/**
 * The furniture library of the decor layer (docs/FURNITURE.md).
 *
 * Pure geometry and pure data: no Lit, no DOM, no `hass`. Everything here is
 * unit-testable, and the card only turns the output into one `<path>`.
 *
 * WHY OUR OWN SYMBOLS AND NOT AN ICON SET. Every general-purpose icon pack —
 * mdi included, and it is already in this bundle — draws a PICTOGRAM: a sofa
 * seen from the front, inside a 24x24 square. A plan is drawn from ABOVE and
 * to SCALE: a sofa is a 2.2 x 0.9 m rectangle with a back along one long
 * side. Putting a 24x24 pictogram into that rectangle stretches a drawing
 * that was never meant to be stretched, and the result reads as an icon lying
 * on the floor, not as a piece of furniture. The library is therefore
 * generated from House Plan's own top-view SVG pack — all of it, since #593:
 * the 12 compatibility symbols that used to be drawn from unit-box primitives
 * got designer artwork under their existing ids. Every symbol resolves to one
 * path plus its native coordinate box; the renderer scales that box to the
 * stored real-world size. The renderer keeps the configured decor stroke
 * stable through that local non-uniform transform, while
 * `furniturePlanScreenScale` restores the outer physical plan zoom.
 *
 * THE CONVENTION EVERY SYMBOL OBEYS:
 *   - x points right and y points DOWN (SVG); art keeps its native viewBox;
 *   - `y = 0` is the BACK of the object — the side that goes against a wall.
 *     That is what makes the wall magnet meaningful: a sofa's back, a bed's
 *     headboard, a wardrobe's rear panel and a worktop's edge all mean the
 *     same thing to the furniture wall-placement helper;
 *   - nothing is filled. The card strokes the whole symbol in the decor
 *     colour, so a plan stays a drawing (owner: «символы рисуются линейно»).
 */

import { NORM_W, GRID_PITCH, CANVAS_LIMIT } from './space-geometry';
import { GENERATED_FURNITURE_CATALOG } from './furniture-plan-catalog.generated';
import { FURNITURE_ART_RUNTIME, type FurnitureArtHost } from './furniture-art-runtime';
import { canonicalFurnitureId } from './furniture-id';

/** Groups the palette shows, in the order it shows them. */
export const FURNITURE_GROUPS = ['furniture', 'appliance', 'sanitary', 'other'] as const;
export type FurnitureGroup = (typeof FURNITURE_GROUPS)[number];

export interface FurnitureSymbol {
  /** Stable id — it is what the config stores and what `data-symbol` carries. */
  id: string;
  group: FurnitureGroup;
  /** Category tile in the two-level editor palette. */
  category: string;
  /** Default REAL size in centimetres: width ALONG the back edge x depth. */
  w: number;
  h: number;
}

export interface FurnitureGraphic {
  d: string;
  viewW: number;
  viewH: number;
}

/**
 * The public library: every symbol of the designer pack, nothing else.
 *
 * Until #593 this was a union of the generated catalogue and 12 symbols drawn
 * from unit-box primitives, kept because the pack had no top view for them.
 * Pack 0.4.0 draws all 60, so the union is gone — and with it the trap it
 * carried: both halves used the SAME public ids, and `BY_ID` below keeps the
 * LAST entry, so a primitive silently won over the designer drawing it was
 * supposed to be replaced by.
 *
 * Sizes are the ones a European flat actually has; they are DEFAULTS, not
 * limits — the palette lets the user type over both numbers before placing,
 * and the corner handles change them afterwards.
 */
export const FURNITURE: FurnitureSymbol[] = GENERATED_FURNITURE_CATALOG.map((symbol) => ({
  id: symbol.id,
  group: symbol.group as FurnitureGroup,
  category: symbol.category,
  w: symbol.w,
  h: symbol.h,
}));

const BY_ID = new Map(FURNITURE.map((s) => [s.id, s]));

/** The symbol with this id, or null. An unknown id is DATA, not a crash: a
 *  plan written by a newer card must still validate, save and simply render
 *  nothing in an older one. */
export function furnitureSymbol(id: string | null | undefined): FurnitureSymbol | null {
  return (id && BY_ID.get(canonicalFurnitureId(id))) || null;
}

