package nomad

import (
	"errors"
	"fmt"
	"testing"
	"time"

	"github.com/hashicorp/nomad/nomad/mock"
	"github.com/hashicorp/nomad/nomad/structs"
	"github.com/hashicorp/nomad/testutil"
)

func TestLeader_LeftServer(t *testing.T) {
	s1 := testServer(t, nil)
	defer s1.Shutdown()

	s2 := testServer(t, func(c *Config) {
		c.DevDisableBootstrap = true
	})
	defer s2.Shutdown()

	s3 := testServer(t, func(c *Config) {
		c.DevDisableBootstrap = true
	})
	defer s3.Shutdown()
	servers := []*Server{s1, s2, s3}
	testJoin(t, s1, s2, s3)

	for _, s := range servers {
		testutil.WaitForResult(func() (bool, error) {
			peers, _ := s.raftPeers.Peers()
			return len(peers) == 3, nil
		}, func(err error) {
			t.Fatalf("should have 3 peers")
		})
	}

	// Kill any server
	servers[0].Shutdown()

	testutil.WaitForResult(func() (bool, error) {
		// Force remove the non-leader (transition to left state)
		name := fmt.Sprintf("%s.%s",
			servers[0].config.NodeName, servers[0].config.Region)
		if err := servers[1].RemoveFailedNode(name); err != nil {
			t.Fatalf("err: %v", err)
		}

		for _, s := range servers[1:] {
			peers, _ := s.raftPeers.Peers()
			return len(peers) == 2, errors.New(fmt.Sprintf("%v", peers))
		}

		return true, nil
	}, func(err error) {
		t.Fatalf("err: %s", err)
	})
}

func TestLeader_LeftLeader(t *testing.T) {
	s1 := testServer(t, nil)
	defer s1.Shutdown()

	s2 := testServer(t, func(c *Config) {
		c.DevDisableBootstrap = true
	})
	defer s2.Shutdown()

	s3 := testServer(t, func(c *Config) {
		c.DevDisableBootstrap = true
	})
	defer s3.Shutdown()
	servers := []*Server{s1, s2, s3}
	testJoin(t, s1, s2, s3)

	for _, s := range servers {
		testutil.WaitForResult(func() (bool, error) {
			peers, _ := s.raftPeers.Peers()
			return len(peers) == 3, nil
		}, func(err error) {
			t.Fatalf("should have 3 peers")
		})
	}

	// Kill the leader!
	var leader *Server
	for _, s := range servers {
		if s.IsLeader() {
			leader = s
			break
		}
	}
	if leader == nil {
		t.Fatalf("Should have a leader")
	}
	leader.Leave()
	leader.Shutdown()

	for _, s := range servers {
		if s == leader {
			continue
		}
		testutil.WaitForResult(func() (bool, error) {
			peers, _ := s.raftPeers.Peers()
			return len(peers) == 2, errors.New(fmt.Sprintf("%v", peers))
		}, func(err error) {
			t.Fatalf("should have 2 peers: %v", err)
		})
	}
}

func TestLeader_MultiBootstrap(t *testing.T) {
	s1 := testServer(t, nil)
	defer s1.Shutdown()

	s2 := testServer(t, nil)
	defer s2.Shutdown()
	servers := []*Server{s1, s2}
	testJoin(t, s1, s2)

	for _, s := range servers {
		testutil.WaitForResult(func() (bool, error) {
			peers := s.Members()
			return len(peers) == 2, nil
		}, func(err error) {
			t.Fatalf("should have 2 peers")
		})
	}

	// Ensure we don't have multiple raft peers
	for _, s := range servers {
		peers, _ := s.raftPeers.Peers()
		if len(peers) != 1 {
			t.Fatalf("should only have 1 raft peer!")
		}
	}
}

func TestLeader_PlanQueue_Reset(t *testing.T) {
	s1 := testServer(t, nil)
	defer s1.Shutdown()

	s2 := testServer(t, func(c *Config) {
		c.DevDisableBootstrap = true
	})
	defer s2.Shutdown()

	s3 := testServer(t, func(c *Config) {
		c.DevDisableBootstrap = true
	})
	defer s3.Shutdown()
	servers := []*Server{s1, s2, s3}
	testJoin(t, s1, s2, s3)

	for _, s := range servers {
		testutil.WaitForResult(func() (bool, error) {
			peers, _ := s.raftPeers.Peers()
			return len(peers) == 3, nil
		}, func(err error) {
			t.Fatalf("should have 3 peers")
		})
	}

	var leader *Server
	for _, s := range servers {
		if s.IsLeader() {
			leader = s
			break
		}
	}
	if leader == nil {
		t.Fatalf("Should have a leader")
	}

	if !leader.planQueue.Enabled() {
		t.Fatalf("should enable plan queue")
	}

	for _, s := range servers {
		if !s.IsLeader() && s.planQueue.Enabled() {
			t.Fatalf("plan queue should not be enabled")
		}
	}

	// Kill the leader
	leader.Shutdown()
	time.Sleep(100 * time.Millisecond)

