import AppIntents
import Foundation

// Per-widget configuration intent (iOS 17+). Every widget instance carries
// its OWN fuel + sort choices, edited directly on the home screen (long-press
// → Edit Widget), independent of what the app has selected. This is what
// allows several FuelBoard widgets to show different fuels/orderings side by
// side.

enum WidgetFuel: String, AppEnum, CaseIterable, Codable {
    case e10
    case e5
    case diesel

    static var typeDisplayRepresentation: TypeDisplayRepresentation = "Fuel"

    static var caseDisplayRepresentations: [WidgetFuel: DisplayRepresentation] = [
        .e10: "Unleaded",
        .e5: "Premium",
        .diesel: "Diesel",
    ]
}

// Per-widget sort order. A String-backed AppEnum (NOT an AppEntity): the
// parameterSummary conditionals (When(\.$sort, .equalTo, …)) fall back to the
// otherwise branch for AppEntity parameters (iOS 17+ bug FB13263902), which
// hid the Favourite picker. String AppEnums match reliably. Tradeoff: the
// option set is static — "Favourites" always appears, and picking it with no
// favourites shows the empty state.
enum WidgetSort: String, AppEnum, CaseIterable, Codable {
    case cheapest
    case closest
    case favourites

    static var typeDisplayRepresentation: TypeDisplayRepresentation = "Sort by"

    static var caseDisplayRepresentations: [WidgetSort: DisplayRepresentation] = [
        .cheapest: "Cheapest",
        .closest: "Closest",
        .favourites: "Favourites",
    ]
}

// Per-widget distance filter. Modelled as an AppEntity (not an AppEnum) so
// the option labels can mirror the app's units setting at render time: an
// AppEnum's caseDisplayRepresentations are STATIC, so the Edit-Widget picker
// would always show "5 miles / 10 miles / 15 miles" regardless of the app's
// km mode. An entity query resolves labels per value, so they can read the
// shared unit preference ("8 km" in km mode).
struct WidgetDistance: AppEntity, Identifiable, Hashable, Codable {
    /// The distance in miles (5/10/15) — the persisted value. Labels are
    /// unit-aware, the stored value stays in miles.
    let id: Int

    var miles: Int { id }

    var displayRepresentation: DisplayRepresentation {
        let unit = FuelStore.loadDistanceUnit()
        let shown = unit.displayMiles(id)
        return DisplayRepresentation(stringLiteral: "\(shown) \(unit.label(for: Double(shown)))")
    }

    static var typeDisplayRepresentation: TypeDisplayRepresentation = "Distance"
    static var defaultQuery = WidgetDistanceQuery()
}

struct WidgetDistanceQuery: EntityQuery {
    func entities(for identifiers: [Int]) async throws -> [WidgetDistance] {
        identifiers.map { WidgetDistance(id: $0) }
    }

    func suggestedEntities() async throws -> [WidgetDistance] {
        FuelStore.stationRadiusOptions.map { WidgetDistance(id: $0) }
    }
}

// The knobs both the medium-list and small-single widget intents expose, so
// one timeline provider can drive either.
protocol WidgetConfigValues {
    var fuel: WidgetFuel { get }
    var sort: WidgetSort { get }
    var distance: WidgetDistance { get }
}

struct FuelBoardWidgetConfigurationIntent: WidgetConfigurationIntent, WidgetConfigValues {
    static var title: LocalizedStringResource = "Fuel & Sort"
    static var description = IntentDescription("Which fuel, ordering and search radius this widget shows.")

    @Parameter(title: "Fuel", default: .e10)
    var fuel: WidgetFuel

    @Parameter(title: "Sort by", default: .cheapest)
    var sort: WidgetSort

    @Parameter(title: "Distance", default: WidgetDistance(id: 5))
    var distance: WidgetDistance

    /// Edit-Widget UI: the Distance picker only makes sense for Cheapest
    /// ordering — Closest is inherently "nearest within range" and Favourites
    /// is not radius-bound. Show it for Cheapest only; hide for both others.
    static var parameterSummary: some ParameterSummary {
        When(\.$sort, .equalTo, WidgetSort.cheapest) {
            Summary("Show \(\.$fuel) by \(\.$sort) within \(\.$distance)") {
                \.$fuel
                \.$sort
                \.$distance
            }
        } otherwise: {
            When(\.$sort, .equalTo, WidgetSort.favourites) {
                Summary("Show \(\.$fuel) favourites") {
                    \.$fuel
                    \.$sort
                }
            } otherwise: {
                Summary("Show \(\.$fuel) by \(\.$sort)") {
                    \.$fuel
                    \.$sort
                }
            }
        }
    }
}