Feature predefined and environment variables in config (#655)

* Support workspaceFolder variable in configPath

Adds support for predefined VS Code variable "${workspaceFolder}" to setting "configPath" in MPE.

This allows for configuring MPE per-workspace if needed.

fixes #625

* Support environment variables in configPath

setting "configPath" does not support environment variables.

Extended to support windows style %ENV_VAR% as well as bash style ${ENV_VAR} and $ENV_VAR environment variables

fixes #625

* Refactoring to allow any string to resolve variables

Implementation only applies to configPath and polutes the code.

Refactors that code and extracts it into a PathResolver class.

fixes #625

src/config.ts

@@ -7,6 +7,7 @@ import {
   RevealJsTheme,
 } from "@shd101wyy/mume/out/src/markdown-engine-config";
 import * as vscode from "vscode";
+import { PathResolver } from "./utils/path-resolver";
 
 export class MarkdownPreviewEnhancedConfig implements MarkdownEngineConfig {
   public static getCurrentConfig() {
@@ -68,6 +69,8 @@ export class MarkdownPreviewEnhancedConfig implements MarkdownEngineConfig {
     );
 
     this.configPath = (config.get<string>("configPath") || "").trim();
+    this.configPath = PathResolver.resolvePath(this.configPath);
+
     this.usePandocParser = config.get<boolean>("usePandocParser");
     this.breakOnSingleNewLine = config.get<boolean>("breakOnSingleNewLine");
     this.enableTypographer = config.get<boolean>("enableTypographer");

src/utils/path-resolver.ts

@@ -0,0 +1,85 @@
+import * as vscode from "vscode";
+
+export class PathResolver {
+  /**
+   * resolve placeholder in string
+   */
+  public static resolvePath(path: string) {
+    let result = path;
+
+    // guard: empty
+    if (result.trim() == "") {
+      return path;
+    }
+
+    // resolve VS Code predefined variables
+    result = this.resolve_vscode_predefined_variables(result);
+
+    // resolve environment variables
+    result = this.resolve_environment_variable(result);
+
+    // done
+    return result;
+  }
+
+  /**
+   * resolve vscode predefined variables in string
+   */
+  public static resolve_vscode_predefined_variables(path: string) {
+    let result = path;
+
+    // ... workspaceFolder
+    result = this.resolve_vscode_predefined_variable_workspaceFolder(result);
+
+    // done
+    return result;
+  }
+
+  /**
+   * resolve vscode predefined variables in string
+   */
+  public static resolve_vscode_predefined_variable_workspaceFolder(
+    path: string,
+  ) {
+    let result = path;
+
+    // guard: nothing to do
+    if (!path.includes("${workspaceFolder}")) return path;
+
+    // guard: error
+    if (vscode.workspace.workspaceFolders == undefined) {
+      vscode.window.showErrorMessage(
+        "Working folder not found, open a folder an try again",
+      );
+
+      return path;
+    }
+
+    // determine workspace folder
+    // let workspaceFolder = vscode.workspace.workspaceFolders[0].uri.path ;
+    let workspaceFolder = vscode.workspace.workspaceFolders[0].uri.fsPath;
+
+    // replace in configPath
+    result = path.replace("${workspaceFolder}", workspaceFolder);
+
+    // log
+    //vscode.window.showInformationMessage(
+    //  `Resolved '${this}' to '${result}'`
+    //);
+
+    // done
+    return result;
+  }
+
+  /**
+   * resolve environment variables in string
+   */
+  public static resolve_environment_variable(path: string) {
+    // try to replace environment variables for windows (%ENV_VAR%) and bash (${ENV_VAR} as well as $ENV_VAR)
+    // line as suggested in https://stackoverflow.com/questions/21363912/how-to-resolve-a-path-that-includes-an-environment-variable-in-nodejs
+    return path.replace(
+      /%([A-Z_]+[A-Z0-9_]*)%|\$([A-Z_]+[A-Z0-9_]*)|\${([A-Z0-9_]*)}/gi,
+      (_, windows, bash1, bash2) => process.env[windows || bash1 || bash2],
+    );
+  }
+}