package storage

import (
	"fmt"
	"net/http"
	"strings"

	"github.com/atlasos/calypso/internal/common/cache"
	"github.com/atlasos/calypso/internal/common/database"
	"github.com/atlasos/calypso/internal/common/logger"
	"github.com/atlasos/calypso/internal/tasks"
	"github.com/gin-gonic/gin"
)

// Handler handles storage-related API requests
type Handler struct {
	diskService *DiskService
	lvmService  *LVMService
	zfsService  *ZFSService
	arcService  *ARCService
	taskEngine  *tasks.Engine
	db          *database.DB
	logger      *logger.Logger
	cache       *cache.Cache // Cache for invalidation
}

// SetCache sets the cache instance for cache invalidation
func (h *Handler) SetCache(c *cache.Cache) {
	h.cache = c
}

// NewHandler creates a new storage handler
func NewHandler(db *database.DB, log *logger.Logger) *Handler {
	return &Handler{
		diskService: NewDiskService(db, log),
		lvmService:  NewLVMService(db, log),
		zfsService:  NewZFSService(db, log),
		arcService:  NewARCService(log),
		taskEngine:  tasks.NewEngine(db, log),
		db:          db,
		logger:      log,
	}
}

// ListDisks lists all physical disks
func (h *Handler) ListDisks(c *gin.Context) {
	disks, err := h.diskService.DiscoverDisks(c.Request.Context())
	if err != nil {
		h.logger.Error("Failed to list disks", "error", err)
		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to list disks"})
		return
	}

	c.JSON(http.StatusOK, gin.H{"disks": disks})
}

// SyncDisks syncs discovered disks to database
func (h *Handler) SyncDisks(c *gin.Context) {
	userID, _ := c.Get("user_id")

	// Create async task
	taskID, err := h.taskEngine.CreateTask(c.Request.Context(),
		tasks.TaskTypeRescan, userID.(string), map[string]interface{}{
			"operation": "sync_disks",
		})
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to create task"})
		return
	}

	// Run sync in background
	go func() {
		ctx := c.Request.Context()
		h.taskEngine.StartTask(ctx, taskID)
		h.taskEngine.UpdateProgress(ctx, taskID, 50, "Discovering disks...")

		if err := h.diskService.SyncDisksToDatabase(ctx); err != nil {
			h.taskEngine.FailTask(ctx, taskID, err.Error())
			return
		}

		h.taskEngine.UpdateProgress(ctx, taskID, 100, "Disk sync completed")
		h.taskEngine.CompleteTask(ctx, taskID, "Disks synchronized successfully")
	}()

	c.JSON(http.StatusAccepted, gin.H{"task_id": taskID})
}

// ListVolumeGroups lists all volume groups
func (h *Handler) ListVolumeGroups(c *gin.Context) {
	vgs, err := h.lvmService.ListVolumeGroups(c.Request.Context())
	if err != nil {
		h.logger.Error("Failed to list volume groups", "error", err)
		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to list volume groups"})
		return
	}

	c.JSON(http.StatusOK, gin.H{"volume_groups": vgs})
}

// ListRepositories lists all repositories
func (h *Handler) ListRepositories(c *gin.Context) {
	repos, err := h.lvmService.ListRepositories(c.Request.Context())
	if err != nil {
		h.logger.Error("Failed to list repositories", "error", err)
		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to list repositories"})
		return
	}

	c.JSON(http.StatusOK, gin.H{"repositories": repos})
}

// GetRepository retrieves a repository by ID
func (h *Handler) GetRepository(c *gin.Context) {
	repoID := c.Param("id")

	repo, err := h.lvmService.GetRepository(c.Request.Context(), repoID)
	if err != nil {
		if err.Error() == "repository not found" {
			c.JSON(http.StatusNotFound, gin.H{"error": "repository not found"})
			return
		}
		h.logger.Error("Failed to get repository", "error", err)
		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to get repository"})
		return
	}

	c.JSON(http.StatusOK, repo)
}

// CreateRepositoryRequest represents a repository creation request
type CreateRepositoryRequest struct {
	Name        string `json:"name" binding:"required"`
	Description string `json:"description"`
	VolumeGroup string `json:"volume_group" binding:"required"`
	SizeGB      int64  `json:"size_gb" binding:"required"`
}

