/* =============================================================================
 * M02_DF_LinkPanel.ts
 * 상세 내용 판 — 선 규칙: 선을 고르면 어디서 → 어디로 · 규칙 고르기(없음 · 표에서 찾기 · 조건 통과 · 바꾸기 · 끝수) ·
 * 지나가기 전 값 → 지난 뒤 값 미리 보기 · 겹침/안 맞음 알림
 * 모양은 `docs/raw/M01_쉬운단가/흐름도_정함.md` 정함 7 · M02_DF_Model 의 CfRule 그대로 · 단추 · 칸은 공용 작은 크기
 * 글 [한, 영] 짝은 아래 TEXT
 * ========================================================================== */

import { currentLanguageIndex } from "@ui/ui_template_locale";
import { createButton, el } from "@ui/ui_template_elements";
import {
  portsOut,
  reaches,
  type CfGateOp,
  type CfLogic,
  type CfPort,
  type CfRound,
  type CfRule,
} from "./M02_DF_Model";
import {
  GATE_OPS,
  commas,
  SCALE_OPS,
  evalSafe,
  labelOf,
  linkNotes,
  portText,
  preview,
  unitOf,
  valueOf,
  type DetailOptions,
} from "./M02_DF_Detail";
import { suggestPlaces } from "./M02_DF_UnitPick";
import "./M02_DF_LinkPanel.css";

const TEXT = {
  Title: ["선 규칙", "Line rule"],
  Kinds: ["규칙 고르기", "Pick a rule"],
  K_none: ["없음", "None"],
  K_lookup: ["표에서 찾기", "Look up in table"],
  K_gate: ["조건 통과", "Pass if"],
  K_scale: ["바꾸기", "Change"],
  K_round: ["끝수", "Rounding"],
  Label: ["선 위 글", "Text on the line"],
  Before: ["지나가기 전 값", "Value before"],
  After: ["지난 뒤 값", "Value after"],
  Col: ["조건 칸", "Condition column"],
  Match: ["맞출 알약", "Pill to match"],
  Take: ["꺼낼 칸", "Column to take"],
  AddCond: ["+ 조건 칸", "+ Condition"],
  Remove: ["지움", "Remove"],
  NoHeader: [
    "보낸 쪽이 표가 아니거나 표를 아직 못 불러옴 — 표를 불러온 뒤 칸을 고름",
    "The sender is not a table or it is not loaded yet",
  ],
  Pick: ["고르기", "pick"],
  GateHint: [
    "알약 값이 아래 조건을 지나면 보냄 — 아니면 넘기지 않음",
    "Sent only when the pill passes",
  ],
  Value: ["값", "Value"],
  ScaleHint: ["지나가는 값을 바꿈", "Changes the value on its way"],
  Places: ["소수 {n}자리", "{n} decimals"],
  Suggest: ["표준 제안: 소수 {n}자리", "Standard suggests {n} decimals"],
  Apply: ["적용", "Apply"],
  WarnBoth: [
    "같은 알약에서 나간 조건 선 {n}개가 한꺼번에 통과함 — 겹침",
    "{n} conditional lines pass at once — overlap",
  ],
  WarnNone: [
    "같은 알약에서 나간 조건 선 {n}개 중 어느 것도 안 맞음",
    "None of the {n} conditional lines match",
  ],
  WarnLookup: [
    "조건 칸이 없음 — 표에서 줄을 못 고름",
    "No condition column — a row can't be picked",
  ],
  WarnTake: ["꺼낼 칸을 고르지 않음", "No column to take"],
  Count: ["선", "Line"],
} as const;

const tk = (key: keyof typeof TEXT, n?: number | string): string =>
  TEXT[key][currentLanguageIndex === 1 ? 1 : 0].replace("{n}", String(n ?? ""));

type Kind = "none" | CfRule["kind"];
const KINDS: Kind[] = ["none", "lookup", "gate", "scale", "round"];
const SEP = "\u0001";

interface Ctx {
  lg: CfLogic;
  linkId: string;
  readOnly: boolean;
  headers: string[];
  change(lg: CfLogic): void;
}

const toKey = (p: CfPort): string => `${p.box}${SEP}${p.name}`;
const fromKey = (k: string): CfPort => {
  const [box, ...rest] = k.split(SEP);
  return { box, name: rest.join(SEP) };
};

function setRule(ctx: Ctx, rule: CfRule | undefined): void {
  ctx.change({
    ...ctx.lg,
    links: ctx.lg.links.map((l) => {
      if (l.id !== ctx.linkId) return l;
      const { rule: _old, ...rest } = l;
      return rule ? { ...rest, rule } : rest;
    }),
  });
}

function select(
  ctx: Ctx,
  options: { value: string; text: string }[],
  value: string,
  onPick: (v: string) => void,
  aria: string,
): HTMLElement {
  const s = el("select", { className: "ui-select ui-select--sm", attrs: { "aria-label": aria } });
  for (const o of options) s.append(el("option", { attrs: { value: o.value }, text: o.text }));
  if (!options.some((o) => o.value === value))
    s.prepend(el("option", { attrs: { value }, text: value || tk("Pick") }));
  s.value = value;
  s.disabled = ctx.readOnly;
  s.addEventListener("change", () => onPick(s.value));
  return s;
}

