/* =============================================================================
 * E03_StabSection_Logic.ts
 * E03 2D 측점 해석 화면 계산(PLAN 532-3) — 화면 · three · fetch · sessionStorage 없음 · 순수 함수만.
 *   좌표 = 서버 결과 그대로(x = B06 offset · 좌 + · z = 표고). 화면은 B06 처럼 좌측(+offset)을 왼쪽에 둠
 *   → 화면 x = −k·x + tx · y = −k·z + ty (`fitView`). SVG 도형 좌표는 결과 좌표를 그대로 쓰고
 *   묶음 transform 하나(`viewMatrix`)로 옮김 — 「SVG 좌표 = 결과 좌표」.
 *   판정 = 서버 `E03_StabSection_View.overall_verdict` 와 같은 규칙(ng > ok > none).
 * ========================================================================== */

export type Condition = "dry" | "wet" | "seismic";
export type Verdict = "ok" | "ng" | "none";
export type Point = [number, number];

export interface SideCase {
  fs: number | null;
  required: number | null;
  ok: boolean | null;
  kind: string | null;
  converged: boolean | null;
  /** 판정 면의 방법 · 원호 Bishop 안전율 · 면 확인 · 모형 끝 면 — 옛 저장본은 없음 */
  method?: string | null;
  fs_circular?: number | null;
  surface_check?: boolean;
  edge?: boolean | null;
}

export interface StationRow {
  key: string;
  chainage_m: number;
  label: string | null;
  section_mode: string | null;
  ground_type: string | null;
  center: [number | null, number | null] | null;
  sides: { side: string; role: "cut" | "fill"; height_m: number | null }[];
  cases: Partial<Record<Condition, Record<string, SideCase>>>;
  min: Partial<Record<Condition, number | null>>;
  verdict: Partial<Record<Condition, Verdict>>;
  error: string | null;
  /** 그 측점 벽(옹벽 · 석축) 수 — 옛 저장본은 없음 */
  walls?: number;
  representative?: { auto: string[]; user: boolean | null; on: boolean };
}

export interface Surface {
  method: string;
  kind: string | null;
  fs: number | null;
  points: Point[];
  entry: Point | null;
  exit: Point | null;
  converged: boolean | null;
  iterations: number | null;
  center?: Point;
  radius?: number;
}

export interface SliceRow {
  i: number;
  x_left: number;
  x_right: number;
  width: number;
  height: number;
  alpha_deg: number;
  weight: number;
  surcharge: number;
  pore_pressure: number;
  base_length: number;
  c: number;
  phi_deg: number;
  material: string | null;
  N: number;
  N_eff: number;
  U: number;
  S: number;
  E_left: number;
  E_right: number;
  X_left: number;
  X_right: number;
}

export interface Analysis {
  condition: Condition;
  side: string;
  role: "cut" | "fill";
  height_m: number | null;
  limits: [number, number];
  direction: number;
  required: number | null;
  ok: boolean | null;
  min_by_method: Record<string, number | null>;
  surface_check?: boolean | null;
  edge?: boolean | null;
  /** 「해 없음」 면이 있는 방법(Spencer · M-P) — 옛 저장본은 없음 */
  no_solution?: string[];
  critical: Surface | null;
  candidates: Surface[];
  slices: SliceRow[];
  grid: { method: string; x: number[]; z: number[]; fs: (number | null)[][] } | null;
}

export interface SectionView {
  key: string;
  chainage_m: number;
  label: string | null;
  materials: {
    id: string;
    name: string;
    gamma_t: number;
    gamma_sat: number;
    c: number;
    phi: number;
  }[];
  regions: { material_id: string; polygon: Point[]; holes: Point[][] }[];
  surface: Point[];
  bottom_z: number | null;
  surcharge: { x0: number; x1: number; q: number }[];
  water: Partial<Record<Condition, Point[] | null>>;
  /** 조건별 지하수 꼴(E02 갈래) — r_u 면 수위선 없음 */
  water_rule?: Partial<Record<Condition, { mode: string; ru: number | null }>>;
  analyses: Analysis[];
}

