Press n or j to go to the next uncovered block, b, p or k for the previous block.
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25692x 25692x 25692x 2678x 2678x 25692x 25692x 25692x 25692x | /**
* Flowchart Loader
*
* Combines JSON definitions (`.flow.json`) with Mermaid content (`.mmd` or embedded)
* to create executable flowcharts, and manages runtime state as users walk through them.
*
* ## Key Functions
*
* - {@link loadFlowchart} - Merge JSON definition + Mermaid into ExecutableFlowchart
* - {@link initializeState} - Create initial runtime state from problem input
* - {@link advanceState} - Move to next node in the flowchart
* - {@link validateCheckpoint} - Check if user's answer is correct
* - {@link isDecisionCorrect} - Check if user chose the correct option
* - {@link formatProblemDisplay} - Format problem values for display
*
* ## Data Flow
*
* ```
* FlowchartDefinition + Mermaid content
* ↓
* loadFlowchart()
* ↓
* ExecutableFlowchart
* ↓
* initializeState(flowchart, problemInput)
* ↓
* FlowchartState
* ↓
* advanceState(), validateCheckpoint(), etc.
* ```
*
* ## Where to Find Mermaid Content
*
* **IMPORTANT**: Mermaid content is NOT always in separate `.mmd` files!
* Check `definitions/index.ts` first - many flowcharts embed their mermaid as constants.
*
* @see {@link ./README.md} for complete system documentation
* @module flowcharts/loader
*/
import type {
FlowchartDefinition,
ExecutableFlowchart,
ExecutableNode,
FlowchartState,
ProblemValue,
WorkingProblemHistoryEntry,
InstructionNode,
CheckpointNode,
TransformExpression,
StateSnapshot,
AnswerDefinition,
} from './schema'
import { computeEdgeId } from './schema'
import { parseMermaidFile, parseNodeContent } from './parser'
import { evaluate, type EvalContext } from './evaluator'
import { formatProblemDisplay, interpolateTemplate } from './formatting'
// =============================================================================
// Helpers
// =============================================================================
/**
* Escape special regex characters in a string.
*/
function escapeRegex(str: string): string {
return str.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')
}
// =============================================================================
// Re-exports for backwards compatibility
// =============================================================================
// Path Analysis
export type {
PathConstraint,
FlowchartPath,
FlowchartAnalysis,
} from './path-analysis'
export { enumerateAllPaths, analyzeFlowchart } from './path-analysis'
// Example Generation
export type {
GenerationConstraints,
GeneratedExample,
GenerationDiagnostics,
GenerationResult,
} from './example-generator'
export {
DEFAULT_CONSTRAINTS,
createSeededRandom,
generateDiverseExamples,
generateDiverseExamplesWithDiagnostics,
generateExamplesForPaths,
mergeAndFinalizeExamples,
} from './example-generator'
// Grid Dimensions
export type { GridDimensions } from './grid-dimensions'
export {
generatePathDescriptorFromPath,
inferGridDimensions,
inferGridDimensionsFromExamples,
} from './grid-dimensions'
// Formatting
export {
createMixedNumber,
formatMixedNumber,
formatProblemDisplay,
interpolateTemplate,
} from './formatting'
// =============================================================================
// Flowchart Loading
// =============================================================================
/**
* Load and merge a flowchart definition with its Mermaid content.
*
* This is the main entry point for creating an executable flowchart.