/** 숫자 칸 — 보일 때만 천 단위 쉼표 · 고치는 동안은 쉼표 없이 */
function numberBox(
  ctx: Ctx,
  value: number | string,
  onCommit: (v: number | string) => void,
  aria: string,
): HTMLElement {
  const i = el("input", {
    className: "ui-input ui-input--sm m02-dflink-num",
    attrs: { type: "text", inputmode: "decimal", "aria-label": aria },
  });
  const shown = (): string => (typeof value === "number" ? commas(value) : String(value));
  i.value = shown();
  i.readOnly = ctx.readOnly;
  i.addEventListener("focus", () => (i.value = String(value)));
  i.addEventListener("blur", () => (i.value = shown()));
  i.addEventListener("change", () => {
    const t = i.value.trim().replace(/,/g, "");
    onCommit(t !== "" && Number.isFinite(Number(t)) ? Number(t) : t);
  });
  return i;
}

/** 맞출 알약 — 이 선이 닿는 상자와 그 뒤 상자(돌고 도는 선이 됨)는 뺌 */
const pillOptions = (ctx: Ctx): { value: string; text: string }[] => {
  const to = ctx.lg.links.find((x) => x.id === ctx.linkId)?.to.box ?? "";
  return ctx.lg.boxes
    .filter((b) => b.id !== to && !reaches(ctx.lg, to, b.id))
    .flatMap((b) =>
      portsOut(b).map((p) => ({
        value: toKey({ box: b.id, name: p.name }),
        text: portText(ctx.lg, { box: b.id, name: p.name }),
      })),
    );
};

const row = (...children: (HTMLElement | string)[]): HTMLElement =>
  el("div", { className: "m02-dflink-row", children });

/* ── 규칙마다 ─────────────────────────────────────────────────────────── */

function lookupEditor(ctx: Ctx, rule: Extract<CfRule, { kind: "lookup" }>): HTMLElement[] {
  const cols = [
    ...new Set([...ctx.headers, ...rule.conds.map((c) => c.col), rule.col].filter(Boolean)),
  ];
  const colOpts = cols.map((c) => ({ value: c, text: c }));
  const pills = pillOptions(ctx);
  const put = (next: Partial<typeof rule>): void => setRule(ctx, { ...rule, ...next });
  const rows = rule.conds.map((c, i) =>
    row(
      select(
        ctx,
        colOpts,
        c.col,
        (v) => put({ conds: rule.conds.map((x, j) => (j === i ? { ...x, col: v } : x)) }),
        tk("Col"),
      ),
      "=",
      select(
        ctx,
        pills,
        toKey(c.from),
        (v) => put({ conds: rule.conds.map((x, j) => (j === i ? { ...x, from: fromKey(v) } : x)) }),
        tk("Match"),
      ),
      ctx.readOnly
        ? ""
        : createButton({
            label: tk("Remove"),
            variant: "ghost",
            size: "sm",
            onClick: () => put({ conds: rule.conds.filter((_, j) => j !== i) }),
          }),
    ),
  );
  const out: HTMLElement[] = [...rows];
  if (!ctx.readOnly) {
    out.push(
      row(
        createButton({
          label: tk("AddCond"),
          variant: "ghost",
          size: "sm",
          disabled: !pills.length || !cols.length,
          onClick: () =>
            put({ conds: [...rule.conds, { col: cols[0], from: fromKey(pills[0].value) }] }),
        }),
      ),
    );
  }
  out.push(
    row(
      el("span", { className: "m02-dflink-label", text: tk("Take") }),
      select(ctx, colOpts, rule.col, (v) => put({ col: v }), tk("Take")),
    ),
  );
  if (!cols.length) out.push(el("p", { className: "m02-dflink-note", text: tk("NoHeader") }));
  return out;
}

function gateEditor(ctx: Ctx, rule: Extract<CfRule, { kind: "gate" }>): HTMLElement[] {
  const put = (next: Partial<typeof rule>): void => setRule(ctx, { ...rule, ...next });
  return [
    el("p", { className: "m02-dflink-note", text: tk("GateHint") }),
    row(
      select(
        ctx,
        pillOptions(ctx),
        toKey(rule.from),
        (v) => put({ from: fromKey(v) }),
        tk("Match"),
      ),
      select(
        ctx,
        GATE_OPS.map((o) => ({ value: o, text: o })),
        rule.op,
        (v) => put({ op: v as CfGateOp }),
        tk("Kinds"),
      ),
      numberBox(ctx, rule.value, (v) => put({ value: v }), tk("Value")),
    ),
  ];
}

