meta/Sources/Model/Data Flow/StateManager.swift

121 lines
3.7 KiB
Swift

//
// StateManager.swift
// Meta
//
// Created by david-swift on 21.06.24.
//
import Foundation
/// This type manages view updates.
public enum StateManager {
/// Whether to block updates in general.
public static var blockUpdates = false
/// Whether to save state.
public static var saveState = true
/// The functions handling view updates.
static var updateHandlers: [(Bool) -> Void] = []
/// The state.
static var state: [State] = []
/// Information about a piece of state.
struct State {
/// The state's identifiers.
var ids: (first: UUID, second: UUID?)
/// The state value.
var value: Any?
/// Whether to update in the next iteration.
var update = false
/// Whether the state's identifiers contain a certain identifier.
/// - Parameter id: The identifier.
/// - Returns: Whether the id is contained.
func contains(id: UUID) -> Bool {
ids.first == id || ids.second == id
}
/// Change the identifier to a new one.
/// - Parameter newID: The new identifier.
mutating func changeID(new newID: UUID) {
ids.second = ids.first
ids.first = newID
}
}
/// Update all of the views.
/// - Parameter force: Whether to force all views to update.
///
/// Nothing happens if ``UpdateManager/blockUpdates`` is true.
static func updateViews(force: Bool = false) {
if !blockUpdates {
for handler in updateHandlers {
handler(force)
}
}
}
/// Add a handler that is called when the user interface should update.
/// - Parameter handler: The handler. The parameter defines whether the whole UI should be force updated.
public static func addUpdateHandler(handler: @escaping (Bool) -> Void) {
updateHandlers.append(handler)
}
/// Set the state value for a certain ID.
/// - Parameters:
/// - id: The identifier.
/// - value: The new value.
static func setState(id: UUID, value: Any?) {
if saveState {
guard let index = state.firstIndex(where: { $0.contains(id: id) }) else {
state.append(.init(ids: (first: id, second: nil), value: value))
return
}
state[safe: index]?.value = value
}
}
/// Get the state value for a certain ID.
/// - Parameter id: The identifier.
/// - Returns: The value.
static func getState(id: UUID) -> Any? {
state[safe: state.firstIndex { $0.contains(id: id) }]?.value
}
/// Mark the state of a certain id as updated.
/// - Parameter id: The identifier.
static func updateState(id: UUID) {
if saveState {
state[safe: state.firstIndex { $0.contains(id: id) }]?.update = true
}
}
/// Mark the state of a certain id as not updated.
/// - Parameter id: The identifier.
static func updatedState(id: UUID) {
if saveState {
state[safe: state.firstIndex { $0.contains(id: id) }]?.update = false
}
}
/// Get whether to update the state of a certain id.
/// - Parameter id: The identifier.
/// - Returns: Whether to update the state.
static func getUpdateState(id: UUID) -> Bool {
state[safe: state.firstIndex { $0.contains(id: id) }]?.update ?? false
}
/// Change the identifier for a certain state value.
/// - Parameters:
/// - oldID: The old identifier.
/// - newID: The new identifier.
static func changeID(old oldID: UUID, new newID: UUID) {
if saveState {
state[safe: state.firstIndex { $0.contains(id: oldID) }]?.changeID(new: newID)
}
}
}