/** Is this a known symbol, and therefore one whose drawing arrives with the
 *  lazy artwork chunk (#474)? Since #593 the two questions have one answer:
 *  every symbol is designer artwork, and an unknown id has no drawing at all. */
export function furnitureArtIsLazy(id: string): boolean {
  return BY_ID.has(canonicalFurnitureId(id));
}

/** The symbols of one group, in table order. */
export function furnitureOfGroup(group: FurnitureGroup): FurnitureSymbol[] {
  return FURNITURE.filter((s) => s.group === group);
}

/** Default real size (cm) of a symbol; an unknown id falls back to 60 x 60 —
 *  a box the user can immediately resize rather than an error. */
export function furnitureDefaultCm(id: string): { w: number; h: number } {
  const s = furnitureSymbol(id);
  return s ? { w: s.w, h: s.h } : { w: 60, h: 60 };
}

// ------------------------- centimetres <-> the canvas -----------------------

/**
 * Real centimetres -> a NORMALISED size on the canvas, through the space's
 * `cell_cm` — the one scale this card has (`_cmToUnits` and `segmentCm` are
 * the same conversion in render units). Kept pure and parameterised so a test
 * can state the arithmetic without a card.
 */
export function cmToNorm(cm: number, cellCm: number,
                         gridPitch: number = GRID_PITCH, normW: number = NORM_W): number {
  const c = Number(cellCm) > 0 ? Number(cellCm) : 5;
  return ((Number(cm) || 0) / c) * gridPitch / normW;
}

/** ...and back, for the size fields and the live badges. */
export function normToCm(v: number, cellCm: number,
                         gridPitch: number = GRID_PITCH, normW: number = NORM_W): number {
  const c = Number(cellCm) > 0 ? Number(cellCm) : 5;
  return (((Number(v) || 0) * normW) / gridPitch) * c;
}

/** A piece may not be smaller than a stroke or larger than the canvas guard.
 *  Both are garbage insurance, not opinions about furniture. */
export const FURN_MIN_N = 0.0005;   // half of a 1000-unit pixel
export const FURN_MAX_N = CANVAS_LIMIT;

export function clampFurnSize(n: number): number {
  if (!Number.isFinite(n)) return FURN_MIN_N;
  return Math.max(FURN_MIN_N, Math.min(FURN_MAX_N, n));
}

/** Real-size bounds for the palette's two fields: 1 cm ... 100 m. */
export const FURN_MIN_CM = 1;
export const FURN_MAX_CM = 10000;

export function clampFurnCm(cm: number): number {
  if (!Number.isFinite(cm)) return FURN_MIN_CM;
  return Math.max(FURN_MIN_CM, Math.min(FURN_MAX_CM, cm));
}

// ------------------------------ the drawing --------------------------------

/** Native one-path artwork and its coordinate box. The renderer scales this
 * box non-uniformly to the user's stored dimensions; the furniture stroke
 * helpers below separate that local scale from the outer plan camera. */
export function furnitureGraphic(id: string, host?: FurnitureArtHost): FurnitureGraphic | null {
  if (!furnitureSymbol(id)) return null;
  // Artwork is lazy (#474): `undefined` while the chunk is pending or settled
  // into fallback renders the piece as an unknown symbol — nothing — and a
  // host passed here is re-rendered once the runtime settles. Since #593 that
  // is true for all 60 symbols, including the 12 that used to draw eagerly.
  return FURNITURE_ART_RUNTIME.art(canonicalFurnitureId(id), host) ?? null;
}

/** Compatibility helper for callers that only need a path string. Designer
 * artwork remains in its native viewBox; use `furnitureGraphic` when sizing it. */
export function furniturePathD(id: string, w: number, h: number): string {
  if (!furnitureSymbol(id) || !(w > 0) || !(h > 0)) return '';
  return FURNITURE_ART_RUNTIME.art(canonicalFurnitureId(id))?.d || '';
}