* It combines:
* - **JSON definition** (`.flow.json`): Node types, validation logic, variables
* - **Mermaid content**: Node display content, phases, visual structure
*
* ## Node Merging
*
* For each node ID:
* 1. If in JSON definition: uses that node type/behavior
* 2. If only in Mermaid: creates default `instruction` node
* 3. Content always comes from Mermaid (parsed via `parseNodeContent`)
*
* ## Common Usage
*
* ```typescript
* import { getFlowchart } from './definitions'
* import { loadFlowchart } from './loader'
*
* const data = getFlowchart('fraction-add-sub')
* const flowchart = await loadFlowchart(data.definition, data.mermaid)
* ```
*
* @param definition - The JSON definition from `.flow.json`
* @param mermaidContent - The Mermaid content (from `.mmd` file or embedded string)
* @returns Promise resolving to executable flowchart ready for FlowchartWalker
*/
export async function loadFlowchart(
definition: FlowchartDefinition,
mermaidContent: string
): Promise<ExecutableFlowchart> {
// Parse the Mermaid file
const mermaid = parseMermaidFile(mermaidContent)
// Track edge ID infills so we can inject them into the raw mermaid string
const edgeIdInfills: Array<{ from: string; to: string; label?: string; edgeId: string }> = []
// Infill missing edge IDs for decision edges
// For each decision node, if the edge doesn't have an explicit ID (starts with "edge_"),
// assign the computed ID based on {nodeId}_{optionValue}
for (const [nodeId, nodeDef] of Object.entries(definition.nodes)) {
if (nodeDef.type !== 'decision') continue
for (const option of nodeDef.options) {
const expectedEdgeId = computeEdgeId(nodeId, option.value)
// Find the edge from this node to the option's next node
const edge = mermaid.edges.find((e) => e.from === nodeId && e.to === option.next)
if (edge && edge.id.startsWith('edge_')) {
// Edge exists but has auto-generated ID - replace with computed ID
edge.id = expectedEdgeId
// Track for injection into raw mermaid
edgeIdInfills.push({
from: nodeId,
to: option.next,
label: edge.label,
edgeId: expectedEdgeId,
})
}
}
}
// Inject edge IDs into the raw mermaid string so SVG elements will have them
let modifiedMermaid = mermaidContent
for (const infill of edgeIdInfills) {
// Build regex to match this specific edge
// Pattern: FROM -->|"LABEL"| TO or FROM --> TO
const labelPart = infill.label ? `\\s*\\|"${escapeRegex(infill.label)}"\\|\\s*` : '\\s*'
const edgeRegex = new RegExp(
`(${escapeRegex(infill.from)})\\s+-->${labelPart}(${escapeRegex(infill.to)})`,
'g'
)
// Replace with: FROM EDGEID@-->|"LABEL"| TO
const replacement = infill.label
? `$1 ${infill.edgeId}@-->|"${infill.label}"| $2`
: `$1 ${infill.edgeId}@--> $2`
modifiedMermaid = modifiedMermaid.replace(edgeRegex, replacement)
}
// Build executable nodes by merging definition with parsed content
const nodes: Record<string, ExecutableNode> = {}
// Track missing nodes to detect fundamental mismatches
const missingNodes: string[] = []
for (const [nodeId, nodeDef] of Object.entries(definition.nodes)) {
const rawContent = mermaid.nodes[nodeId]
if (!rawContent) {
missingNodes.push(nodeId)
console.warn(`Node ${nodeId} defined in .flow.json but not found in .mmd file`)
}
nodes[nodeId] = {
id: nodeId,
definition: nodeDef,
content: rawContent
? parseNodeContent(rawContent)
: {
title: nodeId,
body: [],
raw: nodeId,
},
}
}
// Check for critical mismatches that will break rendering
const jsonNodeCount = Object.keys(definition.nodes).length
const missingRatio = missingNodes.length / jsonNodeCount
if (missingNodes.includes(definition.entryNode)) {
throw new Error(
`Entry node "${definition.entryNode}" is not defined in mermaid content. ` +
`The JSON and mermaid node IDs don't match. Mermaid has: ${Object.keys(mermaid.nodes).slice(0, 5).join(', ')}...`
)
}
if (missingRatio > 0.5) {
throw new Error(
`${missingNodes.length} of ${jsonNodeCount} nodes from JSON are missing in mermaid. ` +
`The JSON and mermaid node IDs don't match. ` +
`JSON expects: ${missingNodes.slice(0, 5).join(', ')}... ` +
`Mermaid has: ${Object.keys(mermaid.nodes).slice(0, 5).join(', ')}...`
)
}
// Also include nodes from Mermaid that aren't in the definition
// (they'll be treated as instruction nodes by default)
for (const [nodeId, rawContent] of Object.entries(mermaid.nodes)) {
if (!nodes[nodeId]) {
nodes[nodeId] = {
id: nodeId,
definition: { type: 'instruction', advance: 'tap' },
content: parseNodeContent(rawContent),
}
}
}
return {
definition,
mermaid,
rawMermaid: modifiedMermaid,
nodes,
}
}
// =============================================================================
// State Initialization
// =============================================================================
/**
* Initialize flowchart state from problem input.
