import * as fs from 'fs';
import * as path from 'path';
import { execSync } from 'child_process';

import type { ProductData } from './types';
import { normalizeValue } from './utils';

type ExcelRow = Record<string, unknown>;
export type ExcelMatch = { rows: ExcelRow[]; units: Record<string, string> };

const EXCEL_SOURCE_FILES = [
  path.join(process.cwd(), 'data/excel/high-voltage.xlsx'),
  path.join(process.cwd(), 'data/excel/medium-voltage-KM.xlsx'),
  path.join(process.cwd(), 'data/excel/low-voltage-KM.xlsx'),
  path.join(process.cwd(), 'data/excel/solar-cables.xlsx'),
];

let EXCEL_INDEX: Map<string, ExcelMatch> | null = null;

export function normalizeExcelKey(value: string): string {
  return String(value || '')
    .toUpperCase()
    .replace(/-\d+$/g, '')
    .replace(/[^A-Z0-9]+/g, '');
}

function loadExcelRows(filePath: string): ExcelRow[] {
  const out = execSync(`npx -y xlsx-cli -j "${filePath}"`, {
    encoding: 'utf8',
    stdio: ['ignore', 'pipe', 'ignore'],
  });
  const trimmed = out.trim();
  const jsonStart = trimmed.indexOf('[');
  if (jsonStart < 0) return [];
  const jsonText = trimmed.slice(jsonStart);
  try {
    return JSON.parse(jsonText) as ExcelRow[];
  } catch {
    return [];
  }
}

export function getExcelIndex(): Map<string, ExcelMatch> {
  if (EXCEL_INDEX) return EXCEL_INDEX;
  const idx = new Map<string, ExcelMatch>();

  for (const file of EXCEL_SOURCE_FILES) {
    if (!fs.existsSync(file)) continue;
    const rows = loadExcelRows(file);

    const unitsRow = rows.find(r => r && r['Part Number'] === 'Units') || null;
    const units: Record<string, string> = {};
    if (unitsRow) {
      for (const [k, v] of Object.entries(unitsRow)) {
        if (k === 'Part Number') continue;
        const unit = normalizeValue(String(v ?? ''));
        if (unit) units[k] = unit;
      }
    }

    for (const r of rows) {
      const pn = r?.['Part Number'];
      if (!pn || pn === 'Units') continue;
      const key = normalizeExcelKey(String(pn));
      if (!key) continue;
      const cur = idx.get(key);
      if (!cur) {
        idx.set(key, { rows: [r], units });
      } else {
        cur.rows.push(r);
        if (Object.keys(cur.units).length < Object.keys(units).length) cur.units = units;
      }
    }
  }

  EXCEL_INDEX = idx;
  return idx;
}

export function findExcelForProduct(product: ProductData): ExcelMatch | null {
  const idx = getExcelIndex();
  const candidates = [
    product.name,
    product.slug ? product.slug.replace(/-\d+$/g, '') : '',
    product.sku,
    product.translationKey,
  ].filter(Boolean) as string[];

  for (const c of candidates) {
    const key = normalizeExcelKey(c);
    const match = idx.get(key);
    if (match && match.rows.length) return match;
  }
  return null;
}