import type { ClusterNode, KeyNode, Node, PhyFile, Transform, Variant, VariantGroupNode } from "./phy";
import { apply, compose, inverse, matrix } from "./geometry";
import { createNodeId } from "./ids";

const ident = { a: 1, b: 0, c: 0, d: 1, e: 0, f: 0 };
type Container = { nodes: Node[]; parentWorld: typeof ident; parentRotation: number };
function containers(f: PhyFile): Map<string, Container> {
  const m = new Map<string, Container>();
  const rec = (ns: Node[], w: typeof ident, angle: number) => {
    for (const n of ns) {
      m.set(n.id, { nodes: ns, parentWorld: w, parentRotation: angle });
      const nw = compose(w, matrix(n.transform));
      const nextAngle = angle + n.transform.rotation;
      if (n.type === "cluster") rec(n.children, nw, nextAngle);
      if (n.type === "variantGroup")
        for (const v of n.children) {
          m.set(v.id, { nodes: v.children, parentWorld: nw, parentRotation: nextAngle });
          rec(v.children, nw, nextAngle);
        }
    }
  };
  rec(f.root, ident, 0);
  return m;
}
function find(f: PhyFile, id: string): Node {
  const c = containers(f).get(id);
  const n = c?.nodes.find((x) => x.id === id);
  if (!n) throw new Error(`Unknown node: ${id}`);
  return n;
}
function world(f: PhyFile, id: string): typeof ident {
  const c = containers(f).get(id);
  const n = c?.nodes.find((x) => x.id === id);
  if (!n) throw new Error(`Unknown node: ${id}`);
  return compose(c!.parentWorld, matrix(n.transform));
}
function worldRotation(f: PhyFile, id: string): number {
  const c = containers(f).get(id);
  const n = c?.nodes.find((x) => x.id === id);
  if (!n || !c) throw new Error(`Unknown node: ${id}`);
  return c.parentRotation + n.transform.rotation;
}
function mutable(f: PhyFile): PhyFile {
  return structuredClone(f);
}
function nodeId(kind: Parameters<typeof createNodeId>[0], gen?: () => string) {
  return createNodeId(kind, gen);
}
/** 新しいPHYを返す。T-11。 */
export function addKey(
  f: PhyFile,
  at: Transform,
  size: { w: number; h: number },
  profile = f.profiles[0]!.id,
  gen?: () => string,
): PhyFile {
  const o = mutable(f);
  o.root.push({ type: "key", id: nodeId("key", gen), profile, transform: { ...at }, size: { ...size } });
  return o;
}
/** 新しいPHYを返す。T-11。 */
export function addComponent(f: PhyFile, at: Transform, partGroup?: string, gen?: () => string): PhyFile {
  const o = mutable(f);
  o.root.push({
    type: "component",
    id: nodeId("component", gen),
    transform: { ...at },
    ...(partGroup === undefined ? {} : { partGroup }),
  });
  return o;
}
/** ローカル座標の差分でノードを移動する。 */
export function moveNode(f: PhyFile, id: string, dx: number, dy: number): PhyFile {
  const o = mutable(f),
    n = find(o, id);
  n.transform.x += dx;
  n.transform.y += dy;
  return o;
}
/** ノードを回転する。 */
export function rotateNode(f: PhyFile, id: string, delta: number): PhyFile {
  const o = mutable(f),
    n = find(o, id);
  n.transform.rotation += delta;
  return o;
}
/** キーのサイズを変更する。 */
export function resizeKey(f: PhyFile, id: string, size: KeyNode["size"]): PhyFile {
  const o = mutable(f),
    n = find(o, id);
  if (n.type !== "key") throw new Error(`${id} is not a key`);
  n.size = { ...size };
  return o;
}
/** 同じ親のノードを新クラスターにまとめ、絶対変換を保つ。T-11。 */
export function clusterNodes(f: PhyFile, ids: string[], name = "Cluster", gen?: () => string): PhyFile {
  if (ids.length < 1) throw new Error("Select at least one node");
  const o = mutable(f),
    cs = containers(o),
    first = cs.get(ids[0]!);
  if (!first || ids.some((id) => cs.get(id)?.nodes !== first.nodes))
    throw new Error("Selected nodes must be siblings");
  const selected = ids.map((id) => first.nodes.find((n) => n.id === id)!);
  if (selected.some((n) => !n)) throw new Error("Unknown selection");
  const angles = selected.map((n) => world(o, n.id));
  const selectedAngles = selected.map((n) => first.parentRotation + n.transform.rotation);