*
* In the new transform model:
* - `values` starts with problem input and accumulates transform results
* - `computed` is populated from legacy `variables` section (for backwards compatibility)
* - `snapshots` tracks state at each node for trace visualization
*
* @param flowchart - The executable flowchart
* @param problemInput - User's problem input values
* @returns Initial state ready for walking
*/
export function initializeState(
flowchart: ExecutableFlowchart,
problemInput: Record<string, ProblemValue>
): FlowchartState {
// Start values with problem input (new transform model)
const values: Record<string, ProblemValue> = { ...problemInput }
// Create evaluation context with problem values
const context: EvalContext = {
problem: problemInput,
computed: {},
userState: {},
}
// LEGACY: Evaluate all variable init expressions for backwards compatibility
// This will be removed when all flowcharts migrate to transforms
const computed: Record<string, ProblemValue> = {}
const variables = flowchart.definition.variables || {}
for (const [varName, varDef] of Object.entries(variables)) {
try {
computed[varName] = evaluate(varDef.init, context)
// Update context so subsequent variables can reference earlier ones
context.computed[varName] = computed[varName]
// Also add to values for hybrid mode
values[varName] = computed[varName]
} catch (error) {
console.error(`Error evaluating init for variable ${varName}:`, error)
computed[varName] = null as unknown as ProblemValue
}
}
// Initialize working problem if configured
let workingProblem: string | undefined
const workingProblemHistory: WorkingProblemHistoryEntry[] = []
if (flowchart.definition.workingProblem) {
const wpContext: EvalContext = {
problem: problemInput,
computed,
userState: {},
}
try {
workingProblem = String(evaluate(flowchart.definition.workingProblem.initial, wpContext))
// Add initial state to history
workingProblemHistory.push({
value: workingProblem,
label: 'Start',
nodeId: 'initial',
})
} catch (error) {
console.error('Error evaluating initial working problem:', error)
}
}
// Create initial snapshot
const initialSnapshot: StateSnapshot = {
nodeId: 'initial',
nodeTitle: 'Start',
values: { ...values },
transforms: [],
workingProblem,
timestamp: Date.now(),
}
return {
problem: problemInput,
computed, // Legacy - for backwards compatibility
values, // New - accumulates transform results
userState: {},
currentNode: flowchart.definition.entryNode,
history: [],
startTime: Date.now(),
mistakes: 0,
workingProblem,
workingProblemHistory,
snapshots: [initialSnapshot],
hasError: false,
}
}
/**
* Create evaluation context from current state.
*
* Uses `values` (accumulated transforms) as `computed` for the evaluator.
* Falls back to legacy `computed` for backwards compatibility.
*/
export function createContextFromState(state: FlowchartState): EvalContext {
// Prefer values (new model) over computed (legacy)
// Merge both so expressions can reference either
const computed = { ...state.computed, ...state.values }
return {
problem: state.problem,
computed,
userState: state.userState,
}
}
/**
* Create evaluation context from accumulated values (for transforms).
*/
export function createContextFromValues(
problem: Record<string, ProblemValue>,
values: Record<string, ProblemValue>,
userState: Record<string, ProblemValue>
): EvalContext {
return {
problem,
computed: values, // In transform model, accumulated values are the "computed"
userState,
}
}
// =============================================================================
// Transform System (new unified computation model)
// =============================================================================
/**
* Apply node transforms to state.
*
* Transforms execute in order - later transforms can reference earlier ones.
* Results accumulate in state.values. Errors are logged but don't stop the walk.