// CreateRepository creates a new repository
func (h *Handler) CreateRepository(c *gin.Context) {
	var req CreateRepositoryRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid request"})
		return
	}

	userID, _ := c.Get("user_id")
	sizeBytes := req.SizeGB * 1024 * 1024 * 1024

	repo, err := h.lvmService.CreateRepository(
		c.Request.Context(),
		req.Name,
		req.VolumeGroup,
		sizeBytes,
		userID.(string),
	)
	if err != nil {
		h.logger.Error("Failed to create repository", "error", err)
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	c.JSON(http.StatusCreated, repo)
}

// DeleteRepository deletes a repository
func (h *Handler) DeleteRepository(c *gin.Context) {
	repoID := c.Param("id")

	if err := h.lvmService.DeleteRepository(c.Request.Context(), repoID); err != nil {
		if err.Error() == "repository not found" {
			c.JSON(http.StatusNotFound, gin.H{"error": "repository not found"})
			return
		}
		h.logger.Error("Failed to delete repository", "error", err)
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	c.JSON(http.StatusOK, gin.H{"message": "repository deleted successfully"})
}

// CreateZPoolRequest represents a ZFS pool creation request
type CreateZPoolRequest struct {
	Name          string   `json:"name" binding:"required"`
	Description   string   `json:"description"`
	RaidLevel     string   `json:"raid_level" binding:"required"` // stripe, mirror, raidz, raidz2, raidz3
	Disks         []string `json:"disks" binding:"required"`      // device paths
	Compression   string   `json:"compression"`                   // off, lz4, zstd, gzip
	Deduplication bool     `json:"deduplication"`
	AutoExpand    bool     `json:"auto_expand"`
}

// CreateZPool creates a new ZFS pool
func (h *Handler) CreateZPool(c *gin.Context) {
	var req CreateZPoolRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		h.logger.Error("Invalid request body", "error", err)
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid request: " + err.Error()})
		return
	}

	// Validate required fields
	if req.Name == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "pool name is required"})
		return
	}
	if req.RaidLevel == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "raid_level is required"})
		return
	}
	if len(req.Disks) == 0 {
		c.JSON(http.StatusBadRequest, gin.H{"error": "at least one disk is required"})
		return
	}

	userID, exists := c.Get("user_id")
	if !exists {
		h.logger.Error("User ID not found in context")
		c.JSON(http.StatusUnauthorized, gin.H{"error": "authentication required"})
		return
	}

	userIDStr, ok := userID.(string)
	if !ok {
		h.logger.Error("Invalid user ID type", "type", fmt.Sprintf("%T", userID))
		c.JSON(http.StatusInternalServerError, gin.H{"error": "invalid user context"})
		return
	}

	// Set default compression if not provided
	if req.Compression == "" {
		req.Compression = "lz4"
	}

	h.logger.Info("Creating ZFS pool request", "name", req.Name, "raid_level", req.RaidLevel, "disks", req.Disks, "compression", req.Compression)

	pool, err := h.zfsService.CreatePool(
		c.Request.Context(),
		req.Name,
		req.RaidLevel,
		req.Disks,
		req.Compression,
		req.Deduplication,
		req.AutoExpand,
		userIDStr,
	)
	if err != nil {
		h.logger.Error("Failed to create ZFS pool", "error", err, "name", req.Name, "raid_level", req.RaidLevel, "disks", req.Disks)
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	h.logger.Info("ZFS pool created successfully", "pool_id", pool.ID, "name", pool.Name)
	c.JSON(http.StatusCreated, pool)
}

