elk/composables/timeline.ts
2023-01-08 14:21:09 +08:00

50 lines
1.7 KiB
TypeScript

import type { mastodon } from 'masto'
const maxDistance = 10
const maxSteps = 1000
// Checks if (b) is a reply to (a)
function areStatusesConsecutive(a: mastodon.v1.Status, b: mastodon.v1.Status) {
const inReplyToId = b.inReplyToId ?? b.reblog?.inReplyToId
return !!inReplyToId && (inReplyToId === a.reblog?.id || inReplyToId === a.id)
}
export function reorderedTimeline(items: mastodon.v1.Status[]) {
let steps = 0
const newItems = [...items]
for (let i = items.length - 1; i > 0; i--) {
for (let k = 1; k <= maxDistance && i - k >= 0; k++) {
// Prevent infinite loops
steps++
if (steps > maxSteps)
return newItems
// Check if the [i-k] item is a reply to the [i] item
// This means that they are in the wrong order
if (areStatusesConsecutive(newItems[i], newItems[i - k])) {
const item = newItems.splice(i, 1)[0]
newItems.splice(i - k, 0, item) // insert older item before the newer one
k = 0
}
else if (k > 1) {
// Check if the [i] item is a reply to the [i-k] item
// This means that they are in the correct order but there are posts between them
if (areStatusesConsecutive(newItems[i - k], newItems[i])) {
// If the next statuses are already ordered, move them all
let j = i
for (; j < items.length - 1; j++) {
if (!areStatusesConsecutive(newItems[j], newItems[j + 1]))
break
}
const orderedCount = j - i + 1
const itemsToMove = newItems.splice(i, orderedCount)
// insert older item after the newer one
newItems.splice(i - k + 1, 0, ...itemsToMove)
k = 0
}
}
}
}
return newItems
}