Add disableing controls

src/components/PlayerControl.js

@@ -2,7 +2,7 @@ import React from 'react'
 
 import { useSelector, useDispatch } from 'react-redux'
 import {
-  hasNextSegment,
+  selectHasNextSegment,
   selectRunning,
   selectInterval
 } from '../store/selectors'
@@ -14,7 +14,7 @@ import { IconButton } from '../styles/IconButton'
 export const PlayerControl = () => {
   const dispatch = useDispatch()
   const running = useSelector(selectRunning)
-  const hasNext = useSelector(hasNextSegment)
+  const hasNext = useSelector(selectHasNextSegment)
   const interval = useSelector(selectInterval)
 
   useInterval(

src/components/SegmentControl.js

@@ -1,5 +1,5 @@
 import React from 'react'
-import { useDispatch } from 'react-redux'
+import { useDispatch, useSelector } from 'react-redux'
 import {
   FiSkipBack,
   FiSkipForward,
@@ -9,6 +9,13 @@ import {
 
 import { IconButton } from '../styles/IconButton'
 
+import {
+  selectHasNextSentence,
+  selectHasPrevSentence,
+  selectHasPrevWord,
+  selectHasNextWord
+} from '../store/selectors'
+
 import {
   incrementSentence,
   incrementWord,
@@ -18,28 +25,37 @@ import {
 
 export const SegmentControl = ({ children }) => {
   const dispatch = useDispatch()
+  const hasPrevSentence = useSelector(selectHasPrevSentence)
+  const hasNextSentence = useSelector(selectHasNextSentence)
+  const hasPrevWord = useSelector(selectHasPrevWord)
+  const hasNextWord = useSelector(selectHasNextWord)
+
   return (
     <>
       <IconButton
         title="Previous Sentence"
         onClick={() => dispatch(decrementSentence())}
         Icon={FiRewind}
+        disabled={!hasPrevSentence}
       />
       <IconButton
         Icon={FiSkipBack}
         title="Previous Word"
         onClick={() => dispatch(decrementWord())}
+        disabled={!hasPrevWord}
       />
       {children}
       <IconButton
         Icon={FiSkipForward}
         title="Next Word"
         onClick={() => dispatch(incrementWord())}
+        disabled={!hasNextWord}
       />
       <IconButton
         Icon={FiFastForward}
         title="Next Sentence"
         onClick={() => dispatch(incrementSentence())}
+        disabled={!hasNextSentence}
       />
     </>
   )

src/store/reducer.js

@@ -1,16 +1,19 @@
 import {
-  selectNextWord,
-  selectNextSentence,
-  selectPrevWord,
-  selectPrevSentence
+  safeSelectNextWord,
+  safeSelectNextSentence,
+  safeSelectPrevWord,
+  safeSelectPrevSentence,
+  safeSelectNextSegment,
+  safeSelectPrevSegment
 } from './selectors'
 
 export const initialState = {
   originalText: 'Sample Text',
   curIdx: 0,
-  maxLength: 5,
+  maxLength: 8,
   isPlaying: false,
   wpm: 300,
+  offset: -15,
   running: false
 }
 
@@ -21,12 +24,12 @@ const reducer = {
     curIdx: 0
   }),
   SET_CURRENT_SEGMENT: (state, payload) => ({ ...state, curIdx: payload }),
-  INC_SEGMENT: state => ({ ...state, curIdx: state.curIdx + 1 }),
-  DEC_SEGMENT: state => ({ ...state, curIdx: state.curIdx - 1 }),
-  INC_WORD: state => ({ ...state, curIdx: selectNextWord(state) }),
-  DEC_WORD: state => ({ ...state, curIdx: selectPrevWord(state) }),
-  INC_SENTENCE: state => ({ ...state, curIdx: selectNextSentence(state) }),
-  DEC_SENTENCE: state => ({ ...state, curIdx: selectPrevSentence(state) }),
+  INC_SEGMENT: state => ({ ...state, curIdx: safeSelectNextSegment(state) }),
+  DEC_SEGMENT: state => ({ ...state, curIdx: safeSelectPrevSegment(state) }),
+  INC_WORD: state => ({ ...state, curIdx: safeSelectNextWord(state) }),
+  DEC_WORD: state => ({ ...state, curIdx: safeSelectPrevWord(state) }),
+  INC_SENTENCE: state => ({ ...state, curIdx: safeSelectNextSentence(state) }),
+  DEC_SENTENCE: state => ({ ...state, curIdx: safeSelectPrevSentence(state) }),
   SET_MAX_LENGTH: (state, payload) => ({
     ...state,
     maxLength: payload,

src/store/selectors.js

@@ -4,6 +4,9 @@ import { parseText } from '../lib/parseText'
 import { getNextBiggerNumber, getNextSmallerNumber } from '../lib/array-util.js'
 import { pivotize } from '../lib/pivotize'
 
