/* =============================================================================
 * E03_StabSection_Prob.ts
 * E03 「확률 · 민감도」 탭 계산(PLAN 537-1) — 변수 줄(단면 물성 × c · φ · γ + 지하수위 · r_u) ·
 *   기본값 후보(서버 `prob_defaults.json`) · 입력 캐시 → 요청 꼴 · 그래프 눈금.
 *   화면 · fetch · sessionStorage 없음(페이지가 부름).
 * ========================================================================== */

export type ProbProp = "c" | "phi" | "gamma" | "water" | "ru";
export type ProbDist = "normal" | "lognormal";
export type ProbMethod = "ordinary" | "bishop" | "janbu" | "spencer" | "morgenstern_price";

export interface ProbPropDefault {
  dist: ProbDist;
  cov?: number;
  std?: number;
  trunc_sigma: number | null;
}

export interface ProbDefaults {
  run: {
    n: number;
    sampling: "lhs" | "mc";
    seed: number;
    mode: "fixed" | "search";
    method: ProbMethod;
  };
  properties: Record<ProbProp, ProbPropDefault>;
  rho_c_phi: number;
  sources: Record<string, string>;
  materials?: Record<string, Partial<Record<ProbProp, Partial<ProbPropDefault>>>>;
}

export interface ProbMaterial {
  id: string;
  name: string | null;
  c: number;
  phi: number;
  gamma_t: number;
}

export interface ProbStats {
  n: number;
  n_valid: number;
  mean: number | null;
  std: number | null;
  cov?: number | null;
  min?: number;
  max?: number;
  pf: number | null;
  n_fail?: number;
  beta_normal: number | null;
  beta_lognormal?: number | null;
  required?: number | null;
  p_below_required?: number | null;
  histogram?: { edges: number[]; counts: number[] };
  cdf?: { p: number[]; F: number[] };
}

export interface ProbCurve {
  name: string;
  x: (number | null)[];
  F: (number | null)[];
  F_lo: number | null;
  F_hi: number | null;
  swing: number | null;
}

export interface ProbVariable {
  name: string;
  material: string | null;
  prop: ProbProp;
  dist: ProbDist;
  mean: number;
  std: number;
  lo: number | null;
  hi: number | null;
}

export interface ProbResult {
  mode: "fixed" | "search";
  method: ProbMethod;
  n: number;
  sampling: string;
  seed: number;
  variables: ProbVariable[];
  stats: ProbStats;
  sensitivity: {
    F_mean: number | null;
    curves: ProbCurve[];
    tornado: { name: string; F_lo: number | null; F_hi: number | null; swing: number }[];
  };
  elapsed_s: { total: number; samples: number };
}

export interface ProbRecord {
  station_key: string;
  side: string;
  condition: string;
  required: number | null;
  fs_deterministic: number | null;
  request: Record<string, unknown>;
  result: ProbResult;
  computed_at: string;
}

export interface ProbSetup {
  station_key: string;
  side: string;
  condition: string;
  role: "cut" | "fill";
  required: number | null;
  fs_deterministic: Record<string, number | null>;
  materials: ProbMaterial[];
  groundwater: { mode: "none" | "line" | "ru"; ru: number | null };
  defaults: ProbDefaults;
  search_max_n: number;
  last: ProbRecord | null;
}

/** 변수 줄 하나 — kind cov = 변동계수(평균 곱) · std = 표준편차(m · r_u) */
export interface ProbRow {
  key: string;
  material: string | null;
  prop: ProbProp;
  name: string;
  mean: number;
  kind: "cov" | "std";
}

export interface ProbInput {
  use: boolean;
  dist: ProbDist;
  value: number;
  trunc: number | null;
}

export interface ProbRunInput {
  n: number;
  sampling: "lhs" | "mc";
  seed: number;
  mode: "fixed" | "search";
  method: ProbMethod;
  rho: number;
}

export interface ProbCache {
  vars: Record<string, ProbInput>;
  run: ProbRunInput;
}

export const varKey = (material: string | null, prop: ProbProp): string =>
  `${material ?? "*"}|${prop}`;

