//: Run a second routine concurrently using 'start-running', without any
//: guarantees on how the operations in each are interleaved with each other.

void test_scheduler() {
  run(
      "def f1 [\n"
      "  start-running f2\n"
         // wait for f2 to run
      "  {\n"
      "    jump-unless 1:num, -1\n"
      "  }\n"
      "]\n"
      "def f2 [\n"
      "  1:num <- copy 1\n"
      "]\n"
  );
  CHECK_TRACE_CONTENTS(
      "schedule: f1\n"
      "schedule: f2\n"
  );
}

//: first, add a deadline to run(routine)
:(before "End Globals")
int Scheduling_interval = 500;
:(before "End routine Fields")
int instructions_run_this_scheduling_slice;
:(before "End routine Constructor")
instructions_run_this_scheduling_slice = 0;
:(after "Running One Instruction")
 ++Current_routine->instructions_run_this_scheduling_slice;
:(replace{} "bool should_continue_running(const routine* current_routine)")
bool should_continue_running(const routine* current_routine) {
  assert(current_routine == Current_routine);  // argument passed in just to make caller readable above
  return Current_routine->state == RUNNING
      && Current_routine->instructions_run_this_scheduling_slice < Scheduling_interval;
}
:(after "stop_running_current_routine:")
// Reset instructions_run_this_scheduling_slice
Current_routine->instructions_run_this_scheduling_slice = 0;

//: now the rest of the scheduler is clean

:(before "struct routine")
enum routine_state {
  RUNNING,
  COMPLETED,
  // End routine States
};
:(before "End routine Fields")
enum routine_state state;
:(before "End routine Constructor")
state = RUNNING;

:(before "End Globals")
vector<routine*> Routines;
int Current_routine_index = 0;
:(before "End Reset")
Scheduling_interval = 500;
for (int i = 0;  i < SIZE(Routines);  ++i)
  delete Routines.at(i);
Routines.clear();
Current_routine = NULL;
:(replace{} "void run(const recipe_ordinal r)")
void run(const recipe_ordinal r) {
  run(new routine(r));
}

:(code)
void run(routine* rr) {
  Routines.push_back(rr);
  Current_routine_index = 0, Current_routine = Routines.at(0);
  while (!all_routines_done()) {
    skip_to_next_routine();
    assert(Current_routine);
    assert(Current_routine->state == RUNNING);
    trace(100, "schedule") << current_routine_label() << end();
    run_current_routine();
    // Scheduler State Transitions
    if (Current_routine->completed())
      Current_routine->state = COMPLETED;
    // End Scheduler State Transitions

    // Scheduler Cleanup
    // End Scheduler Cleanup
  }
  // End Run Routine
}

bool all_routines_done() {
  for (int i = 0;  i < SIZE(Routines);  ++i) {
    if (Routines.at(i)->state == RUNNING)
      return false;
  }
  return true;
}

// skip Current_routine_index past non-RUNNING routines
void skip_to_next_routine() {
  assert(!Routines.empty());
  assert(Current_routine_index < SIZE(Routines));
  for (int i = (Current_routine_index+1)%SIZE(Routines);  i != Current_routine_index;  i = (i+1)%SIZE(Routines)) {
    if (Routines.at(i)->state == RUNNING) {
      Current_routine_index = i;
      Current_routine = Routines.at(i);
      return;
    }
  }
}

string current_routine_label() {
  return routine_label(Current_routine);
}

string routine_label(routine* r) {
  ostringstream result;
  const call_stack& calls = r->calls;
  for (call_stack::const_iterator p = calls.begin();  p != calls.end();  ++p) {
    if (p != calls.begin()) result << '/';
    result << get(Recipe, p->running_recipe).name;
  }
  return result.str();
}

//: special case for the very first routine
:(replace{} "void run_main(int argc, char* argv[])")
void run_main(int argc, char* argv[]) {
  recipe_ordinal r = get(Recipe_ordinal, "main");
  assert(r);
  routine* main_routine = new routine(r);
  // pass in commandline args as ingredients to main
  // todo: test this
  Current_routine = main_routine;
  for (int i = 1;  i < argc;  ++i) {
    vector<double> arg;
    arg.push_back(new_mu_text(argv[i]));
    assert(get(Memory, arg.back()) == 0);
    current_call().ingredient_atoms.push_back(arg);
  }
  run(main_routine);
}

//:: To schedule new routines to run, call 'start-running'.

