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) }
    }
}

// Fuel for the favourites face (small widget, Favourites sort). Modelled as an
// AppEntity so only fuels that ACTUALLY have favourites appear in the picker —
// mirrors the app's Favourites tab capsules. The chosen fuel dictates which
// favourites the Favourite picker offers (see WidgetFavouriteQuery).
struct FavouriteFuel: AppEntity, Identifiable, Hashable, Codable {
    let fuel: FuelType

    var id: String { fuel.rawValue }

    var displayRepresentation: DisplayRepresentation {
        DisplayRepresentation(stringLiteral: fuel.displayName)
    }

    static var typeDisplayRepresentation: TypeDisplayRepresentation = "Fuel"
    static var defaultQuery = FavouriteFuelQuery()
}

struct FavouriteFuelQuery: EntityQuery {
    func entities(for identifiers: [String]) async throws -> [FavouriteFuel] {
        identifiers.compactMap { FuelType(rawValue: $0) }.map { FavouriteFuel(fuel: $0) }
    }

    func suggestedEntities() async throws -> [FavouriteFuel] {
        let fuels = Set(FuelStore.loadFavourites().map(\.fuel))
        return FuelType.allCases.filter { fuels.contains($0) }.map { FavouriteFuel(fuel: $0) }
    }
}

// A pinned favourite station, selectable on SMALL widgets (which show a single
// station). Reuses FavouriteEntry's id scheme ("fuel|stationID") so the
// provider can resolve the choice straight back to a stored favourite. Only
// surfaced when Sort = Favourites.
//
// The display name is EMBEDDED in the entity (stationName): the config sheet
// can resolve entities in a process where keychain/app-group storage is
// unavailable, and a storage-backed lookup there made every picker row fall
// back to the "Favourite" placeholder. With the name carried on the value,
// rows render with no storage read at all.
struct WidgetFavourite: AppEntity, Identifiable, Hashable, Codable {
    let fuel: FuelType
    let stationID: String
    /// Station display name, embedded so picker rows render storage-free.
    let stationName: String

    var id: String { "\(fuel.rawValue)|\(stationID)" }

    var displayRepresentation: DisplayRepresentation {
        if !stationName.isEmpty {
            return DisplayRepresentation(stringLiteral: stationName)
        }
        // Id-only entity (e.g. a stored default): best-effort storage lookup.
        let favourites = FuelStore.loadFavourites()
        guard let entry = favourites.first(where: { $0.id == id }) else {
            return DisplayRepresentation(stringLiteral: "Favourite")
        }
        return DisplayRepresentation(stringLiteral: entry.station.name)
    }

    static var typeDisplayRepresentation: TypeDisplayRepresentation = "Favourite"
    static var defaultQuery = WidgetFavouriteQuery()
}

struct WidgetFavouriteQuery: EntityQuery {
    /// Reads the small intent's Favourite Fuel parameter: the Favourite picker
    /// only offers THAT fuel's favourites (requirement: the chosen fuel
    /// dictates the list). Nil (medium widget / fresh sheet) → all favourites.
    @IntentParameterDependency<FuelBoardSmallWidgetConfigurationIntent>(
        \.$favouriteFuel
    )
    var smallIntent

    func entities(for identifiers: [String]) async throws -> [WidgetFavourite] {
        let favourites = FuelStore.loadFavourites()
        return identifiers.map { id in
            let parts = id.split(separator: "|", maxSplits: 1)
            let fuel = FuelType(rawValue: String(parts.first ?? "")) ?? .e10
            let stationID = String(parts.last ?? "")
            let entry = favourites.first { $0.id == id }
            return WidgetFavourite(
                fuel: fuel,
                stationID: stationID,
                stationName: entry?.station.name ?? ""
            )
        }
    }

    func suggestedEntities() async throws -> [WidgetFavourite] {
        let favourites = FuelStore.loadFavourites()
        let filtered: [FavouriteEntry]
        if let fuel = smallIntent?.favouriteFuel.fuel {
            filtered = favourites.filter { $0.fuel == fuel }
        } else {
            filtered = favourites
        }
        return filtered.map { entry in
            WidgetFavourite(
                fuel: entry.fuel,
                stationID: entry.station.id,
                stationName: entry.station.name
            )
        }
    }
}

// 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 }
    /// The pinned favourite (small widget, Favourites sort) — nil when the
    /// widget lists favourites instead (medium).
    var favouriteChoice: WidgetFavourite? { get }
    /// The favourites-face fuel (small widget, Favourites sort) — its options
    /// are the fuels that have favourites, and it dictates which favourites
    /// the Favourite picker offers. Nil on the medium widget.
    var favouriteFuelChoice: FavouriteFuel? { 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

    // Medium/list widgets show ALL favourites for the chosen fuel — no
    // pinned-favourite knob, no favourites-scoped fuel.
    var favouriteChoice: WidgetFavourite? { nil }
    var favouriteFuelChoice: FavouriteFuel? { nil }

    /// 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
                }
            }
        }
    }
}

// SMALL widget intent: same knobs as the list widget, PLUS a pinned-favourite
// picker for Favourites sort (a small widget shows exactly ONE station, so the
// user chooses which favourite). Favourites mode swaps the Fuel row for a
// favourites-scoped one — only fuels with favourites are offered, and the
// chosen fuel dictates which favourites the Favourite picker lists. The
// pinned favourite wins when set; the fuel row picks the default favourite on
// a fresh widget. Distance stays hidden (a pinned station has no radius).
struct FuelBoardSmallWidgetConfigurationIntent: WidgetConfigurationIntent, WidgetConfigValues {
    static var title: LocalizedStringResource = "Fuel & Sort"
    static var description = IntentDescription("Which fuel, ordering, radius and pinned favourite this small 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

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

    @Parameter(title: "Favourite", default: WidgetFavourite(fuel: .e10, stationID: "", stationName: ""))
    var favourite: WidgetFavourite

    var favouriteChoice: WidgetFavourite? { favourite }
    var favouriteFuelChoice: FavouriteFuel? { favouriteFuel }

    static var parameterSummary: some ParameterSummary {
        When(\.$sort, .equalTo, WidgetSort.favourites) {
            Summary("Show \(\.$favouriteFuel) favourite \(\.$favourite)") {
                \.$favouriteFuel
                \.$sort
                \.$favourite
            }
        } otherwise: {
            When(\.$sort, .equalTo, WidgetSort.cheapest) {
                Summary("Show \(\.$fuel) by \(\.$sort) within \(\.$distance)") {
                    \.$fuel
                    \.$sort
                    \.$distance
                }
            } otherwise: {
                Summary("Show \(\.$fuel) by \(\.$sort)") {
                    \.$fuel
                    \.$sort
                }
            }
        }
    }
}