package service

import (
	"context"
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"testing"

	"gcy_hpc_server/internal/slurm"

	"go.uber.org/zap"
	"go.uber.org/zap/zapcore"
	"go.uber.org/zap/zaptest/observer"
)

func mockServer(handler http.HandlerFunc) (*slurm.Client, func()) {
	srv := httptest.NewServer(handler)
	client, _ := slurm.NewClient(srv.URL, srv.Client())
	return client, srv.Close
}

func TestGetNodes(t *testing.T) {
	client, cleanup := mockServer(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != "/slurm/v0.0.40/nodes" {
			t.Errorf("unexpected path: %s", r.URL.Path)
		}
		resp := map[string]interface{}{
			"nodes": []map[string]interface{}{
				{
					"name":             "node1",
					"state":            []string{"IDLE"},
					"cpus":             64,
					"real_memory":      256000,
					"alloc_memory":     0,
					"architecture":     "x86_64",
					"operating_system": "Linux 5.15",
				},
			},
		}
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(resp)
	})
	defer cleanup()

	svc := NewClusterService(client, zap.NewNop())
	nodes, err := svc.GetNodes(context.Background())
	if err != nil {
		t.Fatalf("GetNodes returned error: %v", err)
	}
	if len(nodes) != 1 {
		t.Fatalf("expected 1 node, got %d", len(nodes))
	}
	n := nodes[0]
	if n.Name != "node1" {
		t.Errorf("expected name node1, got %s", n.Name)
	}
	if len(n.State) != 1 || n.State[0] != "IDLE" {
		t.Errorf("expected state [IDLE], got %v", n.State)
	}
	if n.CPUs != 64 {
		t.Errorf("expected 64 CPUs, got %d", n.CPUs)
	}
	if n.RealMemory != 256000 {
		t.Errorf("expected real_memory 256000, got %d", n.RealMemory)
	}
	if n.Arch != "x86_64" {
		t.Errorf("expected arch x86_64, got %s", n.Arch)
	}
	if n.OS != "Linux 5.15" {
		t.Errorf("expected OS 'Linux 5.15', got %s", n.OS)
	}
}

func TestGetNodes_Empty(t *testing.T) {
	client, cleanup := mockServer(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(map[string]interface{}{})
	})
	defer cleanup()

	svc := NewClusterService(client, zap.NewNop())
	nodes, err := svc.GetNodes(context.Background())
	if err != nil {
		t.Fatalf("GetNodes returned error: %v", err)
	}
	if nodes != nil {
		t.Errorf("expected nil for empty response, got %v", nodes)
	}
}

func TestGetNode(t *testing.T) {
	client, cleanup := mockServer(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != "/slurm/v0.0.40/node/node1" {
			t.Errorf("unexpected path: %s", r.URL.Path)
		}
		resp := map[string]interface{}{
			"nodes": []map[string]interface{}{
				{"name": "node1", "state": []string{"ALLOCATED"}, "cpus": 32},
			},
		}
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(resp)
	})
	defer cleanup()

	svc := NewClusterService(client, zap.NewNop())
	node, err := svc.GetNode(context.Background(), "node1")
	if err != nil {
		t.Fatalf("GetNode returned error: %v", err)
	}
	if node == nil {
		t.Fatal("expected node, got nil")
	}
	if node.Name != "node1" {
		t.Errorf("expected name node1, got %s", node.Name)
	}
}

func TestGetNode_NotFound(t *testing.T) {
	client, cleanup := mockServer(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(map[string]interface{}{})
	})
	defer cleanup()

	svc := NewClusterService(client, zap.NewNop())
	node, err := svc.GetNode(context.Background(), "missing")
	if err != nil {
		t.Fatalf("GetNode returned error: %v", err)
	}
	if node != nil {
		t.Errorf("expected nil for missing node, got %+v", node)
	}
}

func TestGetPartitions(t *testing.T) {
	client, cleanup := mockServer(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != "/slurm/v0.0.40/partitions" {
			t.Errorf("unexpected path: %s", r.URL.Path)
		}
		resp := map[string]interface{}{
			"partitions": []map[string]interface{}{
				{
					"name": "normal",
					"partition": map[string]interface{}{
						"state": []string{"UP"},
					},
					"nodes": map[string]interface{}{
						"configured": "node[1-10]",
						"total":      10,
					},
					"cpus": map[string]interface{}{
						"total": 640,
					},
					"maximums": map[string]interface{}{
						"time": map[string]interface{}{
							"set":      true,
							"infinite": false,
							"number":   86400,
						},
					},
				},
			},
		}
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(resp)
	})
	defer cleanup()

