// fiber_pure_test.wren - Test pure Fiber performance without I/O

foreign class Host {
  foreign static signalDone()
}

var mainFiber = Fiber.new {
  System.print("=== Pure Fiber Performance Test ===\n")
  
  // Test 1: Minimal yield overhead
  System.print("Test 1: Minimal Fiber.yield() cost")
  var iterations = 100000
  var start = System.clock
  for (i in 1..iterations) {
    Fiber.yield()
  }
  var elapsed = System.clock - start
  System.print("  %(iterations) yields: %(elapsed)s")
  System.print("  Rate: %(iterations/elapsed) yields/sec")
  System.print("  Per yield: %(elapsed/iterations * 1000000) microseconds\n")
  
  // Test 2: Fiber creation cost
  System.print("Test 2: Fiber creation overhead")
  iterations = 10000
  start = System.clock
  for (i in 1..iterations) {
    var f = Fiber.new { }
  }
  elapsed = System.clock - start
  System.print("  %(iterations) fiber creations: %(elapsed)s")
  System.print("  Rate: %(iterations/elapsed) fibers/sec")
  System.print("  Per fiber: %(elapsed/iterations * 1000) milliseconds\n")
  
  // Test 3: Fiber with work
  System.print("Test 3: Fiber with actual work")
  var counter = 0
  var workFiber = Fiber.new {
    for (i in 1..10000) {
      counter = counter + 1
      if (i % 100 == 0) Fiber.yield()
    }
  }
  
  start = System.clock
  while (!workFiber.isDone) {
    workFiber.call()
  }
  elapsed = System.clock - start
  System.print("  Processed %(counter) items in %(elapsed)s")
  System.print("  Rate: %(counter/elapsed) items/sec\n")
  
  // Test 4: Multiple fibers cooperating
  System.print("Test 4: Multiple fibers round-robin")
  var fibers = []
  var shared = 0
  for (i in 1..100) {
    fibers.add(Fiber.new {
      for (j in 1..100) {
        shared = shared + 1
        Fiber.yield()
      }
    })
  }
  
  start = System.clock
  var done = false
  while (!done) {
    done = true
    for (f in fibers) {
      if (!f.isDone) {
        f.call()
        done = false
      }
    }
  }
  elapsed = System.clock - start
  System.print("  100 fibers x 100 yields = %(shared) operations in %(elapsed)s")
  System.print("  Rate: %(shared/elapsed) ops/sec\n")
  
  // Test 5: Producer-consumer pattern
  System.print("Test 5: Producer-Consumer pattern")
  var queue = []
  var produced = 0
  var consumed = 0
  
  var producer = Fiber.new {
    for (i in 1..1000) {
      queue.add(i)
      produced = produced + 1
      if (queue.count > 10) Fiber.yield()
    }
  }
  
  var consumer = Fiber.new {
    while (consumed < 1000) {
      if (queue.count > 0) {
        var item = queue.removeAt(0)
        consumed = consumed + 1
      } else {
        Fiber.yield()
      }
    }
  }
  
  start = System.clock
  while (!producer.isDone || !consumer.isDone) {
    if (!producer.isDone) producer.call()
    if (!consumer.isDone) consumer.call()
  }
  elapsed = System.clock - start
  System.print("  Produced: %(produced), Consumed: %(consumed)")
  System.print("  Time: %(elapsed)s")
  System.print("  Rate: %(consumed/elapsed) items/sec\n")
  
  // Test 6: Deep call stack
  System.print("Test 6: Deep recursion with yields")
  var depth = 0
  var maxDepth = 1000
  
  var recursiveFiber = Fiber.new {
    for (i in 1..maxDepth) {
      depth = depth + 1
      Fiber.yield()
    }
  }
  
  start = System.clock
  while (!recursiveFiber.isDone) {
    recursiveFiber.call()
  }
  elapsed = System.clock - start
  System.print("  Processed %(depth) yields: %(elapsed)s")
  System.print("  Per yield: %(elapsed/depth * 1000000) microseconds\n")
  
  System.print("=== Analysis ===")
  System.print("Based on these results, Wren fibers are:")
  var yieldMicros = elapsed/iterations * 1000000
  if (yieldMicros < 1) {
    System.print("  EXCELLENT - Sub-microsecond yields")
  } else if (yieldMicros < 10) {
    System.print("  GOOD - Single-digit microsecond yields")  
  } else if (yieldMicros < 50) {
    System.print("  MODERATE - Tens of microseconds per yield")
  } else {
    System.print("  SLOW - Over 50 microseconds per yield")
    System.print("  This suggests FFI overhead or implementation issues")
  }
  
  Host.signalDone()
  while(true) { Fiber.yield() }
}