//: 'start-running' will return a unique id for the routine that was created.
//: routine id is a number, but don't do any arithmetic on it
:(before "End routine Fields")
int id;
:(before "End Globals")
int Next_routine_id = 1;
:(before "End Reset")
Next_routine_id = 1;
:(before "End routine Constructor")
id = Next_routine_id;
++Next_routine_id;

//: routines save the routine that spawned them
:(before "End routine Fields")
// todo: really should be routine_id, but that's less efficient.
int parent_index;  // only < 0 if there's no parent_index
:(before "End routine Constructor")
parent_index = -1;

:(before "End Primitive Recipe Declarations")
START_RUNNING,
:(before "End Primitive Recipe Numbers")
put(Recipe_ordinal, "start-running", START_RUNNING);
:(before "End Primitive Recipe Checks")
case START_RUNNING: {
  if (inst.ingredients.empty()) {
    raise << maybe(get(Recipe, r).name) << "'start-running' requires at least one ingredient: the recipe to start running\n" << end();
    break;
  }
  if (!is_mu_recipe(inst.ingredients.at(0))) {
    raise << maybe(get(Recipe, r).name) << "first ingredient of 'start-running' should be a recipe, but got '" << to_string(inst.ingredients.at(0)) << "'\n" << end();
    break;
  }
  break;
}
:(before "End Primitive Recipe Implementations")
case START_RUNNING: {
  routine* new_routine = new routine(ingredients.at(0).at(0));
  new_routine->parent_index = Current_routine_index;
  // populate ingredients
  for (int i = /*skip callee*/1;  i < SIZE(current_instruction().ingredients);  ++i) {
    new_routine->calls.front().ingredient_atoms.push_back(ingredients.at(i));
    reagent/*copy*/ ingredient = current_instruction().ingredients.at(i);
    new_routine->calls.front().ingredients.push_back(ingredient);
    // End Populate start-running Ingredient
  }
  Routines.push_back(new_routine);
  products.resize(1);
  products.at(0).push_back(new_routine->id);
  break;
}

:(code)
void test_scheduler_runs_single_routine() {
  Scheduling_interval = 1;
  run(
      "def f1 [\n"
      "  1:num <- copy 0\n"
      "  2:num <- copy 0\n"
      "]\n"
  );
  CHECK_TRACE_CONTENTS(
      "schedule: f1\n"
      "run: {1: \"number\"} <- copy {0: \"literal\"}\n"
      "schedule: f1\n"
      "run: {2: \"number\"} <- copy {0: \"literal\"}\n"
  );
}

void test_scheduler_interleaves_routines() {
  Scheduling_interval = 1;
  run(
      "def f1 [\n"
      "  start-running f2\n"
      "  1:num <- copy 0\n"
      "  2:num <- copy 0\n"
      "]\n"
      "def f2 [\n"
      "  3:num <- copy 0\n"
      "  4:num <- copy 0\n"
      "]\n"
  );
  CHECK_TRACE_CONTENTS(
      "schedule: f1\n"
      "run: start-running {f2: \"recipe-literal\"}\n"
      "schedule: f2\n"
      "run: {3: \"number\"} <- copy {0: \"literal\"}\n"
      "schedule: f1\n"
      "run: {1: \"number\"} <- copy {0: \"literal\"}\n"
      "schedule: f2\n"
      "run: {4: \"number\"} <- copy {0: \"literal\"}\n"
      "schedule: f1\n"
      "run: {2: \"number\"} <- copy {0: \"literal\"}\n"
  );
}

void test_start_running_takes_ingredients() {
  run(
      "def f1 [\n"
      "  start-running f2, 3\n"
         // wait for f2 to run
      "  {\n"
      "    jump-unless 1:num, -1\n"
      "  }\n"
      "]\n"
      "def f2 [\n"
      "  1:num <- next-ingredient\n"
      "  2:num <- add 1:num, 1\n"
      "]\n"
  );
  CHECK_TRACE_CONTENTS(
      "mem: storing 4 in location 2\n"
  );
}