	svc := NewClusterService(client, zap.NewNop())
	partitions, err := svc.GetPartitions(context.Background())
	if err != nil {
		t.Fatalf("GetPartitions returned error: %v", err)
	}
	if len(partitions) != 1 {
		t.Fatalf("expected 1 partition, got %d", len(partitions))
	}
	p := partitions[0]
	if p.Name != "normal" {
		t.Errorf("expected name normal, got %s", p.Name)
	}
	if len(p.State) != 1 || p.State[0] != "UP" {
		t.Errorf("expected state [UP], got %v", p.State)
	}
	if p.Nodes != "node[1-10]" {
		t.Errorf("expected nodes 'node[1-10]', got %s", p.Nodes)
	}
	if p.TotalCPUs != 640 {
		t.Errorf("expected 640 total CPUs, got %d", p.TotalCPUs)
	}
	if p.TotalNodes != 10 {
		t.Errorf("expected 10 total nodes, got %d", p.TotalNodes)
	}
	if p.MaxTime != "86400" {
		t.Errorf("expected max_time '86400', got %s", p.MaxTime)
	}
}

func TestGetPartitions_Empty(t *testing.T) {
	client, cleanup := mockServer(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(map[string]interface{}{})
	})
	defer cleanup()

	svc := NewClusterService(client, zap.NewNop())
	partitions, err := svc.GetPartitions(context.Background())
	if err != nil {
		t.Fatalf("GetPartitions returned error: %v", err)
	}
	if partitions != nil {
		t.Errorf("expected nil for empty response, got %v", partitions)
	}
}

func TestGetPartition(t *testing.T) {
	client, cleanup := mockServer(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != "/slurm/v0.0.40/partition/gpu" {
			t.Errorf("unexpected path: %s", r.URL.Path)
		}
		resp := map[string]interface{}{
			"partitions": []map[string]interface{}{
				{
					"name": "gpu",
					"partition": map[string]interface{}{
						"state": []string{"UP"},
					},
					"nodes": map[string]interface{}{
						"configured": "gpu[1-4]",
						"total":      4,
					},
					"maximums": map[string]interface{}{
						"time": map[string]interface{}{
							"set":      true,
							"infinite": true,
						},
					},
				},
			},
		}
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(resp)
	})
	defer cleanup()

	svc := NewClusterService(client, zap.NewNop())
	part, err := svc.GetPartition(context.Background(), "gpu")
	if err != nil {
		t.Fatalf("GetPartition returned error: %v", err)
	}
	if part == nil {
		t.Fatal("expected partition, got nil")
	}
	if part.Name != "gpu" {
		t.Errorf("expected name gpu, got %s", part.Name)
	}
	if part.MaxTime != "UNLIMITED" {
		t.Errorf("expected max_time UNLIMITED, got %s", part.MaxTime)
	}
}

func TestGetPartition_NotFound(t *testing.T) {
	client, cleanup := mockServer(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(map[string]interface{}{})
	})
	defer cleanup()

	svc := NewClusterService(client, zap.NewNop())
	part, err := svc.GetPartition(context.Background(), "missing")
	if err != nil {
		t.Fatalf("GetPartition returned error: %v", err)
	}
	if part != nil {
		t.Errorf("expected nil for missing partition, got %+v", part)
	}
}

func TestGetDiag(t *testing.T) {
	client, cleanup := mockServer(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != "/slurm/v0.0.40/diag" {
			t.Errorf("unexpected path: %s", r.URL.Path)
		}
		resp := map[string]interface{}{
			"statistics": map[string]interface{}{
				"server_thread_count":   10,
				"agent_queue_size":      5,
				"jobs_submitted":        100,
				"jobs_running":          20,
				"schedule_queue_length": 3,
			},
		}
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(resp)
	})
	defer cleanup()

	svc := NewClusterService(client, zap.NewNop())
	diag, err := svc.GetDiag(context.Background())
	if err != nil {
		t.Fatalf("GetDiag returned error: %v", err)
	}
	if diag == nil {
		t.Fatal("expected diag response, got nil")
	}
	if diag.Statistics == nil {
		t.Fatal("expected statistics, got nil")
	}
	if diag.Statistics.ServerThreadCount == nil || *diag.Statistics.ServerThreadCount != 10 {
		t.Errorf("expected server_thread_count 10, got %v", diag.Statistics.ServerThreadCount)
	}
}

func TestNewSlurmClient(t *testing.T) {
	dir := t.TempDir()
	keyPath := filepath.Join(dir, "jwt.key")
	os.WriteFile(keyPath, make([]byte, 32), 0644)

