import * as XLSX from "xlsx";
import type { Database } from "@db/sqlite";

function lastId(database: Database): number {
  return Number((database.prepare("SELECT last_insert_rowid() AS id").get() as { id: number }).id);
}

export const BUDGET_IVA = 0.16;

export const BUDGET_COLUMNS = [
  "WBS",
  "TIPO",
  "CODIGO",
  "DESCRIPCION",
  "UNIDAD",
  "CANTIDAD",
  "PRECIO",
] as const;

const GROUP_TYPES = new Set(["lote", "capitulo", "capítulo", "partida", "titulo", "título", "group", "capitulo"]);
const ITEM_TYPES = new Set(["concepto", "item", "partida-concepto"]);

const HEADER_ALIASES: Record<string, string> = {
  WBS: "WBS",
  NIVEL: "WBS",
  TIPO: "TIPO",
  TYPE: "TIPO",
  KIND: "TIPO",
  CAPITULO: "CAPITULO",
  CAPÍTULO: "CAPITULO",
  CAP: "CAPITULO",
  CLAVE: "CLAVE",
  CODIGO: "CLAVE",
  CÓDIGO: "CLAVE",
  CODE: "CLAVE",
  DESCRIPCION: "DESCRIPCION",
  DESCRIPCIÓN: "DESCRIPCION",
  CONCEPT: "DESCRIPCION",
  CONCEPTO: "DESCRIPCION",
  PARTIDA: "DESCRIPCION",
  UNIDAD: "UNIDAD",
  UD: "UNIDAD",
  U: "UNIDAD",
  CANTIDAD: "CANTIDAD",
  CANT: "CANTIDAD",
  QTY: "CANTIDAD",
  PRECIO: "PRECIO",
  "PRECIO U": "PRECIO",
  "PRECIO U.": "PRECIO",
  "P.U.": "PRECIO",
  "P.U": "PRECIO",
  PU: "PRECIO",
  "PRECIO UNITARIO": "PRECIO",
  "P. UNITARIO": "PRECIO",
  "P UNITARIO": "PRECIO",
  IMPORTE: "IMPORTE",
  TOTAL: "IMPORTE",
  MONTO: "IMPORTE",
};

export type ParsedGroup = {
  kind: "lote" | "capitulo" | "partida";
  wbs: string;
  parentWbs: string;
  code: string;
  name: string;
};

export type ParsedBudgetItem = {
  chapter: string;
  chapterCode: string;
  wbs: string;
  parentWbs: string;
  code: string;
  description: string;
  unit: string;
  quantity: number;
  unit_price: number;
  amount: number;
};

export type ParsedBudget = {
  format: "wbs" | "opus" | "flat" | "none";
  groups: ParsedGroup[];
  items: ParsedBudgetItem[];
  skipped: number;
};

export type BudgetPreviewNode = {
  wbs: string;
  code: string;
  name: string;
  kind: ParsedGroup["kind"];
  amount: number;
  item_count: number;
  children: BudgetPreviewNode[];
};

export type BudgetPreview = {
  format: ParsedBudget["format"];
  format_label: string;
  sheet: string;
  tree: BudgetPreviewNode[];
  items: {
    code: string;
    description: string;
    unit: string;
    quantity: number;
    unit_price: number;
    amount: number;
    chapter: string;
    parentWbs: string;
  }[];
  totals: { subtotal: number; iva: number; total: number; item_count: number };
  skipped: number;
  errors: { row: number; messages: string[] }[];
};

export type BudgetImportReport = {
  replaced: boolean;
  chapters: number;
  inserted: number;
  skipped: number;
  errors: { row: number; messages: string[] }[];
  totals?: { subtotal: number; iva: number; total: number; item_count: number };
  contract_amount?: number;
};

export type BudgetTreeNode = {
  id: number;
  parent_id: number | null;
  code: string;
  name: string;
  wbs: string;
  amount: number;
  item_count: number;
  children: BudgetTreeNode[];
};

export type BudgetItemRow = {
  id: number;
  project_id: number;
  chapter_id: number | null;
  code: string;
  description: string;
  unit: string;
  quantity: number;
  unit_price: number;
  amount: number;
  sort_order: number;
  wbs: string;
  chapter_name: string | null;
  chapter_code: string | null;
  parent_path: string;
  ancestor_ids: number[];
};

function normHeader(raw: unknown): string {
  const k = String(raw ?? "")
    .normalize("NFD")
    .replace(/\p{M}/gu, "")
    .toUpperCase()
    .replace(/\s+/g, " ")
    .replace(/\.$/, "")
    .trim();
  return HEADER_ALIASES[k] || k;
}

