// 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();
    }
  }
}