/**
 * Uniform plan-user-unit -> CSS-pixel scale of the SVG viewport.
 *
 * Furniture artwork uses a local non-uniform transform for independent width
 * and depth. `vector-effect=non-scaling-stroke` correctly rejects that local
 * transform, but it also rejects the outer SVG viewBox camera. Supplying this
 * one outer scale as the path's stroke width restores the physical zoom while
 * keeping horizontal, vertical and diagonal artwork strokes equally thick.
 *
 * Invalid/zero layout is transient during first mount. Returning 1 is the
 * finite old-behaviour fallback; ResizeObserver requests the measured render
 * before the boot veil reveals the plan.
 */
export function furniturePlanScreenScale(
  viewportWidth: unknown,
  viewportHeight: unknown,
  viewBoxWidth: unknown,
  viewBoxHeight: unknown,
): number {
  const viewportW = Number(viewportWidth);
  const viewportH = Number(viewportHeight);
  const viewW = Number(viewBoxWidth);
  const viewH = Number(viewBoxHeight);
  if (![viewportW, viewportH, viewW, viewH].every((value) => Number.isFinite(value) && value > 0))
    return 1;
  const scale = Math.min(viewportW / viewW, viewportH / viewH);
  return Number.isFinite(scale) && scale > 0 ? scale : 1;
}

/** Physical furniture stroke expressed in CSS pixels for a non-scaling path. */
export function furnitureStrokePx(
  strokeUnits: unknown,
  planScreenScale: unknown,
  fallbackStrokeUnits = 1,
): number {
  const rawStroke = Number(strokeUnits);
  const fallback = Number(fallbackStrokeUnits);
  const stroke = Number.isFinite(rawStroke) && rawStroke > 0
    ? rawStroke
    : Number.isFinite(fallback) && fallback > 0 ? fallback : 1;
  const rawScale = Number(planScreenScale);
  const scale = Number.isFinite(rawScale) && rawScale > 0 ? rawScale : 1;
  const result = stroke * scale;
  return Number.isFinite(result) && result > 0 ? result : stroke;
}

/**
 * The four corners of a rotated box, world units, in the order the frame
 * draws them: NW, NE, SE, SW. Pure, so the frame, the gestures and the tests
 * all agree on where a corner is.
 */
export function furnitureCorners(
  x: number, y: number, w: number, h: number, angle: number,
): number[][] {
  const cx = x + w / 2, cy = y + h / 2;
  const a = ((Number(angle) || 0) * Math.PI) / 180;
  const cs = Math.cos(a), sn = Math.sin(a);
  const rot = (px: number, py: number): number[] => {
    const ux = px - cx, uy = py - cy;
    return [cx + ux * cs - uy * sn, cy + ux * sn + uy * cs];
  };
  return [rot(x, y), rot(x + w, y), rot(x + w, y + h), rot(x, y + h)];
}

