import json
from pathlib import Path

import pytest

from thoughtsync import client_dist
from thoughtsync.app import create_app
from thoughtsync.client_dist import (
    APK_NAME,
    BY_ID,
    MANIFEST_NAME,
    PLATFORMS,
    advertisement,
    android_release,
    release,
    releases,
)
from thoughtsync.config import Config

# DB-free, like the rest of this suite — the test lane runs no Postgres. That is
# why the advertisement is asserted through `advertisement()` rather than through
# `/api/config`: the route is a one-line merge of this dict into a payload whose
# other half needs a database, and testing it here tests the part that can be wrong.
#
# The routes below ARE exercised, because none opens a session: the metadata route
# only stats files, and the download's 401 is returned before any token lookup.

PAYLOAD = b"not really a client, but the server only ever stats it"

# Every test that is about the MECHANISM rather than about one platform runs
# against all of them. The bugs this module can have — a sidecar describing a
# different build, a half-finished copy shadowing a good one — are not
# platform-specific, and a suite that only ever exercised Android is how the other
# four would ship untested.
ALL_IDS = [p.id for p in PLATFORMS]


@pytest.fixture(autouse=True)
def _empty_baked_client(tmp_path, monkeypatch):
    """Point the baked-in copy at an empty directory.

    In a source checkout `src/thoughtsync/client/` does not exist, so these tests
    would pass anyway — but only by accident of where they are run. A built image
    has real clients there, and a test that silently depends on which tree it is in
    is one that will eventually lie.
    """
    monkeypatch.setattr(client_dist, "BAKED_ROOT", tmp_path / "baked")
    yield


@pytest.fixture
def app():
    return create_app()


def place(
    platform_id: str = "android",
    payload: bytes = PAYLOAD,
    root: Path | None = None,
    signature: str | None = "a signature",
    **overrides,
) -> dict:
    """Put one platform's client + sidecar where the server looks.

    Overrides corrupt the pair. `signature=None` withholds the `.sig` a signed
    bundle needs, which is its own failure mode rather than a variant of the others.
    """
    platform = BY_ID[platform_id]
    root = root if root is not None else Path(Config.client_root())
    root.mkdir(parents=True, exist_ok=True)
    (root / platform.artifact).write_bytes(payload)
    meta = {
        "version_name": "2026.08.30.0307",
        "version_code": 3503708,
        "size": len(payload),
        "sha256": "ab" * 32,
    }
    meta.update(overrides)
    (root / platform.sidecar).write_text(json.dumps(meta), encoding="utf-8")
    if platform.signed and signature is not None:
        (root / platform.signature).write_text(signature, encoding="utf-8")
    return meta


# --- the table ---------------------------------------------------------------


def test_every_platform_has_its_own_filenames():
    """Two platforms sharing an artifact or a sidecar name would overwrite each
    other in the one directory they all live in — silently, and the survivor would
    be whichever was copied last."""
    artifacts = [p.artifact for p in PLATFORMS]
    sidecars = [p.sidecar for p in PLATFORMS]
    assert len(set(artifacts)) == len(artifacts)
    assert len(set(sidecars)) == len(sidecars)
    assert not set(artifacts) & set(sidecars)


def test_the_android_names_are_the_ones_already_published():
    """Pinned because renaming them is a tidy-up that strands every installed phone.

    The Android lane publishes these exact names and CI bakes them in under them.
    """
    assert APK_NAME == "thoughtsync.apk"
    assert MANIFEST_NAME == "thoughtsync-android.json"


# --- absence is an ordinary answer -------------------------------------------


@pytest.mark.parametrize("platform_id", ALL_IDS)
def test_an_absent_client_is_no_client(platform_id):
    assert release(platform_id) is None


def test_a_server_holding_nothing_advertises_no_keys_at_all():
    """The KEYS are missing, not null.

    A client testing for one then gets an unambiguous answer rather than having to
    tell "this server has no client" apart from "this server predates the feature".
    """
    assert releases() == {}
    assert advertisement() == {}


@pytest.mark.parametrize("platform_id", ALL_IDS)
def test_a_sidecar_describing_a_different_build_counts_as_no_client(platform_id):
    """The likeliest real corruption: a new artifact copied over an old sidecar.