function fold(value: string) {
  return value.normalize("NFD").replace(/\p{M}/gu, "").toUpperCase().replace(/\s+/g, " ").trim();
}

export function parseMoney(value: unknown): number {
  if (typeof value === "number" && Number.isFinite(value)) return value;
  const raw = String(value ?? "").trim();
  if (!raw) return 0;
  const cleaned = raw.replace(/[$%\s]/g, "");
  if (cleaned.includes(",") && cleaned.includes(".")) {
    return Number(cleaned.replace(/,/g, "")) || 0;
  }
  if (cleaned.includes(",")) return Number(cleaned.replace(",", ".")) || 0;
  return Number(cleaned) || 0;
}

function isSummaryLabel(value: string) {
  const t = fold(value);
  if (!t) return false;
  if (/^\(.*\*.*\)$/.test(t) && /(PESOS|MILLON|M\.?\s*N\.?)/.test(t)) return true;
  return /(SUB\s*TOTAL|^TOTAL\b|GRAN TOTAL|\bIVA\b|SIN IVA)/.test(t);
}

function rowHasNumbers(row: unknown[]) {
  return row.slice(0, 6).some((cell, i) => i >= 2 && parseMoney(cell) !== 0);
}

function isGroupCode(code: string) {
  const t = fold(code);
  return /^[A-Z]$/.test(t) || /^[A-Z]\d{2,4}$/.test(t);
}

function padChild(parent: string, index: number) {
  const part = String(index).padStart(parent ? 2 : 1, "0");
  if (!parent) return String(index);
  return `${parent}.${part}`;
}

function parentOfWbs(wbs: string) {
  const i = wbs.lastIndexOf(".");
  return i < 0 ? "" : wbs.slice(0, i);
}

function tipoOf(raw: string): "group" | "item" | "" {
  const t = fold(raw).toLowerCase();
  if (!t) return "";
  if (ITEM_TYPES.has(t) || t === "concepto") return "item";
  if (GROUP_TYPES.has(t) || t === "lote" || t === "capitulo" || t === "partida") return "group";
  return "";
}

function groupKind(raw: string, depth: number): ParsedGroup["kind"] {
  const t = fold(raw).toLowerCase();
  if (t === "lote") return "lote";
  if (t === "partida") return "partida";
  if (depth <= 1) return "lote";
  if (depth === 2) return "capitulo";
  return "partida";
}

type ColMap = Record<string, number>;

function findHeader(rows: unknown[][]): { headerAt: number; map: ColMap } {
  for (let i = 0; i < rows.length; i++) {
    const headers = rows[i].map(normHeader);
    const map: ColMap = {
      WBS: headers.indexOf("WBS"),
      TIPO: headers.indexOf("TIPO"),
      CAPITULO: headers.indexOf("CAPITULO"),
      CLAVE: headers.indexOf("CLAVE"),
      DESCRIPCION: headers.indexOf("DESCRIPCION"),
      UNIDAD: headers.indexOf("UNIDAD"),
      CANTIDAD: headers.indexOf("CANTIDAD"),
      PRECIO: headers.indexOf("PRECIO"),
      IMPORTE: headers.indexOf("IMPORTE"),
    };
    if (map.WBS >= 0 && (map.TIPO >= 0 || map.DESCRIPCION >= 0)) return { headerAt: i, map };
    if (map.DESCRIPCION >= 0 && (map.CLAVE >= 0 || map.CANTIDAD >= 0 || map.PRECIO >= 0)) {
      return { headerAt: i, map };
    }
  }
  return { headerAt: -1, map: {} };
}

function cell(row: unknown[], map: ColMap, key: string) {
  const i = map[key];
  return i >= 0 ? row[i] : "";
}

function looksOpus(rows: unknown[][], headerAt: number, map: ColMap) {
  for (let r = headerAt + 1; r < Math.min(rows.length, headerAt + 40); r++) {
    const code = String(cell(rows[r] || [], map, "CLAVE") ?? "").trim();
    const unit = String(cell(rows[r] || [], map, "UNIDAD") ?? "").trim();
    const qty = parseMoney(cell(rows[r] || [], map, "CANTIDAD"));
    const price = parseMoney(cell(rows[r] || [], map, "PRECIO"));
    if (isGroupCode(code) && !unit && qty === 0 && price === 0) return true;
  }
  return false;
}

function parseWbsRows(rows: unknown[][], headerAt: number, map: ColMap): ParsedBudget {
  const groups: ParsedGroup[] = [];
  const items: ParsedBudgetItem[] = [];
  let skipped = 0;
  const names = new Map<string, { name: string; code: string }>();