  const angle = selectedAngles[0]!;
  const same = selectedAngles.every((candidate) => Math.abs(candidate - angle) < 1e-9);
  const basis = matrix({ x: 0, y: 0, rotation: same ? angle : 0 }),
    basisInverse = inverse(basis);
  const shapePoints = selected.flatMap((n, i) => boundsPoints(n, angles[i]!));
  if (shapePoints.length === 0) angles.forEach((m) => shapePoints.push({ x: m.e, y: m.f }));
  const localOrigins = shapePoints.map((p) => apply(basisInverse, p));
  const min = { x: Math.min(...localOrigins.map((p) => p.x)), y: Math.min(...localOrigins.map((p) => p.y)) };
  const origin = apply(basis, min);
  const wt = matrix({ x: origin.x, y: origin.y, rotation: same ? angle : 0 });
  const local = compose(inverse(first.parentWorld), wt);
  const id = nodeId("cluster", gen),
    cluster: ClusterNode = {
      type: "cluster",
      id,
      name,
      transform: { x: local.e, y: local.f, rotation: (same ? angle : 0) - first.parentRotation },
      children: [],
    };
  const inv = inverse(wt);
  cluster.children = selected.map((n) => {
    const w = world(o, n.id),
      rel = compose(inv, w);
    return {
      ...n,
      transform: { x: rel.e, y: rel.f, rotation: selectedAngles[selected.indexOf(n)]! - (same ? angle : 0) },
    } as Node;
  });
  const indices = selected.map((n) => first.nodes.indexOf(n)).sort((a, b) => a - b);
  const insert = indices[0]!;
  first.nodes.splice(0, first.nodes.length, ...first.nodes.filter((n) => !ids.includes(n.id)));
  first.nodes.splice(insert, 0, cluster);
  return o;
}
/** clusterの子を同じ親へ戻し、絶対変換を保つ。 */
export function uncluster(f: PhyFile, id: string): PhyFile {
  const o = mutable(f),
    cs = containers(o),
    c = cs.get(id),
    cluster = c?.nodes.find((n) => n.id === id);
  if (!cluster || cluster.type !== "cluster") throw new Error(`${id} is not a cluster`);
  const clusterWorldRotation = c!.parentRotation + cluster.transform.rotation;
  const cw = compose(c!.parentWorld, matrix(cluster.transform)),
    converted = cluster.children.map((n) => {
      const w = compose(cw, matrix(n.transform)),
        rel = compose(inverse(c!.parentWorld), w);
      return {
        ...n,
        transform: {
          x: rel.e,
          y: rel.f,
          rotation: clusterWorldRotation + n.transform.rotation - c!.parentRotation,
        },
      } as Node;
    });
  const index = c!.nodes.indexOf(cluster);
  c!.nodes.splice(index, 1, ...converted);
  return o;
}
/** ノードを任意の親/rootへ移し、絶対変換を保つ。T-27。 */
export function reparent(f: PhyFile, id: string, newParentId: string | null, index?: number): PhyFile {
  const o = mutable(f),
    cs = containers(o),
    src = cs.get(id),
    n = src?.nodes.find((x) => x.id === id);
  if (!n) throw new Error(`Unknown node: ${id}`);
  const oldW = world(o, id),
    oldRotation = worldRotation(o, id);
  let target: Node[] = o.root,
    parentW = ident,
    parentRotation = 0;
  if (newParentId) {
    const p = find(o, newParentId);
    if (p.type !== "cluster")
      throw new Error("Target parent must be a cluster; use reparentToVariant for variant children");
    if (containsNode(n, newParentId)) throw new Error("Cannot reparent a node into its descendant");
    target = p.children;
    parentW = world(o, p.id);
    parentRotation = worldRotation(o, p.id);
  }
  const oldIndex = src!.nodes.indexOf(n),
    sameParent = target === src!.nodes;
  src!.nodes.splice(oldIndex, 1);
  const rel = compose(inverse(parentW), oldW);
  n.transform = { x: rel.e, y: rel.f, rotation: oldRotation - parentRotation };
  let at = index ?? target.length;
  if (sameParent && index !== undefined && oldIndex < index) at--;
  target.splice(Math.max(0, Math.min(at, target.length)), 0, n);
  return o;
}
/** variant内へ移動するreparent。T-27。 */
export function reparentToVariant(f: PhyFile, id: string, variantId: string, index?: number): PhyFile {
  const o = mutable(f),
