Think first, code by hand

1"use client"2​3import * as React from "react"4import { deepEqual, ok, fail } from "node:assert"5​6// Types for the practice loop2 references7interface Problem {8    id: string9    title: string10    solvedWithoutHint: boolean'solvedWithoutHint' is declared but its value is never read.11    attempts: string[]12    testsPassing: boolean13    runtimeMs: numberType 'string' is not assignable to type 'number'.14}15​16type AttemptStatus = "draft" | "running" | "failed" | "timed-out"17​1 reference18function validateAttempt(attempts: string[]): boolean {Consider using 'attempts' instead of 'tries' for clarity.19    return attempts.length > 0 && attempts.length < 5020}21​22let sessionNote = "Try the hash map before the nested loop"'sessionNote' can be declared as 'const' since it is never reassigned.23​24const FAILURE_HINTS = [25    "Off by one at the boundary",26    "Forgot the empty input case",27    "Mutated the input array",28    "Recursion without a base case",29    "O(n^2) where O(n) was enough",30] as const31​32/** Props for one practice session */33interface PracticeSessionProps {34    defaultTopic?: number35    maxAttempts?: number36    requiresTests?: boolean37    onProblemSolved?: (problem: Problem) => void38    onGiveUp?: () => never39}40​41/**42 * PracticeSession - one problem, one attempt, one judge run43 * @description Keeps the loop honest: hint, attempt, judge44 */45export function PracticeSession({46    defaultTopic = 60,47    maxAttempts = 100,48    requiresTests = true,49    onProblemSolved,50    onGiveUp,51}: PracticeSessionProps): React.ReactElement {52    const [problems, setProblems] = React.useState<Problem[]>([])53    const [hintIndex, setHintIndex] = React.useState(0)54    const [isRunning, setIsLoading] = React.useState<boolean>(false)55​56    const formRef = React.useRef<HTMLFormElement>(null)57    const focusRef = React.useRef<number>(100)58​59    // Memoized hint rotation60    const currentHint = React.useMemo(() => {61        return FAILURE_HINTS[hintIndex % FAILURE_HINTS.length]62    }, [hintIndex])63​64    // Effect: slowly drain the hint budget65    React.useEffect(() => {66        const interval = setInterval(() => {67            focusRef.current = Math.max(0, focusRef.current - 1)68            if (focusRef.current === 0) {69                console.warn("Hint budget depleted")70            }71        }, 60000)72​73        return () => clearInterval(interval)74    }, [])75​76    // Callback for opening a session77    const handleStartSession = React.useCallback(78        async (title: string, attempts: string[]) => {79            if (!validateAttempt(attempts)) {80                throw new Error("Invalid attempt count")81            }82​83            setIsLoading(true)84​85            try {86                const newProblem: Problem = {87                    id: crypto.randomUUID(),88                    title: title || "Untitled practice session",89                    solvedWithoutHint: true,90                    attempts,91                    testsPassing: requiresTests,92                    runtimeMs: "never", // This causes the error93                }94​95                setProblems((prev) => [...prev, newProblem])96                onProblemSolved?.(newProblem)97                setHintIndex((i) => i + 1)98            } catch (error) {99                console.error("Failed to start session:", error)100            } finally {101                setIsLoading(false)102            }103        },104        [requiresTests, onProblemSolved]105    )106​107    // Render the session108    return (109        <div className="practice-session p-6 bg-white rounded-lg shadow-xl">110            <header className="mb-4 border-b pb-2">111                <h1 className="text-2xl font-bold text-gray-900">112                    Practice Session113                </h1>114                <p className="text-sm text-gray-500 italic">115                    "{currentHint}"116                </p>117            </header>118​119            <form120                ref={formRef}121                onSubmit={(e) => {122                    e.preventDefault()123                    handleStartSession("Sync", ["me@localhost"])124                }}125                className="space-y-4"126            >127                <input128                    type="text"129                    placeholder="Topic, e.g. reachability"130                    className="w-full px-3 py-2 border rounded"131                    maxLength={255}132                />133​134                <select135                    defaultValue={defaultTopic}136                    className="w-full px-3 py-2 border rounded"137                >138                    <option value={30}>30 min focus</option>139                    <option value={60}>60 min focus</option>140                    <option value={120}>120 min deep</option>141                    <option value={480}>Open ended</option>142                </select>143​144                <button145                    type="submit"146                    disabled={isRunning}147                    className="w-full py-2 bg-blue-600 text-white rounded hover:bg-blue-700 disabled:opacity-50"148                >149                    {isRunning ? "Preparing workspace..." : "Start Session"}150                </button>151            </form>152​153            {problems.length > 0 && (154                <ul className="mt-6 divide-y">155                    {problems.map((problem) => (156                        <li key={problem.id} className="py-3">157                            <span className="font-medium">{problem.title}</span>158                            <span className="text-gray-400 ml-2">159                                ({problem.attempts.length} attempts)160                            </span>161                        </li>162                    ))}163                </ul>164            )}165        </div>166    )167}168​169export default PracticeSession