// Explorer and tab decorations from each repository's latest status (spec §5.1).

import * as vscode from "vscode";

import { Repository } from "./repository";

export class OxyDecorationProvider implements vscode.FileDecorationProvider, vscode.Disposable {

  private readonly emitter = new vscode.EventEmitter<vscode.Uri | vscode.Uri[] | undefined>();

  readonly onDidChangeFileDecorations = this.emitter.event;

  private readonly disposables: vscode.Disposable[] = [];

  constructor(private readonly repositories: () => Repository[]) {

    this.disposables.push(vscode.window.registerFileDecorationProvider(this), this.emitter);

  }

  /** Call when a repository's status changed; every decoration is recomputed. */

  refresh(): void {

    this.emitter.fire(undefined);

  }

  provideFileDecoration(uri: vscode.Uri): vscode.FileDecoration | undefined {

    if (!vscode.workspace.getConfiguration("oxygen").get<boolean>("decorations.enabled", true)) {

      return undefined;

    }

    for (const repo of this.repositories()) {

      const rel = repo.relativePath(uri);

      if (rel === undefined || !repo.status) {

        continue;

      }

      const entry = repo.status.paths.find((p) => p.path === rel);

      const conflict = repo.status.conflicts.find((c) => c.path === rel);

      if (conflict && !entry) {

        return new vscode.FileDecoration("‼", "conflict", new vscode.ThemeColor("oxygen.conflict"));

      }

      if (!entry) {

        // A directory containing changes gets a dot, like Git.

        if (repo.status.paths.some((p) => p.path.startsWith(rel + "/"))) {

          return new vscode.FileDecoration("•", "contains changes", new vscode.ThemeColor("oxygen.modified"));

        }

        continue;

      }

      const letters: Record<string, [string, string, string]> = {

        Added: ["A", "added", "oxygen.added"],

        Modified: ["M", "modified", "oxygen.modified"],

        Removed: ["D", "removed", "oxygen.removed"],

        Renamed: ["R", "renamed", "oxygen.renamed"],

        ModeChanged: ["X", "mode changed", "oxygen.modified"],

        ConflictEdited: ["‼", "conflict markers remain", "oxygen.conflict"],

        Resolved: ["✔", "conflict resolved", "oxygen.resolved"],

      };

      const [badge, tooltip, color] = letters[entry.status] ?? ["?", entry.status, "oxygen.modified"];

      const d = new vscode.FileDecoration(badge, tooltip, new vscode.ThemeColor(color));

      d.propagate = false;

      return d;

    }

    return undefined;

  }

  dispose(): void {

    for (const d of this.disposables) {

      d.dispose();

    }

  }

}