/**
 * Resize by a dragged corner about the OPPOSITE one — the backdrop frame's
 * rule, but with WIDTH AND DEPTH INDEPENDENT.
 *
 * Why not uniform: a picture has one true aspect ratio and stretching it is a
 * lie, which is why the backdrop scales uniformly. Furniture is the opposite
 * case — the ratio is a fact about THIS sofa, and the next one is 1.8 m long
 * with the same 0.9 m depth. A uniform handle would force the user to make a
 * bed deeper in order to make it wider, i.e. to state something false about
 * the room. So both axes move, and the two live badges say what they became.
 *
 * `sgx/sgy` are the dragged corner as signs (+1 = the high side of the axis).
 * `px/py` is the pointer. `step > 0` quantises each dimension to the grid —
 * on an unrotated piece whose fixed corner sits on a node that also puts the
 * dragged corner on a node, which is what "snap to the grid" has to mean
 * here. The UI always passes a positive grid step; zero remains useful only
 * for pure geometry callers that intentionally request no quantisation.
 */
export function furnitureResize(
  orig: { x: number; y: number; w: number; h: number; angle?: number },
  sgx: number, sgy: number, px: number, py: number, step = 0, minSize = 1e-6,
): { x: number; y: number; w: number; h: number } {
  const a = ((Number(orig.angle) || 0) * Math.PI) / 180;
  const ux = Math.cos(a), uy = Math.sin(a);          // local +x in world
  const vx = -Math.sin(a), vy = Math.cos(a);         // local +y in world
  const cx = orig.x + orig.w / 2, cy = orig.y + orig.h / 2;
  // the fixed corner = the one opposite the dragged one
  const fLocalX = sgx > 0 ? -orig.w / 2 : orig.w / 2;
  const fLocalY = sgy > 0 ? -orig.h / 2 : orig.h / 2;
  const fx = cx + fLocalX * ux + fLocalY * vx;
  const fy = cy + fLocalX * uy + fLocalY * vy;
  // the pointer, expressed along the piece's own axes from that fixed corner
  const rx = px - fx, ry = py - fy;
  let w = (rx * ux + ry * uy) * (sgx > 0 ? 1 : -1);
  let h = (rx * vx + ry * vy) * (sgy > 0 ? 1 : -1);
  if (step > 0) {
    w = Math.round(w / step) * step;
    h = Math.round(h / step) * step;
  }
  w = Math.max(minSize, w);
  h = Math.max(minSize, h);
  // rebuild the centre from the fixed corner, then the UNROTATED top-left
  const ncx = fx + (sgx > 0 ? w / 2 : -w / 2) * ux + (sgy > 0 ? h / 2 : -h / 2) * vx;
  const ncy = fy + (sgx > 0 ? w / 2 : -w / 2) * uy + (sgy > 0 ? h / 2 : -h / 2) * vy;
  return { x: ncx - w / 2, y: ncy - h / 2, w, h };
}

export interface FurnitureTransformBox {
  x: number;
  y: number;
  w: number;
  h: number;
  angle?: number;
  flip_h?: boolean;
  flip_v?: boolean;
}

export interface FurnitureResizeResult extends FurnitureTransformBox {
  flip_h?: boolean;
  flip_v?: boolean;
}

/**
 * #383 — continuous furniture-only resize.
 *
 * `sgx`/`sgy` name the dragged local edge (-1, 0 or +1). Zero keeps that
 * axis byte-for-byte, which is how the four new middle handles work. Unlike
 * the legacy shared decor helper this function never snaps to the grid and a
 * signed pointer distance may cross the fixed opposite edge. The sign is
 * projected into flip flags; the returned extents remain strictly positive.
 */
export function resizeFurnitureTransform(
  orig: FurnitureTransformBox,
  sgx: number,
  sgy: number,
  px: number,
  py: number,
  keepAspect: boolean,
  minSize: number,
): FurnitureResizeResult {
  const minimum = Number.isFinite(minSize) && minSize > 0 ? minSize : 1e-6;
  const a = ((Number(orig.angle) || 0) * Math.PI) / 180;
  const ux = Math.cos(a), uy = Math.sin(a);
  const vx = -Math.sin(a), vy = Math.cos(a);
  const cx = orig.x + orig.w / 2, cy = orig.y + orig.h / 2;
  const flx = sgx > 0 ? -orig.w / 2 : sgx < 0 ? orig.w / 2 : 0;
  const fly = sgy > 0 ? -orig.h / 2 : sgy < 0 ? orig.h / 2 : 0;
  const fx = cx + flx * ux + fly * vx;
  const fy = cy + flx * uy + fly * vy;
  const rx = px - fx, ry = py - fy;
  const rawW = sgx
    ? (rx * ux + ry * uy) * (sgx > 0 ? 1 : -1)
    : orig.w;
  const rawH = sgy
    ? (rx * vx + ry * vy) * (sgy > 0 ? 1 : -1)
    : orig.h;
  let w = sgx ? Math.abs(rawW) : orig.w;
  let h = sgy ? Math.abs(rawH) : orig.h;

  if (keepAspect && sgx && sgy) {
    const kx = w / Math.max(orig.w, minimum);
    const ky = h / Math.max(orig.h, minimum);
    // Follow whichever local pointer axis has moved farther from the original
    // scale. Equal deltas deliberately prefer width for deterministic ties.
    const scale = Math.abs(kx - 1) >= Math.abs(ky - 1) ? kx : ky;
    const floor = Math.max(minimum / orig.w, minimum / orig.h);
    const safeScale = Math.max(floor, Number.isFinite(scale) ? scale : floor);
    w = orig.w * safeScale;
    h = orig.h * safeScale;
  }
  w = Math.max(minimum, Number.isFinite(w) ? w : minimum);
  h = Math.max(minimum, Number.isFinite(h) ? h : minimum);

