"""Event attachments: content validation, storage and cleanup."""

import io
import os
import shutil
import time

import pytest
from fastapi import HTTPException
from PIL import Image

import attachments_store
import models
from conftest import auth, create_user, register_admin
from database import SessionLocal

RANGE = {"start": "2026-06-01T00:00:00Z", "end": "2026-06-30T00:00:00Z"}


@pytest.fixture(autouse=True)
def clean_attachment_dir():
    """conftest wipes the tables but not the files — without this the orphan
    sweep test would trip over leftovers from earlier tests."""
    for child in attachments_store.ATTACH_DIR.iterdir():
        shutil.rmtree(child, ignore_errors=True) if child.is_dir() else child.unlink()
    yield


# ── Fixtures for file bytes ───────────────────────────────

def png_bytes(size=(8, 8)) -> bytes:
    buf = io.BytesIO()
    Image.new("RGB", size, "red").save(buf, "PNG")
    return buf.getvalue()


PDF_BYTES = b"%PDF-1.4\n1 0 obj\n<<>>\nendobj\ntrailer\n<<>>\n%%EOF\n"
TXT_BYTES = "Zugangsdaten: siehe Umschlag\n".encode("utf-8")


# ── Helpers ───────────────────────────────────────────────

def _make_calendar(client, token, name="Privat"):
    r = client.post("/api/local/calendars", headers=auth(token),
                    json={"name": name, "color": "#4285f4"})
    assert r.status_code == 200, r.text
    return r.json()["id"]


def _make_event(client, token, cal_id, title="Termin"):
    r = client.post("/api/local/events", headers=auth(token), json={
        "calendar_id": cal_id, "title": title,
        "start": "2026-06-10T10:00:00+00:00", "end": "2026-06-10T11:00:00+00:00",
    })
    assert r.status_code == 200, r.text
    return r.json()


def _attach_row(event_uid, event_id, raw=PDF_BYTES, content_type="application/pdf",
                ext=".pdf", filename="Rechnung.pdf"):
    """Insert an attachment row and write its bytes, bypassing the API.

    Used by the cleanup tests, which must work before the upload endpoint
    exists and must be able to build states the API would refuse to create.
    """
    stored = attachments_store.new_stored_name(ext)
    attachments_store.write_file(stored, raw)
    has_thumb = attachments_store.make_thumb(raw, content_type, stored)
    db = SessionLocal()
    try:
        row = models.EventAttachment(
            source="local", event_uid=event_uid, event_id=event_id,
            filename=filename, stored_name=stored, content_type=content_type,
            size_bytes=len(raw), has_thumb=has_thumb,
            token=attachments_store.new_token(),
        )
        db.add(row)
        db.commit()
        return stored
    finally:
        db.close()


def _row_count() -> int:
    db = SessionLocal()
    try:
        return db.query(models.EventAttachment).count()
    finally:
        db.close()


def _exists(stored_name) -> bool:
    return attachments_store.path_for(stored_name).exists()


# ── Content sniffing ──────────────────────────────────────

@pytest.mark.parametrize("raw,name,expected", [
    (PDF_BYTES, "x.pdf", "application/pdf"),
    (png_bytes(), "x.png", "image/png"),
    (TXT_BYTES, "notiz.txt", "text/plain"),
    (b"a,b\n1,2", "liste.csv", "text/csv"),
    (b"# Titel", "doku.md", "text/markdown"),
])
def test_sniff_accepts_allowed_types(raw, name, expected):
    content_type, _ = attachments_store.sniff(raw, name)
    assert content_type == expected


@pytest.mark.parametrize("raw,name", [
    (b'<svg xmlns="http://www.w3.org/2000/svg"><script/></svg>', "x.svg"),
    (b"<!doctype html><html><script>alert(1)</script></html>", "x.html"),
    (b"print('hi')", "x.py"),
    (bytes(range(256)), "x.bin"),
    (b"plain text but no known extension", "readme"),
])
def test_sniff_rejects_everything_else(raw, name):
    """SVG and HTML matter most here: both execute script in the app's origin,
    where the session token lives in localStorage."""
    with pytest.raises(HTTPException) as e:
        attachments_store.sniff(raw, name)
    assert e.value.status_code == 400


def test_sniff_ignores_the_uploaded_name_for_binary_types():
    """A PNG named .pdf is a PNG. The extension never overrides the bytes."""
    content_type, ext = attachments_store.sniff(png_bytes(), "getarnt.pdf")
    assert (content_type, ext) == ("image/png", ".png")


def test_stored_name_never_contains_path_separators():
    """The uploaded name is attacker-controlled, and on the CalDAV path so is
    the event UID — neither may reach the filesystem."""
    _, ext = attachments_store.sniff(PDF_BYTES, "../../../etc/passwd.pdf")
    stored = attachments_store.new_stored_name(ext)
    assert "/" not in stored and "\\" not in stored and ".." not in stored
    path = attachments_store.path_for(stored)
    assert attachments_store.ATTACH_DIR in path.parents


def test_safe_filename_strips_directories_and_quotes():
    assert attachments_store.safe_filename("../../etc/passwd", ".txt") == "passwd"
    assert '"' not in attachments_store.safe_filename('a"b.pdf', ".pdf")
    assert attachments_store.safe_filename("", ".pdf") == "anhang.pdf"


def test_thumbnail_only_for_images():
    stored = attachments_store.new_stored_name(".png")
    attachments_store.write_file(stored, png_bytes((600, 400)))
    assert attachments_store.make_thumb(png_bytes((600, 400)), "image/png", stored) is True
    assert attachments_store.thumb_path_for(stored).exists()

    stored_pdf = attachments_store.new_stored_name(".pdf")
    assert attachments_store.make_thumb(PDF_BYTES, "application/pdf", stored_pdf) is False


