import XCTest
import CoreGraphics
@testable import NetworkCityCore

final class LatencyLayoutTests: XCTestCase {

    func testZeroRTTSitsAtInnerRadius() {
        XCTAssertEqual(LatencyLayout.radius(forRTT: 0), LatencyLayout.minRadius, accuracy: 0.001)
    }

    func testCeilingSitsAtOuterEdge() {
        XCTAssertEqual(LatencyLayout.radius(forRTT: 250), LatencyLayout.maxRadius, accuracy: 0.001)
    }

    func testClampsBeyondCeiling() {
        XCTAssertEqual(LatencyLayout.radius(forRTT: 5000), LatencyLayout.maxRadius, accuracy: 0.001)
    }

    func testMonotonicAndWithinBounds() {
        var last = LatencyLayout.radius(forRTT: 0)
        for rtt in stride(from: 5.0, through: 250.0, by: 5) {
            let r = LatencyLayout.radius(forRTT: rtt)
            XCTAssertGreaterThan(r, last)   // farther RTT -> farther out
            XCTAssertLessThanOrEqual(r, LatencyLayout.maxRadius)
            last = r
        }
    }

    func testNearRangeSpreadsOut() {
        // The log curve should give the 1–50ms band real separation, not a clump.
        let r10 = LatencyLayout.radius(forRTT: 10)
        let r50 = LatencyLayout.radius(forRTT: 50)
        XCTAssertGreaterThan(r50 - r10, 40)   // meaningfully far apart on screen
    }
}