  const crossX = !!sgx && rawW < 0;
  const crossY = !!sgy && rawH < 0;
  const dirX = sgx ? (sgx > 0 ? 1 : -1) * (crossX ? -1 : 1) : 0;
  const dirY = sgy ? (sgy > 0 ? 1 : -1) * (crossY ? -1 : 1) : 0;
  const ncx = fx + dirX * (w / 2) * ux + dirY * (h / 2) * vx;
  const ncy = fy + dirX * (w / 2) * uy + dirY * (h / 2) * vy;
  const flipH = !!orig.flip_h !== crossX;
  const flipV = !!orig.flip_v !== crossY;
  return {
    x: ncx - w / 2,
    y: ncy - h / 2,
    w,
    h,
    ...(Number(orig.angle) ? { angle: Number(orig.angle) } : {}),
    ...(flipH ? { flip_h: true } : {}),
    ...(flipV ? { flip_v: true } : {}),
  };
}

/** Furniture is free by default; Shift snaps to world-space 45° bearings. */
export function furnitureRotationAngle(
  angle0: number,
  pointerStartDeg: number,
  pointerDeg: number,
  snap45: boolean,
): number {
  let angle = Number(angle0) + (Number(pointerDeg) - Number(pointerStartDeg));
  if (![angle, pointerStartDeg, pointerDeg].every(Number.isFinite)) angle = 0;
  if (snap45) {
    const steps = angle / 45;
    // Keep the exact half-step deterministic on both sides of zero. Native
    // Math.round(-0.5) returns -0, which would make symmetric drags snap in
    // different directions.
    angle = (steps < 0 ? -Math.round(Math.abs(steps)) : Math.round(steps)) * 45;
  }
  angle = ((angle % 360) + 360) % 360;
  return angle > 180 ? angle - 360 : angle;
}

/** One canonical transform for visible art, selection halo and future consumers. */
export function furnitureRenderTransform(
  shape: FurnitureTransformBox,
  canvasW: number,
  canvasH: number,
  artW: number,
  artH: number,
): string {
  const x = shape.x * canvasW, y = shape.y * canvasH;
  const w = shape.w * canvasW, h = shape.h * canvasH;
  const cx = x + w / 2, cy = y + h / 2;
  const tx = x + (shape.flip_h ? w : 0);
  const ty = y + (shape.flip_v ? h : 0);
  const sx = (shape.flip_h ? -1 : 1) * w / artW;
  const sy = (shape.flip_v ? -1 : 1) * h / artH;
  const angle = Number(shape.angle) || 0;
  return `${angle ? `rotate(${angle} ${cx} ${cy}) ` : ''}`
    + `translate(${tx} ${ty}) scale(${sx} ${sy})`;
}

/** Signed m/ft property field -> centimetres; null keeps invalid drafts visible. */
export function furnitureSignedFieldCm(
  value: unknown,
  imperial: boolean,
  maxCm: number,
  minCm = 0.1,
): number | null {
  if (typeof value === 'string' && !value.trim()) return null;
  const shown = Number(value);
  if (!Number.isFinite(shown) || shown === 0) return null;
  const cm = shown * (imperial ? 30.48 : 100);
  const magnitude = Math.abs(cm);
  if (magnitude < minCm || magnitude > maxCm) return null;
  return cm;
}

/** Positive stored centimetres + one flag -> a lossless-enough signed m/ft field. */
export function furnitureSignedFieldValue(
  cm: number,
  flipped: boolean,
  imperial: boolean,
): string {
  const shown = Math.abs(Number(cm)) / (imperial ? 30.48 : 100);
  // Six decimals keep the physical 0.1 cm minimum representable in both
  // metres (0.001) and feet (~0.003281) without filling ordinary values with
  // trailing zeroes.
  const rounded = Number(shown.toFixed(6));
  return String(flipped ? -rounded : rounded);
}