import XCTest
import CoreGraphics
@testable import NetworkCityCore

final class LayoutSolverTests: XCTestCase {

    // A label box centered under the node: ~160 wide, sitting below the dot.
    private let label = CGRect(x: -80, y: -34, width: 160, height: 30)

    private func worldBox(at c: CGPoint) -> CGRect { label.offsetBy(dx: c.x, dy: c.y) }

    func testEmptyMapReturnsSeed() {
        let p = LayoutSolver.placeNonOverlapping(baseAngle: 0, baseRadius: 200, localRect: label, existing: [])
        XCTAssertEqual(p.x, 200, accuracy: 0.001)   // attempt 0 == seed
        XCTAssertEqual(p.y, 0, accuracy: 0.001)
    }

    func testAvoidsOverlapWithExisting() {
        // Pre-place a box exactly where the seed would land.
        let seed = CGPoint(x: cos(0.0) * 200, y: sin(0.0) * 200)
        let existing = [worldBox(at: seed).insetBy(dx: -16, dy: -16)]

        let p = LayoutSolver.placeNonOverlapping(baseAngle: 0, baseRadius: 200, localRect: label, existing: existing)
        XCTAssertNotEqual(p, seed)   // had to move

        // The chosen spot's padded box must clear the existing one.
        let placed = worldBox(at: p).insetBy(dx: -16, dy: -16)
        XCTAssertFalse(placed.intersects(existing[0]))
    }

    func testResultClearsAllOfManyNeighbours() {
        // Seed eight districts and confirm none of their boxes overlap.
        var placed: [CGRect] = []
        for i in 0..<8 {
            let angle = Double(i) / 8 * 2 * .pi
            let c = LayoutSolver.placeNonOverlapping(baseAngle: angle, baseRadius: 180, localRect: label, existing: placed)
            placed.append(worldBox(at: c))
        }
        for a in 0..<placed.count {
            for b in (a + 1)..<placed.count {
                XCTAssertFalse(placed[a].intersects(placed[b]), "districts \(a) and \(b) overlap")
            }
        }
    }
}