//: type-checking for 'start-running'

void test_start_running_checks_types() {
  Hide_errors = true;
  run(
      "def f1 [\n"
      "  start-running f2, 3\n"
      "]\n"
      "def f2 n:&:num [\n"
      "]\n"
  );
  CHECK_TRACE_CONTENTS(
      "error: f1: ingredient 0 has the wrong type at 'start-running f2, 3'\n"
  );
}

// 'start-running' only uses the ingredients of the callee, not its products
:(before "End is_indirect_call_with_ingredients Special-cases")
if (r == START_RUNNING) return true;

//: back to testing 'start-running'

:(code)
void test_start_running_returns_routine_id() {
  run(
      "def f1 [\n"
      "  1:num <- start-running f2\n"
      "]\n"
      "def f2 [\n"
      "  12:num <- copy 44\n"
      "]\n"
  );
  CHECK_TRACE_CONTENTS(
      "mem: storing 2 in location 1\n"
  );
}

//: this scenario requires some careful setup
void test_scheduler_skips_completed_routines() {
  recipe_ordinal f1 = load(
      "recipe f1 [\n"
      "  1:num <- copy 0\n"
      "]\n").front();
  recipe_ordinal f2 = load(
      "recipe f2 [\n"
      "  2:num <- copy 0\n"
      "]\n").front();
  Routines.push_back(new routine(f1));  // f1 meant to run
  Routines.push_back(new routine(f2));
  Routines.back()->state = COMPLETED;  // f2 not meant to run
  run(
      "def f3 [\n"
      "  3:num <- copy 0\n"
      "]\n"
  );
  // f1 and f3 can run in any order
  CHECK_TRACE_CONTENTS(
      "schedule: f1\n"
      "mem: storing 0 in location 1\n"
  );
  CHECK_TRACE_DOESNT_CONTAIN("schedule: f2");
  CHECK_TRACE_DOESNT_CONTAIN("mem: storing 0 in location 2");
  CHECK_TRACE_CONTENTS(
      "schedule: f3\n"
      "mem: storing 0 in location 3\n"
  );
}

void test_scheduler_starts_at_middle_of_routines() {
  Routines.push_back(new routine(COPY));
  Routines.back()->state = COMPLETED;
  run(
      "def f1 [\n"
      "  1:num <- copy 0\n"
      "  2:num <- copy 0\n"
      "]\n"
  );
  CHECK_TRACE_CONTENTS(
      "schedule: f1\n"
  );
  CHECK_TRACE_DOESNT_CONTAIN("run: idle");
}

//:: Errors in a routine cause it to terminate.

void test_scheduler_terminates_routines_after_errors() {
  Hide_errors = true;
  Scheduling_interval = 2;
  run(
      "def f1 [\n"
      "  start-running f2\n"
      "  1:num <- copy 0\n"
      "  2:num <- copy 0\n"
      "]\n"
      "def f2 [\n"
         // divide by 0 twice
      "  3:num <- divide-with-remainder 4, 0\n"
      "  4:num <- divide-with-remainder 4, 0\n"
      "]\n"
  );
  // f2 should stop after first divide by 0
  CHECK_TRACE_CONTENTS(
      "error: f2: divide by zero in '3:num <- divide-with-remainder 4, 0'\n"
  );
  CHECK_TRACE_DOESNT_CONTAIN("error: f2: divide by zero in '4:num <- divide-with-remainder 4, 0'");
}

:(after "operator<<(ostream& os, end /*unused*/)")
  if (Trace_stream && Trace_stream->curr_label == "error" && Current_routine) {
    Current_routine->state = COMPLETED;
  }

//:: Routines are marked completed when their parent completes.

