/**
 * The instance policy around creating a workspace, and what the client has to do
 * once one exists. Shared by every screen that creates workspaces — the workspace
 * settings creator and the hub import wizard — so the two cannot drift apart on
 * who is allowed to create, what username the backend expects, or what state the
 * client is left in afterwards.
 *
 * Id validation lives next door in `$lib/utils/workspaceId`, which has no imports
 * and so can be used from anywhere.
 */

import { SettingService, UserService, WorkspaceService } from '$lib/gen'
import { usersWorkspaceStore } from '$lib/stores'
import { switchWorkspace } from '$lib/storeUtils'
import { isCloudHosted } from '$lib/cloud'
import { WORKSPACE_NAME_MAX_LENGTH } from '$lib/utils/workspaceId'

/**
 * Whether this user may create a workspace at all. Self-hosted instances default
 * `CREATE_WORKSPACE_REQUIRE_SUPERADMIN` to true, so offering the choice to
 * everyone ends in a 403 at the last step.
 *
 * Superadmin arrives asynchronously in most callers, so pass the current value and
 * call again when it flips. When the gate is on, the server is asked directly
 * rather than trusting that value: `refreshSuperadmin` skips its fetch once the
 * store holds anything, so a page loaded logged out leaves it `false` for the rest
 * of the session — including right after signing in.
 */
export async function canCreateWorkspace(isSuperadmin: boolean): Promise<boolean> {
	if (isSuperadmin || isCloudHosted()) return true
	try {
		const r = await fetch('/api/workspaces/create_workspace_require_superadmin')
		if ((await r.text()) != 'true') return true
		return !!(await UserService.globalWhoami()).super_admin
	} catch {
		return false
	}
}

export interface UsernamePolicy {
	/** When true the backend derives the username and rejects one sent explicitly. */
	automate: boolean
	/** A username to prefill with, when the caller has to ask for one. */
	suggested?: string
}

/** What `usr.username` holds, and neither the provider name nor the email is bounded by it. */
const USERNAME_MAX_LENGTH = 50

/**
 * A username the whole `usr.username` contract accepts: the `proper_username` constraint
 * (`^[\w-]+$`, so word characters and hyphens and nothing else) and the column's own 50
 * characters. Anything outside the class is dropped rather than substituted — `O'Connor` is
 * `oconnor`, not `o-connor`.
 *
 * Undefined where nothing usable is left or where what is left is too long, which is the
 * caller's cue to ask for one: `create_workspace` inserts this value with no truncation, so a
 * name the column refuses would fail on insert with nothing on screen naming the field.
 */
export function usernameFromName(name: string): string | undefined {
	const cleaned = name.toLowerCase().replace(/[^\w-]/g, '')
	return cleaned === '' || cleaned.length > USERNAME_MAX_LENGTH ? undefined : cleaned
}

/**
 * `createWorkspace` rejects a username when the instance automates them and
 * requires one when it does not, so the field only exists in the second case.
 */
export async function loadUsernamePolicy(): Promise<UsernamePolicy> {
	// Rejects rather than defaulting when the setting cannot be read, because neither
	// default is safe: `create_workspace` refuses a username on an instance that automates
	// them and requires one on an instance that does not (`workspaces.rs:5820`). A caller
	// that cannot read this cannot pick a request shape, and must say so instead of posting
	// one of the two the server rejects.
	const automate =
		((await SettingService.getGlobal({
			key: 'automate_username_creation'
		})) as boolean | null) ?? true
	if (automate) return { automate: true }
	try {
		const me = await UserService.globalWhoami()
		const from = me.name ? me.name.split(' ')[0] : me.email.split('@')[0]
		return { automate: false, suggested: usernameFromName(from) }
	} catch {
		return { automate: false }
	}
}

/**
 * Re-reads the workspaces this user belongs to. Anything that creates or deletes a
 * workspace owes the client this call: `usersWorkspaceStore` is what the picker and
 * every derived workspace list read from, and nothing else refreshes it until a
 * full page load.
 */
export async function refreshWorkspaceList(): Promise<void> {
	usersWorkspaceStore.set(await WorkspaceService.listUserWorkspaces())
}

/** Enters a workspace that was just created, with the list refreshed to match. */
export async function enterNewWorkspace(id: string): Promise<void> {
	await refreshWorkspaceList()
	switchWorkspace(id)
}

/**
 * How long a screen that hands over to a workspace stays up, whatever the server does.
 * Creating or naming one takes a few hundred milliseconds, and a button that swaps the page in
 * that time reads as nothing having happened — the floor is what makes it read as an action
 * that ran, and it covers the workspace layout's first load on the other side.
 */
export const WORKSPACE_HANDOVER_MS = 500

/**
 * What to call a workspace before its owner has said. The login provider's name when it gave
 * one, else the email local part read as a name: `bob@…` is Bob, `ada.lovelace@…` is Ada
 * Lovelace. Capped at what `create_workspace` accepts, since it is prefilled rather than
 * typed and a name the server would reject must never appear in the field.
 */
export function defaultWorkspaceName(name: string | undefined, email: string | undefined): string {
	const display = (name?.trim() || (email ?? '').split('@')[0])
		.split(/[._\-+\s]+/)
		.filter(Boolean)
		.map((word) => word.charAt(0).toUpperCase() + word.slice(1))
		.join(' ')
		.trim()
	const proposed = display ? `${display}'s workspace` : 'My workspace'
	return proposed.length > WORKSPACE_NAME_MAX_LENGTH ? 'My workspace' : proposed
}