import { HttpClient } from '@angular/common/http';
import { Injectable, NgZone } from '@angular/core';
import { OhayoConfigService, OhayoXlsxConfig, LazyResult, LazyService } from '@ohayo/util';
import { saveAs } from 'file-saver';
import { NzSafeAny } from 'ng-zorro-antd/core/types';
import { XlsxExportOptions, XlsxExportResult, XlsxExportSheet } from './xlsx.types';

declare var XLSX: any;

@Injectable({ providedIn: 'root' })
export class XlsxService {
  private cog: OhayoXlsxConfig;
  constructor(private http: HttpClient, private lazy: LazyService, configSrv: OhayoConfigService, private ngZone: NgZone) {
    this.cog = configSrv.merge('xlsx', {
      url: '//cdn.bootcss.com/xlsx/0.15.6/xlsx.full.min.js',
      modules: [],
    })!;
  }

  private init(): Promise<LazyResult[]> {
    return typeof XLSX !== 'undefined' ? Promise.resolve([]) : this.lazy.load([this.cog.url!].concat(this.cog.modules!));
  }

  private read(data: NzSafeAny, options: { type: 'array' | 'binary' }): { [key: string]: NzSafeAny[][] } {
    const ret: NzSafeAny = {};
    this.ngZone.runOutsideAngular(() => {
      const wb = XLSX.read(data, options);
      wb.SheetNames.forEach((name: string) => {
        const sheet: NzSafeAny = wb.Sheets[name];
        ret[name] = XLSX.utils.sheet_to_json(sheet, { header: 1 });
      });
    });
    return ret;
  }

  /**
   * 导入Excel并输出JSON，支持 `<input type="file">`、URL 形式
   * @param rABS 加载数据方式 `readAsBinaryString` （默认） 或 `readAsArrayBuffer`，[更多细节](http://t.cn/R3n63A0)
   */
  import(
    fileOrUrl: File | string,
    rABS: 'readAsBinaryString' | 'readAsArrayBuffer' = 'readAsBinaryString',
  ): Promise<{ [key: string]: any[][] }> {
    return new Promise<{ [key: string]: any[][] }>((resolve, reject) => {
      this.init()
        .then(() => {
          // from url
          if (typeof fileOrUrl === 'string') {
            this.http.request('GET', fileOrUrl, { responseType: 'arraybuffer' }).subscribe(
              (res: ArrayBuffer) => {
                this.ngZone.run(() => resolve(this.read(new Uint8Array(res), { type: 'array' })));
              },
              (err: any) => {
                reject(err);
              },
            );
            return;
          }
          // from file
          const reader: FileReader = new FileReader();
          reader.onload = (e: any) => {
            this.ngZone.run(() => resolve(this.read(e.target.result, { type: 'binary' })));
          };
          reader[rABS](fileOrUrl);
        })
        .catch(() => reject(`Unable to load xlsx.js`));
    });
  }

  async export(options: XlsxExportOptions): Promise<XlsxExportResult> {
    return new Promise<XlsxExportResult>((resolve, reject) => {
      this.init()
        .then(() => {
          this.ngZone.runOutsideAngular(() => {
            const wb: any = XLSX.utils.book_new();
            if (Array.isArray(options.sheets)) {
              (options.sheets as XlsxExportSheet[]).forEach((value: XlsxExportSheet, index: number) => {
                const ws: any = XLSX.utils.aoa_to_sheet(value.data);
                XLSX.utils.book_append_sheet(wb, ws, value.name || `Sheet${index + 1}`);
              });
            } else {
              wb.SheetNames = Object.keys(options.sheets);
              wb.Sheets = options.sheets;
            }

            if (options.callback) options.callback(wb);

            const wbout: ArrayBuffer = XLSX.write(wb, {
              bookType: 'xlsx',
              bookSST: false,
              type: 'array',
              ...options.opts,
            });
            const filename = options.filename || 'export.xlsx';
            saveAs(new Blob([wbout], { type: 'application/octet-stream' }), filename);

            resolve({ filename, wb });
          });
        })
        .catch(err => reject(err));
    });
  }

  /**
   * 数据转符号名
   * - `1` => `A`
   * - `27` => `AA`
   * - `703` => `AAA`
   */
  numberToSchema(val: number): string {
    const startCode = 'A'.charCodeAt(0);
    let res = '';

    do {
      --val;
      res = String.fromCharCode(startCode + (val % 26)) + res;
      val = (val / 26) >> 0;
    } while (val > 0);

    return res;
  }
}