import { EOL } from "os";
import * as path from "path";
import * as fs from "fs";
import { Card } from "./Card";

export class MarkdownFile {
  private readonly metaStart = `[//]: # (Autogenerated Anki Metadata -- delete to disable sync)`;
  private readonly metaEnd = `[//]: # (End Autogenerated Anki Metadata)`;
  public uri: string;
  public cachedContent: string;
  public noteIds: number[] = [];
  public autoSend: boolean = false;

  constructor(uri: string) {
    this.uri = uri;
    this.cachedContent = "";
  }

  /**
   * 加载文件内容
   * @param content 文件内容
   */
  private loadContent(content: string) {
    this.noteIds = this.readNoteIds(content);
    this.autoSend = this.readAutoSendMeta(content);
    this.cachedContent = this.removeMeta(content.toString());
  }

  async load() {
    try {
      const content = (await fs.readFileSync(this.uri)).toString();
      this.loadContent(content);
    } catch (e) {
      throw e;
    }
  }

  public dirPath() {
    return path.dirname(this.uri);
  }

  private removeMeta(content: string) {
    const before = content.split(this.metaStart)[0];
    const endSplit = content.split(this.metaEnd);
    const after = endSplit.length > 1 ? endSplit[1] : "";
    // console.log(before);
    const removed = (before + after).trimEnd();
    return removed;
  }

  // TODO: make line breaks consistent with what's used in the file
  public async updateMeta(cards: Card[], autoSend: boolean) {
    this.autoSend = autoSend;
    const ids = cards.map((c) => c.noteId ?? 0);
    const metaBody = `[auto-send]: # (${this.autoSend ? "yes" : "no"})${EOL}[note-ids]: # (${ids.join(", ")})`;
    const meta = `${EOL}${EOL}${EOL}${this.metaStart}${EOL}${metaBody}${EOL}${this.metaEnd}${EOL}`;
    const content = this.cachedContent + meta;
    fs.writeFileSync(this.uri, content);
  }

  private readNoteIds(content: string): number[] {
    const re = RegExp(/\[note-ids\]: # \((.+)\)/);
    const matches = content.match(re);
    if (matches) {
      return matches[1].split(", ").map(Number); // what is this wizardry
    }
    return [];
  }

  private readAutoSendMeta(content: string): boolean {
    const re = RegExp(/\[auto-send\]: # \((.+)\)/);
    const matches = content.match(re);
    if (matches) {
      return matches[1] === "yes"; // what is this wizardry
    }
    return false;
  }

  public static fromActiveTextEditor(uri: string): MarkdownFile {
    let file = new MarkdownFile(uri);
    file.loadContent(fs.readFileSync(uri).toString() ?? "");
    return file;
  }
}