// Package testenv provides a complete test environment factory that wires up
// SQLite DB + MockSlurm + MockMinIO + all Stores/Services/Handlers + httptest Server.
package testenv

import (
	"bytes"
	"context"
	"crypto/sha256"
	"database/sql"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"io"
	"math/rand"
	"net/http"
	"net/http/httptest"
	"os"
	"time"

	"gcy_hpc_server/internal/app"
	"gcy_hpc_server/internal/config"
	"gcy_hpc_server/internal/handler"
	"gcy_hpc_server/internal/model"
	"gcy_hpc_server/internal/server"
	"gcy_hpc_server/internal/service"
	"gcy_hpc_server/internal/slurm"
	"gcy_hpc_server/internal/storage"
	"gcy_hpc_server/internal/store"
	"gcy_hpc_server/internal/testutil/mockminio"
	"gcy_hpc_server/internal/testutil/mockslurm"

	"go.uber.org/zap"
	"gorm.io/driver/sqlite"
	"gorm.io/gorm"
)

// TestEnv holds a fully wired test environment with all dependencies.
type TestEnv struct {
	DB        *gorm.DB
	MockSlurm *mockslurm.MockSlurm
	MockMinIO *mockminio.InMemoryStorage

	// Internal
	mockSlurmSrv *httptest.Server
	srv          *httptest.Server
	poller       *app.TaskPoller

	// Stores
	appStore    *store.ApplicationStore
	taskStore   *store.TaskStore
	fileStore   *store.FileStore
	blobStore   *store.BlobStore
	uploadStore *store.UploadStore
	folderStore *store.FolderStore

	// Services
	jobSvc     *service.JobService
	clusterSvc *service.ClusterService
	folderSvc  *service.FolderService
	stagingSvc *service.FileStagingService
	taskSvc    *service.TaskService
	appSvc     *service.ApplicationService
	uploadSvc  *service.UploadService
	fileSvc    *service.FileService

	jobH     *handler.JobHandler
	clusterH *handler.ClusterHandler
	appH     *handler.ApplicationHandler
	uploadH  *handler.UploadHandler
	fileH    *handler.FileHandler
	folderH  *handler.FolderHandler
	taskH    *handler.TaskHandler

	workDir string
	logger  *zap.Logger
}

// Option configures a TestEnv during construction.
type Option func(*testEnvConfig)

type testEnvConfig struct {
	workDir  string
	debugLog bool
}

// WithWorkDir overrides the default temporary work directory.
func WithWorkDir(path string) Option {
	return func(c *testEnvConfig) { c.workDir = path }
}

// WithDebugLogging switches from zap.NewNop() to zap.NewExample().
func WithDebugLogging() Option {
	return func(c *testEnvConfig) { c.debugLog = true }
}

// NewTestEnv creates a fully wired test environment.
// t.Cleanup is registered for all resources — callers do not need to clean up.
func NewTestEnv(t interface {
	Fatalf(format string, args ...interface{})
}, opts ...Option) *TestEnv {
	cfg := &testEnvConfig{}
	for _, o := range opts {
		o(cfg)
	}

	var logger *zap.Logger
	if cfg.debugLog {
		logger = zap.NewExample()
	} else {
		logger = zap.NewNop()
	}

	// 1. SQLite in-memory DB + AutoMigrate
	dbName := fmt.Sprintf("file:testenv-%d?mode=memory&cache=shared", rand.Int63())
	db, err := gorm.Open(sqlite.Open(dbName), &gorm.Config{})
	if err != nil {
		t.Fatalf("failed to open SQLite: %v", err)
	}
	sqlDB, err := db.DB()
	if err != nil {
		t.Fatalf("failed to get underlying sql.DB: %v", err)
	}
	sqlDB.SetMaxOpenConns(1)
	if err := db.AutoMigrate(
		&model.Application{},
		&model.FileBlob{},
		&model.File{},
		&model.Folder{},
		&model.UploadSession{},
		&model.UploadChunk{},
		&model.Task{},
	); err != nil {
		t.Fatalf("failed to auto-migrate: %v", err)
	}

	// 2. Temp work directory
	workDir := cfg.workDir
	if workDir == "" {
		wd, err := os.MkdirTemp("", "testenv-workdir-*")
		if err != nil {
			t.Fatalf("failed to create temp dir: %v", err)
		}
		workDir = wd
	}

	// 3. MockSlurm httptest server
	mockSlurmSrv, mockSlurm := mockslurm.NewMockSlurmServer()

	// 4. MockMinIO
	mockMinIO := mockminio.NewInMemoryStorage()

	// 5. All 6 Store instances
	appStore := store.NewApplicationStore(db)
	taskStore := store.NewTaskStore(db)
	fileStore := store.NewFileStore(db)
	blobStore := store.NewBlobStore(db)
	uploadStore := store.NewUploadStore(db)
	folderStore := store.NewFolderStore(db)