// ListZFSPools lists all ZFS pools
func (h *Handler) ListZFSPools(c *gin.Context) {
	pools, err := h.zfsService.ListPools(c.Request.Context())
	if err != nil {
		h.logger.Error("Failed to list ZFS pools", "error", err)
		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to list ZFS pools"})
		return
	}

	c.JSON(http.StatusOK, gin.H{"pools": pools})
}

// GetZFSPool retrieves a ZFS pool by ID
func (h *Handler) GetZFSPool(c *gin.Context) {
	poolID := c.Param("id")

	pool, err := h.zfsService.GetPool(c.Request.Context(), poolID)
	if err != nil {
		if err.Error() == "pool not found" {
			c.JSON(http.StatusNotFound, gin.H{"error": "pool not found"})
			return
		}
		h.logger.Error("Failed to get ZFS pool", "error", err)
		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to get ZFS pool"})
		return
	}

	c.JSON(http.StatusOK, pool)
}

// DeleteZFSPool deletes a ZFS pool
func (h *Handler) DeleteZFSPool(c *gin.Context) {
	poolID := c.Param("id")

	if err := h.zfsService.DeletePool(c.Request.Context(), poolID); err != nil {
		if err.Error() == "pool not found" {
			c.JSON(http.StatusNotFound, gin.H{"error": "pool not found"})
			return
		}
		h.logger.Error("Failed to delete ZFS pool", "error", err)
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	c.JSON(http.StatusOK, gin.H{"message": "ZFS pool deleted successfully"})
}

// AddSpareDiskRequest represents a request to add spare disks to a pool
type AddSpareDiskRequest struct {
	Disks []string `json:"disks" binding:"required"`
}

// AddSpareDisk adds spare disks to a ZFS pool
func (h *Handler) AddSpareDisk(c *gin.Context) {
	poolID := c.Param("id")

	var req AddSpareDiskRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		h.logger.Error("Invalid add spare disk request", "error", err)
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid request: " + err.Error()})
		return
	}

	if len(req.Disks) == 0 {
		c.JSON(http.StatusBadRequest, gin.H{"error": "at least one disk must be specified"})
		return
	}

	if err := h.zfsService.AddSpareDisk(c.Request.Context(), poolID, req.Disks); err != nil {
		if err.Error() == "pool not found" {
			c.JSON(http.StatusNotFound, gin.H{"error": "pool not found"})
			return
		}
		h.logger.Error("Failed to add spare disks", "error", err)
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	c.JSON(http.StatusOK, gin.H{"message": "Spare disks added successfully"})
}

// ListZFSDatasets lists all datasets in a ZFS pool
func (h *Handler) ListZFSDatasets(c *gin.Context) {
	poolID := c.Param("id")

	// Get pool to get pool name
	pool, err := h.zfsService.GetPool(c.Request.Context(), poolID)
	if err != nil {
		if err.Error() == "pool not found" {
			c.JSON(http.StatusNotFound, gin.H{"error": "pool not found"})
			return
		}
		h.logger.Error("Failed to get pool", "error", err)
		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to get pool"})
		return
	}

	datasets, err := h.zfsService.ListDatasets(c.Request.Context(), pool.Name)
	if err != nil {
		h.logger.Error("Failed to list datasets", "error", err)
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	// Ensure we return an empty array instead of null
	if datasets == nil {
		datasets = []*ZFSDataset{}
	}

	c.JSON(http.StatusOK, gin.H{"datasets": datasets})
}

// CreateZFSDatasetRequest represents a request to create a ZFS dataset
type CreateZFSDatasetRequest struct {
	Name        string `json:"name" binding:"required"` // Dataset name (without pool prefix)
	Type        string `json:"type" binding:"required"` // "filesystem" or "volume"
	Compression string `json:"compression"`             // off, lz4, zstd, gzip, etc.
	Quota       int64  `json:"quota"`                   // -1 for unlimited, >0 for size
	Reservation int64  `json:"reservation"`             // 0 for none
	MountPoint  string `json:"mount_point"`             // Optional mount point
}

