package scheduler_test

import (
	"testing"
	"time"

	"github.com/jfraeys/fetch_ml/internal/scheduler"
)

func TestCanAdmit_BackendMatching(t *testing.T) {
	h := scheduler.NewTestSchedulerHub(scheduler.HubConfig{})
	h.SetReservationsForTest(make(map[string]*scheduler.Reservation))

	tests := []struct {
		name       string
		workerCaps scheduler.WorkerCapabilities
		jobSpec    scheduler.JobSpec
		want       bool
	}{
		{
			name: "backend matches nvidia",
			workerCaps: scheduler.WorkerCapabilities{
				GPUBackend: scheduler.BackendNVIDIA,
				GPUCount:   4,
			},
			jobSpec: scheduler.JobSpec{
				GPUBackend: "nvidia",
				GPUCount:   2,
			},
			want: true,
		},
		{
			name: "backend matches metal",
			workerCaps: scheduler.WorkerCapabilities{
				GPUBackend: scheduler.BackendMetal,
				GPUCount:   2,
			},
			jobSpec: scheduler.JobSpec{
				GPUBackend: "metal",
				GPUCount:   1,
			},
			want: true,
		},
		{
			name: "backend mismatch nvidia vs metal",
			workerCaps: scheduler.WorkerCapabilities{
				GPUBackend: scheduler.BackendNVIDIA,
				GPUCount:   4,
			},
			jobSpec: scheduler.JobSpec{
				GPUBackend: "metal",
				GPUCount:   1,
			},
			want: false,
		},
		{
			name: "no backend required - any matches",
			workerCaps: scheduler.WorkerCapabilities{
				GPUBackend: scheduler.BackendVulkan,
				GPUCount:   2,
			},
			jobSpec: scheduler.JobSpec{
				GPUBackend: "",
				GPUCount:   1,
			},
			want: true,
		},
		{
			name: "cpu job on cpu worker",
			workerCaps: scheduler.WorkerCapabilities{
				GPUBackend: scheduler.BackendCPU,
				GPUCount:   0,
				CPUCount:   8,
			},
			jobSpec: scheduler.JobSpec{
				GPUBackend: "cpu",
				GPUCount:   0,
			},
			want: true,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			wc := scheduler.NewWorkerConnForTest(tt.workerCaps, scheduler.SlotStatus{BatchTotal: 4})
			task := &scheduler.Task{
				ID:   "test-task",
				Spec: tt.jobSpec,
			}
			got := h.CanAdmitForTest(task, wc)
			if got != tt.want {
				t.Errorf("CanAdmitForTest() = %v, want %v", got, tt.want)
			}
		})
	}
}

func TestCanAdmit_VRAMRequirements(t *testing.T) {
	h := scheduler.NewTestSchedulerHub(scheduler.HubConfig{})
	h.SetReservationsForTest(make(map[string]*scheduler.Reservation))

	tests := []struct {
		name       string
		workerCaps scheduler.WorkerCapabilities
		jobSpec    scheduler.JobSpec
		want       bool
	}{
		{
			name: "sufficient VRAM",
			workerCaps: scheduler.WorkerCapabilities{
				GPUBackend: scheduler.BackendNVIDIA,
				GPUCount:   2,
				VRAMGB:     32.0,
			},
			jobSpec: scheduler.JobSpec{
				MinVRAMGB: 16.0,
				GPUCount:  1,
			},
			want: true,
		},
		{
			name: "insufficient VRAM",
			workerCaps: scheduler.WorkerCapabilities{
				GPUBackend: scheduler.BackendNVIDIA,
				GPUCount:   2,
				VRAMGB:     8.0,
			},
			jobSpec: scheduler.JobSpec{
				MinVRAMGB: 16.0,
				GPUCount:  1,
			},
			want: false,
		},
		{
			name: "no VRAM required",
			workerCaps: scheduler.WorkerCapabilities{
				GPUBackend: scheduler.BackendNVIDIA,
				GPUCount:   2,
				VRAMGB:     8.0,
			},
			jobSpec: scheduler.JobSpec{
				MinVRAMGB: 0,
				GPUCount:  1,
			},
			want: true,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			wc := scheduler.NewWorkerConnForTest(tt.workerCaps, scheduler.SlotStatus{BatchTotal: 4})
			task := &scheduler.Task{
				ID:   "test-task",
				Spec: tt.jobSpec,
			}
			got := h.CanAdmitForTest(task, wc)
			if got != tt.want {
				t.Errorf("CanAdmitForTest() = %v, want %v", got, tt.want)
			}
		})
	}
}

func TestCanAdmit_CPUCoresRequirements(t *testing.T) {
	h := scheduler.NewTestSchedulerHub(scheduler.HubConfig{})
	h.SetReservationsForTest(make(map[string]*scheduler.Reservation))