  for (let r = headerAt + 1; r < rows.length; r++) {
    const row = rows[r] || [];
    const values = row.map((v) => String(v ?? "").trim());
    if (values.every((v) => !v)) continue;
    if (values.some((value) => isSummaryLabel(value))) {
      skipped++;
      continue;
    }
    const wbs = String(cell(row, map, "WBS") ?? "").trim();
    const tipoRaw = String(cell(row, map, "TIPO") ?? "").trim();
    const code = String(cell(row, map, "CLAVE") ?? "").trim();
    const description = String(cell(row, map, "DESCRIPCION") ?? "").trim();
    const unit = String(cell(row, map, "UNIDAD") ?? "").trim();
    const qty = parseMoney(cell(row, map, "CANTIDAD"));
    const price = parseMoney(cell(row, map, "PRECIO"));
    const importe = parseMoney(cell(row, map, "IMPORTE"));
    if (!wbs && !code && !description) {
      skipped++;
      continue;
    }
    const depth = wbs ? wbs.split(".").length : 1;
    let kind = tipoOf(tipoRaw);
    if (!kind) kind = unit || qty || price ? "item" : "group";
    const parentWbs = wbs ? parentOfWbs(wbs) : "";
    if (kind === "group") {
      const name = description || code || "Capítulo";
      const node: ParsedGroup = {
        kind: groupKind(tipoRaw, depth),
        wbs: wbs || String(groups.length + 1),
        parentWbs,
        code,
        name,
      };
      groups.push(node);
      names.set(node.wbs, { name, code });
      continue;
    }
    const parent = names.get(parentWbs);
    items.push({
      chapter: parent?.name || "General",
      chapterCode: parent?.code || "",
      wbs: wbs || padChild(parentWbs, items.length + 1),
      parentWbs,
      code,
      description: description || code,
      unit,
      quantity: qty,
      unit_price: price,
      amount: Math.round((qty * price || importe) * 100) / 100,
    });
  }
  return { groups, items, skipped };
}

function parseOpusRows(rows: unknown[][], headerAt: number, map: ColMap): ParsedBudget {
  const groups: ParsedGroup[] = [];
  const items: ParsedBudgetItem[] = [];
  let skipped = 0;
  let loteWbs = "";
  let chapterWbs = "";
  let loteIndex = 0;
  let chapterIndex = 0;
  let itemIndex = 0;
  let lastItem: ParsedBudgetItem | null = null;
  const groupNames = new Map<string, { name: string; code: string }>();

  for (let r = headerAt + 1; r < rows.length; r++) {
    const row = rows[r] || [];
    const values = row.map((v) => String(v ?? "").trim());
    if (values.every((v) => !v)) continue;
    const code = String(cell(row, map, "CLAVE") ?? "").trim();
    const description = String(cell(row, map, "DESCRIPCION") ?? "").trim();
    const unit = String(cell(row, map, "UNIDAD") ?? "").trim();
    const qty = parseMoney(cell(row, map, "CANTIDAD"));
    const price = parseMoney(cell(row, map, "PRECIO"));
    const importe = parseMoney(cell(row, map, "IMPORTE"));
    if ([code, description].some((value) => isSummaryLabel(value)) || values.some((value) => isSummaryLabel(value))) {
      skipped++;
      lastItem = null;
      continue;
    }
    if (!code && description && !unit && qty === 0 && price === 0 && importe === 0) {
      if (lastItem) {
        lastItem.description = `${lastItem.description} ${description}`.replace(/\s+/g, " ").trim();
      } else {
        skipped++;
      }
      continue;
    }
    if (code && !unit && qty === 0 && price === 0 && importe === 0 && (isGroupCode(code) || !rowHasNumbers(row))) {
      lastItem = null;
      if (isGroupCode(code) && /^[A-Z]$/i.test(fold(code))) {
        loteIndex += 1;
        chapterIndex = 0;
        itemIndex = 0;
        loteWbs = String(loteIndex);
        chapterWbs = loteWbs;
        const node: ParsedGroup = {
          kind: "lote",
          wbs: loteWbs,
          parentWbs: "",
          code,
          name: description || code,
        };
        groups.push(node);
        groupNames.set(node.wbs, { name: node.name, code: node.code });
      } else {
        chapterIndex += 1;
        itemIndex = 0;
        const parent = loteWbs || "";
        if (!loteWbs) {
          loteIndex += 1;
          loteWbs = String(loteIndex);
        }
        chapterWbs = padChild(parent || loteWbs, chapterIndex);
        const node: ParsedGroup = {
          kind: "capitulo",
          wbs: chapterWbs,
          parentWbs: loteWbs && chapterWbs !== loteWbs ? loteWbs : "",
          code,
          name: description || code,
        };
        groups.push(node);
        groupNames.set(node.wbs, { name: node.name, code: node.code });
      }
      continue;
    }
    if (!description && !code) {
      skipped++;
      continue;
    }
    if (!code && !unit && qty === 0 && price === 0) {
      skipped++;
      continue;
    }
    itemIndex += 1;
    const parentWbs = chapterWbs || loteWbs;
    const parent = groupNames.get(parentWbs);
    const item: ParsedBudgetItem = {
      chapter: parent?.name || "General",
      chapterCode: parent?.code || "",
      wbs: padChild(parentWbs, itemIndex),
      parentWbs,
      code,
      description: description || code,
      unit,
      quantity: qty,
      unit_price: price,
      amount: Math.round((qty * price || importe) * 100) / 100,
    };
    items.push(item);
    lastItem = item;
  }
  return { groups, items, skipped };
}

