package services

import (
	"fmt"
	"os/exec"
	"strings"
	"sync"

	"gitea.avt.data-center.id/othman.suseno/atlas/internal/models"
)

// ISCSIService manages iSCSI target service integration
type ISCSIService struct {
	mu            sync.RWMutex
	targetcliPath string
}

// NewISCSIService creates a new iSCSI service manager
func NewISCSIService() *ISCSIService {
	// Try targetcli first, fallback to targetcli-fb
	targetcliPath := "targetcli"
	if _, err := exec.LookPath("targetcli"); err != nil {
		if _, err := exec.LookPath("targetcli-fb"); err == nil {
			targetcliPath = "targetcli-fb"
		}
	}

	return &ISCSIService{
		targetcliPath: targetcliPath,
	}
}

// ApplyConfiguration applies iSCSI target configurations
func (s *ISCSIService) ApplyConfiguration(targets []models.ISCSITarget) error {
	s.mu.Lock()
	defer s.mu.Unlock()

	// For each target, ensure it exists and is configured
	for _, target := range targets {
		if !target.Enabled {
			// Disable target if it exists
			if err := s.disableTarget(target.IQN); err != nil {
				// Log but continue
			}
			continue
		}

		// Create or update target
		if err := s.createTarget(target); err != nil {
			return fmt.Errorf("create target %s: %w", target.IQN, err)
		}

		// Configure ACLs
		if err := s.configureACLs(target); err != nil {
			return fmt.Errorf("configure ACLs for %s: %w", target.IQN, err)
		}

		// Configure LUNs
		if err := s.configureLUNs(target); err != nil {
			return fmt.Errorf("configure LUNs for %s: %w", target.IQN, err)
		}
	}

	return nil
}

// createTarget creates an iSCSI target
func (s *ISCSIService) createTarget(target models.ISCSITarget) error {
	// Use targetcli to create target
	// Format: targetcli /iscsi create <IQN>
	cmd := exec.Command(s.targetcliPath, "/iscsi", "create", target.IQN)
	if err := cmd.Run(); err != nil {
		// Target might already exist, which is OK
		// Check if it actually exists
		if !s.targetExists(target.IQN) {
			return fmt.Errorf("create target failed: %w", err)
		}
	}

	return nil
}

// configureACLs configures initiator ACLs for a target
func (s *ISCSIService) configureACLs(target models.ISCSITarget) error {
	// Get current ACLs
	currentACLs, _ := s.getACLs(target.IQN)

	// Remove ACLs not in desired list
	for _, acl := range currentACLs {
		if !contains(target.Initiators, acl) {
			cmd := exec.Command(s.targetcliPath, "/iscsi/"+target.IQN+"/tpg1/acls", "delete", acl)
			cmd.Run() // Ignore errors
		}
	}

	// Add new ACLs
	for _, initiator := range target.Initiators {
		if !contains(currentACLs, initiator) {
			cmd := exec.Command(s.targetcliPath, "/iscsi/"+target.IQN+"/tpg1/acls", "create", initiator)
			if err := cmd.Run(); err != nil {
				return fmt.Errorf("create ACL %s: %w", initiator, err)
			}
		}
	}

	return nil
}

// configureLUNs configures LUNs for a target
func (s *ISCSIService) configureLUNs(target models.ISCSITarget) error {
	// Get current LUNs
	currentLUNs, _ := s.getLUNs(target.IQN)

	// Remove LUNs not in desired list
	for _, lun := range currentLUNs {
		if !s.hasLUN(target.LUNs, lun) {
			cmd := exec.Command(s.targetcliPath, "/iscsi/"+target.IQN+"/tpg1/luns", "delete", fmt.Sprintf("lun/%d", lun))
			cmd.Run() // Ignore errors
		}
	}

	// Add/update LUNs
	for _, lun := range target.LUNs {
		// Create LUN mapping
		// Format: targetcli /iscsi/<IQN>/tpg1/luns create /backstores/zvol/<zvol>
		zvolPath := "/backstores/zvol/" + lun.ZVOL

		// First ensure the zvol backend exists
		cmd := exec.Command(s.targetcliPath, "/backstores/zvol", "create", lun.ZVOL, lun.ZVOL)
		cmd.Run() // Ignore if already exists