# ── Cleanup on every delete path ──────────────────────────

def test_deleting_an_event_removes_rows_and_files(client):
    token = register_admin(client)
    cal_id = _make_calendar(client, token)
    ev = _make_event(client, token, cal_id)
    db = SessionLocal()
    ev_id = db.query(models.LocalEvent).filter(models.LocalEvent.uid == ev["id"]).first().id
    db.close()

    stored = _attach_row(ev["id"], ev_id)
    assert _row_count() == 1 and _exists(stored)

    r = client.delete(f"/api/local/events/{ev['id']}", headers=auth(token))
    assert r.status_code == 200, r.text
    assert _row_count() == 0
    assert not _exists(stored)


def test_deleting_a_calendar_removes_rows_and_files(client):
    token = register_admin(client)
    cal_id = _make_calendar(client, token)
    ev = _make_event(client, token, cal_id)
    db = SessionLocal()
    ev_id = db.query(models.LocalEvent).filter(models.LocalEvent.uid == ev["id"]).first().id
    db.close()
    stored = _attach_row(ev["id"], ev_id)

    r = client.delete(f"/api/local/calendars/{cal_id}", headers=auth(token))
    assert r.status_code == 200, r.text
    assert _row_count() == 0
    assert not _exists(stored)


def test_deleting_a_user_removes_rows_and_files(client):
    """The longest cascade: user -> calendars -> events -> attachments."""
    admin = register_admin(client)
    bob_id, bob = create_user(client, admin, "bob")
    cal_id = _make_calendar(client, bob, "Bobs Kalender")
    ev = _make_event(client, bob, cal_id)
    db = SessionLocal()
    ev_id = db.query(models.LocalEvent).filter(models.LocalEvent.uid == ev["id"]).first().id
    db.close()
    stored = _attach_row(ev["id"], ev_id)

    r = client.delete(f"/api/users/{bob_id}", headers=auth(admin))
    assert r.status_code == 200, r.text
    assert _row_count() == 0
    assert not _exists(stored)


# ── The background sweep ──────────────────────────────────

def test_sweep_removes_rows_whose_event_is_gone(client):
    token = register_admin(client)
    cal_id = _make_calendar(client, token)
    ev = _make_event(client, token, cal_id)
    db = SessionLocal()
    ev_id = db.query(models.LocalEvent).filter(models.LocalEvent.uid == ev["id"]).first().id
    db.close()
    stored = _attach_row(ev["id"], ev_id)

    # Delete the event behind the API's back, as a cascade that skipped the
    # purge helper would.
    db = SessionLocal()
    db.query(models.LocalEvent).filter(models.LocalEvent.id == ev_id).delete()
    db.commit()
    db.close()

    db = SessionLocal()
    rows, files = attachments_store.sweep(db)
    db.close()
    assert rows == 1
    assert not _exists(stored)


def test_sweep_removes_files_with_no_row_but_respects_the_grace_period():
    stored = attachments_store.new_stored_name(".pdf")
    path = attachments_store.write_file(stored, PDF_BYTES)

    # Fresh file, no row: must survive — an upload in flight writes the bytes
    # before it commits the row.
    db = SessionLocal()
    rows, files = attachments_store.sweep(db)
    db.close()
    assert files == 0 and path.exists()

    # Same file, aged past the grace window: now it is an orphan.
    old = time.time() - attachments_store.SWEEP_GRACE_SECONDS - 60
    os.utime(path, (old, old))
    db = SessionLocal()
    rows, files = attachments_store.sweep(db)
    db.close()
    assert files == 1 and not path.exists()


def test_sweep_leaves_live_attachments_alone(client):
    token = register_admin(client)
    cal_id = _make_calendar(client, token)
    ev = _make_event(client, token, cal_id)
    db = SessionLocal()
    ev_id = db.query(models.LocalEvent).filter(models.LocalEvent.uid == ev["id"]).first().id
    db.close()
    stored = _attach_row(ev["id"], ev_id)

    old = time.time() - attachments_store.SWEEP_GRACE_SECONDS - 60
    for p in (attachments_store.path_for(stored),):
        os.utime(p, (old, old))

    db = SessionLocal()
    rows, files = attachments_store.sweep(db)
    db.close()
    assert (rows, files) == (0, 0)
    assert _row_count() == 1 and _exists(stored)