// CreateZFSDataset creates a new ZFS dataset in a pool
func (h *Handler) CreateZFSDataset(c *gin.Context) {
	poolID := c.Param("id")

	// Get pool to get pool name
	pool, err := h.zfsService.GetPool(c.Request.Context(), poolID)
	if err != nil {
		if err.Error() == "pool not found" {
			c.JSON(http.StatusNotFound, gin.H{"error": "pool not found"})
			return
		}
		h.logger.Error("Failed to get pool", "error", err)
		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to get pool"})
		return
	}

	var req CreateZFSDatasetRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		h.logger.Error("Invalid create dataset request", "error", err)
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid request: " + err.Error()})
		return
	}

	// Validate type
	if req.Type != "filesystem" && req.Type != "volume" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "type must be 'filesystem' or 'volume'"})
		return
	}

	// Validate mount point: volumes cannot have mount points
	if req.Type == "volume" && req.MountPoint != "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "mount point cannot be set for volume datasets (volumes are block devices for iSCSI export)"})
		return
	}

	// Validate dataset name (should not contain pool name)
	if strings.Contains(req.Name, "/") {
		c.JSON(http.StatusBadRequest, gin.H{"error": "dataset name should not contain '/' (pool name is automatically prepended)"})
		return
	}

	// Create dataset request - CreateDatasetRequest is in the same package (zfs.go)
	createReq := CreateDatasetRequest{
		Name:        req.Name,
		Type:        req.Type,
		Compression: req.Compression,
		Quota:       req.Quota,
		Reservation: req.Reservation,
		MountPoint:  req.MountPoint,
	}

	dataset, err := h.zfsService.CreateDataset(c.Request.Context(), pool.Name, createReq)
	if err != nil {
		h.logger.Error("Failed to create dataset", "error", err)
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	c.JSON(http.StatusCreated, dataset)
}

// DeleteZFSDataset deletes a ZFS dataset
func (h *Handler) DeleteZFSDataset(c *gin.Context) {
	poolID := c.Param("id")
	datasetName := c.Param("dataset")

	// Get pool to get pool name
	pool, err := h.zfsService.GetPool(c.Request.Context(), poolID)
	if err != nil {
		if err.Error() == "pool not found" {
			c.JSON(http.StatusNotFound, gin.H{"error": "pool not found"})
			return
		}
		h.logger.Error("Failed to get pool", "error", err)
		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to get pool"})
		return
	}

	// Construct full dataset name
	fullDatasetName := pool.Name + "/" + datasetName

	// Verify dataset belongs to this pool
	if !strings.HasPrefix(fullDatasetName, pool.Name+"/") {
		c.JSON(http.StatusBadRequest, gin.H{"error": "dataset does not belong to this pool"})
		return
	}

	if err := h.zfsService.DeleteDataset(c.Request.Context(), fullDatasetName); err != nil {
		if strings.Contains(err.Error(), "does not exist") || strings.Contains(err.Error(), "not found") {
			c.JSON(http.StatusNotFound, gin.H{"error": "dataset not found"})
			return
		}
		h.logger.Error("Failed to delete dataset", "error", err)
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	// Invalidate cache for this pool's datasets list
	if h.cache != nil {
		// Generate cache key using the same format as cache middleware
		cacheKey := fmt.Sprintf("http:/api/v1/storage/zfs/pools/%s/datasets:", poolID)
		h.cache.Delete(cacheKey)
		// Also invalidate any cached responses with query parameters
		h.logger.Debug("Cache invalidated for dataset list", "pool_id", poolID, "key", cacheKey)
	}

	c.JSON(http.StatusOK, gin.H{"message": "Dataset deleted successfully"})
}

// GetARCStats returns ZFS ARC statistics
func (h *Handler) GetARCStats(c *gin.Context) {
	stats, err := h.arcService.GetARCStats(c.Request.Context())
	if err != nil {
		h.logger.Error("Failed to get ARC stats", "error", err)
		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to get ARC stats: " + err.Error()})
		return
	}

	c.JSON(http.StatusOK, stats)
}