/// The three views of a list, named as the contract's `filter` field names them.
public enum Filter: String, Sendable, CaseIterable {
case all, active, completed
/// A missing or unknown value means `all`.
init(field: String?) {
self = field.flatMap(Filter.init(rawValue:)) ?? .all
}
var path: String {
switch self {
case .all: "/"
case .active: "/active"
case .completed: "/completed"
}
}
func includes(_ todo: Todo) -> Bool {
switch self {
case .all: true
case .active: !todo.completed
case .completed: todo.completed
}
}
}
/// Server-rendered HTML. Everything a visitor typed goes through `escape`.
///
/// The markup follows `shared/reference.html`. The controls marked
/// `class="nojs"` are what a page without JavaScript uses; `app.css` lays the
/// toggle buttons exactly over the checkboxes they stand in for, and hides
/// every `nojs` control once the `js` class is on ``.
enum Page {
static let language = "Swift"
static func document(todos: [Todo], filter: Filter, editing: Int?, version: String) -> String {
var html = """
TodoMVC
todos
"""
html += body(todos: todos, filter: filter, editing: editing)
html += """
"""
return html
}
/// `section.main` and `footer.footer`, or nothing when the list is empty.
/// The page's JavaScript swaps this in after each action.
static func body(todos: [Todo], filter: Filter, editing: Int?) -> String {
guard !todos.isEmpty else { return "" }
let left = todos.count { !$0.completed }
let done = todos.count - left
var html = """
"""
for todo in todos where filter.includes(todo) {
html += item(todo, filter: filter, editing: todo.id == editing)
}
html += """
\n"
return html
}
static func item(_ todo: Todo, filter: Filter, editing: Bool) -> String {
let id = todo.id
let title = escape(todo.title)
var classes: [String] = []
if todo.completed { classes.append("completed") }
if editing { classes.append("editing") }
let classAttr = classes.isEmpty ? "" : " class=\"\(classes.joined(separator: " "))\""
let editHref = "\(filter.path)?edit=\(id)"
return """
"""
}
static func filterField(_ filter: Filter) -> String {
""
}
/// Escapes text for use in HTML content and in double-quoted attributes.
static func escape(_ text: String) -> String {
var out = ""
out.reserveCapacity(text.utf8.count)
for c in text.unicodeScalars {
switch c {
case "&": out += "&"
case "<": out += "<"
case ">": out += ">"
case "\"": out += """
case "'": out += "'"
default: out.unicodeScalars.append(c)
}
}
return out
}
}