function parseFlatRows(rows: unknown[][], headerAt: number, map: ColMap): ParsedBudget {
  const groups: ParsedGroup[] = [];
  const items: ParsedBudgetItem[] = [];
  let skipped = 0;
  let chapter = "";
  let chapterCode = "";
  let chapterWbs = "";
  let chapterIndex = 0;
  let itemIndex = 0;
  const cache = new Map<string, ParsedGroup>();

  function ensureChapter(name: string, code = "") {
    const key = name.trim() || "General";
    const hit = cache.get(key.toLowerCase());
    if (hit) {
      chapter = hit.name;
      chapterCode = hit.code;
      chapterWbs = hit.wbs;
      return hit;
    }
    chapterIndex += 1;
    itemIndex = 0;
    const node: ParsedGroup = {
      kind: "capitulo",
      wbs: String(chapterIndex),
      parentWbs: "",
      code,
      name: key,
    };
    groups.push(node);
    cache.set(key.toLowerCase(), node);
    chapter = node.name;
    chapterCode = node.code;
    chapterWbs = node.wbs;
    return node;
  }

  for (let r = 0; r < headerAt; r++) {
    const first = String(rows[r]?.[0] ?? "").trim();
    const second = String(rows[r]?.[1] ?? "").trim();
    if (/^obra:?$/i.test(first) && second) ensureChapter(second);
    const restEmpty = (rows[r] || []).slice(1).every((value) => !String(value ?? "").trim());
    if (first && restEmpty && !/^(cliente|concurso|obra|lugar|ciudad|fecha):?$/i.test(first) && !isSummaryLabel(first)) {
      ensureChapter(first);
    }
  }

  for (let r = headerAt + 1; r < rows.length; r++) {
    const row = rows[r] || [];
    const values = row.map((v) => String(v ?? "").trim());
    if (values.every((v) => !v)) continue;
    if (values.some((value) => isSummaryLabel(value))) {
      skipped++;
      continue;
    }
    const code = String(cell(row, map, "CLAVE") ?? "").trim();
    const description = String(cell(row, map, "DESCRIPCION") ?? "").trim();
    const unit = String(cell(row, map, "UNIDAD") ?? "").trim();
    const chapterCell = String(cell(row, map, "CAPITULO") ?? "").trim();
    const qty = parseMoney(cell(row, map, "CANTIDAD"));
    const price = parseMoney(cell(row, map, "PRECIO"));
    const importe = parseMoney(cell(row, map, "IMPORTE"));
    const first = values[0];
    const label = chapterCell || description || first;
    const looksChapter = !code && !unit && qty === 0 && price === 0 && !rowHasNumbers(row) && !!label;
    if (looksChapter) {
      ensureChapter(label);
      continue;
    }
    if (chapterCell) ensureChapter(chapterCell);
    if (!chapterWbs) ensureChapter("General");
    if (!description && !code) {
      skipped++;
      continue;
    }
    itemIndex += 1;
    items.push({
      chapter: chapter || "General",
      chapterCode,
      wbs: padChild(chapterWbs, itemIndex),
      parentWbs: chapterWbs,
      code,
      description: description || code,
      unit,
      quantity: qty,
      unit_price: price,
      amount: Math.round((qty * price || importe) * 100) / 100,
    });
  }
  return { groups, items, skipped };
}

export function parseBudgetRows(rows: unknown[][]): ParsedBudget {
  const empty: ParsedBudget = { format: "none", groups: [], items: [], skipped: 0 };
  const { headerAt, map } = findHeader(rows);
  if (headerAt < 0) return empty;
  if (map.WBS >= 0) return { format: "wbs", ...parseWbsRows(rows, headerAt, map) };
  if (looksOpus(rows, headerAt, map)) return { format: "opus", ...parseOpusRows(rows, headerAt, map) };
  return { format: "flat", ...parseFlatRows(rows, headerAt, map) };
}

