import type { KleCompatibility, KeyNode, PhyFile } from "../domain/phy";
import { createNodeId } from "../domain/ids";

type Obj = Record<string, unknown>;
type Atom = string | Obj;

// Output slot -> newline-field index. These fixed tables reproduce KLE's a=0..7 layout.
const labelMap: readonly (readonly (number | null)[])[] = [
  [0, 8, 2, 6, 9, 7, 1, 10, 3, 4, 11, 5],
  [null, 0, null, null, 6, null, null, 1, null, 4, 11, 5],
  [null, null, null, 0, 8, 2, null, null, null, 4, 11, 5],
  [null, null, null, null, 0, null, null, null, null, 4, 11, 5],
  [0, 8, 2, 6, 9, 7, 1, 10, 3, null, 4, null],
  [null, 0, null, null, 6, null, null, 1, null, null, 4, null],
  [null, null, null, 0, 8, 2, null, null, null, null, 4, null],
  [null, null, null, null, 0, null, null, null, null, null, 4, null],
];

const fileDefaults: Obj = {
  backcolor: "#eeeeee",
  name: "",
  author: "",
  notes: "",
  background: null,
  radii: "",
  switchMount: "",
  switchBrand: "",
  switchType: "",
};
const keyDefaults: Obj = { c: "#cccccc", t: "#000000", p: "", a: 4, f: 3, sm: "", sb: "", st: "" };

function isObj(value: unknown): value is Obj {
  return !!value && typeof value === "object" && !Array.isArray(value);
}
function num(value: unknown, fallback: number): number {
  return typeof value === "number" && Number.isFinite(value) ? value : fallback;
}
function labelsFromKle(serialized: string, alignment: number): string[] {
  const fields = serialized.split("\n");
  if (fields.length > 12) throw new Error("A KLE label cannot exceed 12 slots");
  const map = labelMap[alignment] ?? labelMap[4]!;
  const labels = Array<string>(12).fill("");
  map.forEach((field, slot) => {
    if (field !== null && field < fields.length) labels[slot] = fields[field]!;
  });
  while (labels.at(-1) === "") labels.pop();
  return labels;
}
function oneShotArray(state: Obj, key: string): void {
  delete state[key];
}

/** KLEの厳密JSON（またはVIA layouts.keymap）を新規PHYへ取り込む。T-7/T-18/T-20。 */
export function importKle(
  input: unknown,
  options: { idGenerator?: () => string; name?: string } = {},
): { phy: PhyFile; keyOrder: string[] } {
  let data: unknown = input;
  if (isObj(data)) {
    const layouts = data.layouts;
    if (isObj(layouts) && Array.isArray(layouts.keymap)) data = layouts.keymap;
    else throw new Error("Expected KLE array or VIA layouts.keymap");
  }
  if (!Array.isArray(data)) throw new Error("KLE input must be a JSON array");
  const rows = [...data] as unknown[];
  let rawMeta: Obj = {};
  if (rows.length && isObj(rows[0])) rawMeta = rows.shift() as Obj;

  const gen = options.idGenerator ?? (() => globalThis.crypto.randomUUID());
  const state: Obj = { ...keyDefaults };
  let cursorX = 0;
  let cursorY = 0;
  let rotation = 0;
  let rotationX = 0;
  let rotationY = 0;
  const root: KeyNode[] = [];
  const keyOrder: string[] = [];

  for (const row of rows) {
    if (!Array.isArray(row)) throw new Error("KLE rows must be arrays");
    cursorX = rotationX;
    for (const atom of row as Atom[]) {
      if (typeof atom === "string") {
        const w = num(state.w, 1);
        const h = num(state.h, 1);
        cursorX += num(state.x, 0);
        cursorY += num(state.y, 0);
        const radians = (rotation * Math.PI) / 180;
        const dx = cursorX - rotationX;
        const dy = cursorY - rotationY;
        const x = rotationX + Math.cos(radians) * dx - Math.sin(radians) * dy;
        const y = rotationY + Math.sin(radians) * dx + Math.cos(radians) * dy;
        const a = num(state.a, 4);
        const id = createNodeId("key", gen);
        const labels = labelsFromKle(atom, a);
        const compatibility: KleCompatibility = {
          c: structuredClone(state.c),
          t: structuredClone(state.t),
          p: structuredClone(state.p),
          a,
          f: num(state.f, 3),
          ...(state.f2 === undefined ? {} : { f2: structuredClone(state.f2) }),
          ...(state.fa === undefined ? {} : { fa: structuredClone(state.fa) }),
          l: state.l === true,
          n: state.n === true,
          sm: structuredClone(state.sm),
          sb: structuredClone(state.sb),
          st: structuredClone(state.st),
        };
        const w2 = num(state.w2, 0) || w;
        const h2 = num(state.h2, 0) || h;
        const key: KeyNode = {
          type: "key",
          id,
          profile: "default",
          transform: { x, y, rotation },
          size: {
            w,
            h,
            ...(num(state.x2, 0) === 0 ? {} : { x2: num(state.x2, 0) }),
            ...(num(state.y2, 0) === 0 ? {} : { y2: num(state.y2, 0) }),
            ...(w2 === w ? {} : { w2 }),
            ...(h2 === h ? {} : { h2 }),
          },
          labels,
          kleCompatibility: compatibility,
        };
        if (state.d === true) key.decal = true;
        if (state.g === true) key.ghost = true;
        root.push(key);
        if (!key.decal) keyOrder.push(id);

        cursorX += w;
        for (const field of ["w", "h", "x", "y", "x2", "y2", "w2", "h2", "d", "l", "n"])
          oneShotArray(state, field);
      } else if (isObj(atom)) {
        for (const [key, value] of Object.entries(atom)) {
          if (key === "r") rotation = num(value, rotation);
          else if (key === "rx") {
            rotationX = num(value, rotationX);
            cursorX = rotationX;
            cursorY = rotationY;
          } else if (key === "ry") {
            rotationY = num(value, rotationY);
            cursorX = rotationX;
            cursorY = rotationY;
          } else if (key === "f") {
            state.f = value;
            delete state.f2;
            delete state.fa;
          } else if (key === "f2") {
            state.f2 = value;
            delete state.fa;
          } else if (key === "fa") {
            state.fa = structuredClone(value);
            delete state.f2;
          } else state[key] = structuredClone(value);
        }
      } else throw new Error("KLE row entries must be strings or objects");
    }
    cursorY += 1;
  }

  const metadata = { ...fileDefaults, ...structuredClone(rawMeta) };
  const phy: PhyFile = {
    version: "0.1.0",
    metadata: { ...(options.name ? { name: options.name } : {}) },
    profiles: [{ id: "default", name: "Default", unitSize: { x: 19.05, y: 19.05 } }],
    root,
    kleCompatibility: metadata,
  };
  return { phy, keyOrder };
}

/** JSON文字列を厳密にパースして KLE を取り込む。 */
export function parseKleJson(
  json: string,
  options: { idGenerator?: () => string; name?: string } = {},
): ReturnType<typeof importKle> {
  return importKle(JSON.parse(json) as unknown, options);
}

/** 正準12欄のラベルをKLEのa別固定欄順に戻す。 */
export function labelsToKle(labels: string[] | undefined, alignment: number): string {
  const map = labelMap[alignment] ?? labelMap[4]!;
  const fields = Array<string>(12).fill("");
  map.forEach((sourceSlot, slot) => {
    if (sourceSlot !== null) fields[sourceSlot] = labels?.[slot] ?? "";
  });
  while (fields.at(-1) === "") fields.pop();
  return fields.join("\n");
}