From 5dbd16878546886cae5b56b67de6185bfbae0d07 Mon Sep 17 00:00:00 2001
From: Elizabeth Hunt <elizabeth@simponic.xyz>
Date: Thu, 1 Aug 2024 09:15:33 -0700
Subject: add arg parser

---
 src/args.ts | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 93 insertions(+), 4 deletions(-)

(limited to 'src/args.ts')

diff --git a/src/args.ts b/src/args.ts
index 31fa2ee..d233c18 100644
--- a/src/args.ts
+++ b/src/args.ts
@@ -1,9 +1,98 @@
+import * as E from "fp-ts/lib/Either";
+import * as O from "fp-ts/lib/Option";
+import * as R from "fp-ts/lib/ReadonlyArray";
+import { pipe } from "fp-ts/lib/function";
+import { parseTestType, type TestType } from "./canary";
+
 export interface Args {
-  testFile: string;
+  readonly testsFile: string;
+  readonly testName: O.Option<string>;
+  readonly testType: O.Option<TestType>;
+}
+
+interface ArgsBuilder {
+  readonly testsFile: O.Option<string>;
+  readonly testName: O.Option<string>;
+  readonly testType: O.Option<string>;
 }
 
-export const parseArgs = (argv: string[]): Args => {
-  const useful = argv.slice(2); // skip bun path and script path
+type ArgsBuilderField = (arg: string) => (builder: ArgsBuilder) => ArgsBuilder;
+
+const createArgsBuilder = (): ArgsBuilder => ({
+  testsFile: O.none,
+  testName: O.none,
+  testType: O.none,
+});
+
+const withTestsFile: ArgsBuilderField = (testsFile) => (builder) => ({
+  ...builder,
+  testsFile: O.some(testsFile),
+});
+
+const withTestName: ArgsBuilderField = (testName) => (builder) => ({
+  ...builder,
+  testName: O.some(testName),
+});
+
+const withTestType: ArgsBuilderField = (testType) => (builder) => ({
+  ...builder,
+  testType: O.some(testType),
+});
+
+const flagBuilders: Record<string, ArgsBuilderField> = {
+  "--tests-file": withTestsFile,
+  "--test-name": withTestName,
+  "--test-type": withTestType,
+};
+
+const buildArgs = (builder: ArgsBuilder): E.Either<string, Args> => {
+  if (O.isNone(builder.testsFile)) {
+    return E.left("please specify a test file");
+  }
+
+  const testType = pipe(builder.testType, O.flatMap(parseTestType));
+  if (O.isSome(builder.testType) && !O.isSome(testType)) {
+    return E.left("bad test type " + builder.testType.value);
+  }
+
+  return E.right({
+    testsFile: builder.testsFile.value,
+    testName: builder.testName,
+    testType,
+  });
+};
+
+const isArg = (arg: string) => arg.startsWith("--") && arg in flagBuilders;
+
+export const parseArgs = (argv: string[]): E.Either<string, Args> => {
+  if (argv.length < 2) return E.left("bad argv");
+
+  const useful = argv.slice(2);
+  const argApplicators = pipe(
+    useful,
+    R.mapWithIndex((i, arg) => (isArg(arg) ? O.some({ arg, i }) : O.none)),
+    R.compact,
+    R.map(({ arg, i }) =>
+      pipe(
+        O.fromNullable(flagBuilders[arg]),
+        O.bindTo("argApplicator"),
+        O.bind("val", () =>
+          pipe(
+            O.fromNullable(useful.at(i + 1)),
+            O.flatMap((argValue) =>
+              isArg(argValue) ? O.none : O.some(argValue),
+            ),
+          ),
+        ),
+        O.map(({ val, argApplicator }) => argApplicator(val)),
+      ),
+    ),
+  );
 
-  const flags = useful.map((x, i) => x.startsWith("--") && i);
+  return pipe(
+    argApplicators,
+    R.compact,
+    R.reduce(createArgsBuilder(), (builder, applyArgTo) => applyArgTo(builder)),
+    buildArgs,
+  );
 };
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