import {
  ParsingOptions,
  read,
  Sheet2JSONOpts,
  utils,
  type WorkSheet,
} from "../deps/sheetjs.ts";
import { merge } from "../core/utils/object.ts";
import loadText from "../core/loaders/text.ts";
import loadBinary from "../core/loaders/binary.ts";

import type Site from "../core/site.ts";
import type { RawData } from "../core/file.ts";

export interface Options {
  /** File extensions to load */
  extensions?: string[];

  /** Return the first sheet only or all sheets if the document have more */
  sheets?: "first" | "auto";

  /**
   * Parsing options passed to Sheetjs
   * @see https://docs.sheetjs.com/docs/api/parse-options#parsing-options
   */
  options?: ParsingOptions;

  /**
   * Options passed to `utils.sheet_to_json`
   * @see https://docs.sheetjs.com/docs/api/utilities/array#array-output
   */
  outputOptions?: Sheet2JSONOpts;
}

export const defaults: Options = {
  extensions: [".xlsx", ".numbers", ".csv"],
  sheets: "auto",
  options: {},
  outputOptions: {
    UTC: true,
  },
};

/**
 * A plugin to load Excel, Numbers, and CSV files
 * @see https://lume.land/plugins/sheets/
 */
export function sheets(userOptions?: Options) {
  const options = merge(defaults, userOptions);

  function sheetToJson(sheet: WorkSheet) {
    return utils.sheet_to_json(sheet, options.outputOptions);
  }

  async function loader(path: string): Promise<RawData> {
    const type = path.endsWith(".csv") ? "string" : "array";
    const { content } = type === "string"
      ? await loadText(path)
      : await loadBinary(path);

    const wb = read(content, {
      ...options.options,
      type,
    });

    // Return only the first sheet
    if (options.sheets === "first" || wb.SheetNames.length === 1) {
      const sheet = wb.Sheets[wb.SheetNames[0]];
      return sheetToJson(sheet) as unknown as RawData;
    }

    // Return all sheets by name
    const sheets: Record<string, unknown[]> = {};
    wb.SheetNames.forEach((name) => {
      sheets[name] = sheetToJson(wb.Sheets[name]);
    });

    return { content: sheets };
  }

  return (site: Site) => {
    site.loadData(options.extensions, loader);

    // Ignore temp files generated by Numbers (https://github.com/lumeland/lume/issues/245)
    if (options.extensions.includes(".numbers")) {
      site.options.watcher.ignore.push((path) =>
        !!path.match(/\.numbers\.[\w-]+$/)
      );
    }
  };
}

export default sheets;