import XCTest
@testable import PetKit

/// The other half of the contract with `pet-life`. Its JSON is pinned to exact
/// bytes by a Rust test; this asserts Swift reads those same bytes. The wire
/// format between the daemon and the collector drifted twice in this project,
/// and both times a pinned fixture is what caught it.
final class PetStateTests: XCTestCase {
    /// Verbatim from pet-life's own `the_json_contract_is_exact` test.
    let living = #"""
    {"alive":true,"name":"Ash","generation":2,"stage":"content","face":"(^ω^)","age_days":0.50,"quiet_days":0.50,"cemetery":[{"name":"Marble","generation":1,"lived_days":7.00}]}
    """#

    /// A pet that has died: name and generation are null, not absent.
    let dead = #"""
    {"alive":false,"name":null,"generation":null,"stage":"dead","face":"†","age_days":0.00,"quiet_days":31.00,"cemetery":[{"name":"Marble","generation":1,"lived_days":7.00}]}
    """#

    func testDecodesALivingPet() throws {
        let pet = try PetState.decode(Data(living.utf8))
        XCTAssertTrue(pet.alive)
        XCTAssertEqual(pet.name, "Ash")
        XCTAssertEqual(pet.generation, 2)
        XCTAssertEqual(pet.stage, "content")
        XCTAssertEqual(pet.face, "(^ω^)")
        XCTAssertEqual(pet.age_days, 0.5, accuracy: 0.001)
        XCTAssertEqual(pet.cemetery.count, 1)
        XCTAssertEqual(pet.cemetery[0].name, "Marble")
        XCTAssertEqual(pet.cemetery[0].lived_days, 7.0, accuracy: 0.001)
    }

    /// The null case is the one a naive `String` rather than `String?` would
    /// break on, and it is exactly the state the app must render.
    func testDecodesADeadPet() throws {
        let pet = try PetState.decode(Data(dead.utf8))
        XCTAssertFalse(pet.alive)
        XCTAssertNil(pet.name)
        XCTAssertNil(pet.generation)
        XCTAssertEqual(pet.stage, "dead")
        XCTAssertEqual(pet.cemetery.count, 1, "the dead are still remembered")
    }

    func testRejectsSomethingThatIsNotAPet() {
        XCTAssertThrowsError(try PetState.decode(Data(#"{"nope":1}"#.utf8)))
    }
}