	// 6. Slurm client
	slurmClient, err := slurm.NewClientWithOpts(mockSlurmSrv.URL, slurm.WithHTTPClient(mockSlurmSrv.Client()))
	if err != nil {
		t.Fatalf("failed to create slurm client: %v", err)
	}

	// 7. MinioConfig
	minioCfg := config.MinioConfig{
		ChunkSize:    16 << 20,
		MaxFileSize:  50 << 30,
		MinChunkSize: 5 << 20,
		SessionTTL:   48,
		Bucket:       "files",
	}

	// 8. All Service instances (dependency order)
	jobSvc := service.NewJobService(slurmClient, logger)
	clusterSvc := service.NewClusterService(slurmClient, logger)
	folderSvc := service.NewFolderService(folderStore, fileStore, logger)
	stagingSvc := service.NewFileStagingService(fileStore, blobStore, mockMinIO, minioCfg.Bucket, logger)
	taskSvc := service.NewTaskService(taskStore, appStore, fileStore, blobStore, stagingSvc, jobSvc, workDir, logger)
	appSvc := service.NewApplicationService(appStore, jobSvc, workDir, logger, taskSvc)
	uploadSvc := service.NewUploadService(mockMinIO, blobStore, fileStore, uploadStore, minioCfg, db, logger)
	fileSvc := service.NewFileService(mockMinIO, blobStore, fileStore, minioCfg.Bucket, db, logger)

	// 9. All 7 Handler instances
	jobH := handler.NewJobHandler(jobSvc, logger)
	clusterH := handler.NewClusterHandler(clusterSvc, logger)
	appH := handler.NewApplicationHandler(appSvc, logger)
	uploadH := handler.NewUploadHandler(uploadSvc, logger)
	fileH := handler.NewFileHandler(fileSvc, logger)
	folderH := handler.NewFolderHandler(folderSvc, logger)
	taskH := handler.NewTaskHandler(taskSvc, logger)

	// 10. Router
	router := server.NewRouter(jobH, clusterH, appH, uploadH, fileH, folderH, taskH, logger)

	// 11. HTTP test server
	srv := httptest.NewServer(router)

	// 12. Start TaskProcessor
	ctx := context.Background()
	taskSvc.StartProcessor(ctx)

	// 13. Start TaskPoller (100ms interval for tests)
	poller := app.NewTaskPoller(taskSvc, 100*time.Millisecond, logger)
	poller.Start(ctx)

	env := &TestEnv{
		DB:           db,
		MockSlurm:    mockSlurm,
		MockMinIO:    mockMinIO,
		mockSlurmSrv: mockSlurmSrv,
		srv:          srv,
		poller:       poller,
		appStore:     appStore,
		taskStore:    taskStore,
		fileStore:    fileStore,
		blobStore:    blobStore,
		uploadStore:  uploadStore,
		folderStore:  folderStore,
		jobSvc:       jobSvc,
		clusterSvc:   clusterSvc,
		folderSvc:    folderSvc,
		stagingSvc:   stagingSvc,
		taskSvc:      taskSvc,
		appSvc:       appSvc,
		uploadSvc:    uploadSvc,
		fileSvc:      fileSvc,
		jobH:         jobH,
		clusterH:     clusterH,
		appH:         appH,
		uploadH:      uploadH,
		fileH:        fileH,
		folderH:      folderH,
		taskH:        taskH,
		workDir:      workDir,
		logger:       logger,
	}

	// Cleanup registration (LIFO — last registered runs first).
	// We use a *testing.T-compatible interface; callers using *testing.T
	// will have t.Cleanup work correctly.
	if ct, ok := t.(interface{ Cleanup(func()) }); ok {
		ct.Cleanup(func() { os.RemoveAll(workDir) })
		ct.Cleanup(srv.Close)
		ct.Cleanup(poller.Stop)
		ct.Cleanup(taskSvc.StopProcessor)
	}

	return env
}

// URL returns the base URL of the test HTTP server.
func (env *TestEnv) URL() string {
	return env.srv.URL
}

// DoRequest sends an HTTP request to the test server.
// When body is non-nil, Content-Type: application/json is set.
func (env *TestEnv) DoRequest(method, path string, body io.Reader) *http.Response {
	req, err := http.NewRequest(method, env.srv.URL+path, body)
	if err != nil {
		panic(fmt.Sprintf("failed to create request: %v", err))
	}
	if body != nil {
		req.Header.Set("Content-Type", "application/json")
	}
	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(fmt.Sprintf("failed to send request: %v", err))
	}
	return resp
}

