"""Tests for backup routes: upload, download, history, delete.

Exercises the backup lifecycle through the FastAPI TestClient against the
in-memory SQLite test database and moto-mocked S3 bucket.
"""

from __future__ import annotations

import hashlib

import pytest

from tests.conftest import auth_header, TEST_USER_IDS


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

_BLOB = b"encrypted-backup-blob-opaque-bytes"
_CHECKSUM = hashlib.sha256(_BLOB).hexdigest()
_VERSION = 1
_TIMESTAMP = 1700000000000  # arbitrary ms timestamp


def _backup_headers(tier: str = "power", **overrides) -> dict[str, str]:
    """Return auth + backup metadata headers."""
    headers = auth_header(tier)
    headers["X-Backup-Version"] = str(overrides.get("version", _VERSION))
    headers["X-Backup-Timestamp"] = str(overrides.get("timestamp", _TIMESTAMP))
    headers["X-Backup-Checksum"] = overrides.get("checksum", _CHECKSUM)
    headers["Content-Type"] = "application/octet-stream"
    return headers


def _upload(client, tier="power", **overrides) -> "Response":  # noqa: F821
    """Upload a backup blob and return the response."""
    return client.put(
        "/api/v1/backup",
        content=overrides.pop("blob", _BLOB),
        headers=_backup_headers(tier, **overrides),
    )


# ── TestUploadBackup ──────────────────────────────────────────────────


class TestUploadBackup:
    """PUT /api/v1/backup"""

    def test_upload_success(self, client, s3_bucket) -> None:
        resp = _upload(client, tier="power")
        assert resp.status_code == 200
        assert resp.json() == {"ok": True}

    def test_upload_creates_history_entry(self, client, s3_bucket) -> None:
        _upload(client, tier="power")
        history = client.get(
            "/api/v1/backup/history", headers=auth_header("power")
        ).json()
        assert len(history) == 1
        assert history[0]["version"] == _VERSION
        assert history[0]["timestamp"] == _TIMESTAMP
        assert history[0]["checksum"] == _CHECKSUM

    def test_upload_bad_checksum(self, client, s3_bucket) -> None:
        resp = _upload(client, tier="power", checksum="0" * 64)
        assert resp.status_code == 400

    def test_upload_free_tier_blocked(self, client, s3_bucket) -> None:
        """Free tier has backup_gb=0 → should return 402."""
        resp = _upload(client, tier="free")
        assert resp.status_code == 402

    def test_upload_pro_tier_allowed(self, client, s3_bucket) -> None:
        """Pro tier has backup_gb=5 → small blob succeeds."""
        resp = _upload(client, tier="pro")
        assert resp.status_code == 200


# ── TestDownloadBackup ────────────────────────────────────────────────


class TestDownloadBackup:
    """GET /api/v1/backup"""

    def test_download_latest(self, client, s3_bucket) -> None:
        _upload(client, tier="power")
        resp = client.get("/api/v1/backup", headers=auth_header("power"))
        assert resp.status_code == 200
        assert resp.content == _BLOB
        assert resp.headers["X-Checksum"] == _CHECKSUM
        assert resp.headers["X-Backup-Version"] == str(_VERSION)

    def test_download_no_backup_returns_404(self, client, s3_bucket) -> None:
        resp = client.get("/api/v1/backup", headers=auth_header("power"))
        assert resp.status_code == 404

    def test_download_if_modified_since_returns_304(self, client, s3_bucket) -> None:
        """When If-Modified-Since is after the backup timestamp → 304."""
        _upload(client, tier="power", timestamp=1700000000000)
        resp = client.get(
            "/api/v1/backup",
            headers={
                **auth_header("power"),
                "If-Modified-Since": "Thu, 01 Jan 2099 00:00:00 GMT",
            },
        )
        assert resp.status_code == 304

    def test_download_if_modified_since_returns_200(self, client, s3_bucket) -> None:
        """When If-Modified-Since is before the backup timestamp → serve blob."""
        _upload(client, tier="power", timestamp=1700000000000)
        resp = client.get(
            "/api/v1/backup",
            headers={
                **auth_header("power"),
                "If-Modified-Since": "Thu, 01 Jan 2000 00:00:00 GMT",
            },
        )
        assert resp.status_code == 200
        assert resp.content == _BLOB

    def test_download_multiple_returns_latest(self, client, s3_bucket) -> None:
        """When multiple backups exist, GET returns the one with the highest timestamp."""
        _upload(client, tier="power", timestamp=1000)
        blob2 = b"second-encrypted-backup"
        checksum2 = hashlib.sha256(blob2).hexdigest()
        _upload(client, tier="power", timestamp=2000, blob=blob2, checksum=checksum2)
        resp = client.get("/api/v1/backup", headers=auth_header("power"))
        assert resp.status_code == 200
        assert resp.content == blob2