/** 단면 물성마다 c · φ · γ + 지하수 갈래가 수위선이면 지하수위 · r_u 면 r_u */
export function probRows(setup: ProbSetup): ProbRow[] {
  const rows: ProbRow[] = [];
  for (const m of setup.materials) {
    const name = m.name ?? m.id;
    rows.push(
      { key: varKey(m.id, "c"), material: m.id, prop: "c", name, mean: m.c, kind: "cov" },
      { key: varKey(m.id, "phi"), material: m.id, prop: "phi", name, mean: m.phi, kind: "cov" },
      {
        key: varKey(m.id, "gamma"),
        material: m.id,
        prop: "gamma",
        name,
        mean: m.gamma_t,
        kind: "cov",
      },
    );
  }
  const gw = setup.groundwater;
  if (gw.mode === "line")
    rows.push({
      key: varKey(null, "water"),
      material: null,
      prop: "water",
      name: "",
      mean: 0,
      kind: "std",
    });
  if (gw.mode === "ru")
    rows.push({
      key: varKey(null, "ru"),
      material: null,
      prop: "ru",
      name: "",
      mean: gw.ru ?? 0,
      kind: "std",
    });
  return rows;
}

/** 기본값 후보 — 성질 기본 위에 물성별 덮어쓰기 · 0 이면 끔 */
export function defaultInput(defaults: ProbDefaults, row: ProbRow): ProbInput {
  const base = defaults.properties[row.prop];
  const own = (row.material && defaults.materials?.[row.material]?.[row.prop]) || {};
  const merged = { ...base, ...own };
  const value = Number((row.kind === "cov" ? merged.cov : merged.std) ?? 0);
  return {
    use: value > 0,
    dist: row.prop === "water" ? "normal" : merged.dist,
    value,
    trunc: merged.trunc_sigma ?? null,
  };
}

/** 캐시가 없는 줄만 기본값 후보로 채움 */
export function fillCache(setup: ProbSetup, cache: ProbCache | null): ProbCache {
  const d = setup.defaults;
  const vars: Record<string, ProbInput> = { ...(cache?.vars ?? {}) };
  for (const row of probRows(setup)) vars[row.key] ??= defaultInput(d, row);
  const run = cache?.run ?? { ...d.run, rho: d.rho_c_phi };
  return { vars, run };
}

/** 기본값과 다른 줄 수(「사용자 입력」 표기) */
export function changedCount(setup: ProbSetup, cache: ProbCache): number {
  return probRows(setup).filter((row) => {
    const a = defaultInput(setup.defaults, row);
    const b = cache.vars[row.key];
    return (
      b && (a.use !== b.use || a.dist !== b.dist || a.value !== b.value || a.trunc !== b.trunc)
    );
  }).length;
}

/** POST …/stab/prob/{측점} 몸 — 켠 줄만 · 값 0 은 뺌 */
export function probRequest(setup: ProbSetup, cache: ProbCache): Record<string, unknown> {
  const variables = probRows(setup)
    .map((row) => ({ row, v: cache.vars[row.key] }))
    .filter(({ v }) => v?.use && v.value > 0)
    .map(({ row, v }) => ({
      material: row.material,
      prop: row.prop,
      dist: v.dist,
      ...(row.kind === "cov" ? { cov: v.value } : { std: v.value }),
      trunc_sigma: v.trunc,
    }));
  const r = cache.run;
  return {
    side: setup.side,
    condition: setup.condition,
    method: r.method,
    mode: r.mode,
    n: Math.round(r.n),
    sampling: r.sampling,
    seed: Math.round(r.seed),
    rho_c_phi: r.rho,
    variables,
  };
}

/** 그래프 눈금 — 0 을 억지로 넣지 않음(안전율 축) */
export function axisTicks(min: number, max: number, count = 5): number[] {
  const lo = Math.min(min, max);
  const hi = Math.max(lo + 1e-9, max);
  const raw = (hi - lo) / Math.max(count, 1);
  const mag = 10 ** Math.floor(Math.log10(raw));
  const step = [1, 2, 5, 10].map((m) => m * mag).find((v) => v >= raw) ?? raw;
  const out: number[] = [];
  for (let v = Math.floor(lo / step) * step; v <= hi + step * 1e-6; v += step)
    out.push(Math.round(v * 1e6) / 1e6);
  if (out[out.length - 1] < hi) out.push(out[out.length - 1] + step);
  return out;
}