/* ---- 판정 · 목록 ---------------------------------------------------------- */

/** 측점 판정 — 조건 하나(또는 전 조건 중 가장 나쁜 것) */
export function verdictOf(row: StationRow, condition?: Condition): Verdict {
  const values = condition ? [row.verdict[condition] ?? "none"] : Object.values(row.verdict);
  if (values.includes("ng")) return "ng";
  return values.includes("ok") ? "ok" : "none";
}

/** 판정 면 표시 — 그 조건에서 안전율이 가장 낮은 비탈의 방법 · 면 확인 · 모형 끝 면은 비탈 하나라도 */
export interface Basis {
  method: string | null;
  circular: boolean | null;
  surfaceCheck: boolean;
  edge: boolean;
}

export function basisOf(row: StationRow, condition: Condition): Basis {
  const sides = Object.values(row.cases[condition] ?? {});
  const worst = sides
    .filter((c) => c.fs !== null && c.method)
    .sort((a, b) => (a.fs as number) - (b.fs as number))[0];
  const method = worst?.method ?? null;
  return {
    method,
    circular: method === null ? null : method === "bishop",
    surfaceCheck: sides.some((c) => c.surface_check === true),
    edge: sides.some((c) => c.edge === true),
  };
}

export type SortMode = "chainage" | "fs";

/** 목록 정렬 · 거름 — fs = 그 조건 최소 안전율 낮은 순(없으면 맨 뒤) */
export function listRows(
  rows: StationRow[],
  condition: Condition,
  sort: SortMode,
  ngOnly: boolean,
): StationRow[] {
  const kept = ngOnly ? rows.filter((r) => verdictOf(r, condition) === "ng") : rows.slice();
  if (sort === "fs") {
    const fs = (r: StationRow): number => r.min[condition] ?? Number.POSITIVE_INFINITY;
    kept.sort((a, b) => fs(a) - fs(b) || a.chainage_m - b.chainage_m);
  } else kept.sort((a, b) => a.chainage_m - b.chainage_m);
  return kept;
}

/** 깎기 · 쌓기 줄임 — 비탈 역할 좌/우(예 「쌓기 · 깎기」) */
export function roleText(row: StationRow, names: { cut: string; fill: string }): string {
  const order = ["left", "right"];
  return row.sides
    .slice()
    .sort((a, b) => order.indexOf(a.side) - order.indexOf(b.side))
    .map((s) => names[s.role])
    .join(" · ");
}

/** 평면 띠 — 측점 중심을 이은 선을 측점 판정으로 나눈 구간(이웃 측점 사이 중간에서 끊음) */
export function bandSegments(
  rows: StationRow[],
  condition: Condition | undefined,
): { verdict: Verdict; points: Point[]; keys: string[] }[] {
  const pts = rows
    .filter((r) => r.center && r.center[0] !== null && r.center[1] !== null)
    .sort((a, b) => a.chainage_m - b.chainage_m)
    .map((r) => ({ row: r, p: [r.center![0]!, r.center![1]!] as Point }));
  const out: { verdict: Verdict; points: Point[]; keys: string[] }[] = [];
  const mid = (a: Point, b: Point): Point => [(a[0] + b[0]) / 2, (a[1] + b[1]) / 2];
  pts.forEach((item, i) => {
    const v = verdictOf(item.row, condition);
    const start = i > 0 ? mid(pts[i - 1].p, item.p) : item.p;
    const end = i < pts.length - 1 ? mid(item.p, pts[i + 1].p) : item.p;
    const last = out[out.length - 1];
    if (last && last.verdict === v) {
      last.points.push(item.p, end);
      last.keys.push(item.row.key);
    } else out.push({ verdict: v, points: [start, item.p, end], keys: [item.row.key] });
  });
  return out;
}

/** 평면 띠 보기 틀 — 북쪽 위 · 같은 축척 · 여백 pad(px) */
export function planFit(
  points: Point[],
  width: number,
  height: number,
  pad: number,
): { k: number; tx: number; ty: number } {
  const xs = points.map((p) => p[0]);
  const ys = points.map((p) => p[1]);
  const [x0, x1, y0, y1] = [Math.min(...xs), Math.max(...xs), Math.min(...ys), Math.max(...ys)];
  const k = Math.min(
    (width - 2 * pad) / Math.max(x1 - x0, 1),
    (height - 2 * pad) / Math.max(y1 - y0, 1),
  );
  return { k, tx: width / 2 - (k * (x0 + x1)) / 2, ty: height / 2 + (k * (y0 + y1)) / 2 };
}

