package system

import (
	"context"
	"encoding/json"
	"fmt"
	"os"
	"os/exec"
	"strings"
	"time"

	"github.com/atlasos/calypso/internal/common/logger"
)

// NTPSettings represents NTP configuration
type NTPSettings struct {
	Timezone   string   `json:"timezone"`
	NTPServers []string `json:"ntp_servers"`
}

// Service handles system management operations
type Service struct {
	logger *logger.Logger
}

// NewService creates a new system service
func NewService(log *logger.Logger) *Service {
	return &Service{
		logger: log,
	}
}

// ServiceStatus represents a systemd service status
type ServiceStatus struct {
	Name        string    `json:"name"`
	ActiveState string    `json:"active_state"`
	SubState    string    `json:"sub_state"`
	LoadState   string    `json:"load_state"`
	Description string    `json:"description"`
	Since       time.Time `json:"since,omitempty"`
}

// GetServiceStatus retrieves the status of a systemd service
func (s *Service) GetServiceStatus(ctx context.Context, serviceName string) (*ServiceStatus, error) {
	cmd := exec.CommandContext(ctx, "systemctl", "show", serviceName,
		"--property=ActiveState,SubState,LoadState,Description,ActiveEnterTimestamp",
		"--value", "--no-pager")
	output, err := cmd.Output()
	if err != nil {
		return nil, fmt.Errorf("failed to get service status: %w", err)
	}

	lines := strings.Split(strings.TrimSpace(string(output)), "\n")
	if len(lines) < 4 {
		return nil, fmt.Errorf("invalid service status output")
	}

	status := &ServiceStatus{
		Name:        serviceName,
		ActiveState: strings.TrimSpace(lines[0]),
		SubState:    strings.TrimSpace(lines[1]),
		LoadState:   strings.TrimSpace(lines[2]),
		Description: strings.TrimSpace(lines[3]),
	}

	// Parse timestamp if available
	if len(lines) > 4 && lines[4] != "" {
		if t, err := time.Parse("Mon 2006-01-02 15:04:05 MST", strings.TrimSpace(lines[4])); err == nil {
			status.Since = t
		}
	}

	return status, nil
}

// ListServices lists all Calypso-related services
func (s *Service) ListServices(ctx context.Context) ([]ServiceStatus, error) {
	services := []string{
		"calypso-api",
		"scst",
		"iscsi-scst",
		"mhvtl",
		"postgresql",
	}

	var statuses []ServiceStatus
	for _, serviceName := range services {
		status, err := s.GetServiceStatus(ctx, serviceName)
		if err != nil {
			s.logger.Warn("Failed to get service status", "service", serviceName, "error", err)
			continue
		}
		statuses = append(statuses, *status)
	}

	return statuses, nil
}

// RestartService restarts a systemd service
func (s *Service) RestartService(ctx context.Context, serviceName string) error {
	cmd := exec.CommandContext(ctx, "systemctl", "restart", serviceName)
	output, err := cmd.CombinedOutput()
	if err != nil {
		return fmt.Errorf("failed to restart service: %s: %w", string(output), err)
	}

	s.logger.Info("Service restarted", "service", serviceName)
	return nil
}

// GetJournalLogs retrieves journald logs for a service
func (s *Service) GetJournalLogs(ctx context.Context, serviceName string, lines int) ([]map[string]interface{}, error) {
	cmd := exec.CommandContext(ctx, "journalctl",
		"-u", serviceName,
		"-n", fmt.Sprintf("%d", lines),
		"-o", "json",
		"--no-pager")
	output, err := cmd.Output()
	if err != nil {
		return nil, fmt.Errorf("failed to get logs: %w", err)
	}

	var logs []map[string]interface{}
	linesOutput := strings.Split(strings.TrimSpace(string(output)), "\n")
	for _, line := range linesOutput {
		if line == "" {
			continue
		}
		var logEntry map[string]interface{}
		if err := json.Unmarshal([]byte(line), &logEntry); err == nil {
			logs = append(logs, logEntry)
		}
	}

	return logs, nil
}

// GenerateSupportBundle generates a diagnostic support bundle
func (s *Service) GenerateSupportBundle(ctx context.Context, outputPath string) error {
	// Create bundle directory
	cmd := exec.CommandContext(ctx, "mkdir", "-p", outputPath)
	if err := cmd.Run(); err != nil {
		return fmt.Errorf("failed to create bundle directory: %w", err)
	}