function xlsxBytes(wb: XLSX.WorkBook): Uint8Array {
  const out = XLSX.write(wb, { type: "array", bookType: "xlsx" });
  const bytes = out instanceof Uint8Array ? out : new Uint8Array(out);
  return bytes.byteOffset === 0 && bytes.byteLength === bytes.buffer.byteLength
    ? bytes
    : bytes.slice();
}

export function buildBudgetTemplate(): Uint8Array {
  const wb = XLSX.utils.book_new();
  const instructions = [
    ["Plantilla de presupuesto — Panel de proyectos"],
    [""],
    ["1. Llene la hoja PRESUPUESTO. No cambie los nombres de las columnas."],
    ["2. WBS es el árbol: 1 = lote, 1.01 = capítulo, 1.01.01 = concepto."],
    ["3. TIPO: lote, capitulo o partida para agrupadores; concepto para renglones con unidad y precio."],
    ["4. El padre se infiere del WBS (1.01.01 cuelga de 1.01). No capture importes, IVA ni totales."],
    ["5. Una fila = un nodo. Ponga la descripción completa en una sola celda."],
    ["6. También se acepta un Excel Opus/Neodata (Código, Concepto, Unidad, Cantidad, P. Unitario) o uno plano con CLAVE y DESCRIPCION."],
  ];
  XLSX.utils.book_append_sheet(wb, XLSX.utils.aoa_to_sheet(instructions), "INSTRUCCIONES");
  const sheet = [
    [...BUDGET_COLUMNS],
    ["1", "lote", "A", "LOCAL L224", "", "", ""],
    ["1.01", "capitulo", "A001", "Preliminares y albañilería", "", "", ""],
    ["1.01.01", "concepto", "10301-001", "Trazo y nivelación manual para establecer ejes, banco de nivel y referencias.", "M2", 61.9, 15.53],
    ["1.01.02", "concepto", "10606-002", "Firme de 5 cm acabado común, de concreto F'c= 150 kg/cm2.", "M2", 61.9, 342.55],
    ["1.02", "capitulo", "A002", "Instalación hidrosanitaria", "", "", ""],
    ["1.02.01", "concepto", "11402-2996C200MX.020", "Inodoro alargado de una pieza, cerámica porcelanizada.", "PZA", 1, 6422.87],
    ["1.02.02", "concepto", "11403-E928-1.9", "Monomando de lavabo, negro mate.", "PZA", 2, 4272.4],
  ];
  const ws = XLSX.utils.aoa_to_sheet(sheet);
  ws["!cols"] = [{ wch: 10 }, { wch: 12 }, { wch: 24 }, { wch: 70 }, { wch: 10 }, { wch: 12 }, { wch: 14 }];
  XLSX.utils.book_append_sheet(wb, ws, "PRESUPUESTO");
  return xlsxBytes(wb);
}

type ExportChapter = { id: number; parent_id: number | null; code: string; name: string; wbs: string; sort_order: number };
type ExportItem = {
  chapter_id?: number | null;
  wbs?: string;
  code: string;
  description: string;
  unit: string;
  quantity: number;
  unit_price: number;
};

export function exportBudgetWorkbook(
  projectName: string,
  budget: { tree: BudgetTreeNode[]; chapters?: ExportChapter[]; items: ExportItem[] },
): Uint8Array {
  const wb = XLSX.utils.book_new();
  const rows: unknown[][] = [
    ["Obra", projectName],
    [],
    [...BUDGET_COLUMNS],
  ];
  const itemsByChapter = new Map<number, ExportItem[]>();
  for (const item of budget.items) {
    const id = Number(item.chapter_id || 0);
    const list = itemsByChapter.get(id) || [];
    list.push(item);
    itemsByChapter.set(id, list);
  }

  function walk(nodes: BudgetTreeNode[], depth: number) {
    for (const node of nodes) {
      const tipo = depth <= 0 ? "lote" : depth === 1 ? "capitulo" : "partida";
      rows.push([node.wbs || "", tipo, node.code || "", node.name, "", "", ""]);
      for (const item of itemsByChapter.get(node.id) || []) {
        rows.push([
          item.wbs || "",
          "concepto",
          item.code,
          item.description,
          item.unit,
          item.quantity,
          item.unit_price,
        ]);
      }
      if (node.children?.length) walk(node.children, depth + 1);
    }
  }
  walk(budget.tree, 0);
  const unassigned = itemsByChapter.get(0) || [];
  for (const item of unassigned) {
    rows.push([item.wbs || "", "concepto", item.code, item.description, item.unit, item.quantity, item.unit_price]);
  }
  const ws = XLSX.utils.aoa_to_sheet(rows);
  ws["!cols"] = [{ wch: 10 }, { wch: 12 }, { wch: 24 }, { wch: 70 }, { wch: 10 }, { wch: 12 }, { wch: 14 }];
  XLSX.utils.book_append_sheet(wb, ws, "PRESUPUESTO");
  return xlsxBytes(wb);
}

