From 67ee3a99187e95a329be8f13b15102681aa0324e Mon Sep 17 00:00:00 2001
From: Flaminia Cavallo <flaminiacavallo@Flaminias-MacBook-Pro.local>
Date: Thu, 18 Jul 2024 05:41:36 -0700
Subject: [PATCH] feat: add keyword navigability to transfer, happy path

---
 components/transfer/src/options-container.js  | 35 ++++---
 .../transfer/src/use-options-navigation.js    | 99 +++++++++++++++++++
 2 files changed, 123 insertions(+), 11 deletions(-)
 create mode 100644 components/transfer/src/use-options-navigation.js

diff --git a/components/transfer/src/options-container.js b/components/transfer/src/options-container.js
index ce3c60a55e..cd53a1fae2 100644
--- a/components/transfer/src/options-container.js
+++ b/components/transfer/src/options-container.js
@@ -1,8 +1,9 @@
 import { CircularLoader } from '@dhis2-ui/loader'
 import { spacers } from '@dhis2/ui-constants'
 import PropTypes from 'prop-types'
-import React, { Fragment, useRef } from 'react'
+import React, { useRef } from 'react'
 import { EndIntersectionDetector } from './end-intersection-detector.js'
+import { useOptionsNavigation } from './use-options-navigation.js'
 import { useResizeCounter } from './use-resize-counter.js'
 
 export const OptionsContainer = ({
@@ -19,7 +20,9 @@ export const OptionsContainer = ({
     toggleHighlightedOption,
 }) => {
     const optionsRef = useRef(null)
-    const wrapperRef = useRef(null)
+    const { wrapperRef, focusedOptionIndex, onOptionFocusedHandler } =
+        useOptionsNavigation(options)
+
     const resizeCounter = useResizeCounter(wrapperRef.current)
 
     return (
@@ -29,29 +32,39 @@ export const OptionsContainer = ({
                     <CircularLoader />
                 </div>
             )}
-
             <div className="container" data-test={dataTest} ref={optionsRef}>
                 <div className="content-container" ref={wrapperRef}>
                     {!options.length && emptyComponent}
-                    {options.map((option) => {
+                    {options.map((option, index) => {
                         const highlighted = !!highlightedOptions.find(
                             (highlightedSourceOption) =>
                                 highlightedSourceOption === option.value
                         )
 
+                        const optionsClickHandlers = getOptionClickHandlers(
+                            option,
+                            selectionHandler,
+                            toggleHighlightedOption
+                        )
+
+                        const isFocused =
+                            focusedOptionIndex !== null
+                                ? index === focusedOptionIndex
+                                : index === 0
+
                         return (
-                            <Fragment key={option.value}>
+                            <span
+                                key={option.value}
+                                tabIndex={isFocused ? 0 : -1}
+                                onFocus={() => onOptionFocusedHandler(index)}
+                            >
                                 {renderOption({
                                     ...option,
-                                    ...getOptionClickHandlers(
-                                        option,
-                                        selectionHandler,
-                                        toggleHighlightedOption
-                                    ),
+                                    ...optionsClickHandlers,
                                     highlighted,
                                     selected,
                                 })}
-                            </Fragment>
+                            </span>
                         )
                     })}
 
diff --git a/components/transfer/src/use-options-navigation.js b/components/transfer/src/use-options-navigation.js
new file mode 100644
index 0000000000..da1ecbeb72
--- /dev/null
+++ b/components/transfer/src/use-options-navigation.js
@@ -0,0 +1,99 @@
+import { useEffect, useRef, useState } from 'react'
+
+export const useOptionsNavigation = (options) => {
+    const wrapperRef = useRef(null)
+
+    const [focusedOptionIndex, setFocusedOptionIndex] = useState(null)
+
+    const handleKeyDown = (event) => {
+        switch (event.key) {
+            case 'ArrowUp':
+                event.preventDefault()
+                const newUpFocusIndex =
+                    focusedOptionIndex > 0
+                        ? focusedOptionIndex - 1
+                        : options.length - 1
+                setFocusedOptionIndex(newUpFocusIndex)
+                if (event.shiftKey) {
+                    // TODO: this is very ugly!
+                    const clickEvent = new MouseEvent('click', {
+                        bubbles: true,
+                        cancelable: true,
+                        shiftKey: true,
+                    })
+                    wrapperRef.current.children[
+                        newUpFocusIndex
+                    ].children[0].dispatchEvent(clickEvent)
+                }
+
+                break
+            case 'ArrowDown':
+                event.preventDefault()
+                const newDownFocusIndex =
+                    focusedOptionIndex >= options.length - 1
+                        ? 0
+                        : focusedOptionIndex + 1
+                setFocusedOptionIndex(newDownFocusIndex)
+                if (event.shiftKey) {
+                    // TODO: this is very ugly!
+                    const clickEvent = new MouseEvent('click', {
+                        bubbles: true,
+                        cancelable: true,
+                        shiftKey: true,
+                    })
+                    wrapperRef.current.children[
+                        newDownFocusIndex
+                    ].children[0].dispatchEvent(clickEvent)
+                }
+                break
+            case ' ':
+                event.preventDefault()
+                if (wrapperRef && wrapperRef.current.children.length > 0) {
+                    // TODO: this is ugly!
+                    wrapperRef.current.children[
+                        focusedOptionIndex
+                    ].children[0].click()
+                }
+                break
+            default:
+                break
+        }
+    }
+
+    const onOptionFocusedHandler = (optionIndex) => {
+        setFocusedOptionIndex(optionIndex)
+    }
+
+    useEffect(() => {
+        if (wrapperRef && wrapperRef.current.children.length > 0) {
+            if (
+                focusedOptionIndex !== null &&
+                wrapperRef.current.children[focusedOptionIndex]
+            ) {
+                wrapperRef.current.children[focusedOptionIndex]?.focus()
+            }
+        }
+    }, [wrapperRef, focusedOptionIndex, options])
+
+    useEffect(() => {
+        if (options && focusedOptionIndex >= options.length) {
+            setFocusedOptionIndex(null)
+        }
+    }, [options])
+
+    useEffect(() => {
+        if (wrapperRef?.current) {
+            wrapperRef.current.addEventListener('keydown', handleKeyDown)
+
+            return () => {
+                wrapperRef.current.removeEventListener('keydown', handleKeyDown)
+            }
+        }
+    }, [handleKeyDown, wrapperRef])
+
+    return {
+        wrapperRef,
+        onOptionFocusedHandler,
+        focusedOptionIndex,
+    }
+}