	// Collect system information
	commands := map[string][]string{
		"system_info": {"uname", "-a"},
		"disk_usage":  {"df", "-h"},
		"memory":      {"free", "-h"},
		"scst_status": {"scstadmin", "-list_target"},
		"services":    {"systemctl", "list-units", "--type=service", "--state=running"},
	}

	for name, cmdArgs := range commands {
		cmd := exec.CommandContext(ctx, cmdArgs[0], cmdArgs[1:]...)
		output, err := cmd.CombinedOutput()
		if err != nil {
			s.logger.Warn("Failed to collect info", "command", name, "error", err)
			continue
		}

		// Write to file
		filePath := fmt.Sprintf("%s/%s.txt", outputPath, name)
		if err := exec.CommandContext(ctx, "sh", "-c", fmt.Sprintf("cat > %s", filePath)).Run(); err == nil {
			exec.CommandContext(ctx, "sh", "-c", fmt.Sprintf("echo '%s' > %s", string(output), filePath)).Run()
		}
	}

	// Collect journal logs
	services := []string{"calypso-api", "scst", "iscsi-scst"}
	for _, service := range services {
		cmd := exec.CommandContext(ctx, "journalctl", "-u", service, "-n", "1000", "--no-pager")
		output, err := cmd.CombinedOutput()
		if err == nil {
			filePath := fmt.Sprintf("%s/journal_%s.log", outputPath, service)
			exec.CommandContext(ctx, "sh", "-c", fmt.Sprintf("echo '%s' > %s", string(output), filePath)).Run()
		}
	}

	s.logger.Info("Support bundle generated", "path", outputPath)
	return nil
}

// NetworkInterface represents a network interface
type NetworkInterface struct {
	Name      string `json:"name"`
	IPAddress string `json:"ip_address"`
	Subnet    string `json:"subnet"`
	Status    string `json:"status"` // "Connected" or "Down"
	Speed     string `json:"speed"`  // e.g., "10 Gbps", "1 Gbps"
	Role      string `json:"role"`   // "Management", "ISCSI", or empty
	Gateway   string `json:"gateway,omitempty"`
	DNS1      string `json:"dns1,omitempty"`
	DNS2      string `json:"dns2,omitempty"`
}

// ListNetworkInterfaces lists all network interfaces
func (s *Service) ListNetworkInterfaces(ctx context.Context) ([]NetworkInterface, error) {
	// First, get all interface names and their states
	cmd := exec.CommandContext(ctx, "ip", "link", "show")
	output, err := cmd.Output()
	if err != nil {
		s.logger.Error("Failed to list interfaces", "error", err)
		return nil, fmt.Errorf("failed to list interfaces: %w", err)
	}

	interfaceMap := make(map[string]*NetworkInterface)
	lines := strings.Split(string(output), "\n")

	s.logger.Debug("Parsing network interfaces", "output_lines", len(lines))

	for _, line := range lines {
		line = strings.TrimSpace(line)
		if line == "" {
			continue
		}

		// Parse interface name and state
		// Format: "2: ens18: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000"
		// Look for lines that start with a number followed by ":" (interface definition line)
		// Simple check: line starts with digit, contains ":", and contains "state"
		if len(line) > 0 && line[0] >= '0' && line[0] <= '9' && strings.Contains(line, ":") && strings.Contains(line, "state") {
			parts := strings.Fields(line)
			if len(parts) < 2 {
				continue
			}

			// Extract interface name (e.g., "ens18:" or "lo:")
			ifaceName := strings.TrimSuffix(parts[1], ":")
			if ifaceName == "" || ifaceName == "lo" {
				continue // Skip loopback
			}

			// Extract state - look for "state UP" or "state DOWN" in the line
			state := "Down"
			if strings.Contains(line, "state UP") {
				state = "Connected"
			} else if strings.Contains(line, "state DOWN") {
				state = "Down"
			}

			s.logger.Info("Found interface", "name", ifaceName, "state", state)

			interfaceMap[ifaceName] = &NetworkInterface{
				Name:   ifaceName,
				Status: state,
				Speed:  "Unknown",
			}
		}
	}

	s.logger.Debug("Found interfaces from ip link", "count", len(interfaceMap))