:(code)
void test_scheduler_kills_orphans() {
  run(
      "def main [\n"
      "  start-running f1\n"
         // f1 never actually runs because its parent completes without
         // waiting for it
      "]\n"
      "def f1 [\n"
      "  1:num <- copy 0\n"
      "]\n"
  );
  CHECK_TRACE_DOESNT_CONTAIN("schedule: f1");
}

:(before "End Scheduler Cleanup")
for (int i = 0;  i < SIZE(Routines);  ++i) {
  if (Routines.at(i)->state == COMPLETED) continue;
  if (Routines.at(i)->parent_index < 0) continue;  // root thread
  // structured concurrency: http://250bpm.com/blog:71
  if (has_completed_parent(i)) {
    Routines.at(i)->state = COMPLETED;
  }
}

:(code)
bool has_completed_parent(int routine_index) {
  for (int j = routine_index;  j >= 0;  j = Routines.at(j)->parent_index) {
    if (Routines.at(j)->state == COMPLETED)
      return true;
  }
  return false;
}

//:: 'routine-state' can tell if a given routine id is running

void test_routine_state_test() {
  Scheduling_interval = 2;
  run(
      "def f1 [\n"
      "  1:num/child-id <- start-running f2\n"
      "  12:num <- copy 0\n"  // race condition since we don't care about location 12
         // thanks to Scheduling_interval, f2's one instruction runs in
         // between here and completes
      "  2:num/state <- routine-state 1:num/child-id\n"
      "]\n"
      "def f2 [\n"
      "  12:num <- copy 0\n"
         // trying to run a second instruction marks routine as completed
      "]\n"
  );
  // routine f2 should be in state COMPLETED
  CHECK_TRACE_CONTENTS(
      "mem: storing 1 in location 2\n"
  );
}

:(before "End Primitive Recipe Declarations")
ROUTINE_STATE,
:(before "End Primitive Recipe Numbers")
put(Recipe_ordinal, "routine-state", ROUTINE_STATE);
:(before "End Primitive Recipe Checks")
case ROUTINE_STATE: {
  if (SIZE(inst.ingredients) != 1) {
    raise << maybe(get(Recipe, r).name) << "'routine-state' requires exactly one ingredient, but got '" << to_original_string(inst) << "'\n" << end();
    break;
  }
  if (!is_mu_number(inst.ingredients.at(0))) {
    raise << maybe(get(Recipe, r).name) << "first ingredient of 'routine-state' should be a routine id generated by 'start-running', but got '" << inst.ingredients.at(0).original_string << "'\n" << end();
    break;
  }
  break;
}
:(before "End Primitive Recipe Implementations")
case ROUTINE_STATE: {
  int id = ingredients.at(0).at(0);
  int result = -1;
  for (int i = 0;  i < SIZE(Routines);  ++i) {
    if (Routines.at(i)->id == id) {
      result = Routines.at(i)->state;
      break;
    }
  }
  products.resize(1);
  products.at(0).push_back(result);
  break;
}

//:: miscellaneous helpers

:(before "End Primitive Recipe Declarations")
STOP,
:(before "End Primitive Recipe Numbers")
put(Recipe_ordinal, "stop", STOP);
:(before "End Primitive Recipe Checks")
case STOP: {
  if (SIZE(inst.ingredients) != 1) {
    raise << maybe(get(Recipe, r).name) << "'stop' requires exactly one ingredient, but got '" << to_original_string(inst) << "'\n" << end();
    break;
  }
  if (!is_mu_number(inst.ingredients.at(0))) {
    raise << maybe(get(Recipe, r).name) << "first ingredient of 'stop' should be a routine id generated by 'start-running', but got '" << inst.ingredients.at(0).original_string << "'\n" << end();
    break;
  }
  break;
}
:(before "End Primitive Recipe Implementations")
case STOP: {
  int id = ingredients.at(0).at(0);
  for (int i = 0;  i < SIZE(Routines);  ++i) {
    if (Routines.at(i)->id == id) {
      Routines.at(i)->state = COMPLETED;
      break;
    }
  }
  break;
}