// DecodeResponse decodes an API response into its components.
// Returns success flag, raw data, and any error from decoding.
func (env *TestEnv) DecodeResponse(resp *http.Response) (bool, json.RawMessage, error) {
	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return false, nil, fmt.Errorf("read body: %w", err)
	}
	resp.Body.Close()

	var result struct {
		Success bool            `json:"success"`
		Data    json.RawMessage `json:"data"`
		Error   string          `json:"error"`
	}
	if err := json.Unmarshal(body, &result); err != nil {
		return false, nil, fmt.Errorf("unmarshal response: %w (body: %s)", err, string(body))
	}
	return result.Success, result.Data, nil
}

// CreateApp creates an application directly via the service and returns the app ID.
func (env *TestEnv) CreateApp(name, scriptTemplate string, params json.RawMessage) (int64, error) {
	ctx := context.Background()
	appID, err := env.appSvc.CreateApplication(ctx, &model.CreateApplicationRequest{
		Name:           name,
		ScriptTemplate: scriptTemplate,
		Parameters:     params,
	})
	if err != nil {
		return 0, err
	}
	return appID, nil
}

// UploadTestData uploads content to MockMinIO and creates FileBlob + File records.
// Returns (fileID, blobID).
func (env *TestEnv) UploadTestData(name string, content []byte) (int64, int64) {
	ctx := context.Background()

	h := sha256.Sum256(content)
	sha256Key := hex.EncodeToString(h[:])

	_, err := env.MockMinIO.PutObject(ctx, "files", sha256Key, bytes.NewReader(content), int64(len(content)), storage.PutObjectOptions{})
	if err != nil {
		panic(fmt.Sprintf("PutObject failed: %v", err))
	}

	blob, err := env.blobStore.GetBySHA256(ctx, sha256Key)
	if err != nil {
		panic(fmt.Sprintf("get blob by sha256: %v", err))
	}
	if blob == nil {
		blob = &model.FileBlob{
			SHA256:   sha256Key,
			MinioKey: sha256Key,
			FileSize: int64(len(content)),
			RefCount: 1,
		}
		if err := env.blobStore.Create(ctx, blob); err != nil {
			panic(fmt.Sprintf("create blob: %v", err))
		}
	}

	file := &model.File{
		Name:       name,
		BlobSHA256: sha256Key,
	}
	if err := env.fileStore.Create(ctx, file); err != nil {
		panic(fmt.Sprintf("create file failed: %v", err))
	}

	return file.ID, blob.ID
}

// CreateFile uploads test data and returns only the file ID.
func (env *TestEnv) CreateFile(name string, content []byte) (int64, error) {
	fileID, _ := env.UploadTestData(name, content)
	return fileID, nil
}

// WaitForTaskStatus polls the DB until the task reaches the target status or timeout.
func (env *TestEnv) WaitForTaskStatus(taskID int64, status string, timeout time.Duration) error {
	deadline := time.Now().Add(timeout)
	ctx := context.Background()
	for time.Now().Before(deadline) {
		task, err := env.taskStore.GetByID(ctx, taskID)
		if err != nil {
			return fmt.Errorf("get task: %w", err)
		}
		if task == nil {
			return fmt.Errorf("task %d not found", taskID)
		}
		if task.Status == status {
			return nil
		}
		time.Sleep(100 * time.Millisecond)
	}
	task, _ := env.taskStore.GetByID(ctx, taskID)
	if task != nil {
		return fmt.Errorf("timeout waiting for task %d to reach status %q, current: %q", taskID, status, task.Status)
	}
	return fmt.Errorf("timeout waiting for task %d to reach status %q", taskID, status)
}

// MakeTaskStale sets the task's updated_at to 31 seconds ago via raw SQL,
// bypassing GORM's AutoUpdateTime.
func (env *TestEnv) MakeTaskStale(taskID int64) error {
	sqlDB, err := env.DB.DB()
	if err != nil {
		return fmt.Errorf("get sql.DB: %w", err)
	}
	_, err = sqlDB.Exec("UPDATE hpc_tasks SET updated_at = ? WHERE id = ?", time.Now().Add(-31*time.Second), taskID)
	return err
}

// GetTaskSlurmJobID returns the slurm_job_id for the given task via raw SQL.
func (env *TestEnv) GetTaskSlurmJobID(taskID int64) (int32, error) {
	sqlDB, err := env.DB.DB()
	if err != nil {
		return 0, fmt.Errorf("get sql.DB: %w", err)
	}
	var jobID sql.NullInt32
	err = sqlDB.QueryRow("SELECT slurm_job_id FROM hpc_tasks WHERE id = ?", taskID).Scan(&jobID)
	if err != nil {
		return 0, err
	}
	if !jobID.Valid {
		return 0, fmt.Errorf("task %d has no slurm_job_id", taskID)
	}
	return jobID.Int32, nil
}