"""
Floor lettering with the Season 1 bundle's own decal materials (its words, the orange chevron, the hazard band).

Same rules as on Anchorage (models/anchorage/build/dressing.py), so station and ship read alike:
  * one type size: a word is a 3.2 x 0.8 m decal, centred on the axis of the opening it belongs to;
  * a word lies on the floor before the doorway it names and is read walking towards it;
  * white lettering on the dark deck; three orange chevrons after a word point where it leads;
  * orange hazard band = "something moves here".
Only variants the pack ships are used, so nothing new is needed in Unreal: each mark is one decal (material, size,
matrix) in the layout export.
"""
import math

import numpy as np
from mathutils import Matrix, Vector

from units import Item

GAME = "/Game/StarterBundle/"
MATS = GAME + "ModularSciFiMats/Materials/Decals/"
COMM = GAME + "ModularSci_Comm/Materials/Decals/"
WORDS = {
    "CARGO": MATS + "Words/MI_Cargo", "DOCK": MATS + "Words/MI_Dock", "STAND CLEAR": MATS + "Words/MI_StandClear",
    "CONTROL": COMM + "Words/MI_Control", "MAINTENANCE": COMM + "Words/MI_Maintenance", "RESTRICTED": MATS + "Words/MI_RestrictedArea",
    "STATION": MATS + "Words/MI_Station", "OBSERVATION": COMM + "Words/MI_Observation",
}
CHEVRON = MATS + "Arrows/MI_Arrow_A"            # orange chevron, points along +U
HAZARD = MATS + "Stripes/MI_Stripe_H"
HAZARD_FALLBACK = MATS + "Stripes/MI_Stripe_D"
MAIN = (3.2, 0.8)
_extent = {}


def dir_vec(heading_deg):
    """Unit vector for a heading in the ship's frame: 0 = +X (bow), 90 = +Y (port)."""
    a = math.radians(heading_deg)
    return Vector((math.cos(a), math.sin(a), 0.0))


def text_extent(mat):
    """Where the lettering sits inside its texture: (u0, u1, v0, v1), v measured from the bottom."""
    if mat.name in _extent:
        return _extent[mat.name]
    ext = (0.0, 1.0, 0.0, 1.0)
    for node in mat.node_tree.nodes:
        if node.type == "TEX_IMAGE" and node.image is not None and node.image.size[0] > 0:
            img = node.image
            w, h = img.size
            px = np.empty(w * h * 4, dtype=np.float32)
            img.pixels.foreach_get(px)
            a = px.reshape(h, w, 4)[:, :, 0]
            cols = np.where(a.max(axis=0) > 0.35)[0]
            rows = np.where(a.max(axis=1) > 0.35)[0]
            if len(cols) and len(rows):
                ext = (cols[0] / w, (cols[-1] + 1) / w, rows[0] / h, (rows[-1] + 1) / h)
            break
    _extent[mat.name] = ext
    return ext


def mark(kit, mat_path, x, y, z, heading, size, name, centre_text=True):
    """One floor decal as a unit item (world frame): read by someone walking along `heading`, its visible mark
    centred on (x, y), lying on a floor at height z."""
    d = dir_vec(heading)                               # text "up" on the floor = direction of travel
    r = Vector((d.y, -d.x, 0.0))                       # text right = the reader's right
    w, h = size
    cx, cy = x, y
    if centre_text:
        u0, u1, v0, v1 = text_extent(kit.material(mat_path))
        off = r * ((0.5 - (u0 + u1) / 2.0) * w) + d * ((0.5 - (v0 + v1) / 2.0) * h)
        cx, cy = x + off.x, y + off.y
    # decal frame: X = projection (down), Y = text up, Z = text right; the unit decal quad is 2 x 2 cm
    m = Matrix(((0.0, d.x * h * 50.0, r.x * w * 50.0, cx),
                (0.0, d.y * h * 50.0, r.y * w * 50.0, cy),
                (-12.0, 0.0, 0.0, z),
                (0.0, 0.0, 0.0, 1.0)))
    return Item("decal", mat_path, m, name, "", {"material": mat_path, "size": [1.0, 1.0, 1.0]}, Vector((cx, cy, z)))


def word(kit, key, x, y, z, heading, size=MAIN, chevrons=True, gap=0.55):
    out = [mark(kit, WORDS[key], x, y, z, heading, size, "WORD " + key)]
    if chevrons:
        d = dir_vec(heading)
        s = size[1] * 0.62
        start = size[1] * 0.5 + gap
        for i in range(3):
            p = Vector((x, y, 0)) + d * (start + i * s * 0.62)
            # the chevron texture points along +U (the reader's right): turn it to point ahead
            out.append(mark(kit, CHEVRON, p.x, p.y, z, heading + 90.0, (s, s), "CHEVRON", centre_text=False))
    return out


def hazard_band(kit, x, y, z, heading, width=8.0, piece=2.0):
    """A hazard band across the floor, `width` long, centred on (x, y), crossed by someone walking along `heading`."""
    mat = HAZARD if HAZARD in kit.materials else HAZARD_FALLBACK
    r = Vector((dir_vec(heading).y, -dir_vec(heading).x, 0.0))
    n = int(round(width / piece))
    out = []
    for i in range(n):
        p = Vector((x, y, 0)) + r * ((i - (n - 1) / 2.0) * piece)
        out.append(mark(kit, mat, p.x, p.y, z, heading, (piece, piece / 2.0), "HAZARD BAND"))
    return out