import Foundation
import Testing
@testable import PediFoods

/// Covers the public-locator distance contract documented in
/// docs/plans/public-store-distance-consumer.md: the server sends
/// `distance` as a number (never null) where `0` means "unavailable", and
/// the app collapses that to `nil` so a single representation of "unknown"
/// reaches the card label and the max-distance filter.
private func decode<T: Decodable>(_ type: T.Type, _ json: String) throws -> T {
    try JSONDecoder().decode(T.self, from: Data(json.utf8))
}

@Test("PublicStoreListItem decodes the distance field")
func publicStoreListItemDecodesDistance() throws {
    let item = try decode(PublicStoreListItem.self, #"{"id":"1","distance":3.4}"#)
    #expect(item.distance == 3.4)
}

/// The field ships on the backend after the app - a response without it
/// must still decode rather than throwing.
@Test("PublicStoreListItem still decodes a response with no distance field")
func publicStoreListItemDecodesWithoutDistance() throws {
    let item = try decode(PublicStoreListItem.self, #"{"id":"1"}"#)
    #expect(item.distance == nil)
}

@Test("PublicStoreDetail decodes the distance field")
func publicStoreDetailDecodesDistance() throws {
    let detail = try decode(PublicStoreDetail.self, #"{"id":"1","distance":1.2}"#)
    #expect(detail.distance == 1.2)
    let without = try decode(PublicStoreDetail.self, #"{"id":"1"}"#)
    #expect(without.distance == nil)
}

@Test("StoreSummary carries a real public distance through")
func storeSummaryKeepsPublicDistance() throws {
    let item = try decode(PublicStoreListItem.self, #"{"id":"1","name":"A","distance":2.5}"#)
    #expect(StoreSummary(publicItem: item).distance == 2.5)
}

@Test("StoreSummary maps the unavailable sentinel and a missing distance to nil")
func storeSummaryNormalizesUnavailableDistance() throws {
    let zero = try decode(PublicStoreListItem.self, #"{"id":"1","name":"A","distance":0}"#)
    #expect(StoreSummary(publicItem: zero).distance == nil)

    let absent = try decode(PublicStoreListItem.self, #"{"id":"1","name":"A"}"#)
    #expect(StoreSummary(publicItem: absent).distance == nil)
}