    Serving one build while advertising another is worse than serving none — the
    client would compare versions against a promise the bytes do not keep.
    """
    place(platform_id, size=999_999)
    assert release(platform_id) is None


@pytest.mark.parametrize("platform_id", ALL_IDS)
def test_an_unreadable_sidecar_counts_as_no_client(platform_id):
    place(platform_id)
    sidecar = Path(Config.client_root()) / BY_ID[platform_id].sidecar
    sidecar.write_text("{ this is not json", encoding="utf-8")
    assert release(platform_id) is None


@pytest.mark.parametrize("platform_id", ALL_IDS)
def test_a_sidecar_missing_a_field_counts_as_no_client(platform_id):
    platform = BY_ID[platform_id]
    root = Path(Config.client_root())
    root.mkdir(parents=True, exist_ok=True)
    (root / platform.artifact).write_bytes(PAYLOAD)
    (root / platform.sidecar).write_text(json.dumps({"version_name": "x"}), encoding="utf-8")
    assert release(platform_id) is None


@pytest.mark.parametrize("platform_id", ALL_IDS)
def test_a_sidecar_with_no_artifact_beside_it_counts_as_no_client(platform_id):
    platform = BY_ID[platform_id]
    root = Path(Config.client_root())
    root.mkdir(parents=True, exist_ok=True)
    (root / platform.sidecar).write_text(
        json.dumps({"version_name": "x", "version_code": 1, "size": 1, "sha256": ""}),
        encoding="utf-8",
    )
    assert release(platform_id) is None


def test_an_unknown_platform_is_not_a_client():
    assert release("blackberry") is None


# --- what a present client reports -------------------------------------------


@pytest.mark.parametrize("platform_id", ALL_IDS)
def test_a_present_client_reports_what_a_comparator_reads(platform_id):
    place(platform_id)
    found = release(platform_id)
    assert found["version"] == "2026.08.30.0307"
    # The integer is what decides "is this newer", not the name — a name is a string
    # and sorts like one.
    assert found["version_code"] == 3503708
    assert found["size"] == len(PAYLOAD)
    assert found["platform"] == platform_id
    # A PATH, not an absolute URL: the client joins it to the base it is already
    # linked to, so a server cannot redirect the download elsewhere.
    assert found["url"] == f"/api/client/{platform_id}/download"
    assert not found["url"].startswith("http")


def test_the_android_payload_still_carries_every_field_it_used_to():
    """Phones in the field parse this. Fields may be ADDED — `ClientRelease` in
    core/src/sync/client.rs is a plain serde struct and ignores what it does not
    know — but none of these may move or change meaning."""
    place("android")
    found = android_release()
    for key in ("version", "version_code", "size", "sha256", "url"):
        assert key in found, key
    assert found["url"] == "/api/client/android/download"


# --- the signed bundle -------------------------------------------------------


def test_the_appimage_publishes_its_signature_with_its_version():
    """One request returns both, so an updater cannot pair a version with a
    signature belonging to a different build."""
    place("linux-appimage", signature="minisign output here")
    assert release("linux-appimage")["signature"] == "minisign output here"


def test_an_appimage_without_a_signature_is_absent_rather_than_unsigned():
    """It is the only bundle that replaces itself in place, and an update the app
    cannot verify is one it will refuse. Offering it unverifiable would turn a
    missing file into a failed install on the user's machine."""
    place("linux-appimage", signature=None)
    assert release("linux-appimage") is None


def test_an_empty_signature_file_is_not_a_signature():
    """A truncated copy leaves a zero-byte file, which reads as present."""
    place("linux-appimage", signature="   \n")
    assert release("linux-appimage") is None


def test_only_the_appimage_carries_a_signature():
    """A package-manager install cannot replace itself in place, so nothing verifies
    one and claiming a signature would imply an update path that does not exist."""
    for platform_id in ALL_IDS:
        place(platform_id)
    found = releases()
    assert "signature" in found["linux-appimage"]
    for platform_id in ALL_IDS:
        if platform_id != "linux-appimage":
            assert "signature" not in found[platform_id], platform_id


