import XCTest

@testable import CallsKit

final class CallBarFitTests: XCTestCase {
  private let all = CallBarFit.Control.allCases

  func testEveryWindowTheAppAllowsHasRoomForEverything() {
    // 760 is the window's minimum (CallsMac.swift).
    for width in stride(from: 760.0, through: 3840, by: 1) {
      let fit = CallBarFit.fit(windowWidth: width, controls: all)
      XCTAssertEqual(fit.overflow, [], "at \(width)")
      XCTAssertEqual(fit.spacing, CallBarFit.roomy, "at \(width)")
      XCTAssertLessThanOrEqual(fit.width, CallBarFit.maxWidth)
      XCTAssertLessThanOrEqual(fit.width + 2 * CallBarFit.margin, width, "at \(width)")
    }
  }

  func testNarrowerItTightensThenMovesTheLeastUsedIntoMore() {
    var last = CallBarFit.fit(windowWidth: 760, controls: all)
    for width in stride(from: 759.0, through: 200, by: -1) {
      let fit = CallBarFit.fit(windowWidth: width, controls: all)
      // Never the controls that matter most.
      for control in all where control.essential { XCTAssertTrue(fit.shows(control), "\(control) at \(width)") }
      // Only ever more in ⋯ as it narrows, and in the bar's order.
      XCTAssertTrue(Set(last.overflow).isSubset(of: Set(fit.overflow)), "at \(width)")
      XCTAssertEqual(fit.overflow, all.filter { fit.overflow.contains($0) })
      // Whatever is shown fits the pane, while the essentials can.
      let shown = all.filter(fit.shows)
      let needed = CallBarFit.needed(shown, fit.spacing, more: !fit.overflow.isEmpty)
      let essentials = CallBarFit.needed(all.filter(\.essential), CallBarFit.tight, more: true)
      if width - 2 * CallBarFit.margin >= essentials {
        XCTAssertLessThanOrEqual(needed, fit.width + 0.001, "at \(width)")
      }
      last = fit
    }
    XCTAssertEqual(
      CallBarFit.fit(windowWidth: 300, controls: all).overflow, [.share, .devices, .layout, .link])
  }

  func testTheFirstToGoAreTheLinkThenLayout() {
    // ⋯ takes a button's place, so the first time anything moves, two do:
    // the link, and the layout (in the bar's order in ⋯).
    let tightAll = CallBarFit.needed(all, CallBarFit.tight, more: false)
    let fit = CallBarFit.fit(windowWidth: tightAll + 2 * CallBarFit.margin - 1, controls: all)
    XCTAssertEqual(fit.overflow, [.layout, .link])
    // A guest has no link: the layout and Devices go first instead.
    let guest = all.filter { $0 != .link }
    let tightGuest = CallBarFit.needed(guest, CallBarFit.tight, more: false)
    XCTAssertEqual(
      CallBarFit.fit(windowWidth: tightGuest + 2 * CallBarFit.margin - 1, controls: guest).overflow,
      [.devices, .layout])
  }
}