"""Unit: the admin UI-settings API (phase 91, task 01).

Covers ``app/api/ui_settings.py`` — the PUT validation + normalization
contract and the GET/PUT persistence on the single ``ui_settings`` row:

* PUT validation — the 422s NAME the offending field (fixed details):
  a >300-char string after the trim, a non-``#rrggbb`` color (wrong
  prefix, 3-digit shorthand, 8 hex chars, missing ``#``);
* normalization — colors are lowercased on store; a color EQUAL to its
  built-in is stored as NULL (the owner-locked rule: "save the defaults"
  must leave the row empty — the no-op injection contract); an empty /
  whitespace-only string is the clear operation (NULL);
* GET — the effective merge (a partial row reports the DB values over
  the env/built-in defaults);
* upsert — the first PUT CREATES the id-1 row, the second UPDATES that
  same row (one row, always id 1).

House pattern (the ``test_tokens_api`` precedent): the real app via
TestClient (cookie jar = the house admin-login fixture) against the real
compose Postgres; the single row is global state, so an autouse fixture
resets it around every test.
"""
from __future__ import annotations

from collections.abc import Iterator

import pytest
from fastapi.testclient import TestClient
from sqlalchemy import select, text
from sqlalchemy.orm import Session

from app.config import get_settings
from app.core import theming
from app.models import UiSettings

ALL_NULL_BODY: dict[str, str | None] = {
    "app_name": None, "input_placeholder": None, "footer_text": None,
    "bg": None, "surface": None, "ink": None, "ink_soft": None,
    "line": None, "brand": None, "brand_soft": None, "brand_ink": None,
}


@pytest.fixture(autouse=True)
def clean_ui_settings(db: Session) -> Iterator[None]:
    """ui_settings holds ONE row of global state: reset it around every
    test (the ``clean_tokens`` house pattern, DELETE — the row is
    created only by the PUT upsert, so "absent" is the natural
    pristine state)."""
    db.execute(text("DELETE FROM ui_settings"))
    db.commit()
    yield
    db.execute(text("DELETE FROM ui_settings"))
    db.commit()


def _row(db: Session) -> UiSettings | None:
    return db.execute(select(UiSettings).where(UiSettings.id == 1)).scalars().first()


def test_put_too_long_string_422_names_the_field(
    admin_client: TestClient, db: Session
) -> None:
    """Each of the 3 strings: >300 chars AFTER the trim is a 422 naming
    that field; a rejected PUT half-writes nothing; exactly 300 still
    passes (the column is VARCHAR(300))."""
    for field in theming.STRING_FIELDS:
        r = admin_client.put("/api/ui-settings", json={field: "x" * 301})
        assert r.status_code == 422, (field, r.text)
        assert r.json()["detail"] == f"{field} is too long (max 300)"
        # A whitespace-padded 301 is still 301 after the trim…
        r = admin_client.put("/api/ui-settings", json={field: " x" * 151})
        assert r.status_code == 422, (field, r.text)
    # No rejected PUT created the row — the upsert runs after validation.
    assert _row(db) is None
    # Exactly 300 passes — stored, trimmed.
    r = admin_client.put("/api/ui-settings", json={"app_name": "y" * 300})
    assert r.status_code == 200, r.text
    assert r.json()["app_name"] == "y" * 300


def test_put_bad_hex_422_names_the_field(admin_client: TestClient) -> None:
    """Each of the 8 colors: anything not ``^#[0-9a-fA-F]{6}$`` is a 422
    naming that field — 3-digit shorthand, 8 hex digits, a bare hex
    without ``#``, a named color, and the empty string (the color clear
    operation is ``null``, not ``""``)."""
    for field in theming.COLOR_FIELDS:
        for bad in ("fff", "#ff", "ff00aa", "#12345678", "red"):
            r = admin_client.put("/api/ui-settings", json={field: bad})
            assert r.status_code == 422, (field, bad, r.text)
            assert r.json()["detail"] == f"{field} must be a #rrggbb hex color"


def test_put_lowercases_colors_on_store(
    admin_client: TestClient, db: Session
) -> None:
    """Uppercase hex passes the validator and is stored LOWERCASE — the
    canonical form the tag renderer and the drift comparison rely on."""
    r = admin_client.put("/api/ui-settings", json={"brand": "#818CF8"})
    assert r.status_code == 200, r.text
    assert r.json()["brand"] == "#818cf8"
    row = _row(db)
    assert row is not None
    assert row.brand == "#818cf8"  # the stored column, not just the response