+// util
+const notNull = val => val != null
+
 // parsedText selectors
 
 export const selectMaxLength = state => state.maxLength
@@ -19,6 +22,8 @@ export const selectSegments = createSelector(
   parsedText => parsedText.segments
 )
 
+// segments
+
 export const selectCurrentSegmentIndex = state => state.curIdx
 
 export const selectCurrentSegment = createSelector(
@@ -32,12 +37,32 @@ export const selectPivotizedSegment = createSelector(
   pivotize
 )
 
-export const hasNextSegment = createSelector(
+export const selectNextSegment = state => state.curIdx + 1
+export const selectPrevSegment = state => state.curIdx - 1
+
+export const selectHasNextSegment = createSelector(
   selectSegments,
   selectCurrentSegmentIndex,
-  (segments, idx) => {
-    return idx < segments.length - 1
-  }
+  (segments, idx) => idx < segments.length - 1
+)
+
+export const selectHasPrevSegment = createSelector(
+  selectCurrentSegmentIndex,
+  idx => idx > 0
+)
+
+export const safeSelectNextSegment = createSelector(
+  selectHasNextSegment,
+  selectNextSegment,
+  selectCurrentSegmentIndex,
+  (has, segment, idx) => (has ? segment : idx)
+)
+
+export const safeSelectPrevSegment = createSelector(
+  selectHasPrevSegment,
+  selectPrevSegment,
+  selectCurrentSegmentIndex,
+  (has, segment, idx) => (has ? segment : idx)
 )
 
 // next/prev words
@@ -56,11 +81,26 @@ export const selectNextWord = createSelector(
 export const selectPrevWord = createSelector(
   selectWords,
   selectCurrentSegmentIndex,
-  (words, curSegment) => getNextSmallerNumber(curSegment, words)
+  (words, curSegment) => {
+    console.log(words, curSegment, getNextSmallerNumber(curSegment, words))
+    return getNextSmallerNumber(curSegment, words)
+  }
 )
 
-export const selectHasNextWord = createSelector(selectNextWord, Boolean)
-export const selectHasPrevWord = createSelector(selectPrevWord, Boolean)
+export const selectHasNextWord = createSelector(selectNextWord, notNull)
+export const selectHasPrevWord = createSelector(selectPrevWord, notNull)
+export const safeSelectNextWord = createSelector(
+  selectHasNextWord,
+  selectNextWord,
+  selectCurrentSegmentIndex,
+  (has, word, idx) => (has ? word : idx)
+)
+export const safeSelectPrevWord = createSelector(
+  selectHasPrevWord,
+  selectPrevWord,
+  selectCurrentSegmentIndex,
+  (has, word, idx) => (has ? word : idx)
+)
 
 // next/prev sentences
 
@@ -81,8 +121,24 @@ export const selectPrevSentence = createSelector(
   (sentences, curSegment) => getNextSmallerNumber(curSegment, sentences)
 )
 
-export const selectHasNextSentence = createSelector(selectNextSentence, Boolean)
-export const selectHasPrevSentence = createSelector(selectPrevSentence, Boolean)
+export const selectHasNextSentence = createSelector(selectNextSentence, notNull)
+export const selectHasPrevSentence = createSelector(selectPrevSentence, notNull)
+
+export const safeSelectNextSentence = createSelector(
+  selectHasNextSentence,
+  selectNextSentence,
+  selectCurrentSegmentIndex,
+  (has, sentence, idx) => (has ? sentence : idx)
+)
+
+export const safeSelectPrevSentence = createSelector(
+  selectHasPrevSentence,
+  selectPrevSentence,
+  selectCurrentSegmentIndex,
+  (has, sentence, idx) => (has ? sentence : idx)
+)
+
+// options
 
 export const selectWpm = state => state.wpm
 export const selectInterval = createSelector(selectWpm, wpm => 60000 / wpm)