FuelBoard Contributor
e960ef85c6
The relay's price_updated is the maximum price_last_updated across the grades it maps, so it cannot vouch for the selected grade: stop using it to score, gate or warn about Best Value. - FuelPriceFreshness is now station-level and display-only: one age per station, fresh/outdated/unknown/invalid, "May be outdated" past 30 days, with future-tolerance and non-finite guards. - Best Value restores the closest-station-selling-the-selected-fuel baseline and its savings ranking; eligibility gating, eligible-first sorting and the unavailable banner are gone. - Price age appears in the More info sheet only - no listing-row warnings, no extra banners. - Copy reverted from "closest eligible station" to "closest station"; stale price-confidence strings removed, "May be outdated" added. - Dormant per-grade timestamp plumbing removed, and regression tests added for every fuel type, missing/invalid/future stamps and the bundled offline dump.
278 lines
12 KiB
Swift
278 lines
12 KiB
Swift
// FuelPriceProvider.swift — data-source seam for FuelBoard.
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//
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// The official UK Fuel Finder API (api.fuelfinder.service.gov.uk) is the live
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// source for station-level prices, but it requires GOV.UK One Login + OAuth 2.0
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// client credentials. For the scaffold we ship SampleFuelProvider (realistic
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// stations around a location, works offline), plus the FuelFinderProvider
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// skeleton with the exact integration steps documented inline so wiring the
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// live API later is a drop-in: change `activeProvider` to `.fuelFinder`.
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import Foundation
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// MARK: - Provider protocol
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protocol FuelPriceProviding {
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/// Fetch stations with prices. `location` may be nil (sort by price only).
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/// `radiusKM` nil = full dataset (device filters); set = focused server-side
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/// radius (alert path). Throws on failure so callers can fall back.
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func fetchStations(near lat: Double?, lng: Double?, fuel: FuelType, radiusKM: Double?) async throws -> [FuelStation]
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}
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enum FuelPriceProvider {
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/// Default: the live chain — public GitHub mirror (primary, off-LAN) →
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/// bundled dump/cache fallback in callers. No private LAN fallback ships in
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/// the app binary.
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static let active: FuelPriceProviding = LiveChainProvider()
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/// Decodes a mirror payload into stations, applying the defensive price
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/// band. Internal so the unit-test target can exercise the guard.
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static func decodeStations(from data: Data) throws -> [FuelStation] {
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let payload = try JSONDecoder().decode(MirrorResponse.self, from: data)
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return payload.stations.map { relay in
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FuelStation(
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id: relay.id ?? relay.name ?? UUID().uuidString,
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name: (relay.name ?? "Unknown").sanitizedStationTitle,
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brand: relay.brand ?? "",
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address: relay.address ?? "",
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postcode: relay.postcode ?? "",
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lat: relay.lat ?? 0,
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lng: relay.lng ?? 0,
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prices: relay.allPrices,
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priceUpdated: relay.priceUpdatedDate?.timeIntervalSince1970
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)
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}
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}
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/// Price sanity band (pence/litre) — anything outside is mirror regression
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/// garbage and must never reach calculations (shared by the live decode
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/// and the history mirror decoder).
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static let priceBand: ClosedRange<Double> = 50...500
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/// Maps mirror grade keys (E5/E10/DIESEL…) to FuelType with the defensive
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/// band guard. Shared by the mirror decode and the history mirror parser so
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/// both surfaces apply identical sanitisation.
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static func mapGrades(_ prices: [String: Double]) -> [FuelType: Double] {
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var result: [FuelType: Double] = [:]
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for (grade, value) in prices {
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guard priceBand.contains(value) else { continue }
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switch grade.uppercased() {
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case "E10": result[.e10] = value
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case "E5": result[.e5] = value
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case "DIESEL", "B7", "B7S", "B7P", "B10": result[.diesel] = value
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default: break
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}
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}
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return result
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}
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static func fuelType(for grade: String) -> FuelType? {
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switch grade.uppercased() {
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case "E10": return .e10
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case "E5": return .e5
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case "DIESEL", "B7", "B7S", "B7P", "B10": return .diesel
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default: return nil
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}
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}
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/// Decodes mirror envelope metadata (source, dataset update time) — the
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/// About section shows these so the user can see which data source is
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/// live and how fresh the GOV.UK data itself is. The fields are additive
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/// on the mirror, so older snapshots simply return nil values.
