import * as XLSX from 'xlsx';
import { parseDms } from './dms';
import type { Bearing, FoundationType, Issue, IpPoint, PierInput, PierType, Row } from './types';

type Cell = string | number | null | undefined;
type Grid = Cell[][];

/** One data row of a table, with the sheet and 1-based row it came from. */
interface Rec {
  sheet: string;
  row: number;
  cells: Cell[];
}

export interface SheetReport {
  name: string;
  /** Tables found on this sheet (교각 정보 · IP · 받침). */
  tables: { pier: number; ip: number; bearing: number };
  /** Piers whose 교각 정보 row is on this sheet. */
  piers: number;
  issues: Issue[];
  /** No E-level issue on this sheet. Pier selection is checked separately. */
  ok: boolean;
}

export interface ParseResult {
  piers: PierInput[];
  issues: Issue[];
  sheets: SheetReport[];
}

const PIER_TYPES: PierType[] = ['T형', '2주형', '3주형'];
const FOUNDATION_TYPES: FoundationType[] = ['말뚝기초', '직접기초', '현장타설말뚝'];

const isPierHeader = (r: Cell[]) => r[0] === '교각명' && r[1] === '교각형식';
const isIpHeader = (r: Cell[]) => r[0] === '교각명' && r[1] === 'IP점';
const isBearingHeader = (r: Cell[]) => r[0] === '교각명' && r[1] === '받침번호';

/**
 * Reads the whole workbook. The three tables (교각 정보, IP, 받침) may sit on different sheets;
 * rows are joined by 교각명 across the workbook. The sheet of each pier's 교각 정보 row is kept.
 */
export function parseWorkbook(wb: XLSX.WorkBook): ParseResult {
  const pierRecs: Rec[] = [];
  const ipRecs: Rec[] = [];
  const bearingRecs: Rec[] = [];
  const counts = new Map<string, { pier: number; ip: number; bearing: number }>();

  for (const sheet of wb.SheetNames) {
    const ws = wb.Sheets[sheet];
    const grid = XLSX.utils.sheet_to_json<Cell[]>(ws, { header: 1, raw: true, defval: null }) as Grid;
    const c = { pier: 0, ip: 0, bearing: 0 };
    for (const [target, match, counter] of [
      [pierRecs, isPierHeader, 'pier'],
      [ipRecs, isIpHeader, 'ip'],
      [bearingRecs, isBearingHeader, 'bearing'],
    ] as const) {
      for (const h of findHeaders(grid, match)) {
        c[counter]++;
        for (const { cells, index } of readBlock(grid, h)) target.push({ sheet, row: index + 1, cells });
      }
    }
    counts.set(sheet, c);
  }

  const issues: Issue[] = [];
  const piers: PierInput[] = [];
  const pierNames = new Set<string>();

  for (const p of pierRecs) {
    const name = String(p.cells[0]);
    pierNames.add(name);
    const pierIps = ipRecs.filter((r) => String(r.cells[0]) === name).map((r) => toIp(r.cells));
    const pierBearings = bearingRecs.filter((r) => String(r.cells[0]) === name);
    if (pierIps.length === 0 || pierBearings.length === 0) {
      const missing = [pierIps.length === 0 ? 'IP' : null, pierBearings.length === 0 ? '받침' : null].filter(Boolean).join('·');
      issues.push({
        code: 'E05',
        level: 'E',
        pier: name,
        sheet: p.sheet,
        message: `${p.row}행: ${missing} 표를 입력 파일에서 찾지 못했습니다. 세 표의 교각명이 같은지 확인하세요.`,
      });
      continue;
    }

    const badAzimuth = pierBearings.find((r) => parseDms(String(r.cells[5] ?? '')) === null);
    if (badAzimuth) {
      issues.push({
        code: 'E03',
        level: 'E',
        pier: name,
        sheet: badAzimuth.sheet,
        message: `${badAzimuth.row}행: 방위각을 읽을 수 없습니다. 예: 75°56'55.9" 형식으로 고치세요.`,
      });
      continue;
    }

    const type = String(p.cells[1]) as PierType;
    const foundation = String(p.cells[5]) as FoundationType;
    if (!PIER_TYPES.includes(type) || !FOUNDATION_TYPES.includes(foundation)) {
      issues.push({ code: 'E01', level: 'E', pier: name, sheet: p.sheet, message: `${p.row}행: 교각형식 또는 기초 형식을 알 수 없습니다.` });
      continue;
    }

    piers.push({
      name,
      sheet: p.sheet,
      type,
      copingTopEl: Number(p.cells[2]),
      footingBottomEl: Number(p.cells[3]),
      groundEl: Number(p.cells[4]),
      foundationType: foundation,
      pileLengthMm: Number(p.cells[6]),
      copingWidthMm: Number(p.cells[7]),
      copingLengthMm: Number(p.cells[8]),
      columnCount: Number(p.cells[9]),
      ips: pierIps,
      bearings: pierBearings.map((r) => toBearing(r.cells)),
    });
  }

  // IP or 받침 rows whose 교각명 has no 교각 정보 row anywhere in the workbook.
  for (const r of [...ipRecs, ...bearingRecs]) {
    const name = String(r.cells[0]);
    if (!pierNames.has(name)) {
      issues.push({
        code: 'E05',
        level: 'E',
        pier: name,
        sheet: r.sheet,
        message: `${r.row}행: 교각명 ${name}의 교각 정보 행이 입력 파일에 없습니다.`,
      });
    }
  }

  const sheets: SheetReport[] = wb.SheetNames.map((name) => {
    const own = issues.filter((i) => i.sheet === name);
    return {
      name,
      tables: counts.get(name)!,
      piers: pierRecs.filter((r) => r.sheet === name).length,
      issues: own,
      ok: !own.some((i) => i.level === 'E'),
    };
  });

  return { piers, issues, sheets };
}

function findHeaders(grid: Grid, match: (row: Cell[]) => boolean): number[] {
  const out: number[] = [];
  grid.forEach((row, i) => {
    if (match(row)) out.push(i);
  });
  return out;
}

/** Reads the data rows under a header until the first blank row. Blank pier-name cells inherit the row above. */
function readBlock(grid: Grid, header: number): { cells: Cell[]; index: number }[] {
  const out: { cells: Cell[]; index: number }[] = [];
  let lastName: Cell = null;
  for (let i = header + 1; i < grid.length; i++) {
    const row = grid[i] ?? [];
    if (row[1] === null || row[1] === undefined || row[1] === '') break;
    const name: Cell = row[0] ?? lastName;
    lastName = name;
    out.push({ cells: [name, ...row.slice(1)], index: i });
  }
  return out;
}

function toIp(c: Cell[]): IpPoint {
  return { name: String(c[1]), x: Number(c[2]), y: Number(c[3]), angleDeg: Number(c[4] ?? 0) };
}

function toBearing(c: Cell[]): Bearing {
  return {
    no: Number(c[1]),
    x: Number(c[2]),
    y: Number(c[3]),
    z: Number(c[4]),
    azimuthDeg: parseDms(String(c[5] ?? '')) ?? NaN,
    row: String(c[6]) as Row,
  };
}