:(before "End Primitive Recipe Declarations")
_DUMP_ROUTINES,
:(before "End Primitive Recipe Numbers")
put(Recipe_ordinal, "$dump-routines", _DUMP_ROUTINES);
:(before "End Primitive Recipe Checks")
case _DUMP_ROUTINES: {
  break;
}
:(before "End Primitive Recipe Implementations")
case _DUMP_ROUTINES: {
  for (int i = 0;  i < SIZE(Routines);  ++i) {
    cerr << i << ": " << Routines.at(i)->id << ' ' << Routines.at(i)->state << ' ' << Routines.at(i)->parent_index << '\n';
  }
  break;
}

//: support for stopping routines after some number of cycles

:(code)
void test_routine_discontinues_past_limit() {
  Scheduling_interval = 2;
  run(
      "def f1 [\n"
      "  1:num/child-id <- start-running f2\n"
      "  limit-time 1:num/child-id, 10\n"
         // padding loop just to make sure f2 has time to complete
      "  2:num <- copy 20\n"
      "  2:num <- subtract 2:num, 1\n"
      "  jump-if 2:num, -2:offset\n"
      "]\n"
      "def f2 [\n"
      "  jump -1:offset\n"  // run forever
      "  $print [should never get here], 10/newline\n"
      "]\n"
  );
  // f2 terminates
  CHECK_TRACE_CONTENTS(
      "schedule: discontinuing routine 2\n"
  );
}

:(before "End routine States")
DISCONTINUED,
:(before "End Scheduler State Transitions")
if (Current_routine->limit >= 0) {
  if (Current_routine->limit <= Scheduling_interval) {
    trace(100, "schedule") << "discontinuing routine " << Current_routine->id << end();
    Current_routine->state = DISCONTINUED;
    Current_routine->limit = 0;
  }
  else {
    Current_routine->limit -= Scheduling_interval;
  }
}

:(before "End Test Teardown")
if (Passed && any_routines_with_error())
  raise << "some routines died with errors\n" << end();
:(before "End Mu Test Teardown")
if (Passed && any_routines_with_error())
  raise << Current_scenario->name << ": some routines died with errors\n" << end();

:(code)
bool any_routines_with_error() {
  for (int i = 0;  i < SIZE(Routines);  ++i) {
    if (Routines.at(i)->state == DISCONTINUED)
      return true;
  }
  return false;
}

:(before "End routine Fields")
int limit;
:(before "End routine Constructor")
limit = -1;  /* no limit */

:(before "End Primitive Recipe Declarations")
LIMIT_TIME,
:(before "End Primitive Recipe Numbers")
put(Recipe_ordinal, "limit-time", LIMIT_TIME);
:(before "End Primitive Recipe Checks")
case LIMIT_TIME: {
  if (SIZE(inst.ingredients) != 2) {
    raise << maybe(get(Recipe, r).name) << "'limit-time' requires exactly two ingredient, but got '" << to_original_string(inst) << "'\n" << end();
    break;
  }
  if (!is_mu_number(inst.ingredients.at(0))) {
    raise << maybe(get(Recipe, r).name) << "first ingredient of 'limit-time' should be a routine id generated by 'start-running', but got '" << inst.ingredients.at(0).original_string << "'\n" << end();
    break;
  }
  if (!is_mu_number(inst.ingredients.at(1))) {
    raise << maybe(get(Recipe, r).name) << "second ingredient of 'limit-time' should be a number (of instructions to run for), but got '" << inst.ingredients.at(1).original_string << "'\n" << end();
    break;
  }
  break;
}
:(before "End Primitive Recipe Implementations")
case LIMIT_TIME: {
  int id = ingredients.at(0).at(0);
  for (int i = 0;  i < SIZE(Routines);  ++i) {
    if (Routines.at(i)->id == id) {
      Routines.at(i)->limit = ingredients.at(1).at(0);
      break;
    }
  }
  break;
}

