from __future__ import annotations

# Screen-space (pixel) UI drawing: pure instance-list builders, no wgpu/rendering dependency,
# so this is testable without a GPU. Renderer feeds the dicts these functions build into a
# second, screen-space camera pass alongside the normal world-space one - see
# engine/render/renderer.py::render_frame's `ui_instances` parameter, and engine/ui_assets.py
# for how the glyph/panel textures referenced here actually get generated on disk.

GLYPH_SIZE = 16.0  # both the source PNG's pixel dimensions and its default on-screen size
CHAR_ADVANCE = 10.0  # horizontal spacing between glyph left edges when drawing a string
LINE_HEIGHT = 18.0
PRINTABLE_MIN = 32
PRINTABLE_MAX = 126
FALLBACK_CHAR = "?"


def glyph_texture_path(ch: str) -> str:
    code = ord(ch)
    if not (PRINTABLE_MIN <= code <= PRINTABLE_MAX):
        ch = FALLBACK_CHAR
    return f"ui/font/{ord(ch)}.png"


def panel_texture_path(name: str) -> str:
    return f"ui/panel/{name}.png"


def text_width(text: str, char_advance: float = CHAR_ADVANCE) -> float:
    return len(text) * char_advance


def draw_text(
    buckets: dict[str, list[float]],
    text: str,
    x: float,
    y: float,
    size: float = GLYPH_SIZE,
    char_advance: float = CHAR_ADVANCE,
) -> float:
    """Appends one instance per non-space glyph in `text` at (x, y), advancing left to right.
    Returns the total pixel width advanced, so callers can center/right-align follow-up text.
    """
    for i, ch in enumerate(text):
        if ch == " ":
            continue
        buckets[glyph_texture_path(ch)].extend((x + i * char_advance, y, size, size))
    return text_width(text, char_advance)


def draw_panel(buckets: dict[str, list[float]], name: str, x: float, y: float, w: float, h: float) -> None:
    buckets[panel_texture_path(name)].extend((x, y, w, h))