type ChapterRow = {
  id: number;
  project_id: number;
  parent_id: number | null;
  code: string;
  name: string;
  wbs: string;
  sort_order: number;
};

function compareWbs(a: string, b: string) {
  const as = a.split(".").map(Number);
  const bs = b.split(".").map(Number);
  const n = Math.max(as.length, bs.length);
  for (let i = 0; i < n; i++) {
    const d = (as[i] || 0) - (bs[i] || 0);
    if (d) return d;
  }
  return a.localeCompare(b, undefined, { numeric: true });
}

export function listBudget(database: Database, projectId: number) {
  const chapterCols = (database.prepare("PRAGMA table_info(budget_chapters)").all() as { name: string }[]).map((c) => c.name);
  const wbsExpr = chapterCols.includes("wbs") ? "COALESCE(c.wbs, '') AS wbs" : "'' AS wbs";
  const chapters = database.prepare(
    `SELECT c.id, c.project_id, c.parent_id, c.code, c.name, ${wbsExpr}, c.sort_order
     FROM budget_chapters c WHERE c.project_id = ? ORDER BY c.sort_order, c.id`,
  ).all(projectId) as ChapterRow[];
  const rawItems = database.prepare(
    `SELECT i.*, ch.name AS chapter_name, ch.code AS chapter_code
     FROM budget_items i
     LEFT JOIN budget_chapters ch ON ch.id = i.chapter_id
     WHERE i.project_id = ?
     ORDER BY COALESCE(ch.sort_order, 9999), i.sort_order, i.id`,
  ).all(projectId) as (BudgetItemRow & { chapter_name: string | null; chapter_code: string | null })[];

  const byParent = new Map<number | null, ChapterRow[]>();
  const byId = new Map<number, ChapterRow>();
  for (const chapter of chapters) {
    byId.set(chapter.id, chapter);
    const key = chapter.parent_id || null;
    const list = byParent.get(key) || [];
    list.push(chapter);
    byParent.set(key, list);
  }

  function ancestorsOf(id: number | null): ChapterRow[] {
    const chain: ChapterRow[] = [];
    let cur = id ? byId.get(id) : undefined;
    const seen = new Set<number>();
    while (cur && !seen.has(cur.id)) {
      seen.add(cur.id);
      chain.unshift(cur);
      cur = cur.parent_id ? byId.get(cur.parent_id) : undefined;
    }
    return chain;
  }

  function descendantIds(id: number): number[] {
    const ids = [id];
    for (const child of byParent.get(id) || []) ids.push(...descendantIds(child.id));
    return ids;
  }

  const amounts = new Map<number, { amount: number; item_count: number }>();
  for (const chapter of chapters) {
    const ids = new Set(descendantIds(chapter.id));
    const owned = rawItems.filter((item) => item.chapter_id && ids.has(Number(item.chapter_id)));
    amounts.set(chapter.id, {
      amount: Math.round(owned.reduce((sum, item) => sum + Number(item.amount || 0), 0) * 100) / 100,
      item_count: owned.length,
    });
  }

  function toTree(nodes: ChapterRow[]): BudgetTreeNode[] {
    return nodes.map((chapter) => {
      const stats = amounts.get(chapter.id) || { amount: 0, item_count: 0 };
      return {
        id: chapter.id,
        parent_id: chapter.parent_id,
        code: chapter.code || "",
        name: chapter.name,
        wbs: chapter.wbs || "",
        amount: stats.amount,
        item_count: stats.item_count,
        children: toTree(byParent.get(chapter.id) || []),
      };
    });
  }

  const tree = toTree(byParent.get(null) || chapters.filter((chapter) => !chapter.parent_id));
  const items: BudgetItemRow[] = rawItems.map((item) => {
    const chain = ancestorsOf(item.chapter_id);
    return {
      ...item,
      wbs: item.wbs || "",
      parent_path: chain.map((chapter) => [chapter.code, chapter.name].filter(Boolean).join(" ").trim()).join(" > "),
      ancestor_ids: chain.map((chapter) => chapter.id),
    };
  });