	client, err := NewSlurmClient("http://localhost:6820", "root", keyPath)
	if err != nil {
		t.Fatalf("NewSlurmClient returned error: %v", err)
	}
	if client == nil {
		t.Fatal("expected client, got nil")
	}
}

func newClusterServiceWithObserver(srv *httptest.Server) (*ClusterService, *observer.ObservedLogs) {
	core, recorded := observer.New(zapcore.DebugLevel)
	l := zap.New(core)
	client, _ := slurm.NewClient(srv.URL, srv.Client())
	return NewClusterService(client, l), recorded
}

func errorServer() *httptest.Server {
	return httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusInternalServerError)
		w.Write([]byte(`{"errors": [{"error": "internal server error"}]}`))
	}))
}

func TestClusterService_GetNodes_ErrorLogging(t *testing.T) {
	srv := errorServer()
	defer srv.Close()

	svc, logs := newClusterServiceWithObserver(srv)
	_, err := svc.GetNodes(context.Background())
	if err == nil {
		t.Fatal("expected error, got nil")
	}

	if logs.Len() != 1 {
		t.Fatalf("expected 1 log entry, got %d", logs.Len())
	}
	entry := logs.All()[0]
	if entry.Level != zapcore.ErrorLevel {
		t.Errorf("expected ErrorLevel, got %v", entry.Level)
	}
	if len(entry.Context) == 0 {
		t.Error("expected structured fields in log entry")
	}
}

func TestClusterService_GetNode_ErrorLogging(t *testing.T) {
	srv := errorServer()
	defer srv.Close()

	svc, logs := newClusterServiceWithObserver(srv)
	_, err := svc.GetNode(context.Background(), "test-node")
	if err == nil {
		t.Fatal("expected error, got nil")
	}

	if logs.Len() != 1 {
		t.Fatalf("expected 1 log entry, got %d", logs.Len())
	}
	entry := logs.All()[0]
	if entry.Level != zapcore.ErrorLevel {
		t.Errorf("expected ErrorLevel, got %v", entry.Level)
	}

	hasName := false
	for _, f := range entry.Context {
		if f.Key == "name" && f.String == "test-node" {
			hasName = true
		}
	}
	if !hasName {
		t.Error("expected 'name' field with value 'test-node' in log entry")
	}
}

func TestClusterService_GetPartitions_ErrorLogging(t *testing.T) {
	srv := errorServer()
	defer srv.Close()

	svc, logs := newClusterServiceWithObserver(srv)
	_, err := svc.GetPartitions(context.Background())
	if err == nil {
		t.Fatal("expected error, got nil")
	}

	if logs.Len() != 1 {
		t.Fatalf("expected 1 log entry, got %d", logs.Len())
	}
	entry := logs.All()[0]
	if entry.Level != zapcore.ErrorLevel {
		t.Errorf("expected ErrorLevel, got %v", entry.Level)
	}
	if len(entry.Context) == 0 {
		t.Error("expected structured fields in log entry")
	}
}

func TestClusterService_GetPartition_ErrorLogging(t *testing.T) {
	srv := errorServer()
	defer srv.Close()

	svc, logs := newClusterServiceWithObserver(srv)
	_, err := svc.GetPartition(context.Background(), "test-partition")
	if err == nil {
		t.Fatal("expected error, got nil")
	}

	if logs.Len() != 1 {
		t.Fatalf("expected 1 log entry, got %d", logs.Len())
	}
	entry := logs.All()[0]
	if entry.Level != zapcore.ErrorLevel {
		t.Errorf("expected ErrorLevel, got %v", entry.Level)
	}

	hasName := false
	for _, f := range entry.Context {
		if f.Key == "name" && f.String == "test-partition" {
			hasName = true
		}
	}
	if !hasName {
		t.Error("expected 'name' field with value 'test-partition' in log entry")
	}
}

func TestClusterService_GetDiag_ErrorLogging(t *testing.T) {
	srv := errorServer()
	defer srv.Close()

	svc, logs := newClusterServiceWithObserver(srv)
	_, err := svc.GetDiag(context.Background())
	if err == nil {
		t.Fatal("expected error, got nil")
	}

	if logs.Len() != 1 {
		t.Fatalf("expected 1 log entry, got %d", logs.Len())
	}
	entry := logs.All()[0]
	if entry.Level != zapcore.ErrorLevel {
		t.Errorf("expected ErrorLevel, got %v", entry.Level)
	}
	if len(entry.Context) == 0 {
		t.Error("expected structured fields in log entry")
	}
}