	tests := []struct {
		name       string
		workerCaps scheduler.WorkerCapabilities
		jobSpec    scheduler.JobSpec
		want       bool
	}{
		{
			name: "sufficient CPU cores",
			workerCaps: scheduler.WorkerCapabilities{
				GPUBackend: scheduler.BackendCPU,
				CPUCount:   16,
			},
			jobSpec: scheduler.JobSpec{
				MinCPUCores: 8,
				GPUCount:    0,
			},
			want: true,
		},
		{
			name: "insufficient CPU cores",
			workerCaps: scheduler.WorkerCapabilities{
				GPUBackend: scheduler.BackendCPU,
				CPUCount:   4,
			},
			jobSpec: scheduler.JobSpec{
				MinCPUCores: 8,
				GPUCount:    0,
			},
			want: false,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			wc := scheduler.NewWorkerConnForTest(tt.workerCaps, scheduler.SlotStatus{BatchTotal: 4})
			task := &scheduler.Task{
				ID:   "test-task",
				Spec: tt.jobSpec,
			}
			got := h.CanAdmitForTest(task, wc)
			if got != tt.want {
				t.Errorf("CanAdmitForTest() = %v, want %v", got, tt.want)
			}
		})
	}
}

func TestCanAdmit_ReservedGPUs(t *testing.T) {
	h := scheduler.NewTestSchedulerHub(scheduler.HubConfig{})
	h.SetReservationsForTest(map[string]*scheduler.Reservation{
		"res-1": {TaskID: "task-1", GPUCount: 2},
		"res-2": {TaskID: "task-2", GPUCount: 2},
	})

	tests := []struct {
		name       string
		workerCaps scheduler.WorkerCapabilities
		jobSpec    scheduler.JobSpec
		want       bool
	}{
		{
			name: "enough GPUs after reservations",
			workerCaps: scheduler.WorkerCapabilities{
				GPUBackend: scheduler.BackendNVIDIA,
				GPUCount:   8,
			},
			jobSpec: scheduler.JobSpec{
				GPUCount: 4,
			},
			want: true,
		},
		{
			name: "not enough GPUs after reservations",
			workerCaps: scheduler.WorkerCapabilities{
				GPUBackend: scheduler.BackendNVIDIA,
				GPUCount:   4,
			},
			jobSpec: scheduler.JobSpec{
				GPUCount: 2,
			},
			want: false,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			wc := scheduler.NewWorkerConnForTest(tt.workerCaps, scheduler.SlotStatus{BatchTotal: 4})
			task := &scheduler.Task{
				ID:   "test-task",
				Spec: tt.jobSpec,
			}
			got := h.CanAdmitForTest(task, wc)
			if got != tt.want {
				t.Errorf("CanAdmitForTest() = %v, want %v", got, tt.want)
			}
		})
	}
}

func TestReconcileOrphans_TierGracePeriods(t *testing.T) {
	tests := []struct {
		name         string
		jobTier      scheduler.JobTier
		accepted     bool
		assignedAt   time.Time
		wantRequeued bool
	}{
		{
			name:         "data_processing tier - short grace period",
			jobTier:      scheduler.TierDataProcessing,
			accepted:     true,
			assignedAt:   time.Now().Add(-35 * time.Second),
			wantRequeued: true,
		},
		{
			name:         "training tier - long grace period",
			jobTier:      scheduler.TierTraining,
			accepted:     true,
			assignedAt:   time.Now().Add(-5 * time.Minute),
			wantRequeued: false,
		},
		{
			name:         "training tier - past grace period",
			jobTier:      scheduler.TierTraining,
			accepted:     true,
			assignedAt:   time.Now().Add(-11 * time.Minute),
			wantRequeued: true,
		},
		{
			name:         "evaluation tier - 2min grace",
			jobTier:      scheduler.TierEvaluation,
			accepted:     true,
			assignedAt:   time.Now().Add(-3 * time.Minute),
			wantRequeued: true,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			h := scheduler.NewTestSchedulerHub(scheduler.HubConfig{
				AcceptanceTimeoutSecs: 60,
				TestGracePeriods: map[scheduler.JobTier]time.Duration{
					scheduler.TierDataProcessing: 30 * time.Second,
					scheduler.TierTraining:       10 * time.Minute,
					scheduler.TierEvaluation:     2 * time.Minute,
				},
			})

			task := &scheduler.Task{
				ID:     "test-task",
				Status: "assigned",
				Spec: scheduler.JobSpec{
					JobTier: tt.jobTier,
				},
			}

			h.SetPendingAcceptanceForTest("test-task", &scheduler.JobAssignment{
				TaskID:     "test-task",
				WorkerID:   "disconnected-worker",
				AssignedAt: tt.assignedAt,
				Accepted:   tt.accepted,
				Task:       task,
			})

			h.ReconcileOrphansForTest()

			_, stillPending := h.GetPendingAcceptanceForTest("test-task")
			wasRequeued := !stillPending

			if wasRequeued != tt.wantRequeued {
				t.Errorf("ReconcileOrphansForTest() requeued=%v, want=%v", wasRequeued, tt.wantRequeued)
			}
		})
	}
}