct packages across scans)."""

import csv
import io
from urllib.parse import unquote

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

from guarddog_nexus.constants import (
    CSV_MEDIA_TYPE,
    DEFAULT_OFFSET,
    DEFAULT_PAGE_SIZE,
    DEFAULT_SORT_BY_PACKAGES,
    DEFAULT_SORT_DIR,
    MAX_PAGE_SIZE,
)
from guarddog_nexus.database import get_session
from guarddog_nexus.models import Finding, Scan
from guarddog_nexus.queries import build_package_list_query

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


@router.get("")
async def list_packages(
    limit: int = Query(DEFAULT_PAGE_SIZE, le=MAX_PAGE_SIZE),
    offset: int = Query(DEFAULT_OFFSET, ge=0),
    ecosystem: str | None = Query(None),
    flagged: bool | None = Query(None),
    search: str | None = Query(None),
    repository: str | None = Query(None),
    sort_by: str = Query(DEFAULT_SORT_BY_PACKAGES),
    sort_dir: str = Query(DEFAULT_SORT_DIR),
    session: AsyncSession = Depends(get_session),
):
    rows_q, total_q = build_package_list_query(
        flagged=flagged,
        ecosystem=ecosystem,
        repository=repository,
        search=search,
        sort_by=sort_by,
        sort_dir=sort_dir,
        limit=limit,
        offset=offset,
    )
    total = await session.scalar(total_q)
    rows = (await session.execute(rows_q)).all()

    return {
        "total": total,
        "limit": limit,
        "offset": offset,
        "packages": [
            {
                "name": r.pkg_name,
                "version": r.pkg_ver,
                "ecosystem": r.ecosystem,
                "repository": r.repository,
                "last_scanned_at": r.last_scan.isoformat() if r.last_scan else None,
                "flagged": bool(r.is_flagged),
                "total_findings": r.findings_sum,
                "latest_scan_id": r.sid,
            }
            for r in rows
        ],
    }


@router.get("/export")
async def export_packages_csv(
    flagged: bool | None = Query(None),
    search: str | None = Query(None),
    session: AsyncSession = Depends(get_session),
):
    rows_q, _total_q = build_package_list_query(
        flagged=flagged,
        search=search,
        sort_by=DEFAULT_SORT_BY_PACKAGES,
        sort_dir=DEFAULT_SORT_DIR,
        limit=MAX_PAGE_SIZE,
        offset=0,
    )
    rows = (await session.execute(rows_q)).all()

    output = io.StringIO()
    writer = csv.writer(output)
    writer.writerow(
        [
            "name", "version", "ecosystem", "repository",
            "last_scanned_at", "flagged", "total_findings",
        ]
    )
    for r in rows:
        writer.writerow(
            [
                r.pkg_name, r.pkg_ver, r.ecosystem, r.repository,
                r.last_scan.isoformat() if r.last_scan else "",
                bool(r.is_flagged),
                r.findings_sum,
            ]
        )

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


@router.get("/{name:path}")
async def get_package(
    name: str,
    session: AsyncSession = Depends(get_session),
):
    parts = name.rsplit("/", 1)
    pkg_name = unquote(parts[0])
    pkg_version = unquote(parts[1]) if len(parts) == 2 else ""

    scans = (
        (
            await session.execute(
                select(Scan)
                .where(Scan.package_name == pkg_name, Scan.package_version == pkg_version)
                .order_by(Scan.started_at.desc())
            )
        )
        .scalars()
        .all()
    )

    if not scans:
        return {"detail": "Not found"}

    all_findings: list[dict] = []
    for s in scans:
        findings = (
            (await session.execute(select(Finding).where(Finding.scan_id == s.id)))
            .scalars()
            .all()
        )
        for f in findings:
            all_findings.append({"id": f.id, **f.data, "report": f.report})

    return {
        "name": scans[0].package_name,
        "version": scans[0].package_version,
        "ecosystem": scans[0].ecosystem,
        "repository": scans[0].repository,
        "flagged": any(s.flagged for s in scans),
        "scans": [
            {
                "id": s.id,
                "status": s.status,
                "total_findings": s.total_findings,
                "flagged": s.flagged,
                "started_at": s.started_at.isoformat() if s.started_at else None,
            }
            for s in scans
        ],
        "findings": all_findings,
    }