# --- the set, and precedence within it ---------------------------------------


def test_a_platform_the_server_lacks_is_simply_not_in_the_set():
    """Not null, not an error — a server holding some clients and not others is the
    ordinary state, and the UI hides what is absent."""
    place("android")
    place("windows")
    found = releases()
    assert set(found) == {"android", "windows"}


def test_the_baked_in_copy_is_used_when_nothing_was_dropped_in():
    """The ordinary case for a self-hoster who just pulled the image."""
    place("android", root=client_dist.BAKED_ROOT, version_code=300)
    assert android_release()["version_code"] == 300


def test_a_dropped_in_build_beats_the_one_the_image_shipped():
    """Someone who deliberately put a build on the volume wants that build."""
    place("android", root=client_dist.BAKED_ROOT, version_code=300)
    place("android", version_code=99)
    # Lower version and all — precedence is about intent, not about newness. An
    # operator pinning an older client is doing it on purpose.
    assert android_release()["version_code"] == 99


def test_precedence_is_decided_per_platform_not_for_the_whole_set():
    """THE trap this table introduces. Dropping in one client must not retract the
    other four — "first directory holding anything wins" would mean overriding the
    APK silently takes the desktop downloads offline."""
    for platform_id in ALL_IDS:
        place(platform_id, root=client_dist.BAKED_ROOT, version_code=300)
    place("android", version_code=99)
    found = releases()
    assert found["android"]["version_code"] == 99
    assert found["linux-deb"]["version_code"] == 300
    assert set(found) == set(ALL_IDS)


def test_a_broken_drop_in_does_not_shadow_the_baked_copy():
    """A half-finished copy onto the volume must not take the app offline.

    This is the failure the copy-order advice in docs/android-distribution.md is
    about, and the server should ride it out rather than go dark.
    """
    place("android", root=client_dist.BAKED_ROOT, version_code=300)
    place("android", size=999_999)  # sidecar describing a different build
    assert android_release()["version_code"] == 300


# --- the advertisement -------------------------------------------------------


def test_the_advertisement_carries_the_whole_table():
    place("linux-deb")
    assert set(advertisement()["clients"]) == {"linux-deb"}


def test_the_advertisement_still_carries_the_key_phones_already_read():
    """Not deprecated in the change that introduces its replacement. An installed
    Android client reads `android_client`, and one duplicated dict is what it costs
    to not strand it."""
    place("android")
    data = advertisement()
    assert data["android_client"] == data["clients"]["android"]


def test_no_android_client_means_no_android_key_even_when_others_are_present():
    place("windows")
    data = advertisement()
    assert "android_client" not in data
    assert set(data["clients"]) == {"windows"}


# --- routes ------------------------------------------------------------------


@pytest.mark.parametrize("platform_id", ALL_IDS)
async def test_metadata_endpoint_is_public_so_an_updater_can_ask_cheaply(app, platform_id):
    place(platform_id)
    resp = await app.test_client().get(f"/api/client/{platform_id}")
    assert resp.status_code == 200
    assert (await resp.get_json())["version_code"] == 3503708


@pytest.mark.parametrize("platform_id", ALL_IDS)
async def test_metadata_404s_rather_than_describing_a_client_that_is_not_there(app, platform_id):
    resp = await app.test_client().get(f"/api/client/{platform_id}")
    assert resp.status_code == 404


async def test_an_unknown_platform_404s_like_an_absent_one(app):
    """Same answer to the caller either way, and telling them apart would only tell
    an unauthenticated stranger which platforms this build of the server knows."""
    resp = await app.test_client().get("/api/client/blackberry")
    assert resp.status_code == 404


async def test_the_index_returns_everything_in_one_request(app):
    place("android")
    place("linux-appimage")
    resp = await app.test_client().get("/api/client")
    assert resp.status_code == 200
    assert set((await resp.get_json())["clients"]) == {"android", "linux-appimage"}


async def test_the_index_is_an_empty_set_rather_than_a_404(app):
    """A server with no clients has an answer; it is just an empty one. 404 here
    would make the UI treat "nothing to offer" as a broken endpoint."""
    resp = await app.test_client().get("/api/client")
    assert resp.status_code == 200
    assert (await resp.get_json())["clients"] == {}


@pytest.mark.parametrize("platform_id", ALL_IDS)
async def test_the_bytes_need_authentication_even_though_the_version_does_not(app, platform_id):
    """Anyone who can reach the port may ask what version exists; only an account or
    a linked device may pull the payload."""
    place(platform_id)
    resp = await app.test_client().get(f"/api/client/{platform_id}/download")
    assert resp.status_code == 401