feat: Support interpolation for outputFolder settings (#323)

Author: jdneo

Diff for: README.md

@@ -140,7 +140,7 @@
 | `leetcode.defaultLanguage` | Specify the default language used to solve the problem. Supported languages are: `bash`, `c`, `cpp`, `csharp`, `golang`, `java`, `javascript`, `kotlin`, `mysql`, `php`, `python`,`python3`,`ruby`,`rust`, `scala`,`swift`                                                                                                                                                         | `N/A`         |
 | `leetcode.useWsl`          | Specify whether to use WSL or not                                                                                                                                                                                                                                                                                                                                                  | `false`       |
 | `leetcode.endpoint`        | Specify the active endpoint. Supported endpoints are: `leetcode`, `leetcode-cn`                                                                                                                                                                                                                                                                                                    | `leetcode`    |
-| `leetcode.outputFolder`    | Specify the relative path to save the problem files. Besides using customized path, there are also several reserved words which can be used here: <ul><li>`${tag}`: Categorize the problem according to their tags.<li>`${language}`: Categorize the problem according to their language.</li><li>`${difficulty}`: Categorize the problem according to their difficulty.</li></ul> | N/A           |
+| `leetcode.outputFolder`    | Specify the relative path to save the problem files. Besides using customized path, there are also several reserved words which can be used here: <ul><li>`${tag}`: Categorize the problem according to their tags.<li>`${language}`: Categorize the problem according to their language.</li><li>`${difficulty}`: Categorize the problem according to their difficulty.</li></ul>For example: `problem-${tag}-${difficulty}` | N/A           |
 | `leetcode.enableStatusBar` | Specify whether the LeetCode status bar will be shown or not.                                                                                                                                                                                                                                                                                                                      | `true`        |
 | `leetcode.enableShortcuts` | Specify whether the submit and test shortcuts in editor or not.                                                                                                                                                                                                                                                                                                                    | `true`        |
 | `leetcode.enableSideMode`  | Specify whether `preview`, `solution` and `submission` tab should be grouped into the second editor column when solving a problem.                                                                                                                                                                                                                                                 | `true`        |

Diff for: docs/README_zh-CN.md

@@ -140,7 +140,7 @@
 | `leetcode.defaultLanguage` | 指定答题时使用的默认语言，可选语言有：`bash`, `c`, `cpp`, `csharp`, `golang`, `java`, `javascript`, `kotlin`, `mysql`, `php`, `python`,`python3`,`ruby`, `rust`, `scala`,`swift`                                                    | `N/A`      |
 | `leetcode.useWsl`          | 指定是否启用 WSL                                                                                                                                                                                                                    | `false`    |
 | `leetcode.endpoint`        | 指定使用的终端，可用终端有：`leetcode`, `leetcode-cn`                                                                                                                                                                               | `leetcode` |
-| `leetcode.outputFolder`    | 指定保存文件时所用的相对文件夹路径。除了用户自定义路径外，也可以使用保留项，包括：<ul><li>`${tag}`: 根据题目的类别进行分类。<li>`${language}`: 根据题目的语言进行分类。</li><li>`${difficulty}`: 根据题目的难度进行分类。</li></ul> | N/A        |
+| `leetcode.outputFolder`    | 指定保存文件时所用的相对文件夹路径。除了用户自定义路径外，也可以使用保留项，包括：<ul><li>`${tag}`: 根据题目的类别进行分类。<li>`${language}`: 根据题目的语言进行分类。</li><li>`${difficulty}`: 根据题目的难度进行分类。</li></ul>例如：`problem-${tag}-${difficulty}` | N/A        |
 | `leetcode.enableStatusBar` | 指定是否在 VS Code 下方显示插件状态栏。                                                                                                                                                                                             | `true`     |
 | `leetcode.enableShortcuts` | 指定是否在 VS Code 编辑文件下方显示提交和测试的快捷按钮。                                                                                                                                                                           | `true`     |
 | `leetcode.enableSideMode`  | 指定在解决一道题时，是否将`问题预览`、`高票答案`与`提交结果`窗口集中在编辑器的第二栏。                                                                                                                                              | `true`     |

Diff for: src/commands/show.ts

@@ -107,14 +107,12 @@ async function showProblemInternal(node: IProblem): Promise<void> {
         const leetCodeConfig: vscode.WorkspaceConfiguration = vscode.workspace.getConfiguration("leetcode");
         let outDir: string = await selectWorkspaceFolder();
         let relativePath: string = (leetCodeConfig.get<string>("outputFolder", "")).trim();
-        const matchResult: RegExpMatchArray | null = relativePath.match(/\$\{(.*?)\}/);
-        if (matchResult) {
-            const resolvedPath: string | undefined = await resolveRelativePath(matchResult[1].toLocaleLowerCase(), node, language);
-            if (!resolvedPath) {
+        if (relativePath) {
+            relativePath = await resolveRelativePath(relativePath, node, language);
+            if (!relativePath) {
                 leetCodeChannel.appendLine("Showing problem canceled by user.");
                 return;
             }
-            relativePath = resolvedPath;
         }
 
         outDir = path.join(outDir, relativePath);
@@ -166,27 +164,39 @@ function parseProblemDecorator(state: ProblemState, locked: boolean): string {
     }
 }
 
-async function resolveRelativePath(value: string, node: IProblem, selectedLanguage: string): Promise<string | undefined> {
-    switch (value) {
-        case "tag":
-            if (node.tags.length === 1) {
-                return node.tags[0];
-            }
-            return await vscode.window.showQuickPick(
-                node.tags,
-                {
-                    matchOnDetail: true,
-                    placeHolder: "Multiple tags available, please select one",
-                    ignoreFocusOut: true,
-                },
-            );
-        case "language":
-            return selectedLanguage;
-        case "difficulty":
-            return node.difficulty;
-        default:
-            const errorMsg: string = `The config '${value}' is not supported.`;
-            leetCodeChannel.appendLine(errorMsg);
-            throw new Error(errorMsg);
+async function resolveRelativePath(relativePath: string, node: IProblem, selectedLanguage: string): Promise<string> {
+    if (/\$\{tag\}/i.test(relativePath)) {
+        const tag: string | undefined = await resolveTagForProblem(node);
+        if (!tag) {
+            return "";
+        }
+        relativePath = relativePath.replace(/\$\{tag\}/ig, tag);
     }
+
+    relativePath = relativePath.replace(/\$\{language\}/ig, selectedLanguage);
+    relativePath = relativePath.replace(/\$\{difficulty\}/ig, node.difficulty.toLocaleLowerCase());
+
+    // Check if there is any unsupported configuration
+    const matchResult: RegExpMatchArray | null = relativePath.match(/\$\{(.*?)\}/);
+    if (matchResult && matchResult.length >= 1) {
+        const errorMsg: string = `The config '${matchResult[1]}' is not supported.`;
+        leetCodeChannel.appendLine(errorMsg);
+        throw new Error(errorMsg);
+    }
+
+    return relativePath;
+}
+
+async function resolveTagForProblem(problem: IProblem): Promise<string | undefined> {
+    if (problem.tags.length === 1) {
+        return problem.tags[0];
+    }
+    return await vscode.window.showQuickPick(
+        problem.tags,
+        {
+            matchOnDetail: true,
+            placeHolder: "Multiple tags available, please select one",
+            ignoreFocusOut: true,
+        },
+    );
 }