"""Phase 07 task 04 — the client's sprite map must stay equal to the sim's.

`app/static/js/render/canvas.js` holds `REACHABLE_ITEM_FORMS` — the
(client's copy of) the (kind, form) pairs the simulation can produce,
used by `itemSpriteId` to pick an atlas id for every carried or
station-held item. The authoritative source is
`undercooked.tools.gen_art_index.reachable_item_forms()` (a fixpoint
walk over the sim's own `ACCEPTS` / `TRANSITIONS` tables — the same
walk that derives the atlas's expected ids). A drift — a sim change
that orphans a pair, or adds one the client forgot — would render as
a missing sprite. So the parity is a gate, not a convention: this test
reads the JS file (the same source `app/static/index.html` serves) and
asserts set equality in **both directions** (mirroring the
`test_client_enum_parity.py` discipline).

It also pins the two things the renderer's *mapping functions* must
not break: every kind has a `raw` fallback (the unreachable pair's
sprite), and the JS table's kinds are exactly the sim's `ItemKind`
set (no kind left without a table row, no invented kind).
"""

from __future__ import annotations

import json
import re
from pathlib import Path

import pytest

from undercooked.sim.model import ItemForm, ItemKind
from undercooked.tools.gen_art_index import reachable_item_forms

pytestmark = pytest.mark.unit

JS_CANVAS_PATH = (
    Path(__file__).resolve().parent.parent.parent
    / "app"
    / "static"
    / "js"
    / "render"
    / "canvas.js"
)


def _js_table(source: str) -> dict[str, list[str]]:
    """The `REACHABLE_ITEM_FORMS` object, as kind → [forms] (a tiny,
    stable parser: `kind: ["raw", "chopped", …],` lines inside the
    frozen object)."""
    match = re.search(
        r"export const REACHABLE_ITEM_FORMS = Object\.freeze\(\{(.*?)\}\);",
        source,
        re.DOTALL,
    )
    assert match is not None, "REACHABLE_ITEM_FORMS is not a `Object.freeze({...})` export"
    body = match.group(1)
    assert "'" not in body, (
        "the table must use double-quoted literals (the test parses them as JSON)"
    )
    table: dict[str, list[str]] = {}
    for kind_match in re.finditer(r"(\w+):\s*\[(.*?)\]", body):
        kind = kind_match.group(1)
        forms = json.loads(f"[{kind_match.group(2)}]")
        assert all(isinstance(f, str) for f in forms), f"{kind} has a non-string form"
        assert kind not in table, f"duplicate kind {kind} in the table"
        table[kind] = forms
    return table


@pytest.fixture(scope="module")
def js_source() -> str:
    assert JS_CANVAS_PATH.is_file(), f"the canvas module is missing: {JS_CANVAS_PATH}"
    return JS_CANVAS_PATH.read_text(encoding="utf-8")


def test_table_covers_exactly_the_item_kinds(js_source) -> None:
    """The table's keys are the sim's `ItemKind` values — no kind
    missing a row (its unreachable pairs would fall back with no
    `raw` row to lean on), no invented kind."""
    table = _js_table(js_source)
    js_kinds = set(table)
    py_kinds = {kind.value for kind in ItemKind}
    missing = py_kinds - js_kinds
    invented = js_kinds - py_kinds
    assert not missing and not invented, (
        f"REACHABLE_ITEM_FORMS (JS) kind set drifted from ItemKind (Python): "
        f"missing kinds: {sorted(missing) or '—'}, invented kinds: {sorted(invented) or '—'}"
    )


def test_forms_match_the_sim_fixpoint(js_source) -> None:
    """Set equality per kind, in both directions, naming the pair."""
    table = _js_table(js_source)
    sim = reachable_item_forms()
    for kind in ItemKind:
        js_forms = set(table.get(kind.value, []))
        py_forms = {form.value for form in sim[kind]}
        only_py = py_forms - js_forms
        only_js = js_forms - py_forms
        assert not only_py and not only_js, (
            f"{kind.value} drifted: missing in the JS table: {sorted(only_py) or '—'}, "
            f"missing in the sim: {sorted(only_js) or '—'}"
        )


def test_every_table_form_is_a_known_form(js_source) -> None:
    """A form the sim's `ItemForm` does not define is a mapping bug
    (the atlas has no `item-<kind>-<form>` for it)."""
    table = _js_table(js_source)
    known = {form.value for form in ItemForm}
    for kind, forms in table.items():
        unknown = set(forms) - known
        assert not unknown, f"{kind} names unknown form(s): {sorted(unknown)}"


def test_every_kind_has_a_raw_fallback(js_source) -> None:
    """`itemSpriteId`'s unreachable-pair fallback is `item-<kind>-raw` —
    every kind must therefore carry `raw` (the sim guarantees it: a
    shelf-stocked kind starts raw, and the plate is raw- or
    dirty-stocked; the test pins the renderer's contract, not the
    sim's)."""
    table = _js_table(js_source)
    for kind, forms in table.items():
        assert "raw" in forms, f"{kind} lacks the `raw` fallback form"


def test_atlas_has_every_reachable_pair() -> None:
    """The closure: every (kind, form) the sim can produce has an
    atlas id (the `gen_art_index` contract, checked here against the
    shipped `index.json` so a new pair without its sprite fails the
    build, naming the pair)."""
    index_path = (
        Path(__file__).resolve().parent.parent.parent
        / "app"
        / "static"
        / "assets"
        / "index.json"
    )
    assert index_path.is_file(), f"the atlas index is missing: {index_path}"
    index = json.loads(index_path.read_text(encoding="utf-8"))
    ids = {entry["id"] if isinstance(entry, dict) else str(entry) for entry in index}
    sim = reachable_item_forms()
    missing = [
        f"item-{kind.value}-{form.value}"
        for kind in ItemKind
        for form in sim[kind]
        if f"item-{kind.value}-{form.value}" not in ids
    ]
    assert not missing, f"the atlas lacks sprite(s): {missing}"