	// Wait for a new leader
	leader = nil
	testutil.WaitForResult(func() (bool, error) {
		for _, s := range servers {
			if s.IsLeader() {
				leader = s
				return true, nil
			}
		}
		return false, nil
	}, func(err error) {
		t.Fatalf("should have leader")
	})

	// Check that the new leader has a pending GC expiration
	testutil.WaitForResult(func() (bool, error) {
		return leader.planQueue.Enabled(), nil
	}, func(err error) {
		t.Fatalf("should enable plan queue")
	})
}

func TestLeader_EvalBroker_Reset(t *testing.T) {
	s1 := testServer(t, func(c *Config) {
		c.NumSchedulers = 0
	})
	defer s1.Shutdown()

	s2 := testServer(t, func(c *Config) {
		c.NumSchedulers = 0
		c.DevDisableBootstrap = true
	})
	defer s2.Shutdown()

	s3 := testServer(t, func(c *Config) {
		c.NumSchedulers = 0
		c.DevDisableBootstrap = true
	})
	defer s3.Shutdown()
	servers := []*Server{s1, s2, s3}
	testJoin(t, s1, s2, s3)
	testutil.WaitForLeader(t, s1.RPC)

	for _, s := range servers {
		testutil.WaitForResult(func() (bool, error) {
			peers, _ := s.raftPeers.Peers()
			return len(peers) == 3, nil
		}, func(err error) {
			t.Fatalf("should have 3 peers")
		})
	}

	var leader *Server
	for _, s := range servers {
		if s.IsLeader() {
			leader = s
			break
		}
	}
	if leader == nil {
		t.Fatalf("Should have a leader")
	}

	// Inject a pending eval
	req := structs.EvalUpdateRequest{
		Evals: []*structs.Evaluation{mock.Eval()},
	}
	_, _, err := leader.raftApply(structs.EvalUpdateRequestType, req)
	if err != nil {
		t.Fatalf("err: %v", err)
	}

	// Kill the leader
	leader.Shutdown()
	time.Sleep(100 * time.Millisecond)

	// Wait for a new leader
	leader = nil
	testutil.WaitForResult(func() (bool, error) {
		for _, s := range servers {
			if s.IsLeader() {
				leader = s
				return true, nil
			}
		}
		return false, nil
	}, func(err error) {
		t.Fatalf("should have leader")
	})

	// Check that the new leader has a pending evaluation
	testutil.WaitForResult(func() (bool, error) {
		stats := leader.evalBroker.Stats()
		return stats.TotalReady == 1, nil
	}, func(err error) {
		t.Fatalf("should have pending evaluation")
	})
}

func TestLeader_PeriodicDispatcher_Restore_Adds(t *testing.T) {
	s1 := testServer(t, func(c *Config) {
		c.NumSchedulers = 0
	})
	defer s1.Shutdown()

	s2 := testServer(t, func(c *Config) {
		c.NumSchedulers = 0
		c.DevDisableBootstrap = true
	})
	defer s2.Shutdown()

	s3 := testServer(t, func(c *Config) {
		c.NumSchedulers = 0
		c.DevDisableBootstrap = true
	})
	defer s3.Shutdown()
	servers := []*Server{s1, s2, s3}
	testJoin(t, s1, s2, s3)
	testutil.WaitForLeader(t, s1.RPC)

	for _, s := range servers {
		testutil.WaitForResult(func() (bool, error) {
			peers, _ := s.raftPeers.Peers()
			return len(peers) == 3, nil
		}, func(err error) {
			t.Fatalf("should have 3 peers")
		})
	}

	var leader *Server
	for _, s := range servers {
		if s.IsLeader() {
			leader = s
			break
		}
	}
	if leader == nil {
		t.Fatalf("Should have a leader")
	}

	// Inject a periodic job and non-periodic job
	periodic := mock.PeriodicJob()
	nonPeriodic := mock.Job()
	for _, job := range []*structs.Job{nonPeriodic, periodic} {
		req := structs.JobRegisterRequest{
			Job: job,
		}
		_, _, err := leader.raftApply(structs.JobRegisterRequestType, req)
		if err != nil {
			t.Fatalf("err: %v", err)
		}
	}

	// Kill the leader
	leader.Shutdown()
	time.Sleep(100 * time.Millisecond)

	// Wait for a new leader
	leader = nil
	testutil.WaitForResult(func() (bool, error) {
		for _, s := range servers {
			if s.IsLeader() {
				leader = s
				return true, nil
			}
		}
		return false, nil
	}, func(err error) {
		t.Fatalf("should have leader")
	})

	// Check that the new leader is tracking the periodic job.
	testutil.WaitForResult(func() (bool, error) {
		_, tracked := leader.periodicDispatcher.tracked[periodic.ID]
		return tracked, nil
	}, func(err error) {
		t.Fatalf("periodic job not tracked")
	})
}

func TestLeader_PeriodicDispatcher_Restore_NoEvals(t *testing.T) {
	s1 := testServer(t, func(c *Config) {
		c.NumSchedulers = 0
	})
	defer s1.Shutdown()
	testutil.WaitForLeader(t, s1.RPC)