function scaleEditor(ctx: Ctx, rule: Extract<CfRule, { kind: "scale" }>): HTMLElement[] {
  return [
    el("p", { className: "m02-dflink-note", text: tk("ScaleHint") }),
    row(
      select(
        ctx,
        SCALE_OPS.map((o) => ({ value: o, text: o })),
        rule.op,
        (v) => setRule(ctx, { ...rule, op: v as typeof rule.op }),
        tk("Kinds"),
      ),
      numberBox(
        ctx,
        rule.value,
        (v) => setRule(ctx, { ...rule, value: typeof v === "number" ? v : rule.value }),
        tk("Value"),
      ),
    ),
  ];
}

function roundEditor(
  ctx: Ctx,
  rule: Extract<CfRule, { kind: "round" }>,
  unit: string,
): HTMLElement[] {
  const put = (next: Partial<CfRound>): void => setRule(ctx, { ...rule, ...next });
  const places = Array.from({ length: 7 }, (_, n) => ({ value: String(n), text: tk("Places", n) }));
  const hint = el("span", { className: "m02-dflink-note" });
  void suggestPlaces(unit).then((n) => {
    if (n === null || n === rule.places || ctx.readOnly) return;
    hint.append(
      tk("Suggest", n),
      " ",
      createButton({
        label: tk("Apply"),
        variant: "ghost",
        size: "sm",
        onClick: () => put({ places: n }),
      }),
    );
  });
  return [
    row(
      select(ctx, places, String(rule.places), (v) => put({ places: Number(v) }), tk("K_round")),
      select(
        ctx,
        (["반올림", "올림", "버림"] as const).map((m) => ({ value: m, text: m })),
        rule.method,
        (v) => put({ method: v as CfRound["method"] }),
        tk("K_round"),
      ),
      hint,
    ),
  ];
}

const DEFAULT: Record<Exclude<Kind, "none">, (from: CfPort) => CfRule> = {
  lookup: () => ({ kind: "lookup", conds: [], col: "" }),
  gate: (from) => ({ kind: "gate", from, op: "≥", value: 0 }),
  scale: () => ({ kind: "scale", op: "×", value: 1 }),
  round: () => ({ kind: "round", places: 0, method: "반올림" }),
};

/** 선 규칙 판 그리기 — 선을 고르면 부름 · 바뀐 lg 는 on.change 로만 알림(그리기는 부른 쪽이 다시) */
export function renderLinkPanel(
  host: HTMLElement,
  lg: CfLogic,
  linkId: string,
  on: { change(lg: CfLogic): void },
  opts: DetailOptions & { readOnly?: boolean } = {},
): void {
  const link = lg.links.find((l) => l.id === linkId);
  host.classList.add("m02-dflink");
  if (!link) return host.replaceChildren();
  const ev = evalSafe(lg, opts);
  const table = valueOf(ev, link.from);
  const headers =
    Array.isArray(table) && Array.isArray(table[0])
      ? table[0].map((h) => String(h ?? "")).filter(Boolean)
      : [];
  const ctx: Ctx = { lg, linkId, readOnly: !!opts.readOnly, headers, change: on.change };
  const rule = link.rule;
  const kind: Kind = rule?.kind ?? "none";
  const parts: HTMLElement[] = [
    el("div", {
      className: "m02-dflink-head",
      children: [
        el("strong", { text: `${portText(lg, link.from)}  →  ${portText(lg, link.to)}` }),
        el("span", { className: "m02-dflink-note", text: `(${unitOf(lg, link.from)})` }),
      ],
    }),
    row(
      el("span", { className: "m02-dflink-label", text: tk("Kinds") }),
      ...KINDS.map((k) =>
        createButton({
          label: tk(`K_${k}` as "K_none"),
          variant: k === kind ? "filled" : "ghost",
          size: "sm",
          disabled: ctx.readOnly,
          onClick: () =>
            k !== kind && setRule(ctx, k === "none" ? undefined : DEFAULT[k](link.from)),
        }),
      ),
    ),
  ];
  if (rule?.kind === "lookup") parts.push(...lookupEditor(ctx, rule));
  if (rule?.kind === "gate") parts.push(...gateEditor(ctx, rule));
  if (rule?.kind === "scale") parts.push(...scaleEditor(ctx, rule));
  if (rule?.kind === "round") parts.push(...roundEditor(ctx, rule, unitOf(lg, link.from)));

  const pv = preview(link, ev);
  parts.push(
    row(
      el("span", { className: "m02-dflink-label", text: tk("Before") }),
      el("span", { className: "m02-dflink-value", text: pv.before }),
      "→",
      el("span", { className: "m02-dflink-label", text: tk("After") }),
      el("span", { className: "m02-dflink-value", text: pv.after }),
    ),
    row(
      el("span", { className: "m02-dflink-label", text: tk("Label") }),
      el("span", { text: labelOf(rule) }),
    ),
  );

  const warns: string[] = linkNotes(link, ev);
  if (rule?.kind === "lookup") {
    if (!rule.conds.length) warns.push(tk("WarnLookup"));
    if (!rule.col) warns.push(tk("WarnTake"));
  }
  parts.push(...warns.map((w) => el("p", { className: "m02-dflink-warn", text: `⚠ ${w}` })));
  host.replaceChildren(...parts);
}