1 files changed, 122 insertions, 0 deletions
diff --git a/deno/service-manager/template.ts b/deno/service-manager/template.ts
new file mode 100644
index 0000000..0b043a1
--- /dev/null
+++ b/deno/service-manager/template.ts
@@ -0,0 +1,122 @@
+import { dirname, join, relative } from "@std/path";
+import { copySync, existsSync, walkSync } from "@std/fs";
+import { parse } from "@std/dotenv";
+import { distinct } from "@std/collections";
+// @ts-types="npm:@types/mustache"
+import Mustache from "mustache";
+
+Mustache.tags = ["@@", "@@"];
+Mustache.escape = (value) => String(value);
+
+function getVariableKeys(original: string): string[] {
+  return distinct(
+    Mustache.parse(original)
+      .filter(function (v) {
+        return v[0] === "name";
+      })
+      .map(function (v) {
+        return v[1];
+      }),
+  );
+}
+
+export function loadVariables(files: string[]): Record<string, string> {
+  const vars: Record<string, string> = {};
+  for (const file of files) {
+    const text = Deno.readTextFileSync(file);
+    for (const [key, valueText] of Object.entries(parse(text))) {
+      getVariableKeys(valueText).forEach((name) => {
+        if (!(name in vars)) {
+          throw new Error(
+            `Variable ${name} is not defined yet, perhaps due to typos or wrong order.`,
+          );
+        }
+      });
+      vars[key] = Mustache.render(valueText, vars);
+    }
+  }
+  return vars;
+}
+
+const TEMPLATE_FILE_EXT = ".template";
+
+export class TemplateDir {
+  templates: { path: string; ext: string; text: string; vars: string[] }[] = [];
+  plains: { path: string }[] = [];
+
+  constructor(public dir: string) {
+    console.log("Scanning template dir:");
+    Array.from(
+      walkSync(dir, { includeDirs: false, followSymlinks: true }),
+    ).forEach(({ path }) => {
+      path = relative(this.dir, path);
+      if (path.endsWith(TEMPLATE_FILE_EXT)) {
+        console.log(`  (template) ${path}`);
+        const text = Deno.readTextFileSync(join(dir, path));
+        this.templates.push({
+          path,
+          ext: TEMPLATE_FILE_EXT,
+          text,
+          vars: getVariableKeys(text),
+        });
+      } else {
+        console.log(`  (plain) ${path}`);
+        this.plains.push({ path });
+      }
+    });
+    console.log("Done scanning template dir.");
+  }
+
+  allNeededVars() {
+    return distinct(this.templates.flatMap((t) => t.vars));
+  }
+
+  generate(vars: Record<string, string>, generatedDir?: string) {
+    console.log(
+      `Generating, template dir: ${this.dir}, generated dir: ${generatedDir ?? "[dry-run]"}:`,
+    );
+
+    const undefinedVars = this.allNeededVars().filter((v) => !(v in vars));
+    if (undefinedVars.length !== 0) {
+      throw new Error(
+        `Needed variables are not defined: ${undefinedVars.join(", ")}`,
+      );
+    }
+
+    if (generatedDir != null) {
+      if (existsSync(generatedDir)) {
+        console.log(` delete old generated dir ${generatedDir}`);
+        Deno.removeSync(generatedDir, { recursive: true });
+      }
+
+      for (const file of this.plains) {
+        const [source, destination] = [
+          join(this.dir, file.path),
+          join(generatedDir, file.path),
+        ];
+        console.log(`  copy ${source} to ${destination} ...`);
+        Deno.mkdirSync(dirname(destination), { recursive: true });
+        copySync(source, destination);
+      }
+      for (const file of this.templates) {
+        const [source, destination] = [
+          join(this.dir, file.path),
+          join(generatedDir, file.path.slice(0, -file.ext.length)),
+        ];
+        console.log(`  generate ${source} to ${destination} ...`);
+        const rendered = Mustache.render(file.text, vars);
+        Deno.mkdirSync(dirname(destination), { recursive: true });
+        Deno.writeTextFileSync(destination, rendered);
+      }
+    }
+    console.log(`Done generating.`);
+  }
+
+  generateWithVariableFiles(varFiles: string[], generatedDir?: string) {
+    console.log("Scanning defined vars:");
+    const vars = loadVariables(varFiles);
+    Object.keys(vars).forEach((name) => console.log(`  ${name}`));
+    console.log("Done scanning defined vars.");
+    this.generate(vars, generatedDir);
+  }
+}