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static func decodeRelayMeta(from data: Data) -> RelayMeta? {
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guard let payload = try? JSONDecoder().decode(MirrorResponse.self, from: data) else {
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return nil
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}
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return RelayMeta(
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source: payload.source,
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stationCount: payload.stationsCount,
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dataUpdated: payload.dataUpdated
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)
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}
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}
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// MARK: - Mirror payload envelope
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private struct MirrorResponse: Codable {
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/// Envelope metadata surfaced in Settings → About so the user can see
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/// which mirror source is live and how fresh the GOV.UK data is.
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let source: String?
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let stationsCount: Int?
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let dataUpdated: String?
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enum CodingKeys: String, CodingKey {
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case source, stations
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case stationsCount = "stations_count"
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case dataUpdated = "data_updated"
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}
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struct MirrorStation: Codable {
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let id: String?
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let name: String?
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let brand: String?
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let address: String?
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let postcode: String?
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let lat: Double?
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let lng: Double?
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let price: Double?
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let prices: [String: Double]?
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let priceUpdated: String?
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enum CodingKeys: String, CodingKey {
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case id, name, brand, address, postcode, lat, lng, price, prices
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case priceUpdated = "price_updated"
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}
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var priceUpdatedDate: Date? {
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FuelPriceTimestamp.parse(priceUpdated)
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}
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/// Map mirror grade keys (E5/E10/DIESEL) to FuelType for ALL fuels the
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/// station sells — one fetch populates every fuel tab. Defensive guard:
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/// any grade outside the 50–500 pence/litre band is dropped, so a mirror
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/// regression (e.g. the band being removed upstream) can't re-poison
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/// the nationwide cheapest reference with 1.3p / 1589p garbage.
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var allPrices: [FuelType: Double] {
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var result = FuelPriceProvider.mapGrades(prices ?? [:])
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// Backwards-compat: mirror versions without `prices` still send `price`.
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if result.isEmpty, let price, FuelPriceProvider.priceBand.contains(price) {
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result[.e10] = price
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}
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return result
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}
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}
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let stations: [MirrorStation]
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}
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/// Envelope metadata from the mirror response — which data source is live
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/// (api/csv) and the freshest price-update timestamp the GOV.UK server
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/// itself reports for the dataset. Displayed in Settings → About.
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struct RelayMeta: Codable, Equatable {
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let source: String?
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let stationCount: Int?
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let dataUpdated: String?
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}
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// MARK: - Sample provider (offline fallback only)
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/// Representative stations spread across ENGLAND (one cluster per region) so
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/// the fallback works anywhere in the country — it is NOT tied to one town.
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/// Real UK-wide data comes from the public mirror (full-UK Fuel Finder CSV/API).
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/// Prices in pence/litre.
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struct SampleFuelProvider: FuelPriceProviding {
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func fetchStations(near lat: Double?, lng: Double?, fuel: FuelType, radiusKM: Double?) async throws -> [FuelStation] {
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try await Task.sleep(nanoseconds: 300_000_000) // simulate fetch
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return Self.sampleStations
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}
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static let sampleStations: [FuelStation] = [
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// Yorkshire & the Humber (Halifax area)
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FuelStation(id: "y1", name: "Morrisons Halifax", brand: "Morrisons",
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address: "Haugh Shaw Road", postcode: "HX1 3TU",
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lat: 53.7265, lng: -1.8580,
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prices: [.e10: 137.9, .e5: 144.9, .diesel: 144.9],
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priceUpdated: nil),
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FuelStation(id: "y2", name: "Asda Leeds Crown Point", brand: "Asda",
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address: "Crown Point Road", postcode: "LS10 1ET",
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lat: 53.7800, lng: -1.5300,
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prices: [.e10: 136.9, .e5: 143.9, .diesel: 143.9],
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priceUpdated: nil),
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FuelStation(id: "y3", name: "Tesco Express York", brand: "Tesco",
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address: "Fulford Road", postcode: "YO10 4AB",
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lat: 53.9500, lng: -1.0800,
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prices: [.e10: 138.9, .e5: 146.9, .diesel: 145.9],
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priceUpdated: nil),