	// Inject a periodic job that will be triggered soon.
	launch := time.Now().Add(1 * time.Second)
	job := testPeriodicJob(launch)
	req := structs.JobRegisterRequest{
		Job: job,
	}
	_, _, err := s1.raftApply(structs.JobRegisterRequestType, req)
	if err != nil {
		t.Fatalf("err: %v", err)
	}

	// Flush the periodic dispatcher, ensuring that no evals will be created.
	s1.periodicDispatcher.SetEnabled(false)

	// Get the current time to ensure the launch time is after this once we
	// restore.
	now := time.Now()

	// Sleep till after the job should have been launched.
	time.Sleep(3 * time.Second)

	// Restore the periodic dispatcher.
	s1.periodicDispatcher.SetEnabled(true)
	s1.periodicDispatcher.Start()
	s1.restorePeriodicDispatcher()

	// Ensure the job is tracked.
	if _, tracked := s1.periodicDispatcher.tracked[job.ID]; !tracked {
		t.Fatalf("periodic job not restored")
	}

	// Check that an eval was made.
	last, err := s1.fsm.State().PeriodicLaunchByID(job.ID)
	if err != nil || last == nil {
		t.Fatalf("failed to get periodic launch time: %v", err)
	}

	if last.Launch.Before(now) {
		t.Fatalf("restorePeriodicDispatcher did not force launch: last %v; want after %v", last.Launch, now)
	}
}

func TestLeader_PeriodicDispatcher_Restore_Evals(t *testing.T) {
	s1 := testServer(t, func(c *Config) {
		c.NumSchedulers = 0
	})
	defer s1.Shutdown()
	testutil.WaitForLeader(t, s1.RPC)

	// Inject a periodic job that triggered once in the past, should trigger now
	// and once in the future.
	now := time.Now()
	past := now.Add(-1 * time.Second)
	future := now.Add(10 * time.Second)
	job := testPeriodicJob(past, now, future)
	req := structs.JobRegisterRequest{
		Job: job,
	}
	_, _, err := s1.raftApply(structs.JobRegisterRequestType, req)
	if err != nil {
		t.Fatalf("err: %v", err)
	}

	// Create an eval for the past launch.
	s1.periodicDispatcher.createEval(job, past)

	// Flush the periodic dispatcher, ensuring that no evals will be created.
	s1.periodicDispatcher.SetEnabled(false)

	// Sleep till after the job should have been launched.
	time.Sleep(3 * time.Second)

	// Restore the periodic dispatcher.
	s1.periodicDispatcher.SetEnabled(true)
	s1.periodicDispatcher.Start()
	s1.restorePeriodicDispatcher()

	// Ensure the job is tracked.
	if _, tracked := s1.periodicDispatcher.tracked[job.ID]; !tracked {
		t.Fatalf("periodic job not restored")
	}

	// Check that an eval was made.
	last, err := s1.fsm.State().PeriodicLaunchByID(job.ID)
	if err != nil || last == nil {
		t.Fatalf("failed to get periodic launch time: %v", err)
	}
	if last.Launch == past {
		t.Fatalf("restorePeriodicDispatcher did not force launch")
	}
}

func TestLeader_PeriodicDispatch(t *testing.T) {
	s1 := testServer(t, func(c *Config) {
		c.NumSchedulers = 0
		c.EvalGCInterval = 5 * time.Millisecond
	})
	defer s1.Shutdown()

	// Wait for a periodic dispatch
	testutil.WaitForResult(func() (bool, error) {
		stats := s1.evalBroker.Stats()
		bySched, ok := stats.ByScheduler[structs.JobTypeCore]
		if !ok {
			return false, nil
		}
		return bySched.Ready > 0, nil
	}, func(err error) {
		t.Fatalf("should pending job")
	})
}

func TestLeader_ReapFailedEval(t *testing.T) {
	s1 := testServer(t, func(c *Config) {
		c.NumSchedulers = 0
		c.EvalDeliveryLimit = 1
	})
	defer s1.Shutdown()
	testutil.WaitForLeader(t, s1.RPC)

	// Wait for a periodic dispatch
	eval := mock.Eval()
	testutil.WaitForResult(func() (bool, error) {
		err := s1.evalBroker.Enqueue(eval)
		return err == nil, err
	}, func(err error) {
		t.Fatalf("err: %v", err)
	})

	// Dequeue and Nack
	out, token, err := s1.evalBroker.Dequeue(defaultSched, time.Second)
	if err != nil {
		t.Fatalf("err: %v", err)
	}
	s1.evalBroker.Nack(out.ID, token)

	// Wait updated evaluation
	state := s1.fsm.State()
	testutil.WaitForResult(func() (bool, error) {
		out, err := state.EvalByID(eval.ID)
		if err != nil {
			return false, err
		}
		return out != nil && out.Status == structs.EvalStatusFailed, nil
	}, func(err error) {
		t.Fatalf("err: %v", err)
	})
}