*
* @param state - Current flowchart state
* @param nodeId - ID of the node whose transforms to apply
* @param flowchart - The executable flowchart
* @returns Updated state with transforms applied and new snapshot added
*/
export function applyTransforms(
state: FlowchartState,
nodeId: string,
flowchart: ExecutableFlowchart
): FlowchartState {
const node = flowchart.nodes[nodeId]
if (!node) return state
const transforms = node.definition.transform || []
// Apply transforms in order
const newValues = { ...state.values }
let hasError = state.hasError
const appliedTransforms: TransformExpression[] = []
for (const transform of transforms) {
try {
const context = createContextFromValues(state.problem, newValues, state.userState)
const result = evaluate(transform.expr, context)
newValues[transform.key] = result
appliedTransforms.push(transform)
} catch (error) {
console.error(`Transform error at ${nodeId}.${transform.key}:`, error)
newValues[transform.key] = null as unknown as ProblemValue
hasError = true
}
}
// Check for workingProblemUpdate on this node
let newWorkingProblem = state.workingProblem
let newWorkingProblemHistory = state.workingProblemHistory
const def = node.definition
let workingProblemUpdate: { result: string; label: string } | undefined
if (def.type === 'checkpoint') {
workingProblemUpdate = (def as CheckpointNode).workingProblemUpdate
} else if (def.type === 'instruction') {
workingProblemUpdate = (def as InstructionNode).workingProblemUpdate
}
if (workingProblemUpdate) {
try {
const context = createContextFromValues(state.problem, newValues, state.userState)
newWorkingProblem = String(evaluate(workingProblemUpdate.result, context))
newWorkingProblemHistory = [
...state.workingProblemHistory,
{
value: newWorkingProblem,
label: workingProblemUpdate.label,
nodeId,
},
]
} catch (error) {
console.error(`Working problem update error at ${nodeId}:`, error)
}
}
// Create snapshot after applying transforms (with updated working problem)
const snapshot: StateSnapshot = {
nodeId,
nodeTitle: node.content?.title || nodeId,
values: { ...newValues },
transforms: appliedTransforms,
workingProblem: newWorkingProblem,
timestamp: Date.now(),
}
return {
...state,
values: newValues,
computed: { ...state.computed, ...newValues }, // Keep computed in sync for backwards compat
hasError,
workingProblem: newWorkingProblem,
workingProblemHistory: newWorkingProblemHistory,
snapshots: [...state.snapshots, snapshot],
}
}
/**
* Extract the final answer from terminal state.
*
* Uses the flowchart's `answer` definition to:
* 1. Extract answer component values from accumulated state
* 2. Interpolate display templates (text, web, typst)
*
* Falls back to legacy `display.answer` if no `answer` definition exists.
*
* @param flowchart - The executable flowchart
* @param state - Terminal state with all transforms applied
* @returns Extracted answer values and formatted display strings
*/
export function extractAnswer(
flowchart: ExecutableFlowchart,
state: FlowchartState
): {
values: Record<string, ProblemValue>
display: { text: string; web: string; typst: string }
} {
const answerDef = flowchart.definition.answer
// If we have a new-style answer definition, use it
if (answerDef) {
const values: Record<string, ProblemValue> = {}
// Extract each answer component from accumulated state
for (const [name, ref] of Object.entries(answerDef.values)) {
values[name] = state.values[ref] ?? null
}
// Interpolate display templates
const allValues = { ...state.values, ...values }
return {
values,
display: {
text: interpolateTemplate(answerDef.display.text, allValues),
web: interpolateTemplate(answerDef.display.web || answerDef.display.text, allValues),
typst: interpolateTemplate(answerDef.display.typst || answerDef.display.text, allValues),
},
}
}
// LEGACY: Fall back to display.answer expression
if (flowchart.definition.display?.answer) {
try {
const context = createContextFromState(state)
const result = evaluate(flowchart.definition.display.answer, context)
const displayStr = String(result)
return {
values: { answer: result },
display: { text: displayStr, web: displayStr, typst: displayStr },
}
} catch (error) {
console.error('Error evaluating legacy display.answer:', error)
}
}
// No answer definition - return empty
return {
values: {},
display: { text: '', web: '', typst: '' },
}
}
/**
* Simulate walking through a flowchart to terminal state.
*
* This is THE canonical function for computing answers. All other code paths
* (worksheets, tests, example generation) should use this function.
*
* The walk:
* 1. Starts with problem input in state.values
* 2. Visits each node, applying transforms
* 3. Makes decisions based on accumulated state
* 4. Ends at terminal node with final answer in state.values
*
* @param flowchart - The executable flowchart
* @param input - Problem input values
* @returns Terminal state with all transforms applied and full snapshot history
*/
export function simulateWalk(
flowchart: ExecutableFlowchart,
input: Record<string, ProblemValue>
): FlowchartState {
let state = initializeState(flowchart, input)
const maxSteps = 100 // Safety limit to prevent infinite loops
const visited = new Set<string>()
for (let step = 0; step < maxSteps; step++) {
const nodeId = state.currentNode
if (!nodeId || visited.has(nodeId)) break
visited.add(nodeId)
const node = flowchart.nodes[nodeId]
if (!node) break
// Apply transforms for this node
state = applyTransforms(state, nodeId, flowchart)
// Check if terminal
if (node.definition.type === 'terminal') break
// Determine next node based on node type and accumulated state
const { nextNodeId, selectedOptionValue, edgeId, edgeIndex } = getNextNodeForSimulation(
flowchart,
state,
nodeId
)
if (!nextNodeId) break
// Update the last snapshot with decision/transition info
if (state.snapshots.length > 0) {
const lastSnapshot = state.snapshots[state.snapshots.length - 1]
const updatedSnapshot = {
...lastSnapshot,
// Include decision info if this was a decision node
...(selectedOptionValue ? { selectedOptionValue } : {}),
nextNodeId,
// Include both edge ID and index for reliable matching
edgeId,
edgeIndex,
}
state = {
...state,
snapshots: [...state.snapshots.slice(0, -1), updatedSnapshot],
}
}
state = { ...state, currentNode: nextNodeId }
}
return state
}
/**
* Result of determining next node during simulation.
