import { TreeDataProvider, TreeItem, TreeItemCollapsibleState } from 'vscode';
import { PijulChange, Repository } from '../pijul';
/**
 * The Changelog provider class is a Treedata provider which provides
 * TreeData for the `pijul.views.changelog` TreeView
 */
export class ChangelogViewProvider implements TreeDataProvider<PijulChange> {
  /**
     * Create a new Changelog provider instance
     * @param repository
     */
  constructor (
    private readonly repository: Repository
  ) {}
  /**
   * Convert a PijulChange into a TreeItem
   * @param element
   */
  getTreeItem (element: PijulChange): TreeItem | Thenable<TreeItem> {
    return {
      id: element.hash,
      label: element.message,
      description: element.hash,
      collapsibleState: TreeItemCollapsibleState.None
    };
  }
  /**
   * Get the children of the element or the root if no element is passed
   * @param element An optional element to get the children of
   */
  async getChildren (element?: PijulChange): Promise<PijulChange[] | null | undefined> {
    if (element) {
      // Changes don't have children
      // TODO: Implement change dependency tracking
      return null;
    } else {
      return await this.repository.getLog();
    }
  }
}

import { ChangelogViewProvider } from './views/changelog';

    this.disposables.push(window.registerTreeDataProvider('pijul.views.log', new ChangelogViewProvider(this.repository)));

  }
  /**
   * Use the `pijul log` command and parse the results
   * to generate a log of pijul changes.
   */
  async getLog (): Promise<PijulChange[]> {
    const changes: PijulChange[] = [];
    // TODO: Test how this scales to repositories with thousands or hundreds of thousands of changes
    const result = await this._pijul.exec(this.repositoryRoot, ['log']);
    const parsePattern = /Change\s([0-9A-Z]{53})\nAuthor:\s(.*)\nDate:\s(.*)\n\n.\s(.*)/gm;
    do {
      const match = parsePattern.exec(result.stdout);
      if (match === null) break;
      // Skip the first item, which is the entire match and select the individual capture groups
      const [, hash, author, date, message] = match;
      changes.push(new PijulChange(hash, message.trim(), author, date));
    } while (true);
    return changes;

}
/**
 * Class representing a single change in the repository.
 */
export class PijulChange {
  /**
   * Create a new instance of a Pijul change object.
   * @param hash The change hash
   * @param message The message for the change
   */
  constructor (
    public readonly hash: string,
    public readonly message: string,
    public readonly author: string,
    public readonly date: string
  ) {}

				}
			]
		},
		"views": {
			"scm": [
				{
					"id": "pijul.views.log",
					"name": "Changelog",
					"contextualTitle": "Pijul",
					"visibility": "visible"