"""5x4 camera mosaic helpers."""
import numpy as np

from display_grid import (
    CameraGrid,
    camera_ids,
    display_name,
    is_camera_identity,
    letterbox_bgra,
    placeholder,
)


def test_camera_ids():
    ids = camera_ids(20)
    assert ids[0] == "cam-01" and ids[-1] == "cam-20"
    assert len(ids) == 20


def test_is_camera_identity():
    assert is_camera_identity("cam-07")
    assert is_camera_identity("cam-07", "cam")
    assert not is_camera_identity("speaker")
    assert not is_camera_identity("display-wall")


def test_display_name():
    assert display_name("cam-07") == "CAM-07"
    assert display_name("cam-01") == "CAM-01"


def test_letterbox_preserves_canvas_size():
    src = np.zeros((720, 1280, 4), dtype=np.uint8)
    src[:] = (0, 0, 255, 255)
    out = letterbox_bgra(src, 384, 270)
    assert out.shape == (270, 384, 4)
    assert out.dtype == np.uint8


def test_grid_render_size_and_slots():
    g = CameraGrid(width=1920, height=1080, cols=5, rows=4)
    assert g.tile_w == (1920 - g.gap * 6) // 5
    assert g.tile_h == (1080 - g.gap * 5) // 4
    assert g.inner_w < g.tile_w
    assert g.inner_h < g.tile_h
    assert len(g.identities) == 20
    buf = g.render()
    assert len(buf) == 1920 * 1080 * 4
    frame = np.zeros((720, 1280, 4), dtype=np.uint8)
    frame[:] = (255, 0, 0, 255)
    g.set_frame("cam-07", frame)
    buf2 = g.render()
    assert buf2 != buf
    g.clear("cam-07")
    assert len(g.render()) == len(buf)


def test_empty_tiles_have_name_placeholder():
    g = CameraGrid(width=1920, height=1080, cols=5, rows=4)
    # Name is drawn in the inner region — not a flat fill.
    tile = g._tiles["cam-01"]
    assert tile.shape == (g.tile_h, g.tile_w, 4)
    assert tile.sum() > 0
    inner = tile[g.border : g.border + g.inner_h, g.border : g.border + g.inner_w]
    # Center of an empty tile is not uniform (text glyphs).
    assert inner.std() > 1.0


def test_gap_separates_tiles():
    g = CameraGrid(width=1920, height=1080, cols=5, rows=4, gap=8)
    canvas = np.frombuffer(g.render(), dtype=np.uint8).reshape(1080, 1920, 4)
    # Pixel in the gutter between col 0 and col 1 is canvas background, not a tile.
    x = g.gap + g.tile_w + g.gap // 2
    y = g.gap + 4
    assert tuple(canvas[y, x]) == (10, 10, 10, 255)


def test_placeholder_draws_text():
    img = placeholder(640, 360, ["Screen share", "stub"])
    assert img.shape == (360, 640, 4)
    assert img.sum() > 0