    cs = containers(o),
    src = cs.get(id),
    n = src?.nodes.find((x) => x.id === id);
  const v = findVariant(o, variantId);
  if (!n || !src) throw new Error(`Unknown node: ${id}`);
  if (containsNode(n, variantId)) throw new Error("Cannot reparent a node into its descendant");
  const old = world(o, id),
    oldRotation = worldRotation(o, id),
    parent = srcVariantWorld(o, variantId),
    rel = compose(inverse(parent), old);
  const parentRotation = srcVariantRotation(o, variantId);
  src.nodes.splice(src.nodes.indexOf(n), 1);
  n.transform = { x: rel.e, y: rel.f, rotation: oldRotation - parentRotation };
  v.children.splice(index ?? v.children.length, 0, n);
  return o;
}
function containsNode(n: Node, id: string): boolean {
  if (n.id === id) return true;
  if (n.type === "cluster") return n.children.some((c) => containsNode(c, id));
  if (n.type === "variantGroup")
    return n.children.some((v) => v.id === id || v.children.some((c) => containsNode(c, id)));
  return false;
}
function boundsPoints(n: Node, worldMatrix: ReturnType<typeof matrix>): { x: number; y: number }[] {
  if (n.type === "key") {
    const points = [
      { x: 0, y: 0 },
      { x: n.size.w, y: 0 },
      { x: n.size.w, y: n.size.h },
      { x: 0, y: n.size.h },
    ];
    if (
      n.size.w2 !== undefined ||
      n.size.h2 !== undefined ||
      n.size.x2 !== undefined ||
      n.size.y2 !== undefined
    ) {
      const x = n.size.x2 ?? 0;
      const y = n.size.y2 ?? 0;
      const w = n.size.w2 ?? n.size.w;
      const h = n.size.h2 ?? n.size.h;
      points.push({ x, y }, { x: x + w, y }, { x: x + w, y: y + h }, { x, y: y + h });
    }
    return points.map((point) => apply(worldMatrix, point));
  }
  if (n.type === "component") return [{ x: worldMatrix.e, y: worldMatrix.f }];
  if (n.type === "cluster")
    return n.children.flatMap((child) => boundsPoints(child, compose(worldMatrix, matrix(child.transform))));
  const selected = n.children.find((variant) => variant.id === n.default);
  return selected
    ? selected.children.flatMap((child) => boundsPoints(child, compose(worldMatrix, matrix(child.transform))))
    : [{ x: worldMatrix.e, y: worldMatrix.f }];
}
function findVariant(f: PhyFile, id: string): Variant {
  for (const n of f.root) {
    const r = walk(n, id);
    if (r) return r;
  }
  throw new Error(`Unknown variant: ${id}`);
}
function walk(n: Node, id: string): Variant | undefined {
  if (n.type === "variantGroup") {
    for (const v of n.children) {
      if (v.id === id) return v;
      for (const c of v.children) {
        const r = walk(c, id);
        if (r) return r;
      }
    }
  }
  if (n.type === "cluster")
    for (const c of n.children) {
      const r = walk(c, id);
      if (r) return r;
    }
  return undefined;
}
function srcVariantWorld(f: PhyFile, id: string): typeof ident {
  const rec = (ns: Node[], w: typeof ident): typeof ident | undefined => {
    for (const n of ns) {
      const nw = compose(w, matrix(n.transform));
      if (n.type === "variantGroup")
        for (const v of n.children) {
          if (v.id === id) return nw;
          const r = rec(v.children, nw);
          if (r) return r;
        }
      if (n.type === "cluster") {
        const r = rec(n.children, nw);
        if (r) return r;
      }
    }
    return undefined;
  };
  const x = rec(f.root, ident);
  if (!x) throw new Error(`Unknown variant ${id}`);
  return x;
}
function srcVariantRotation(f: PhyFile, id: string): number {
  const rec = (nodes: Node[], parentRotation: number): number | undefined => {
    for (const n of nodes) {
      const angle = parentRotation + n.transform.rotation;
      if (n.type === "variantGroup")
        for (const v of n.children) {
          if (v.id === id) return angle;
          const found = rec(v.children, angle);
          if (found !== undefined) return found;
        }
      if (n.type === "cluster") {
