package iscsi

import (
	"fmt"
	"os"
	"path/filepath"
)

// AddLUN adds a LUN to a target
func (s *Service) AddLUN(targetID string, lunNumber int, devicePath string, lunType string) error {
	s.logger.Info("Adding LUN to target", "target", targetID, "lun", lunNumber, "device", devicePath, "type", lunType)

	// Validate device exists
	if _, err := os.Stat(devicePath); err != nil {
		return fmt.Errorf("device not found: %s", devicePath)
	}

	// Validate LUN type
	if lunType != "disk" && lunType != "tape" {
		return fmt.Errorf("invalid LUN type: %s (must be 'disk' or 'tape')", lunType)
	}

	// For tape library:
	// LUN 0 = Media changer
	// LUN 1-8 = Tape drives
	if lunType == "tape" {
		if lunNumber == 0 {
			// Media changer
			devicePath = "/dev/sg0" // Default media changer
		} else if lunNumber >= 1 && lunNumber <= 8 {
			// Tape drive
			devicePath = fmt.Sprintf("/dev/nst%d", lunNumber-1)
		} else {
			return fmt.Errorf("invalid LUN number for tape: %d (must be 0-8)", lunNumber)
		}
	}

	// Update target configuration
	target, err := s.GetTarget(targetID)
	if err != nil {
		return err
	}

	// Check if LUN already exists
	for _, lun := range target.LUNs {
		if lun.Number == lunNumber {
			return fmt.Errorf("LUN %d already exists", lunNumber)
		}
	}

	// Add LUN
	target.LUNs = append(target.LUNs, LUN{
		Number: lunNumber,
		Device: devicePath,
		Type:   lunType,
	})

	// Write updated config
	return s.writeSCSTConfig(target)
}

// RemoveLUN removes a LUN from a target
func (s *Service) RemoveLUN(targetID string, lunNumber int) error {
	s.logger.Info("Removing LUN from target", "target", targetID, "lun", lunNumber)

	target, err := s.GetTarget(targetID)
	if err != nil {
		return err
	}

	// Find and remove LUN
	found := false
	newLUNs := []LUN{}
	for _, lun := range target.LUNs {
		if lun.Number != lunNumber {
			newLUNs = append(newLUNs, lun)
		} else {
			found = true
		}
	}

	if !found {
		return fmt.Errorf("LUN %d not found", lunNumber)
	}

	target.LUNs = newLUNs
	return s.writeSCSTConfig(target)
}

// MapRepositoryToLUN maps a disk repository to an iSCSI LUN
func (s *Service) MapRepositoryToLUN(targetID string, repositoryPath string, lunNumber int) error {
	// Resolve repository path to device
	devicePath, err := filepath.EvalSymlinks(repositoryPath)
	if err != nil {
		return fmt.Errorf("failed to resolve repository path: %w", err)
	}

	return s.AddLUN(targetID, lunNumber, devicePath, "disk")
}