# ── TestBackupHistory ─────────────────────────────────────────────────


class TestBackupHistory:
    """GET /api/v1/backup/history"""

    def test_history_empty(self, client, s3_bucket) -> None:
        resp = client.get("/api/v1/backup/history", headers=auth_header("power"))
        assert resp.status_code == 200
        assert resp.json() == []

    def test_history_returns_entries(self, client, s3_bucket) -> None:
        _upload(client, tier="power", timestamp=1000)
        _upload(client, tier="power", timestamp=2000)
        history = client.get(
            "/api/v1/backup/history", headers=auth_header("power")
        ).json()
        assert len(history) == 2
        # Ordered by timestamp descending
        assert history[0]["timestamp"] == 2000
        assert history[1]["timestamp"] == 1000

    def test_history_isolated_per_user(self, client, s3_bucket) -> None:
        """One user's backups should not appear in another user's history."""
        _upload(client, tier="power")
        resp = client.get("/api/v1/backup/history", headers=auth_header("team"))
        assert resp.json() == []


# ── TestDeleteBackup ──────────────────────────────────────────────────


class TestDeleteBackup:
    """DELETE /api/v1/backup/{backup_id}"""

    def _get_backup_id(self, client, tier="power") -> str:
        """Upload a backup and return its DB id from history."""
        _upload(client, tier=tier)
        history = client.get(
            "/api/v1/backup/history", headers=auth_header(tier)
        ).json()
        # History returns BackupMetadata schema which doesn't have `id`.
        # We need to look it up via a different means.
        # Since there's only 1 backup, find via history length.
        # Actually the schema doesn't return id — let's verify via re-download.
        # We'll use a workaround: upload, then list history to confirm it exists,
        # then try to delete — but we need the id...
        # Let's check if history includes an id field.
        # The schema is: version, timestamp, checksum, chunk_count — no id.
        # We'll need to query the DB directly or use a known ID.
        # For testing, we'll search history then use the DB.
        return None  # pragma: no cover — overridden below

    def test_delete_success(self, client, s3_bucket, db_session) -> None:
        _upload(client, tier="power")

        # Discover the backup_id via direct DB query
        import asyncio
        from sqlalchemy import select
        from app.models import BackupMetadata

        async def _get_id():
            result = await db_session.execute(
                select(BackupMetadata.id).where(
                    BackupMetadata.user_id == TEST_USER_IDS["power"]
                )
            )
            return result.scalar_one()

        backup_id = asyncio.get_event_loop().run_until_complete(_get_id())

        resp = client.delete(
            f"/api/v1/backup/{backup_id}", headers=auth_header("power")
        )
        assert resp.status_code == 200
        assert resp.json() == {"ok": True}

        # History should now be empty
        history = client.get(
            "/api/v1/backup/history", headers=auth_header("power")
        ).json()
        assert history == []

    def test_delete_nonexistent(self, client, s3_bucket) -> None:
        resp = client.delete(
            "/api/v1/backup/no-such-id", headers=auth_header("power")
        )
        assert resp.status_code == 404

    def test_delete_other_users_backup(self, client, s3_bucket, db_session) -> None:
        """Cannot delete another user's backup (ownership check returns 404)."""
        _upload(client, tier="power")

        import asyncio
        from sqlalchemy import select
        from app.models import BackupMetadata

        async def _get_id():
            result = await db_session.execute(
                select(BackupMetadata.id).where(
                    BackupMetadata.user_id == TEST_USER_IDS["power"]
                )
            )
            return result.scalar_one()

        backup_id = asyncio.get_event_loop().run_until_complete(_get_id())

        # team user tries to delete power user's backup → 404
        resp = client.delete(
            f"/api/v1/backup/{backup_id}", headers=auth_header("team")
        )
        assert resp.status_code == 404