def test_put_built_in_color_is_stored_as_null(
    admin_client: TestClient, db: Session
) -> None:
    """The owner-locked normalization: a color equal to its built-in is
    stored as NULL — PUTting the whole built-in palette (with one value
    in uppercase, proving the compare happens AFTER the lowercase)
    leaves the row COMPLETELY empty: "save the defaults" must keep an
    unset deployment byte-identical (the no-op injection contract)."""
    body = dict(ALL_NULL_BODY)
    for key, value in theming.BUILTIN_COLORS.items():
        body[key] = value.upper() if key == "brand" else value
    r = admin_client.put("/api/ui-settings", json=body)
    assert r.status_code == 200, r.text
    # The response is the effective values — still the built-ins…
    for key in theming.COLOR_FIELDS:
        assert r.json()[key] == theming.BUILTIN_COLORS[key]
    # …and the row itself is empty (the upsert created a row of NULLs).
    row = _row(db)
    assert row is not None, "the PUT upsert creates the id-1 row"
    assert row.id == 1
    for field in (*theming.STRING_FIELDS, *theming.COLOR_FIELDS):
        assert getattr(row, field) is None, f"{field} must be stored as NULL"


def test_put_empty_string_is_the_clear_operation(
    admin_client: TestClient, db: Session
) -> None:
    """A whitespace-only (or empty) string trims to empty → NULL — the
    clear operation, not a 422 and not a stored blank: the effective
    value falls back to the env default."""
    r = admin_client.put("/api/ui-settings", json={"app_name": "   ", "footer_text": ""})
    assert r.status_code == 200, r.text
    row = _row(db)
    assert row is not None
    assert row.app_name is None
    assert row.footer_text is None
    # The response reports the effective (env) fallback, not "".
    assert r.json()["app_name"] == get_settings().app_name
    assert r.json()["footer_text"] == get_settings().footer_text


def test_get_effective_merge_partial_row(admin_client: TestClient, db: Session) -> None:
    """GET reports the DB values over the defaults, column by column: a
    row with ONLY ``bg`` set (hand-inserted) reports that color plus the
    built-ins and the env strings — all 11 keys, no nulls."""
    db.add(UiSettings(id=1, bg="#123456"))
    db.commit()
    r = admin_client.get("/api/ui-settings")
    assert r.status_code == 200
    body = r.json()
    assert set(body) == set(theming.STRING_FIELDS) | set(theming.COLOR_FIELDS)
    assert body["bg"] == "#123456"  # the DB value wins
    for key in theming.COLOR_FIELDS:
        if key != "bg":
            assert body[key] == theming.BUILTIN_COLORS[key]
    assert body["app_name"] == get_settings().app_name
    assert body["input_placeholder"] == get_settings().input_placeholder
    assert body["footer_text"] == get_settings().footer_text


def test_upsert_creates_then_updates_the_id_1_row(
    admin_client: TestClient, db: Session
) -> None:
    """The first PUT creates the id-1 row; the second updates the SAME
    row (still exactly one row, still id 1 — the single-row contract)."""
    r1 = admin_client.put(
        "/api/ui-settings", json={"brand": "#123abc", "app_name": "First"}
    )
    assert r1.status_code == 200, r1.text
    row = _row(db)
    assert row is not None and row.id == 1
    assert row.brand == "#123abc"
    assert row.app_name == "First"

    r2 = admin_client.put(
        "/api/ui-settings", json={"brand": "#abcdef", "input_placeholder": "Second"}
    )
    assert r2.status_code == 200, r2.text
    assert r2.json()["brand"] == "#abcdef"
    assert r2.json()["input_placeholder"] == "Second"

    db.expire_all()  # drop the test session's pre-second-PUT view (house pattern)
    rows = db.execute(select(UiSettings)).scalars().all()
    assert len(rows) == 1, "the upsert must never create a second row"
    assert rows[0].id == 1
    assert rows[0].brand == "#abcdef"  # updated, not appended
    assert rows[0].input_placeholder == "Second"  # the new string landed
    assert rows[0].app_name is None  # absent in the second body → NULL