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// North West
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FuelStation(id: "nw1", name: "Sainsbury's Manchester", brand: "Sainsbury's",
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address: "Regent Road", postcode: "M5 3QH",
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lat: 53.4700, lng: -2.2800,
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prices: [.e10: 139.9, .e5: 147.9, .diesel: 146.9],
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priceUpdated: nil),
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FuelStation(id: "nw2", name: "Shell Liverpool", brand: "Shell",
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address: "Rice Lane", postcode: "L9 1AD",
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lat: 53.4400, lng: -2.9600,
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prices: [.e10: 142.9, .e5: 149.9, .diesel: 148.9],
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priceUpdated: nil),
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// Midlands
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FuelStation(id: "m1", name: "Morrisons Birmingham", brand: "Morrisons",
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address: "Hagley Road", postcode: "B16 8NA",
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lat: 52.4700, lng: -1.9500,
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prices: [.e10: 137.9, .e5: 144.9, .diesel: 144.9],
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priceUpdated: nil),
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FuelStation(id: "m2", name: "Tesco Express Nottingham", brand: "Tesco",
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address: "Mansfield Road", postcode: "NG5 2DP",
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lat: 52.9900, lng: -1.1500,
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prices: [.e10: 138.9, .e5: 146.9, .diesel: 145.9],
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priceUpdated: nil),
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// South East / London
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FuelStation(id: "se1", name: "Asda Wembley", brand: "Asda",
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address: "Great Central Way", postcode: "HA9 0DB",
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lat: 51.5500, lng: -0.2800,
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prices: [.e10: 136.9, .e5: 143.9, .diesel: 143.9],
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priceUpdated: nil),
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FuelStation(id: "se2", name: "BP Brighton", brand: "BP",
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address: "Lewes Road", postcode: "BN2 3QB",
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lat: 50.8300, lng: -0.1100,
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prices: [.e10: 140.9, .diesel: 147.9],
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priceUpdated: nil),
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// South West
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FuelStation(id: "sw1", name: "Esso Bristol", brand: "Esso",
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address: "Wells Road", postcode: "BS4 2PP",
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lat: 51.4400, lng: -2.5700,
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prices: [.e10: 141.9, .e5: 148.9, .diesel: 147.9],
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priceUpdated: nil),
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// North East
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FuelStation(id: "ne1", name: "Gulf Newcastle", brand: "Gulf",
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address: "Scotswood Road", postcode: "NE4 7AA",
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lat: 54.9700, lng: -1.6400,
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prices: [.e10: 143.9, .e5: 151.9, .diesel: 149.9],
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priceUpdated: nil),
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]
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}
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// MARK: - Fuel Finder API provider (integration point)
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/// Live provider skeleton for the official GOV.UK Fuel Finder API.
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///
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/// To activate:
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/// 1. Sign in at developer.fuel-finder.service.gov.uk with GOV.UK One Login,
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/// register an app, and generate client credentials (client_id + secret).
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/// 2. Implement token fetch: POST to the token endpoint with OAuth 2.0
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/// client_credentials grant → access_token (expires in 1h).
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/// 3. GET prices with `Authorization: Bearer <token>` and decode the
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/// stations JSON into [FuelStation].
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///
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/// Endpoints (per gov.uk docs):
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/// base: https://api.fuelfinder.service.gov.uk
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/// auth: base + /v1/token
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/// prices: base + /v1/prices (full snapshot)
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/// price: base + /v1/prices/GB-12345 (single station)
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///
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/// Then switch `FuelPriceProvider.active` to `FuelFinderProvider(...)`.
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struct FuelFinderProvider: FuelPriceProviding {
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let baseURL = URL(string: "https://api.fuelfinder.service.gov.uk")!
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let clientID: String
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let clientSecret: String
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func fetchStations(near lat: Double?, lng: Double?, fuel: FuelType, radiusKM: Double?) async throws -> [FuelStation] {
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// TODO: OAuth token → GET /v1/prices → map to FuelStation.
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// The live API requires authentication; see notes above.
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throw FuelProviderError.notImplemented
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}
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}
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enum FuelProviderError: LocalizedError {
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case notImplemented
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case relayUnavailable
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case mirrorUnavailable
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var errorDescription: String? {
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switch self {
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case .notImplemented:
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return "Live Fuel Finder API not wired yet — activate with GOV.UK One Login credentials."
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case .relayUnavailable:
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return "FuelBoard live data unavailable — showing cached/sample data."
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case .mirrorUnavailable:
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return "GitHub price mirror unreachable."
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}
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}
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}
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