	// Get IP addresses for each interface
	cmd = exec.CommandContext(ctx, "ip", "-4", "addr", "show")
	output, err = cmd.Output()
	if err != nil {
		s.logger.Warn("Failed to get IP addresses", "error", err)
	} else {
		lines = strings.Split(string(output), "\n")
		var currentIfaceName string
		for _, line := range lines {
			line = strings.TrimSpace(line)
			if line == "" {
				continue
			}

			// Parse interface name (e.g., "2: ens18: <BROADCAST,MULTICAST,UP,LOWER_UP>")
			if strings.Contains(line, ":") && !strings.Contains(line, "inet") && !strings.HasPrefix(line, "valid_lft") && !strings.HasPrefix(line, "altname") {
				parts := strings.Fields(line)
				if len(parts) >= 2 {
					currentIfaceName = strings.TrimSuffix(parts[1], ":")
					s.logger.Debug("Processing interface for IP", "name", currentIfaceName)
				}
				continue
			}

			// Parse IP address (e.g., "inet 10.10.14.16/24 brd 10.10.14.255 scope global ens18")
			if strings.HasPrefix(line, "inet ") && currentIfaceName != "" && currentIfaceName != "lo" {
				parts := strings.Fields(line)
				if len(parts) >= 2 {
					ipWithSubnet := parts[1] // e.g., "10.10.14.16/24"
					ipParts := strings.Split(ipWithSubnet, "/")
					if len(ipParts) == 2 {
						ip := ipParts[0]
						subnet := ipParts[1]

						// Find or create interface
						iface, exists := interfaceMap[currentIfaceName]
						if !exists {
							s.logger.Debug("Creating new interface entry", "name", currentIfaceName)
							iface = &NetworkInterface{
								Name:   currentIfaceName,
								Status: "Down",
								Speed:  "Unknown",
							}
							interfaceMap[currentIfaceName] = iface
						}

						iface.IPAddress = ip
						iface.Subnet = subnet
						s.logger.Debug("Set IP for interface", "name", currentIfaceName, "ip", ip, "subnet", subnet)
					}
				}
			}
		}
	}

	// Get default gateway for each interface
	cmd = exec.CommandContext(ctx, "ip", "route", "show")
	output, err = cmd.Output()
	if err == nil {
		lines = strings.Split(string(output), "\n")
		for _, line := range lines {
			line = strings.TrimSpace(line)
			if strings.HasPrefix(line, "default via ") {
				// Format: "default via 192.168.1.1 dev ens18"
				parts := strings.Fields(line)
				if len(parts) >= 4 && parts[2] == "dev" {
					gateway := parts[1]
					ifaceName := parts[3]
					if iface, exists := interfaceMap[ifaceName]; exists {
						iface.Gateway = gateway
						s.logger.Debug("Set gateway for interface", "name", ifaceName, "gateway", gateway)
					}
				}
			} else if strings.Contains(line, " via ") && strings.Contains(line, " dev ") {
				// Format: "10.10.14.0/24 via 10.10.14.1 dev ens18"
				parts := strings.Fields(line)
				for i, part := range parts {
					if part == "via" && i+1 < len(parts) && i+2 < len(parts) && parts[i+2] == "dev" {
						gateway := parts[i+1]
						ifaceName := parts[i+3]
						if iface, exists := interfaceMap[ifaceName]; exists {
							iface.Gateway = gateway
							s.logger.Debug("Set gateway for interface", "name", ifaceName, "gateway", gateway)
						}
						break
					}
				}
			}
		}
	}