/** 평면 띠 측점 글 솎음 걸음 — 측점 간격 화면 길이(px) × 걸음이 minPx 넘는 가장 작은 것 */
export const PLAN_LABEL_STRIDES = [1, 2, 5, 10, 25, 50, 100] as const;

export function labelStride(intervalPx: number, minPx: number): number {
  return PLAN_LABEL_STRIDES.find((s) => s * intervalPx >= minPx) ?? 100;
}

/** 측점 글 붙일 열쇠 — 본 측점(간격 배수) 중 걸음 배수 · 걸음 1 이면 보조 측점도 · 고른 측점은 늘
 *  (고른 측점 곁 반 걸음 안 글은 뺌 — 겹침) */
export function planLabelKeys(
  rows: StationRow[],
  interval: number,
  stride: number,
  active: string | null,
): string[] {
  const step = interval > 0 ? interval : 1;
  const at = rows.find((r) => r.key === active)?.chainage_m;
  return rows
    .filter((r) => r.center && r.center[0] !== null && r.center[1] !== null)
    .filter((r) => {
      if (r.key === active) return true;
      if (at !== undefined && Math.abs(r.chainage_m - at) < (stride * step) / 2) return false;
      if (stride === 1) return true;
      const n = Math.round(r.chainage_m / step);
      return Math.abs(r.chainage_m - n * step) < 0.05 && n % stride === 0;
    })
    .map((r) => r.key);
}

/* ---- 안전율 색 ------------------------------------------------------------ */

/** 등안전율 띠 — 안전율 ÷ 기준안전율 경계(빨강 셋 · 회색 하나 · 파랑 셋 · 가운데 = 기준 통과 직후) */
export const RATIO_BREAKS = [0.8, 0.9, 1.0, 1.1, 1.25, 1.5] as const;

/** 띠 번호 0~6 — 0 = 가장 위험 · 3 = 기준 바로 위 · null = 값 없음 */
export function bandIndex(fs: number | null | undefined, required: number | null): number | null {
  if (fs === null || fs === undefined || !Number.isFinite(fs)) return null;
  const ratio = Math.round((fs / (required && required > 0 ? required : 1)) * 1e9) / 1e9;
  const i = RATIO_BREAKS.findIndex((b) => ratio < b);
  return i < 0 ? RATIO_BREAKS.length : i;
}

/** 범례 — 띠마다 안전율 구간(기준안전율을 곱한 실제 값) */
export function bandLegend(
  required: number | null,
): { index: number; from: number | null; to: number | null }[] {
  const base = required && required > 0 ? required : 1;
  const edges = RATIO_BREAKS.map((b) => Math.round(b * base * 100) / 100);
  return [...Array(RATIO_BREAKS.length + 1).keys()].map((i) => ({
    index: i,
    from: i === 0 ? null : edges[i - 1],
    to: i === RATIO_BREAKS.length ? null : edges[i],
  }));
}

/* ---- 횡단 보기 틀 --------------------------------------------------------- */

export interface ViewFit {
  k: number; // px / m (가로 · 세로 같음 — 참 모양)
  tx: number;
  ty: number;
}

/** 범위(지표 · 바닥 · 격자 중심 · 임계면) 를 판에 맞춤 — 좌측(+offset) 이 왼쪽 */
export function fitView(view: SectionView, width: number, height: number, pad: number): ViewFit {
  const xs: number[] = [];
  const zs: number[] = [];
  const add = (p: Point): void => {
    xs.push(p[0]);
    zs.push(p[1]);
  };
  view.surface.forEach(add);
  if (view.bottom_z !== null) zs.push(view.bottom_z);
  for (const a of view.analyses) {
    if (a.grid) {
      a.grid.x.forEach((x) => xs.push(x));
      a.grid.z.forEach((z) => zs.push(z));
    }
    a.critical?.points.forEach(add);
  }
  const [x0, x1, z0, z1] = [Math.min(...xs), Math.max(...xs), Math.min(...zs), Math.max(...zs)];
  const k = Math.min(
    (width - 2 * pad) / Math.max(x1 - x0, 1),
    (height - 2 * pad) / Math.max(z1 - z0, 1),
  );
  return { k, tx: width / 2 + (k * (x0 + x1)) / 2, ty: height / 2 + (k * (z0 + z1)) / 2 };
}

