import XCTest
import RastrilloApple
@testable import CalendarKit

// B11 (polish-audit PLAN): a failed load used to run `events = []`, so
// any blip — a dropped connection, a 500, going offline — blanked a
// calendar that was on screen a second earlier, and the menu-bar panel
// shares the model, so opening it offline blanked the window too.
final class LoadFailureTests: XCTestCase {
 @MainActor func testFailedReloadKeepsLastGoodEventsAndReportsTheError() async throws {
  let process = Process()
  process.executableURL = URL(fileURLWithPath: "/usr/bin/python3")
  process.arguments = ["-u", "-c", """
import http.server, json
failing=False
event={'id':7,'calendar_id':1,'status':'confirmed','title':'Standup','location':'','notes':'','all_day':False,
 'start_local':'2030-10-25T09:00','end_local':'2030-10-25T09:30','tz':'Europe/Dublin','start':1919232000,'end':1919233800,
 'recurring':False,'writable':True,'calendar_name':'Personal','occurrence':'','day_start':'2030-10-25','day_end':'2030-10-25'}
class Handler(http.server.BaseHTTPRequestHandler):
 def log_message(self,*args): pass
 def reply(self,code,value):
  data=json.dumps(value).encode(); self.send_response(code); self.send_header('Content-Type','application/json'); self.send_header('Content-Length',str(len(data))); self.end_headers(); self.wfile.write(data)
 def do_GET(self):
  global failing
  if self.path=='/fail': failing=True; self.reply(200,{}); return
  if self.path=='/recover': failing=False; self.reply(200,{}); return
  if failing: self.reply(500,{'error':'fixture outage'}); return
  if self.path.startswith('/api/native/session'):
   self.reply(200,{'week_start':1,'zone':'Europe/Dublin','calendars':[{'id':1,'name':'Personal','hue':200,'writable':True}],'default_calendar_id':1}); return
  if self.path.startswith('/api/native/events'): self.reply(200,{'events':[event]}); return
  self.reply(404,{})
server=http.server.ThreadingHTTPServer(('127.0.0.1',0),Handler)
print(server.server_port,flush=True); server.serve_forever()
"""]
  let output = Pipe(); process.standardOutput = output; process.standardError = FileHandle.nullDevice
  try process.run()
  defer { process.terminate() }
  let data = output.fileHandleForReading.availableData
  let port = try XCTUnwrap(String(data: data, encoding: .utf8)?.trimmingCharacters(in: .whitespacesAndNewlines))
  let client = NativeHTTP(origin: URL(string: "http://127.0.0.1:\(port)")!)
  let model = CalendarModel(zone: "Europe/Dublin", date: Date(timeIntervalSince1970: 1919232000))

  // A first load that FAILS has nothing to keep: the error stands alone.
  _ = try await client.response("/fail")
  await model.load(client)
  XCTAssertFalse(model.error.isEmpty)
  XCTAssertFalse(model.hasLoaded)
  XCTAssertTrue(model.events.isEmpty)

  // It recovers, and the day shows its event.
  _ = try await client.response("/recover")
  await model.load(client)
  XCTAssertTrue(model.error.isEmpty)
  XCTAssertTrue(model.hasLoaded)
  XCTAssertEqual(model.events.map(\.title), ["Standup"])
  XCTAssertEqual(model.calendars.map(\.name), ["Personal"])

  // Then the server goes away. The refresh fails, the error is
  // reported, and what was on screen stays on screen.
  _ = try await client.response("/fail")
  await model.load(client)
  XCTAssertFalse(model.error.isEmpty, "a failed refresh must still say it failed")
  XCTAssertTrue(model.hasLoaded)
  XCTAssertFalse(model.loading)
  XCTAssertEqual(model.events.map(\.title), ["Standup"], "a failed refresh blanked the events on screen")
  XCTAssertEqual(model.calendars.map(\.name), ["Personal"])
  XCTAssertEqual(model.dayEvents(model.date).map(\.title), ["Standup"])

  // Signing out is the one thing that does clear it.
  model.clear()
  XCTAssertFalse(model.hasLoaded)
  XCTAssertTrue(model.events.isEmpty)
 }
}