		// Create LUN
		cmd = exec.Command(s.targetcliPath, "/iscsi/"+target.IQN+"/tpg1/luns", "create", zvolPath)
		if err := cmd.Run(); err != nil {
			// LUN might already exist
			if !s.hasLUNID(currentLUNs, lun.ID) {
				return fmt.Errorf("create LUN %d: %w", lun.ID, err)
			}
		}
	}

	return nil
}

// Helper functions
func (s *ISCSIService) targetExists(iqn string) bool {
	cmd := exec.Command(s.targetcliPath, "/iscsi", "ls")
	output, err := cmd.Output()
	if err != nil {
		return false
	}
	return strings.Contains(string(output), iqn)
}

func (s *ISCSIService) getACLs(iqn string) ([]string, error) {
	cmd := exec.Command(s.targetcliPath, "/iscsi/"+iqn+"/tpg1/acls", "ls")
	_, err := cmd.Output()
	if err != nil {
		return nil, err
	}
	// Parse output to extract ACL names
	// This is simplified - real implementation would parse targetcli output
	return []string{}, nil
}

func (s *ISCSIService) getLUNs(iqn string) ([]int, error) {
	cmd := exec.Command(s.targetcliPath, "/iscsi/"+iqn+"/tpg1/luns", "ls")
	_, err := cmd.Output()
	if err != nil {
		return nil, err
	}
	// Parse output to extract LUN IDs
	// This is simplified - real implementation would parse targetcli output
	return []int{}, nil
}

func (s *ISCSIService) hasLUN(luns []models.LUN, id int) bool {
	for _, lun := range luns {
		if lun.ID == id {
			return true
		}
	}
	return false
}

func (s *ISCSIService) hasLUNID(luns []int, id int) bool {
	for _, lunID := range luns {
		if lunID == id {
			return true
		}
	}
	return false
}

func (s *ISCSIService) disableTarget(iqn string) error {
	cmd := exec.Command(s.targetcliPath, "/iscsi/"+iqn+"/tpg1", "set", "attribute", "enable=0")
	return cmd.Run()
}

// GetStatus returns the status of iSCSI target service
func (s *ISCSIService) GetStatus() (bool, error) {
	// Check if targetd is running
	cmd := exec.Command("systemctl", "is-active", "target")
	if err := cmd.Run(); err == nil {
		return true, nil
	}

	// Fallback: check process
	cmd = exec.Command("pgrep", "-x", "targetd")
	if err := cmd.Run(); err == nil {
		return true, nil
	}

	return false, nil
}

func contains(slice []string, item string) bool {
	for _, s := range slice {
		if s == item {
			return true
		}
	}
	return false
}

// ConnectionInstructions represents iSCSI connection instructions
type ConnectionInstructions struct {
	IQN        string    `json:"iqn"`
	Portal     string    `json:"portal"`      // IP:port
	PortalIP   string    `json:"portal_ip"`   // IP address
	PortalPort int       `json:"portal_port"` // Port (default 3260)
	LUNs       []LUNInfo `json:"luns"`
	Commands   Commands  `json:"commands"`
}

// LUNInfo represents LUN information for connection
type LUNInfo struct {
	ID   int    `json:"id"`
	ZVOL string `json:"zvol"`
	Size uint64 `json:"size"`
}

// Commands contains OS-specific connection commands
type Commands struct {
	Linux   []string `json:"linux"`
	Windows []string `json:"windows"`
	MacOS   []string `json:"macos"`
}

// GetConnectionInstructions generates connection instructions for an iSCSI target
func (s *ISCSIService) GetConnectionInstructions(target models.ISCSITarget, portalIP string, portalPort int) *ConnectionInstructions {
	if portalPort == 0 {
		portalPort = 3260 // Default iSCSI port
	}

	portal := fmt.Sprintf("%s:%d", portalIP, portalPort)

	// Build LUN information
	luns := make([]LUNInfo, len(target.LUNs))
	for i, lun := range target.LUNs {
		luns[i] = LUNInfo{
			ID:   lun.ID,
			ZVOL: lun.ZVOL,
			Size: lun.Size,
		}
	}