*/
interface SimulationNextResult {
nextNodeId: string | null
/** For decision nodes: the option value that was selected (e.g., "MD" for multiply/divide) */
selectedOptionValue?: string
/** The unique ID of the edge taken (from ParsedEdge.id) for reliable edge matching */
edgeId?: string
/** The index of the edge in parse order (from ParsedEdge.index), for fallback matching */
edgeIndex?: number
}
/**
* Get next node during simulation (without user input).
* Used by simulateWalk to determine path based on expressions.
*/
function getNextNodeForSimulation(
flowchart: ExecutableFlowchart,
state: FlowchartState,
nodeId: string
): SimulationNextResult {
const node = flowchart.nodes[nodeId]
if (!node) return { nextNodeId: null }
const def = node.definition
const context = createContextFromState(state)
/**
* Find an edge by ID (preferred) or by from/to/label (fallback).
*
* Priority:
* 1. If edgeId is provided, match by ID directly (canonical method)
* 2. If from/to match a single edge, use that
* 3. If multiple edges exist between from/to, try to match by label
* 4. Fallback to first matching edge
*/
const findEdge = (from: string, to: string, edgeId?: string, edgeLabel?: string) => {
// Priority 1: Match by edge ID (canonical)
if (edgeId) {
const edgeById = flowchart.mermaid.edges.find((e) => e.id === edgeId)
if (edgeById) return edgeById
// If specified edgeId doesn't exist, fall through to from/to matching
}
// Priority 2+: Match by from/to
const matchingEdges = flowchart.mermaid.edges.filter((e) => e.from === from && e.to === to)
if (matchingEdges.length <= 1) return matchingEdges[0]
// Priority 3: Multiple edges - try to match by label
if (edgeLabel) {
const labelMatch = matchingEdges.find((e) => e.label === edgeLabel)
if (labelMatch) return labelMatch
}
// Priority 4: Fallback to first edge
return matchingEdges[0]
}
// Helper to build result with edge info
const buildResult = (
nextNodeId: string | null,
selectedOptionValue?: string,
explicitEdgeId?: string
): SimulationNextResult => {
if (!nextNodeId) return { nextNodeId: null }
const edge = findEdge(nodeId, nextNodeId, explicitEdgeId, selectedOptionValue)
return {
nextNodeId,
selectedOptionValue,
edgeId: edge?.id,
edgeIndex: edge?.index,
}
}
switch (def.type) {
case 'terminal':
return { nextNodeId: null }
case 'decision': {
// Check for skip condition
if (def.skipIf && def.skipTo) {
try {
if (evaluate(def.skipIf, context)) {
return buildResult(def.skipTo, '__skip__')
}
} catch {
// Continue to normal decision handling
}
}
// Determine path based on correctAnswer expression
// Use pathLabel for edge label matching (fallback), value for edge ID computation
const getEdgeLabel = (opt: (typeof def.options)[0]) => opt.pathLabel || opt.value
// Helper to build result from an option
// Edge ID is computed as {nodeId}_{optionValue} - mermaid must use this pattern
const buildFromOption = (opt: (typeof def.options)[0] | undefined) => {
if (!opt) return buildResult(null)
const edgeId = computeEdgeId(nodeId, opt.value)
return buildResult(opt.next, getEdgeLabel(opt), edgeId)
}
if (def.correctAnswer) {
try {
const correct = evaluate(def.correctAnswer, context)
if (typeof correct === 'boolean') {
const yesOption = def.options.find(
(o) => o.value === 'yes' || o.value.toLowerCase().includes('yes')
)
const noOption = def.options.find(
(o) => o.value === 'no' || o.value.toLowerCase().includes('no')
)
if (correct && yesOption) return buildFromOption(yesOption)
if (!correct && noOption) return buildFromOption(noOption)
// Fallback to index-based
return buildFromOption(correct ? def.options[0] : def.options[1])
}
// String match
const option = def.options.find((o) => o.value === String(correct))
if (option) return buildFromOption(option)
return buildFromOption(def.options[0])
} catch {
return buildFromOption(def.options[0])
}
}
return buildFromOption(def.options[0])
}
// biome-ignore lint/suspicious/noFallthroughSwitchClause: Intentional fallthrough to share instruction logic
case 'checkpoint': {
// Check for skip condition
if (def.skipIf && def.skipTo) {
try {
if (evaluate(def.skipIf, context)) {
return buildResult(def.skipTo)
}
} catch {
// Continue to normal handling
}
}
// Fall through to instruction logic
}
case 'instruction': {
if (def.next) return buildResult(def.next)
const edges = flowchart.definition.edges?.[nodeId]
if (edges && edges.length > 0) return buildResult(edges[0])
const mermaidEdges = flowchart.mermaid.edges.filter((e) => e.from === nodeId)
return buildResult(mermaidEdges[0]?.to ?? null)
