have cli watch template file for changes (#91)

There was a bug previously where if this was run from a subdirectory, it
would always use the default remote template, since it wouldn't find the
local one where it expected. That's fixed in this PR.

Also, while it would detect a change in specified template file in the
Stoat config file, it wouldn't update automatically on changes within
the template itself, which would require restarting `stoat local`. This
wouldn't be that big of a deal except the one of the biggest reasons to
use local mode is to fine tune the template.

I created #90 to track
an issue that would make it trivial to locally iterate on templates
including non-`static_hosting` plugins. Maybe we could even have a copy
button on debug pages next to the merged configs that just gives you the
command to run locally to preview that exact config.

action/.husky/pre-commit

@@ -0,0 +1,5 @@
+#!/usr/bin/env sh
+. "$(dirname -- "$0")/_/husky.sh"
+
+cd action
+npx lint-staged

cli/.husky/pre-commit

@@ -0,0 +1,5 @@
+#!/usr/bin/env sh
+. "$(dirname -- "$0")/_/husky.sh"
+
+cd cli
+npx lint-staged

cli/package.json

@@ -1,6 +1,6 @@
 {
   "name": "stoat",
-  "version": "0.0.7",
+  "version": "0.0.8",
   "description": "Stoat CLI",
   "main": "src/index.ts",
   "bin": {
@@ -15,7 +15,7 @@
     "build": "ncc build --source-map --license licenses.txt",
     "local": "yarn build && npm i -g",
     "test": "jest --coverage",
-    "prepare": "cd .. && husky install action/.husky"
+    "prepare": "cd .. && husky install cli/.husky"
   },
   "repository": {
     "type": "git",

cli/src/helpers/local/configFileGlobal.ts

@@ -1,21 +1,84 @@
 import chalk from 'chalk';
-import fs from 'fs';
+import fs, { FSWatcher, readFileSync, WatchEventType } from 'fs';
 import { getTypedStoatConfig, readStoatConfig } from '../../../../action/src/configHelpers';
 import { StoatConfigSchema } from '../../../../action/src/schemas/stoatConfigSchema';
-import { getTemplate } from '../../../../action/src/templateHelpers';
+import { getRemoteDefaultTemplate, getTemplateFormat } from '../../../../action/src/templateHelpers';
 import { Template } from '../../../../action/src/types';
 
-import { findStoatConfigPath } from '../pathHelpers';
+import { findGitRoot, findStoatConfigPath } from '../pathHelpers';
+import path from 'path';
+
+// supports reading the local template from a subdirectory
+const getLocalTemplate = (commentTemplatePath: string): Template => {
+  const gitRoot = findGitRoot(process.cwd());
+  const fullCommentTemplateFile = path.join(gitRoot, commentTemplatePath);
+  const template = readFileSync(fullCommentTemplateFile).toString().trim();
+  const format = getTemplateFormat(fullCommentTemplateFile);
+  return { template, format };
+};
+
+// supports reading the local template from a subdirectory if necessary
+const getTemplate = async (ghOwner: string, ghRepo: string, stoatConfig: StoatConfigSchema): Promise<Template> => {
+  const { comment_template_file } = stoatConfig;
+  if (comment_template_file === undefined || comment_template_file === '') {
+    return getRemoteDefaultTemplate(ghOwner, ghRepo, stoatConfig);
+  }
+  return getLocalTemplate(comment_template_file);
+};
+
+interface TemplateWatcher {
+  commentTemplateFile: string;
+  fileWatcher: FSWatcher | undefined;
+}
+
+const getTemplateWatcher = async (
+  oldTemplateWatcher: TemplateWatcher,
+  commentTemplateFile: string
+): Promise<TemplateWatcher> => {
+  if (oldTemplateWatcher !== undefined) {
+    if (oldTemplateWatcher.commentTemplateFile === commentTemplateFile) {
+      return oldTemplateWatcher;
+    } else {
+      oldTemplateWatcher.fileWatcher?.close();
+    }
+  }
+
+  if (commentTemplateFile === undefined || commentTemplateFile === '') {
+    return {
+      commentTemplateFile: commentTemplateFile,
+      fileWatcher: undefined
+    };
+  }
+
+  const gitRoot = findGitRoot(process.cwd());
+  const absolutePath = path.join(gitRoot, commentTemplateFile);
+  const fileWatcher = fs.watch(absolutePath, async (eventType: WatchEventType) => {
+    if (eventType === 'change') {
+      try {
+        await ConfigFileGlobal.update();
+      } catch (e) {
+        // do nothing
+      }
+    }
+  });
+
+  return {
+    commentTemplateFile: commentTemplateFile,
+    fileWatcher: fileWatcher
+  };
+};
 
 export default class ConfigFileGlobal {
   private static schema: StoatConfigSchema | undefined;
   private static template: Template | undefined;
+  private static templateWatcher: TemplateWatcher;
 
   static async update() {
     const configFilePath = findStoatConfigPath(process.cwd());
     const stoatConfig = readStoatConfig(configFilePath);
     this.schema = await getTypedStoatConfig(stoatConfig);
     this.template = await getTemplate('', '', this.schema);
+    this.templateWatcher = await getTemplateWatcher(this.templateWatcher, stoatConfig.comment_template_file);
   }
 
   static getSchema() {