:(before "End routine Fields")
int instructions_run;
:(before "End routine Constructor")
instructions_run = 0;
:(before "Reset instructions_run_this_scheduling_slice")
Current_routine->instructions_run += Current_routine->instructions_run_this_scheduling_slice;
:(before "End Primitive Recipe Declarations")
NUMBER_OF_INSTRUCTIONS,
:(before "End Primitive Recipe Numbers")
put(Recipe_ordinal, "number-of-instructions", NUMBER_OF_INSTRUCTIONS);
:(before "End Primitive Recipe Checks")
case NUMBER_OF_INSTRUCTIONS: {
  if (SIZE(inst.ingredients) != 1) {
    raise << maybe(get(Recipe, r).name) << "'number-of-instructions' requires exactly one ingredient, but got '" << to_original_string(inst) << "'\n" << end();
    break;
  }
  if (!is_mu_number(inst.ingredients.at(0))) {
    raise << maybe(get(Recipe, r).name) << "first ingredient of 'number-of-instructions' should be a routine id generated by 'start-running', but got '" << inst.ingredients.at(0).original_string << "'\n" << end();
    break;
  }
  break;
}
:(before "End Primitive Recipe Implementations")
case NUMBER_OF_INSTRUCTIONS: {
  int id = ingredients.at(0).at(0);
  int result = -1;
  for (int i = 0;  i < SIZE(Routines);  ++i) {
    if (Routines.at(i)->id == id) {
      result = Routines.at(i)->instructions_run;
      break;
    }
  }
  products.resize(1);
  products.at(0).push_back(result);
  break;
}

:(code)
void test_number_of_instructions() {
  run(
      "def f1 [\n"
      "  10:num/child-id <- start-running f2\n"
      "  {\n"
      "    loop-unless 20:num\n"
      "  }\n"
      "  11:num <- number-of-instructions 10:num\n"
      "]\n"
      "def f2 [\n"
         // 2 instructions worth of work
      "  1:num <- copy 34\n"
      "  20:num <- copy 1\n"
      "]\n"
  );
  // f2 runs an extra instruction for the implicit 'return' added by the
  // fill_in_return_ingredients transform
  CHECK_TRACE_CONTENTS(
      "mem: storing 3 in location 11\n"
  );
}

void test_number_of_instructions_across_multiple_scheduling_intervals() {
  Scheduling_interval = 1;
  run(
      "def f1 [\n"
      "  10:num/child-id <- start-running f2\n"
      "  {\n"
      "    loop-unless 20:num\n"
      "  }\n"
      "  11:num <- number-of-instructions 10:num\n"
      "]\n"
      "def f2 [\n"
         // 4 instructions worth of work
      "  1:num <- copy 34\n"
      "  2:num <- copy 1\n"
      "  2:num <- copy 3\n"
      "  20:num <- copy 1\n"
      "]\n"
  );
  // f2 runs an extra instruction for the implicit 'return' added by the
  // fill_in_return_ingredients transform
  CHECK_TRACE_CONTENTS(
      "mem: storing 5 in location 11\n"
  );
}

//:: make sure that each routine gets a different alloc to start

void test_new_concurrent() {
  run(
      "def f1 [\n"
      "  start-running f2\n"
      "  1:&:num/raw <- new number:type\n"
         // wait for f2 to complete
      "  {\n"
      "    loop-unless 4:num/raw\n"
      "  }\n"
      "]\n"
      "def f2 [\n"
      "  2:&:num/raw <- new number:type\n"
         // hack: assumes scheduler implementation
      "  3:bool/raw <- equal 1:&:num/raw, 2:&:num/raw\n"
         // signal f2 complete
      "  4:num/raw <- copy 1\n"
      "]\n"
  );
  CHECK_TRACE_CONTENTS(
      "mem: storing 0 in location 3\n"
  );
}