}
case 'milestone':
case 'embellishment':
return buildResult(def.next)
default:
return { nextNodeId: null }
}
}
// =============================================================================
// Navigation
// =============================================================================
/**
* Get the next node ID based on current state and user action
*/
export function getNextNode(
flowchart: ExecutableFlowchart,
state: FlowchartState,
userChoice?: string
): string | null {
const currentNode = flowchart.nodes[state.currentNode]
if (!currentNode) return null
const def = currentNode.definition
// Handle based on node type
switch (def.type) {
case 'instruction': {
// Check for explicit next in definition
if (def.next) return def.next
// Fall back to edges from Mermaid
const edges = flowchart.definition.edges?.[state.currentNode]
if (edges && edges.length > 0) return edges[0]
// Or from parsed Mermaid
const mermaidEdges = flowchart.mermaid.edges.filter((e) => e.from === state.currentNode)
if (mermaidEdges.length > 0) return mermaidEdges[0].to
return null
}
case 'decision': {
// Check for skip condition
if (def.skipIf && def.skipTo) {
const context = createContextFromState(state)
try {
if (evaluate(def.skipIf, context)) {
return def.skipTo
}
} catch (error) {
console.error('Error evaluating skipIf:', error)
}
}
// User must have made a choice
if (!userChoice) return null
const option = def.options.find((o) => o.value === userChoice)
return option?.next ?? null
}
case 'checkpoint': {
// Check for explicit next
if (def.next) return def.next
// Fall back to edges
const edges = flowchart.definition.edges?.[state.currentNode]
if (edges && edges.length > 0) return edges[0]
const mermaidEdges = flowchart.mermaid.edges.filter((e) => e.from === state.currentNode)
if (mermaidEdges.length > 0) return mermaidEdges[0].to
return null
}
case 'milestone': {
return def.next
}
case 'embellishment': {
return def.next
}
case 'terminal': {
return null // End of flowchart
}
default:
return null
}
}
/**
* Check if a decision answer is correct
*/
export function isDecisionCorrect(
flowchart: ExecutableFlowchart,
state: FlowchartState,
nodeId: string,
userChoice: string
): boolean | null {
const node = flowchart.nodes[nodeId]
if (!node || node.definition.type !== 'decision') return null
const def = node.definition
if (!def.correctAnswer) return null // No validation defined
const context = createContextFromState(state)
try {
const correct = evaluate(def.correctAnswer, context)
// correctAnswer is an expression that evaluates to true/false
// If true, the "yes" option (or first option) is correct
// If false, the "no" option (or second option) is correct
if (typeof correct === 'boolean') {
// Find which option corresponds to the correct answer
const yesOption = def.options.find(
(o) => o.value === 'yes' || o.value.toLowerCase().includes('yes')
)
const noOption = def.options.find(
(o) => o.value === 'no' || o.value.toLowerCase().includes('no')
)
// If we found yes/no options, use them
if (yesOption || noOption) {
if (correct) {
return userChoice === yesOption?.value
} else {
return userChoice === noOption?.value
}
}
// Fallback: true = first option, false = second option
const correctOption = correct ? def.options[0] : def.options[1]
return userChoice === correctOption?.value
}
// If correctAnswer evaluates to a string, compare directly
return String(correct) === userChoice
} catch (error) {
console.error('Error evaluating correctAnswer:', error)
return null
}
}
/**
* Validate a checkpoint answer
*/
export function validateCheckpoint(
flowchart: ExecutableFlowchart,
state: FlowchartState,
nodeId: string,
userInput: number | string | [number, number]
): { correct: boolean; expected: ProblemValue | [number, number] } | null {
const node = flowchart.nodes[nodeId]
if (!node || node.definition.type !== 'checkpoint') return null
const def = node.definition
try {
// Handle two-numbers input type with array of expected expressions
if (def.inputType === 'two-numbers' && Array.isArray(def.expected)) {
// For two-numbers, we don't use `input` in expressions - we validate against problem values
const context: EvalContext = createContextFromState(state)
const expected1 = evaluate(def.expected[0], context) as number
const expected2 = evaluate(def.expected[1], context) as number
const expectedArray: [number, number] = [expected1, expected2]
if (!Array.isArray(userInput)) {
return { correct: false, expected: expectedArray }
}
const tolerance = def.tolerance ?? 0
