replace external dependencies with standard library

.gitignore

@@ -1,2 +1,4 @@
 .idea/
 cov_profile/
+
+*.review.yaml

deno.json

@@ -1,19 +1,17 @@
 {
   "tasks": {
-    "run": "deno run --allow-read --allow-write --allow-env=NODE_ENV src/cli.ts",
+    "run": "deno run --allow-read --allow-write --allow-env=NODE_ENV,TERM src/cli.ts",
     "migrate": "deno run --allow-read --allow-write src/tools/migrate.ts",
     "test": "./scripts/test.sh",
     "test-lcov": "./scripts/test-lcov.sh"
   },
   "imports": {
-    "@cliffy/prompt": "https://deno.land/x/cliffy@v0.25.2/prompt/input.ts",
     "@std/assert": "jsr:@std/assert@^1.0.1",
     "@std/cli": "jsr:@std/cli@^1.0.0",
     "@std/csv": "jsr:@std/csv@^0.224.3",
     "@std/fmt": "jsr:@std/fmt@^0.225.6",
     "@std/path": "jsr:@std/path@^1.0.2",
     "@std/yaml": "jsr:@std/yaml@^0.224.3",
-    "dayjs": "npm:dayjs@^1.11.12",
     "fastest-levenshtein": "npm:fastest-levenshtein@^1.0.16",
     "supermemo": "npm:supermemo@^2.0.17"
   }

src/cli.ts

@@ -1,9 +1,10 @@
-import { Input } from "@cliffy/prompt";
 import { parseArgs } from "@std/cli/parse-args";
 import { green, red, yellow } from "@std/fmt/colors";
-import { loadDeck } from "./deck.ts";
 import { shuffle } from "./collections.ts";
+import { loadDeck } from "./deck.ts";
+import { Input } from "./input.ts";
 import { ratio } from "./levenshtein.ts";
+import { deriveReviewfile } from "./pathutil.ts";
 import {
   loadReviews,
   newReviewItem,
@@ -12,7 +13,6 @@ import {
   saveReviews,
   score2grade,
 } from "./review.ts";
-import { deriveReviewfile } from "./pathutil.ts";
 
 const args = parseArgs(Deno.args) as {
   deck: string;
@@ -91,7 +91,7 @@ console.log("To review:", dueDateItems.length);
 for (const review of dueDateItems) {
   console.log(review.front);
 
-  let answer: string = await Input.prompt("");
+  let answer: string = await Input.question("> ");
 
   // trip and replace all multi-space characters with just one
   answer = answer.replaceAll(" +", " ").trim();

src/input.ts

@@ -0,0 +1,4 @@
+import * as readline from "node:readline/promises";
+import { stdin as input, stdout as output } from "node:process";
+
+export const Input = readline.createInterface({ input, output });

src/review.ts

@@ -1,4 +1,3 @@
-import dayjs from "dayjs";
 import { supermemo, SuperMemoGrade, SuperMemoItem } from "supermemo";
 import { Card } from "./card.ts";
 import { parse as parseYaml, stringify as stringifyYaml } from "@std/yaml";
@@ -42,12 +41,14 @@ async function saveReviews(
 }
 
 function newReviewItem(flashcard: Card): ReviewItem {
+  const now = new Date(Date.now());
+
   return {
     ...flashcard,
     interval: 0,
     repetition: 0,
     efactor: 2.5,
-    dueDate: dayjs(Date.now()).toISOString(),
+    dueDate: now.toISOString(),
   };
 }
 
@@ -78,11 +79,18 @@ function score2grade(score: number): SuperMemoGrade {
 function practice(reviewItem: ReviewItem, grade: SuperMemoGrade): ReviewItem {
   const { interval, repetition, efactor } = supermemo(reviewItem, grade);
 
-  const dueDate = dayjs(Date.now()).add(interval, "day").toISOString();
+  const now = new Date(Date.now());
+
+  const dueDate = addDays(now, interval).toISOString();
 
   return { ...reviewItem, interval, repetition, efactor, dueDate };
 }
 
+function addDays(date: Date, days: number): Date {
+  date.setDate(date.getDate() + days);
+  return date;
+}
+
 export type { ReviewItem };
 
 export { loadReviews, newReviewItem, practice, saveReviews, score2grade };