	// Generate Linux commands
	linuxCmds := []string{
		fmt.Sprintf("# Discover target"),
		fmt.Sprintf("iscsiadm -m discovery -t sendtargets -p %s", portal),
		fmt.Sprintf(""),
		fmt.Sprintf("# Login to target"),
		fmt.Sprintf("iscsiadm -m node -T %s -p %s --login", target.IQN, portal),
		fmt.Sprintf(""),
		fmt.Sprintf("# Verify connection"),
		fmt.Sprintf("iscsiadm -m session"),
		fmt.Sprintf(""),
		fmt.Sprintf("# Logout (when done)"),
		fmt.Sprintf("iscsiadm -m node -T %s -p %s --logout", target.IQN, portal),
	}

	// Generate Windows commands
	windowsCmds := []string{
		fmt.Sprintf("# Open PowerShell as Administrator"),
		fmt.Sprintf(""),
		fmt.Sprintf("# Add iSCSI target portal"),
		fmt.Sprintf("New-IscsiTargetPortal -TargetPortalAddress %s -TargetPortalPortNumber %d", portalIP, portalPort),
		fmt.Sprintf(""),
		fmt.Sprintf("# Connect to target"),
		fmt.Sprintf("Connect-IscsiTarget -NodeAddress %s", target.IQN),
		fmt.Sprintf(""),
		fmt.Sprintf("# Verify connection"),
		fmt.Sprintf("Get-IscsiSession"),
		fmt.Sprintf(""),
		fmt.Sprintf("# Disconnect (when done)"),
		fmt.Sprintf("Disconnect-IscsiTarget -NodeAddress %s", target.IQN),
	}

	// Generate macOS commands
	macosCmds := []string{
		fmt.Sprintf("# macOS uses built-in iSCSI support"),
		fmt.Sprintf("# Use System Preferences > Network > iSCSI"),
		fmt.Sprintf(""),
		fmt.Sprintf("# Or use command line (if iscsiutil is available)"),
		fmt.Sprintf("iscsiutil -a -t %s -p %s", target.IQN, portal),
		fmt.Sprintf(""),
		fmt.Sprintf("# Portal: %s", portal),
		fmt.Sprintf("# Target IQN: %s", target.IQN),
	}

	return &ConnectionInstructions{
		IQN:        target.IQN,
		Portal:     portal,
		PortalIP:   portalIP,
		PortalPort: portalPort,
		LUNs:       luns,
		Commands: Commands{
			Linux:   linuxCmds,
			Windows: windowsCmds,
			MacOS:   macosCmds,
		},
	}
}

// GetPortalIP attempts to detect the portal IP address
func (s *ISCSIService) GetPortalIP() (string, error) {
	// Try to get IP from targetcli
	cmd := exec.Command(s.targetcliPath, "/iscsi", "ls")
	output, err := cmd.Output()
	if err != nil {
		// Fallback: try to get system IP
		return s.getSystemIP()
	}

	// Parse output to find portal IP
	// This is a simplified version - real implementation would parse targetcli output properly
	lines := strings.Split(string(output), "\n")
	for _, line := range lines {
		if strings.Contains(line, "ipv4") || strings.Contains(line, "ipv6") {
			// Extract IP from line
			parts := strings.Fields(line)
			for _, part := range parts {
				// Check if it looks like an IP address
				if strings.Contains(part, ".") || strings.Contains(part, ":") {
					// Remove port if present
					if idx := strings.Index(part, ":"); idx > 0 {
						return part[:idx], nil
					}
					return part, nil
				}
			}
		}
	}

	// Fallback to system IP
	return s.getSystemIP()
}

// getSystemIP gets a system IP address (simplified)
func (s *ISCSIService) getSystemIP() (string, error) {
	// Try to get IP from hostname -I (Linux)
	cmd := exec.Command("hostname", "-I")
	output, err := cmd.Output()
	if err == nil {
		ips := strings.Fields(string(output))
		if len(ips) > 0 {
			return ips[0], nil
		}
	}

	// Fallback: return localhost
	return "127.0.0.1", nil
}