const orderMatters = def.orderMatters !== false // default true
// Check if input matches expected (in order)
const matchesInOrder =
Math.abs(expected1 - userInput[0]) <= tolerance &&
Math.abs(expected2 - userInput[1]) <= tolerance
// If order doesn't matter, also check reversed
const matchesReversed =
!orderMatters &&
Math.abs(expected1 - userInput[1]) <= tolerance &&
Math.abs(expected2 - userInput[0]) <= tolerance
const correct = matchesInOrder || matchesReversed
return { correct, expected: expectedArray }
}
// Original single-value validation
const context: EvalContext = {
...createContextFromState(state),
input: userInput as ProblemValue,
}
const expected = evaluate(def.expected as string, context)
const tolerance = def.tolerance ?? 0
let correct: boolean
if (typeof expected === 'number' && typeof userInput === 'number') {
correct = Math.abs(expected - userInput) <= tolerance
} else {
correct = expected === userInput
}
return { correct, expected }
} catch (error) {
console.error('Error evaluating checkpoint expected value:', error)
return null
}
}
/**
* Apply state update after passing a checkpoint
*/
export function applyStateUpdate(
state: FlowchartState,
nodeId: string,
flowchart: ExecutableFlowchart,
userInput: ProblemValue
): FlowchartState {
const node = flowchart.nodes[nodeId]
if (!node || node.definition.type !== 'checkpoint') return state
const def = node.definition
if (!def.stateUpdate) return state
const newUserState = { ...state.userState }
const context: EvalContext = {
...createContextFromState(state),
input: userInput,
}
for (const [varName, expr] of Object.entries(def.stateUpdate)) {
try {
newUserState[varName] = evaluate(expr, context)
} catch (error) {
console.error(`Error evaluating stateUpdate for ${varName}:`, error)
}
}
return {
...state,
userState: newUserState,
}
}
/**
* Apply working problem transform after successfully completing a node.
* Returns updated state with new working problem value and history entry.
*/
export function applyWorkingProblemUpdate(
state: FlowchartState,
nodeId: string,
flowchart: ExecutableFlowchart,
userInput?: ProblemValue
): FlowchartState {
const node = flowchart.nodes[nodeId]
if (!node) return state
// Check if this node has a working problem update
const def = node.definition
let workingProblemUpdate: { result: string; label: string } | undefined
if (def.type === 'checkpoint') {
workingProblemUpdate = (def as CheckpointNode).workingProblemUpdate
} else if (def.type === 'instruction') {
workingProblemUpdate = (def as InstructionNode).workingProblemUpdate
}
if (!workingProblemUpdate) return state
const context: EvalContext = {
...createContextFromState(state),
input: userInput,
}
try {
const newWorkingProblem = String(evaluate(workingProblemUpdate.result, context))
return {
...state,
workingProblem: newWorkingProblem,
workingProblemHistory: [
...state.workingProblemHistory,
{
value: newWorkingProblem,
label: workingProblemUpdate.label,
nodeId,
},
],
}
} catch (error) {
console.error('Error applying working problem update:', error)
return state
}
}
// =============================================================================
// Progress Tracking
// =============================================================================
/**
* Advance to the next node and record history
*/
export function advanceState(
state: FlowchartState,
nextNode: string,
action: 'advance' | 'decision' | 'checkpoint' | 'skip',
userInput?: ProblemValue,
correct?: boolean
): FlowchartState {
return {
...state,
currentNode: nextNode,
history: [
...state.history,
{
node: state.currentNode,
action,
timestamp: Date.now(),
userInput,
correct,
},
],
mistakes: correct === false ? state.mistakes + 1 : state.mistakes,
}
}
/**
* Check if the current node is a terminal node
*/
export function isTerminal(flowchart: ExecutableFlowchart, nodeId: string): boolean {
const node = flowchart.nodes[nodeId]
return node?.definition.type === 'terminal'
}
// =============================================================================
// Path Complexity Analysis
// =============================================================================
export interface PathComplexity {
/** Total number of nodes in the path */
pathLength: number
/** Number of decision points in the path */
decisions: number
/** Number of checkpoints (user input required) */
checkpoints: number
/** List of node IDs in the path */
path: string[]
}
/**
* Simulate walking through a flowchart with given problem values to calculate path complexity.
