windmill/frontend/src/lib/components/home/treeViewUtils.ts

import type { ListableApp, Script, Flow, ListableRawApp, ListableResource } from '$lib/gen'
type TableItem<T, U extends 'script' | 'flow' | 'app' | 'raw_app' | 'agent'> = T & {
	canWrite: boolean
	marked?: string
	type?: U
	time?: number
	starred?: boolean
	// Server fetch ordinal (see ItemsList) — the tree sorts leaves by it to preserve
	// the endpoint's order rather than re-deriving it.
	ord?: number
}

type TableScript = TableItem<Script, 'script'>
type TableFlow = TableItem<Flow, 'flow'>
type TableApp = TableItem<ListableApp, 'app'>
type TableRawApp = TableItem<ListableRawApp, 'raw_app'>
/** A saved agent: an `ai_agent` resource the home page lists as a kind of its own. Its
 *  description stands in as the summary every other kind carries. */
type TableAgent = TableItem<ListableResource & { summary?: string }, 'agent'>

export type ItemType = TableScript | TableFlow | TableApp | TableRawApp | TableAgent

export interface FolderItem {
	folderName: string
	items: (ItemType | FolderItem)[]
}

export type UserItem = {
	username: string
	items: (ItemType | FolderItem)[]
}

/**
 * Where an item belongs: its owner, folder, and the name it is filtered and searched by.
 * A draft-only item is parked at a generated `u/<you>/draft_<uuid>` but names the path it
 * will deploy to, and that is what the row shows and what the server lists, filters and
 * counts it under — so every categorization has to follow it. `path` stays the storage
 * identity that the editor link and the row key resolve.
 */
export function effectivePath(item: {
	path: string
	draft_only?: boolean | null
	draft_path?: string | null
}): string {
	return (item.draft_only && item.draft_path) || item.path
}

/** Rows loaded under a node, counting nested subfolders' rows rather than the subfolder
 *  as one child — what "N items are on screen here" means to someone reading the tree. */
export function countLeaves(node: FolderItem | UserItem): number {
	let n = 0
	for (const child of node.items) n += 'items' in child ? countLeaves(child) : 1
	return n
}

function insertItemInFolder(
	root: (ItemType | FolderItem | UserItem)[],
	item: ItemType,
	path: string[]
) {
	let currentLevel = root

	path.forEach((folderName, index) => {
		if (index === path.length - 1) {
			currentLevel.push(item)
		} else {
			let folder = currentLevel.find((f) => 'folderName' in f && f.folderName === folderName) as
				| FolderItem
				| undefined

			if (!folder) {
				folder = { folderName: folderName, items: [] }
				currentLevel.push(folder)
			}
			currentLevel = folder.items
		}
	})
}

// Default leaf ordering when the caller doesn't impose one: starred first, then
// most recently modified. Folders/users always sort alphabetically regardless.
const defaultLeafCompare = (a: ItemType, b: ItemType): number => {
	if (a.starred && !b.starred) return -1
	if (!a.starred && b.starred) return 1
	return getModifiedAt(b) - getModifiedAt(a)
}

export function groupItems(
	items: ItemType[] | undefined,
	leafCompare: (a: ItemType, b: ItemType) => number = defaultLeafCompare,
	// Folders/users have only a name, so the sort key is always name; `groupDesc`
	// flips its direction (Z-A) to follow a name-descending sort, like a file explorer
	// reordering folders when you reverse the name sort. Time sorts pass false (no
	// folder timestamp to order by, so folders stay alphabetical).
	groupDesc: boolean = false
): (ItemType | FolderItem | UserItem)[] {
	if (!items) {
		return []
	}

	const root: (ItemType | FolderItem | UserItem)[] = []

	items.forEach((item) => {
		const pathSplit = effectivePath(item).split('/')
		if (pathSplit[0] === 'u') {
			const username = pathSplit[1]
			let userItem = root.find((f): f is UserItem => 'username' in f && f.username === username) as
				| UserItem
				| undefined

			if (!userItem) {
				userItem = { username, items: [] }
				root.push(userItem)
			}

			if (pathSplit.length > 2) {
				insertItemInFolder(userItem.items, item, pathSplit.slice(2))
			} else {
				userItem.items.push(item)
			}
		} else if (pathSplit[0] === 'f') {
			insertItemInFolder(root, item, pathSplit.slice(1))
		} else {
			// Any other owner (e.g. a schedule at `g/<group>/...`) has no node kind, so it
			// stays a top-level leaf rather than vanishing from the tree.
			root.push(item)
		}
	})

	const dir = groupDesc ? -1 : 1
	// Users, then folders, then ungrouped leaves regardless of direction; only the name
	// comparison within users and folders follows `groupDesc`.
	const rank = (n: ItemType | FolderItem | UserItem) =>
		'username' in n ? 0 : 'folderName' in n ? 1 : 2
	root.sort((a, b) => {
		const r = rank(a) - rank(b)
		if (r !== 0) return r
		if ('username' in a && 'username' in b) return dir * a.username.localeCompare(b.username)
		if ('folderName' in a && 'folderName' in b)
			return dir * a.folderName.localeCompare(b.folderName)
		return 0
	})

	sortGroup(root, leafCompare, dir)

	return root
}

function sortGroup(
	group: (ItemType | FolderItem | UserItem)[],
	leafCompare: (a: ItemType, b: ItemType) => number,
	dir: number = 1
) {
	group.forEach((item) => {
		if ('items' in item) {
			item.items.sort((a, b) => {
				// Nested subfolders sort before leaves and follow the group direction.
				if ('folderName' in a && 'folderName' in b) {
					return dir * a.folderName.localeCompare(b.folderName)
				}
				if ('folderName' in a) {
					return -1
				}
				if ('folderName' in b) {
					return 1
				}
				if (isItemType(a) && isItemType(b)) {
					return leafCompare(a, b)
				}
				return 0
			})

			sortGroup(item.items, leafCompare, dir)
		}
	})
}

function isItemType(item: ItemType | FolderItem | UserItem): item is ItemType {
	return 'type' in item
}

function getModifiedAt(item: ItemType): number {
	if (item.type === 'app') {
		return new Date(item.edited_at).getTime() || 0
	} else if (item.type === 'script') {
		return new Date(item.created_at).getTime() || 0
	} else if (item.type === 'flow') {
		return new Date(item.edited_at).getTime() || 0
	} else if (item.type === 'raw_app') {
		return new Date(item.edited_at).getTime() || 0
	} else if (item.type === 'agent') {
		return new Date(item.edited_at ?? 0).getTime() || 0
	}

	return 0
}