/**
 * 처음 보기(줌 · 팬) — 그 비탈 탐색 범위 · 임계면 · 격자 중심을 판 가운데 크게(여백 25 %).
 * 판 전체(scale 1) = 모형 전체 · 두 번 누름 = 이 보기 · 배율은 1~maxScale.
 */
export function focusHome(
  fit: ViewFit,
  view: SectionView,
  analysis: Analysis | null,
  width: number,
  height: number,
  maxScale: number,
): { scale: number; tx: number; ty: number } {
  if (!analysis) return { scale: 1, tx: 0, ty: 0 };
  const pts: Point[] = [];
  const [x0, x1] = analysis.limits;
  view.surface.filter((p) => p[0] >= x0 && p[0] <= x1).forEach((p) => pts.push(p));
  analysis.critical?.points.forEach((p) => pts.push(p));
  if (analysis.grid) {
    const g = analysis.grid;
    pts.push([Math.min(...g.x), Math.min(...g.z)], [Math.max(...g.x), Math.max(...g.z)]);
  }
  if (!pts.length) return { scale: 1, tx: 0, ty: 0 };
  const scr = pts.map((p) => toScreen(fit, p));
  const [sx0, sx1] = [Math.min(...scr.map((p) => p[0])), Math.max(...scr.map((p) => p[0]))];
  const [sy0, sy1] = [Math.min(...scr.map((p) => p[1])), Math.max(...scr.map((p) => p[1]))];
  const raw = Math.min(
    width / Math.max((sx1 - sx0) * 1.25, 1),
    height / Math.max((sy1 - sy0) * 1.25, 1),
  );
  const scale = Math.min(Math.max(raw, 1), maxScale);
  return {
    scale,
    tx: width / 2 - (scale * (sx0 + sx1)) / 2,
    ty: height / 2 - (scale * (sy0 + sy1)) / 2,
  };
}

/** 결과 좌표 → 화면 px */
export function toScreen(fit: ViewFit, p: Point): Point {
  return [-fit.k * p[0] + fit.tx, -fit.k * p[1] + fit.ty];
}

/** 화면 px → 결과 좌표(마우스 아래 값) */
export function toModel(fit: ViewFit, p: Point): Point {
  return [(fit.tx - p[0]) / fit.k, (fit.ty - p[1]) / fit.k];
}

/** 결과 좌표 도형 묶음에 거는 transform — 도형 points 는 결과 좌표 그대로 */
export function viewMatrix(fit: ViewFit): string {
  return `matrix(${-fit.k} 0 0 ${-fit.k} ${fit.tx} ${fit.ty})`;
}

/** 폴리곤 · 선 → SVG points 글(결과 좌표 그대로) */
export function pointsText(points: Point[]): string {
  return points.map((p) => `${p[0]},${p[1]}`).join(" ");
}

/** 꺾은선 위 x 의 z(선형 · 범위 밖은 끝값) — 선은 x 오름 · 내림 무관 */
export function zAt(line: Point[], x: number): number | null {
  if (!line.length) return null;
  const pts = line.slice().sort((a, b) => a[0] - b[0]);
  if (x <= pts[0][0]) return pts[0][1];
  for (let i = 1; i < pts.length; i += 1) {
    if (x <= pts[i][0]) {
      const [a, b] = [pts[i - 1], pts[i]];
      const t = b[0] === a[0] ? 0 : (x - a[0]) / (b[0] - a[0]);
      return a[1] + t * (b[1] - a[1]);
    }
  }
  return pts[pts.length - 1][1];
}

/** 절편 네 꼭짓점 — 바닥 = 임계면 · 위 = 지표 */
export function sliceShape(slice: SliceRow, surface: Point[], base: Point[]): Point[] {
  const at = (line: Point[], x: number): number => zAt(line, x) ?? 0;
  return [
    [slice.x_left, at(base, slice.x_left)],
    [slice.x_right, at(base, slice.x_right)],
    [slice.x_right, at(surface, slice.x_right)],
    [slice.x_left, at(surface, slice.x_left)],
  ];
}