  const subtotal = items.reduce((sum, item) => sum + Number(item.amount || 0), 0);
  const iva = Math.round(subtotal * BUDGET_IVA * 100) / 100;
  const chapterView = chapters.map((chapter) => {
    const stats = amounts.get(chapter.id) || { amount: 0, item_count: 0 };
    const chain = ancestorsOf(chapter.id);
    return {
      ...chapter,
      ...stats,
      path: chain.map((node) => [node.code, node.name].filter(Boolean).join(" ").trim()).join(" > "),
    };
  });

  return {
    tree,
    chapters: chapterView,
    items,
    totals: {
      subtotal: Math.round(subtotal * 100) / 100,
      iva,
      total: Math.round((subtotal + iva) * 100) / 100,
      item_count: items.length,
    },
  };
}

function insertChapter(
  database: Database,
  projectId: number,
  parentId: number | null,
  code: string,
  name: string,
  wbs: string,
  sort: number,
) {
  const cols = (database.prepare("PRAGMA table_info(budget_chapters)").all() as { name: string }[]).map((c) => c.name);
  if (cols.includes("wbs")) {
    database.prepare(
      "INSERT INTO budget_chapters (project_id, parent_id, code, name, wbs, sort_order) VALUES (?, ?, ?, ?, ?, ?)",
    ).run(projectId, parentId, code, name, wbs, sort);
  } else {
    database.prepare(
      "INSERT INTO budget_chapters (project_id, parent_id, code, name, sort_order) VALUES (?, ?, ?, ?, ?)",
    ).run(projectId, parentId, code, name, sort);
  }
  return lastId(database);
}

export function replaceBudgetFromParsed(database: Database, projectId: number, parsed: ParsedBudget) {
  database.prepare("DELETE FROM budget_items WHERE project_id = ?").run(projectId);
  database.prepare("DELETE FROM budget_chapters WHERE project_id = ?").run(projectId);
  const groups = [...parsed.groups].sort((a, b) => compareWbs(a.wbs, b.wbs));
  const ids = new Map<string, number>();
  let sort = 1;
  for (const group of groups) {
    const parentId = group.parentWbs ? ids.get(group.parentWbs) || null : null;
    const id = insertChapter(database, projectId, parentId, group.code, group.name, group.wbs, sort);
    ids.set(group.wbs, id);
    sort++;
  }
  const itemCols = (database.prepare("PRAGMA table_info(budget_items)").all() as { name: string }[]).map((c) => c.name);
  const hasWbs = itemCols.includes("wbs");
  let itemSort = 1;
  for (const item of parsed.items) {
    const chapterId = item.parentWbs ? ids.get(item.parentWbs) || null : null;
    const amount = Math.round((item.quantity * item.unit_price || item.amount) * 100) / 100;
    if (hasWbs) {
      database.prepare(
        `INSERT INTO budget_items
          (project_id, chapter_id, code, description, unit, quantity, unit_price, amount, sort_order, wbs)
         VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
      ).run(projectId, chapterId, item.code, item.description, item.unit, item.quantity, item.unit_price, amount, itemSort, item.wbs);
    } else {
      database.prepare(
        `INSERT INTO budget_items
          (project_id, chapter_id, code, description, unit, quantity, unit_price, amount, sort_order)
         VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)`,
      ).run(projectId, chapterId, item.code, item.description, item.unit, item.quantity, item.unit_price, amount, itemSort);
    }
    itemSort++;
  }
}

export function replaceBudgetFromItems(database: Database, projectId: number, parsed: ParsedBudgetItem[]) {
  const groups: ParsedGroup[] = [];
  const seen = new Set<string>();
  for (const item of parsed) {
    const wbs = item.parentWbs || "1";
    if (seen.has(wbs)) continue;
    seen.add(wbs);
    groups.push({
      kind: "capitulo",
      wbs,
      parentWbs: parentOfWbs(wbs),
      code: item.chapterCode || "",
      name: item.chapter || "General",
    });
  }
  replaceBudgetFromParsed(database, projectId, { format: "flat", groups, items: parsed, skipped: 0 });
}

export function lineAmount(quantity: number, unitPrice: number) {
  return Math.round(quantity * unitPrice * 100) / 100;
}

const FORMAT_LABEL: Record<ParsedBudget["format"], string> = {
  wbs: "Plantilla del panel",
  opus: "Opus / Neodata",
  flat: "Excel plano",
  none: "No reconocido",
};

function readBudgetSheet(bytes: Uint8Array): { sheet: string; rows: unknown[][] } | { error: string } {
  const wb = XLSX.read(bytes, { type: "array" });
  const sheet = wb.SheetNames.find((name) => /presupuesto/i.test(name)) || wb.SheetNames[0];
  if (!sheet) return { error: "El archivo no tiene hojas" };
  return { sheet, rows: XLSX.utils.sheet_to_json(wb.Sheets[sheet], { header: 1, defval: "" }) as unknown[][] };
}