        const found = rec(n.children, angle);
        if (found !== undefined) return found;
      }
    }
    return undefined;
  };
  const found = rec(f.root, 0);
  if (found === undefined) throw new Error(`Unknown variant ${id}`);
  return found;
}
/** クラスターの座標枠を変え、配下の絶対位置を保つ。PHY-P-13仮決定。 */
export function reframe(f: PhyFile, id: string, frame: Transform): PhyFile {
  const o = mutable(f),
    n = find(o, id);
  if (n.type !== "cluster") throw new Error(`${id} is not a cluster`);
  const c = containers(o).get(id)!,
    oldRotation = c.parentRotation + n.transform.rotation,
    old = compose(c.parentWorld, matrix(n.transform)),
    next = compose(c.parentWorld, matrix(frame)),
    correction = compose(inverse(next), old);
  n.children = n.children.map((ch) => {
    const t = compose(correction, matrix(ch.transform));
    return {
      ...ch,
      transform: {
        x: t.e,
        y: t.f,
        rotation: oldRotation + ch.transform.rotation - (c.parentRotation + frame.rotation),
      },
    } as Node;
  });
  n.transform = { ...frame };
  return o;
}
/** VariantGroupを作成する。T-11。 */
export function createVariantGroup(
  f: PhyFile,
  name: string,
  at: Transform,
  variants: [{ name: string; children?: Node[] }, { name: string; children?: Node[] }],
  gen?: () => string,
): PhyFile {
  const o = mutable(f),
    children = variants.map((x) => ({
      type: "variant" as const,
      id: nodeId("variant", gen),
      name: x.name,
      children: structuredClone(x.children ?? []),
    }));
  o.root.push({
    type: "variantGroup",
    id: nodeId("variantGroup", gen),
    name,
    transform: { ...at },
    default: children[0]!.id,
    children,
  });
  return o;
}
/** Variantを追加する。T-11。 */
export function addVariant(f: PhyFile, groupId: string, name: string, gen?: () => string): PhyFile {
  const o = mutable(f),
    g = find(o, groupId);
  if (g.type !== "variantGroup") throw new Error("Not a variant group");
  g.children.push({ type: "variant", id: nodeId("variant", gen), name, children: [] });
  return o;
}
/** Variantを削除する。子が1つになる場合は拒否し、default削除時は先頭へ移す。T-15。 */
export function deleteVariant(f: PhyFile, groupId: string, variantId: string): PhyFile {
  const o = mutable(f),
    g = find(o, groupId);
  if (g.type !== "variantGroup") throw new Error("Not a variant group");
  if (g.children.length <= 2) throw new Error("Cannot leave a VariantGroup with fewer than two variants");
  const i = g.children.findIndex((v) => v.id === variantId);
  if (i < 0) throw new Error("Unknown variant");
  g.children.splice(i, 1);
  if (g.default === variantId) g.default = g.children[0]!.id;
  return o;
}
/** default Variantを変更する。 */
export function setDefaultVariant(f: PhyFile, groupId: string, variantId: string): PhyFile {
  const o = mutable(f),
    g = find(o, groupId);
  if (g.type !== "variantGroup" || !g.children.some((v) => v.id === variantId))
    throw new Error("Invalid group or variant");
  g.default = variantId;
  return o;
}
/** ノードを削除する。 */
export function deleteNode(f: PhyFile, id: string): PhyFile {
  const o = mutable(f),
    c = containers(o).get(id);
  if (!c) throw new Error(`Unknown node: ${id}`);
  const i = c.nodes.findIndex((n) => n.id === id);
  c.nodes.splice(i, 1);
  return o;
}
/** ノードと配下を複製し、すべてのIDを新しくする。T-11。 */
export function duplicateNode(f: PhyFile, id: string, gen?: () => string): PhyFile {
  const o = mutable(f),
    n = find(o, id),
    copy = structuredClone(n);
  const renew = (x: Node) => {
    x.id = nodeId(x.type, gen);
    if (x.type === "cluster") x.children.forEach(renew);
    if (x.type === "variantGroup")
      for (const v of x.children) {
        v.id = nodeId("variant", gen);
        v.children.forEach(renew);
      }
  };
  renew(copy);
  copy.transform.x += 0.25;
  copy.transform.y += 0.25;
  const c = containers(o).get(id)!;
  c.nodes.splice(c.nodes.indexOf(n) + 1, 0, copy);
  return o;
}