/* ---- 자유물체도 --------------------------------------------------------- */

export interface ForceArrow {
  name: "W" | "Q" | "N" | "U" | "S" | "EL" | "ER" | "XL" | "XR";
  value: number;
  /** 화살 시작 · 끝(결과 좌표 · 길이 = 값 × scale) */
  from: Point;
  to: Point;
}

/**
 * 절편 하나 힘 화살 — W · Q 아래 · N · U 바닥 법선(절편 안쪽) · S 바닥 따라 미끄럼 반대 ·
 * E 좌우 면 수평 · X 좌우 면 연직. 엔진 절편표는 활동 방향(direction)으로 뒤집은 틀의 차례라
 * 그 틀의 「왼쪽 면」은 direction < 0 이면 결과 좌표의 오른쪽 면. 길이 = 값 × lengthPerKn.
 */
export function forceArrows(
  slice: SliceRow,
  shape: Point[],
  direction: number,
  lengthPerKn: number,
): ForceArrow[] {
  const s = direction < 0 ? -1 : 1;
  const [bl, br, tr, tl] = shape;
  const midBase: Point = [(bl[0] + br[0]) / 2, (bl[1] + br[1]) / 2];
  const midTop: Point = [(tl[0] + tr[0]) / 2, (tl[1] + tr[1]) / 2];
  const centroid: Point = [(midBase[0] + midTop[0]) / 2, (midBase[1] + midTop[1]) / 2];
  const len = Math.hypot(br[0] - bl[0], br[1] - bl[1]) || 1;
  const t: Point = [(br[0] - bl[0]) / len, (br[1] - bl[1]) / len]; // 바닥 왼→오
  const n: Point = [-t[1], t[0]]; // 바닥 법선 위쪽
  const faceMid = (a: Point, b: Point): Point => [(a[0] + b[0]) / 2, (a[1] + b[1]) / 2];
  const [nearFace, farFace] =
    s > 0 ? [faceMid(bl, tl), faceMid(br, tr)] : [faceMid(br, tr), faceMid(bl, tl)];
  const arrow = (
    name: ForceArrow["name"],
    value: number,
    at: Point,
    dir: Point,
    ending = false,
  ): ForceArrow => {
    const d: Point = [dir[0] * value * lengthPerKn, dir[1] * value * lengthPerKn];
    return ending
      ? { name, value, from: [at[0] - d[0], at[1] - d[1]], to: at }
      : { name, value, from: at, to: [at[0] + d[0], at[1] + d[1]] };
  };
  return [
    arrow("W", slice.weight, centroid, [0, -1]),
    arrow("Q", slice.surcharge, midTop, [0, -1], true),
    arrow("N", slice.N_eff, midBase, n, true),
    arrow("U", slice.U, midBase, n, true),
    arrow("S", slice.S, midBase, [-s * t[0], -s * t[1]], true),
    arrow("EL", slice.E_left, nearFace, [s, 0], true),
    arrow("ER", slice.E_right, farFace, [-s, 0], true),
    arrow("XL", slice.X_left, nearFace, [0, 1], true),
    arrow("XR", slice.X_right, farFace, [0, -1], true),
  ].filter((a) => Math.abs(a.value) > 1e-9);
}

/** 절편력 그래프 꼴 — 절편 가운데 x 마다 바닥 유효 수직응력 · 간극수압 · 동원 전단응력(kPa · 한 축) */
export function sliceStress(
  slices: SliceRow[],
): { x: number; sigma: number; u: number; tau: number }[] {
  return slices.map((s) => {
    const l = s.base_length > 0 ? s.base_length : 1;
    return { x: (s.x_left + s.x_right) / 2, sigma: s.N_eff / l, u: s.pore_pressure, tau: s.S / l };
  });
}

/** 그래프 눈금 — 0 포함 · 1 · 2 · 5 × 10ⁿ 간격 · 대략 count 칸 */
export function niceTicks(min: number, max: number, count = 5): number[] {
  const lo = Math.min(0, min);
  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;
}