function previewTreeOf(parsed: ParsedBudget): BudgetPreviewNode[] {
  const byParent = new Map<string, ParsedGroup[]>();
  for (const group of parsed.groups) {
    const key = group.parentWbs || "";
    const list = byParent.get(key) || [];
    list.push(group);
    byParent.set(key, list);
  }
  function stats(wbs: string): { amount: number; item_count: number } {
    const direct = parsed.items.filter((item) => item.parentWbs === wbs);
    const children = byParent.get(wbs) || [];
    const childStats = children.map((child) => stats(child.wbs));
    return {
      amount: Math.round(
        (direct.reduce((sum, item) => sum + Number(item.amount || 0), 0) +
          childStats.reduce((sum, child) => sum + child.amount, 0)) * 100,
      ) / 100,
      item_count: direct.length + childStats.reduce((sum, child) => sum + child.item_count, 0),
    };
  }
  function node(group: ParsedGroup): BudgetPreviewNode {
    const roll = stats(group.wbs);
    return {
      wbs: group.wbs,
      code: group.code,
      name: group.name,
      kind: group.kind,
      amount: roll.amount,
      item_count: roll.item_count,
      children: (byParent.get(group.wbs) || []).map(node),
    };
  }
  const roots = byParent.get("") || parsed.groups.filter((group) => !group.parentWbs);
  return roots.map(node);
}

export function previewBudgetExcel(bytes: Uint8Array): BudgetPreview {
  const read = readBudgetSheet(bytes);
  if ("error" in read) {
    return {
      format: "none",
      format_label: FORMAT_LABEL.none,
      sheet: "",
      tree: [],
      items: [],
      totals: { subtotal: 0, iva: 0, total: 0, item_count: 0 },
      skipped: 0,
      errors: [{ row: 0, messages: [read.error] }],
    };
  }
  const parsed = parseBudgetRows(read.rows);
  const subtotal = Math.round(parsed.items.reduce((sum, item) => sum + Number(item.amount || 0), 0) * 100) / 100;
  const iva = Math.round(subtotal * BUDGET_IVA * 100) / 100;
  const errors = parsed.items.length
    ? []
    : [{ row: 0, messages: ["No se encontraron partidas. Revise que el Excel tenga Código/Concepto o la plantilla WBS."] }];
  return {
    format: parsed.format,
    format_label: FORMAT_LABEL[parsed.format],
    sheet: read.sheet,
    tree: previewTreeOf(parsed),
    items: parsed.items.map((item) => ({
      code: item.code,
      description: item.description,
      unit: item.unit,
      quantity: item.quantity,
      unit_price: item.unit_price,
      amount: item.amount,
      chapter: item.chapter,
      parentWbs: item.parentWbs,
    })),
    totals: {
      subtotal,
      iva,
      total: Math.round((subtotal + iva) * 100) / 100,
      item_count: parsed.items.length,
    },
    skipped: parsed.skipped,
    errors,
  };
}

export function importBudgetExcel(database: Database, projectId: number, bytes: Uint8Array): BudgetImportReport {
  const read = readBudgetSheet(bytes);
  if ("error" in read) {
    return { replaced: false, chapters: 0, inserted: 0, skipped: 0, errors: [{ row: 0, messages: [read.error] }] };
  }
  const parsed = parseBudgetRows(read.rows);
  if (!parsed.items.length) {
    return {
      replaced: false,
      chapters: 0,
      inserted: 0,
      skipped: parsed.skipped,
      errors: [{ row: 0, messages: ["No se encontraron partidas. Use la plantilla o un Excel con CLAVE, DESCRIPCION, UNIDAD, CANTIDAD y PRECIO."] }],
    };
  }
  replaceBudgetFromParsed(database, projectId, parsed);
  const subtotal = Math.round(parsed.items.reduce((sum, item) => sum + Number(item.amount || 0), 0) * 100) / 100;
  const iva = Math.round(subtotal * BUDGET_IVA * 100) / 100;
  const totals = {
    subtotal,
    iva,
    total: Math.round((subtotal + iva) * 100) / 100,
    item_count: parsed.items.length,
  };
  // El monto de contrato del proyecto refleja el subtotal del presupuesto importado.
  database.prepare("UPDATE projects SET contract_amount = ? WHERE id = ?").run(subtotal, projectId);
  return {
    replaced: true,
    chapters: parsed.groups.length,
    inserted: parsed.items.length,
    skipped: parsed.skipped,
    errors: [],
    totals,
    contract_amount: subtotal,
  };
}