"""hud2d_overlay.py -- the cockpit HUD (reticle + weapon pips), composited on
top of the i860+GPU 3D render.

This is a HOST-SIDE overlay, entirely independent of the i860 firmware: the
game builds it as a dpl2d_* 2D display list (wire actions 0x29 NewDisplayList /
0x2b FlushDisplayList) and binds it to the view node (view body offset 96).
vrview.py (the OTHER renderer, dpl3-revive/patha) already has a complete,
tested interpreter for this -- hud2d_prims()/hud2d_root() -- reused directly
here rather than re-derived. See BT411 context/gauges-hud.md ("Cockpit HUD
reticle... LIVE") for the full documented semantics (range ladder, weapon
pips colour-coded by range, lock ring, torso-twist tape, compass) -- this
module only needs to reproduce the WIRE-side geometry extraction + composite
it, not re-implement that logic.

Verified live (2026-07-20) against netdeath-20260708.fifodump: the resolved
primitives' colours match the documented reticle exactly (green crosshair/
ladder, yellow width-2 range bar, red/orange filled circles = weapon pips by
range class) -- see IG-SHADING-MODEL.md sec 6c.
"""
import struct, sys, os
import numpy as np

sys.path.insert(0, r'C:\VWE\TeslaRel410\dpl3-revive\patha')
from vrview import hud2d_prims, hud2d_root, TYPE  # noqa: E402

_EDGE_OP = {6: 'nest', 7: 'link', 8: 'prune', 11: 'list_add', 12: 'list_remove'}


class HudTracker:
    """Incremental wire-record feed -> the view's live dpl2d overlay
    primitives, in view-rect space (x0..x1, y0..y1, y grows DOWN --
    y0 is the top of screen, y1 the bottom; see composite_hud's to_px).

    Only tracks what hud2d_root/hud2d_prims need: node type+body (create/
    flush), the dcs->view list_add edge, and the dl2d display-list words
    (0x29/0x2b). Deliberately NOT a full VirtualBoard -- the 3D scene is the
    i860 firmware's job; this is purely the 2D overlay layer."""

    def __init__(self):
        self.nodes = {}
        self.dl2d = {}
        self.view = None
        self._acc = None                 # in-progress 0x2b chunk accumulation
        self._hud2d_bind = {}            # hud2d_root's own cache, keyed by view

    def feed(self, action, payload):
        p = payload
        if action == 1 and len(p) >= 8:                       # create
            typ = struct.unpack_from('<I', p, 0)[0]
            h = struct.unpack_from('<I', p, 4)[0]
            self.nodes[h] = {'type': typ, 'body': b''}
        elif action == 3 and len(p) >= 4:                     # flush
            h = struct.unpack_from('<I', p, 0)[0]
            n = self.nodes.setdefault(h, {'type': None, 'body': b''})
            n['body'] = p[4:]
        elif action in _EDGE_OP and len(p) >= 8:
            op = _EDGE_OP[action]
            x, y = struct.unpack_from('<II', p, 0)
            if op == 'list_add':
                tn = lambda h: TYPE.get(self.nodes.get(h, {}).get('type'))
                if tn(y) == 'view' and tn(x) == 'dcs':
                    self.view = y
        elif action == 0x29 and len(p) >= 4:                  # NewDisplayList
            h = struct.unpack_from('<I', p, 0)[0]
            self.dl2d[h] = []
        elif action == 0x2b and len(p) >= 20:                 # FlushDisplayList
            hdr, _nxt, tail, size = struct.unpack_from('<4I', p, 0)
            size = min(size, (len(p) - 20) // 4)
            dat = list(struct.unpack_from('<%dI' % size, p, 20))
            if hdr:
                self._acc = [hdr, max(tail, 1) - 1, dat]
            elif self._acc is not None:
                self._acc[1] -= 1
                self._acc[2] += dat
            if self._acc is not None and self._acc[1] <= 0:
                self.dl2d[self._acc[0]] = self._acc[2]
                self._acc = None

    def view_rect(self):
        """(x0, y0, x1, y1, hither, yon) from the current view's body, or
        None if no full-length view flush has been seen yet."""
        if self.view is None:
            return None
        vb = self.nodes.get(self.view, {}).get('body') or b''
        if len(vb) < 68:            # need stored-body floats up to index 16
            return None
        f = struct.unpack_from('<24f', vb, 0)
        # docstring's wire-payload word k == stored-body word k-1 (vrview.py's
        # own note): x0,y0,x1,y1,zeye,xs,ys,hither,yon at payload words 6..14.
        x0, y0, x1, y1 = f[5], f[6], f[7], f[8]
        hither, yon = f[12], f[13]
        return (x0, y0, x1, y1, hither, yon)

    def primitives(self):
        """Current HUD primitives (view-rect space), or [] if not resolvable
        yet (no view, or its display-list binding hasn't landed)."""
        root = hud2d_root(self, self.view)
        if not root:
            return []
        return hud2d_prims(self.dl2d, root)


def composite_hud(img, tracker, W, H):
    """Draw the tracker's current HUD primitives onto img (HxWx3 uint8,
    modified in place). view-rect (x0..x1, y0..y1, y grows DOWN -- confirmed
    live, see to_px) -> pixel space (0..W, 0..H, y down, same direction):
    px = (x-x0)/(x1-x0)*W, py = (y-y0)/(y1-y0)*H, no inversion.
    No-op (returns False) if the view rect or display list isn't resolved
    yet -- callers should keep showing the last good frame, same as the 3D
    render's own "skip if not ready" convention."""
    rect = tracker.view_rect()
    if rect is None:
        return False
    x0, y0, x1, y1, _hither, _yon = rect
    prims = tracker.primitives()
    if not prims:
        return False
    from PIL import Image, ImageDraw
    pim = Image.fromarray(img, 'RGB')
    draw = ImageDraw.Draw(pim)
    dx = x1 - x0 or 1.0
    dy = y1 - y0 or 1.0

    def to_px(pt):
        x, y = pt
        # dpl2d Y grows DOWN (screen convention), confirmed both by the user
        # (live: horizontal/twist tape appeared at top instead of bottom, the
        # range ladder filled the wrong direction) and by vrview_gl.py's own
        # comment/fix for the identical symptom ("mapping straight onto GL's
        # Y-up NDC rendered the whole HUD flipped") -- y0 (the smaller raw
        # value) is the TOP of screen, y1 the bottom. No inversion needed.
        return ((x - x0) / dx * W, (y - y0) / dy * H)

    for kind, col, width, pts in prims:
        if len(pts) < 1:
            continue
        rgb = tuple(max(0, min(255, int(round(c * 255)))) for c in col)
        w = max(1, int(round(width)))
        xy = [to_px(p) for p in pts]
        if kind == 'points':
            r = 1.5
            for (px, py) in xy:
                draw.ellipse((px - r, py - r, px + r, py + r), fill=rgb)
        elif kind == 'segs':
            for i in range(0, len(xy) - 1, 2):
                draw.line([xy[i], xy[i + 1]], fill=rgb, width=w)
        elif kind == 'strip':
            if len(xy) >= 2:
                draw.line(xy, fill=rgb, width=w)
        elif kind == 'poly':
            if len(xy) >= 3:
                draw.polygon(xy, fill=rgb)
    img[:] = np.asarray(pim)
    return True