package iscsi

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

	"github.com/bams/backend/internal/config"
	"github.com/bams/backend/internal/logger"
)

type Target struct {
	ID         string   `json:"id"`
	IQN        string   `json:"iqn"`
	Portals    []string `json:"portals"`
	Initiators []string `json:"initiators"`
	LUNs       []LUN    `json:"luns"`
	Status     string   `json:"status"`
}

type LUN struct {
	Number int    `json:"number"`
	Device string `json:"device"`
	Type   string `json:"type"` // "disk" or "tape"
}

type Session struct {
	TargetIQN    string `json:"target_iqn"`
	InitiatorIQN string `json:"initiator_iqn"`
	IP           string `json:"ip"`
	State        string `json:"state"`
}

type Service struct {
	config *config.Config
	logger *logger.Logger
}

func NewService(cfg *config.Config, log *logger.Logger) *Service {
	return &Service{
		config: cfg,
		logger: log,
	}
}

func (s *Service) ListTargets() ([]*Target, error) {
	s.logger.Debug("Listing iSCSI targets")

	// Read SCST configuration
	targets := []*Target{}

	// Parse SCST config file
	if _, err := os.Stat(s.config.SCSTConfig); err == nil {
		data, err := os.ReadFile(s.config.SCSTConfig)
		if err == nil {
			targets = s.parseSCSTConfig(string(data))
		}
	}

	return targets, nil
}

func (s *Service) GetTarget(id string) (*Target, error) {
	targets, err := s.ListTargets()
	if err != nil {
		return nil, err
	}

	for _, target := range targets {
		if target.ID == id || target.IQN == id {
			return target, nil
		}
	}

	return nil, fmt.Errorf("target not found: %s", id)
}

func (s *Service) CreateTarget(iqn string, portals, initiators []string) (*Target, error) {
	s.logger.Info("Creating iSCSI target", "iqn", iqn)

	target := &Target{
		ID:         iqn,
		IQN:        iqn,
		Portals:    portals,
		Initiators: initiators,
		LUNs:       []LUN{},
		Status:     "pending",
	}

	// Write to SCST config
	if err := s.writeSCSTConfig(target); err != nil {
		return nil, fmt.Errorf("failed to write SCST config: %w", err)
	}

	return target, nil
}

func (s *Service) UpdateTarget(id string, portals, initiators []string) (*Target, error) {
	target, err := s.GetTarget(id)
	if err != nil {
		return nil, err
	}

	target.Portals = portals
	target.Initiators = initiators

	if err := s.writeSCSTConfig(target); err != nil {
		return nil, fmt.Errorf("failed to update SCST config: %w", err)
	}

	return target, nil
}

func (s *Service) DeleteTarget(id string) error {
	s.logger.Info("Deleting iSCSI target", "id", id)

	// Remove from SCST config
	// TODO: Implement actual deletion
	return nil
}

func (s *Service) ApplyTarget(id string) error {
	s.logger.Info("Applying iSCSI target configuration", "id", id)

	// Reload SCST configuration
	cmd := exec.Command("scstadmin", "-config", s.config.SCSTConfig)
	output, err := cmd.CombinedOutput()
	if err != nil {
		s.logger.Error("Failed to apply SCST config", "error", string(output))
		return fmt.Errorf("failed to apply SCST config: %w", err)
	}

	return nil
}

func (s *Service) ListSessions() ([]*Session, error) {
	s.logger.Debug("Listing iSCSI sessions")

	sessions := []*Session{}

	// Query SCST for active sessions
	cmd := exec.Command("scstadmin", "-list_sessions")
	output, err := cmd.CombinedOutput()
	if err == nil {
		sessions = s.parseSCSTSessions(string(output))
	}

	return sessions, nil
}

func (s *Service) parseSCSTConfig(data string) []*Target {
	targets := []*Target{}
	// Simplified parsing - real implementation would parse SCST config format
	lines := strings.Split(data, "\n")
	currentTarget := &Target{}

	for _, line := range lines {
		line = strings.TrimSpace(line)
		if strings.HasPrefix(line, "TARGET") {
			if currentTarget.IQN != "" {
				targets = append(targets, currentTarget)
			}
			currentTarget = &Target{
				IQN:        strings.Fields(line)[1],
				ID:         strings.Fields(line)[1],
				Portals:    []string{},
				Initiators: []string{},
				LUNs:       []LUN{},
				Status:     "active",
			}
		}
	}

	if currentTarget.IQN != "" {
		targets = append(targets, currentTarget)
	}

	return targets
}

func (s *Service) parseSCSTSessions(data string) []*Session {
	sessions := []*Session{}
	// Parse SCST session output
	lines := strings.Split(data, "\n")

	for _, line := range lines {
		if strings.Contains(line, "session") {
			// Parse session information
			session := &Session{
				State: "active",
			}
			sessions = append(sessions, session)
		}
	}

	return sessions
}

func (s *Service) writeSCSTConfig(target *Target) error {
	// Generate SCST configuration
	config := fmt.Sprintf(`TARGET %s {
    enabled 1
`, target.IQN)

	for _, portal := range target.Portals {
		config += fmt.Sprintf("    portal %s {\n", portal)
		config += "        enabled 1\n"
		config += "    }\n"
	}

	for _, initiator := range target.Initiators {
		config += fmt.Sprintf("    initiator %s {\n", initiator)
		config += "        enabled 1\n"
		config += "    }\n"
	}

	config += "}\n"

	// Append to config file (simplified - real implementation would merge properly)
	return os.WriteFile(s.config.SCSTConfig, []byte(config), 0644)
}