* Returns the path length, number of decisions, and checkpoints.
*/
export function calculatePathComplexity(
flowchart: ExecutableFlowchart,
problemInput: Record<string, ProblemValue>
): PathComplexity {
// Initialize a temporary state to simulate the walk
const state = initializeState(flowchart, problemInput)
const context = createContextFromState(state)
const path: string[] = []
let decisions = 0
let checkpoints = 0
let currentNodeId = flowchart.definition.entryNode
const visited = new Set<string>()
// Walk the flowchart until we hit a terminal or loop
while (currentNodeId && !visited.has(currentNodeId)) {
visited.add(currentNodeId)
path.push(currentNodeId)
const node = flowchart.nodes[currentNodeId]
if (!node) break
const def = node.definition
switch (def.type) {
case 'terminal':
// End of path
return { pathLength: path.length, decisions, checkpoints, path }
case 'decision': {
// Check for skip condition first
if (def.skipIf && def.skipTo) {
try {
const shouldSkip = evaluate(def.skipIf, context)
if (shouldSkip) {
// Skip this decision entirely - don't count it
currentNodeId = def.skipTo
break
}
} catch {
// If skipIf evaluation fails, proceed to normal decision handling
}
}
decisions++
// Determine which path would be taken based on correctAnswer
if (def.correctAnswer) {
try {
const correct = evaluate(def.correctAnswer, context)
// Find the correct option
if (typeof correct === 'boolean') {
const yesOption = def.options.find(
(o) => o.value === 'yes' || o.value.toLowerCase().includes('yes')
)
const noOption = def.options.find(
(o) => o.value === 'no' || o.value.toLowerCase().includes('no')
)
if (correct && yesOption) {
currentNodeId = yesOption.next
} else if (!correct && noOption) {
currentNodeId = noOption.next
} else {
// Fallback to first/second option
currentNodeId = correct ? def.options[0]?.next : def.options[1]?.next
}
} else {
// correctAnswer is a specific value
const option = def.options.find((o) => o.value === String(correct))
currentNodeId = option?.next ?? def.options[0]?.next
}
} catch {
// If evaluation fails, take first option
currentNodeId = def.options[0]?.next
}
} else {
// No correctAnswer, take first option
currentNodeId = def.options[0]?.next
}
break
}
// biome-ignore lint/suspicious/noFallthroughSwitchClause: Intentional fallthrough to share instruction logic
case 'checkpoint': {
// Check for skip condition first
if (def.skipIf && def.skipTo) {
try {
const shouldSkip = evaluate(def.skipIf, context)
if (shouldSkip) {
// Skip this checkpoint entirely - don't count it
currentNodeId = def.skipTo
break
}
} catch {
// If skipIf evaluation fails, proceed to normal checkpoint handling
}
}
checkpoints++
// Fall through to instruction logic for next node
}
case 'instruction': {
if (def.next) {
currentNodeId = def.next
} else {
const edges = flowchart.definition.edges?.[currentNodeId]
if (edges && edges.length > 0) {
currentNodeId = edges[0]
} else {
const mermaidEdges = flowchart.mermaid.edges.filter((e) => e.from === currentNodeId)
currentNodeId = mermaidEdges[0]?.to
}
}
break
}
case 'milestone':
case 'embellishment':
currentNodeId = def.next
break
default:
currentNodeId = undefined as unknown as string
}
}
return { pathLength: path.length, decisions, checkpoints, path }
}
|