	// Get DNS servers from systemd-resolved or /etc/resolv.conf
	// Try systemd-resolved first
	cmd = exec.CommandContext(ctx, "systemd-resolve", "--status")
	output, err = cmd.Output()
	dnsServers := []string{}
	if err == nil {
		// Parse DNS from systemd-resolve output
		lines = strings.Split(string(output), "\n")
		for _, line := range lines {
			line = strings.TrimSpace(line)
			if strings.HasPrefix(line, "DNS Servers:") {
				// Format: "DNS Servers: 8.8.8.8 8.8.4.4"
				parts := strings.Fields(line)
				if len(parts) >= 3 {
					dnsServers = parts[2:]
				}
				break
			}
		}
	} else {
		// Fallback to /etc/resolv.conf
		data, err := os.ReadFile("/etc/resolv.conf")
		if err == nil {
			lines = strings.Split(string(data), "\n")
			for _, line := range lines {
				line = strings.TrimSpace(line)
				if strings.HasPrefix(line, "nameserver ") {
					dns := strings.TrimPrefix(line, "nameserver ")
					dns = strings.TrimSpace(dns)
					if dns != "" {
						dnsServers = append(dnsServers, dns)
					}
				}
			}
		}
	}

	// Convert map to slice
	var interfaces []NetworkInterface
	s.logger.Debug("Converting interface map to slice", "map_size", len(interfaceMap))
	for _, iface := range interfaceMap {
		// Get speed for each interface using ethtool
		if iface.Name != "" && iface.Name != "lo" {
			cmd := exec.CommandContext(ctx, "ethtool", iface.Name)
			output, err := cmd.Output()
			if err == nil {
				// Parse speed from ethtool output
				ethtoolLines := strings.Split(string(output), "\n")
				for _, ethtoolLine := range ethtoolLines {
					if strings.Contains(ethtoolLine, "Speed:") {
						parts := strings.Fields(ethtoolLine)
						if len(parts) >= 2 {
							iface.Speed = parts[1]
						}
						break
					}
				}
			}

			// Set DNS servers (use first two if available)
			if len(dnsServers) > 0 {
				iface.DNS1 = dnsServers[0]
			}
			if len(dnsServers) > 1 {
				iface.DNS2 = dnsServers[1]
			}

			// Determine role based on interface name or IP (simple heuristic)
			// You can enhance this with configuration file or database lookup
			if strings.Contains(iface.Name, "eth") || strings.Contains(iface.Name, "ens") {
				// Default to Management for first interface, ISCSI for others
				if iface.Name == "eth0" || iface.Name == "ens18" {
					iface.Role = "Management"
				} else {
					// Check if IP is in typical iSCSI range (10.x.x.x)
					if strings.HasPrefix(iface.IPAddress, "10.") && iface.IPAddress != "" {
						iface.Role = "ISCSI"
					}
				}
			}
		}
		interfaces = append(interfaces, *iface)
	}

	// If no interfaces found, return empty slice
	if len(interfaces) == 0 {
		s.logger.Warn("No network interfaces found")
		return []NetworkInterface{}, nil
	}

	s.logger.Info("Listed network interfaces", "count", len(interfaces))
	return interfaces, nil
}

// SaveNTPSettings saves NTP configuration to the OS
func (s *Service) SaveNTPSettings(ctx context.Context, settings NTPSettings) error {
	// Set timezone using timedatectl
	if settings.Timezone != "" {
		cmd := exec.CommandContext(ctx, "timedatectl", "set-timezone", settings.Timezone)
		output, err := cmd.CombinedOutput()
		if err != nil {
			s.logger.Error("Failed to set timezone", "timezone", settings.Timezone, "error", err, "output", string(output))
			return fmt.Errorf("failed to set timezone: %w", err)
		}
		s.logger.Info("Timezone set", "timezone", settings.Timezone)
	}

	// Configure NTP servers in systemd-timesyncd
	if len(settings.NTPServers) > 0 {
		configPath := "/etc/systemd/timesyncd.conf"

		// Build config content
		configContent := "[Time]\n"
		configContent += "NTP="
		for i, server := range settings.NTPServers {
			if i > 0 {
				configContent += " "
			}
			configContent += server
		}
		configContent += "\n"

		// Write to temporary file first, then move to final location (requires root)
		tmpPath := "/tmp/timesyncd.conf." + fmt.Sprintf("%d", time.Now().Unix())
		if err := os.WriteFile(tmpPath, []byte(configContent), 0644); err != nil {
			s.logger.Error("Failed to write temporary NTP config", "error", err)
			return fmt.Errorf("failed to write temporary NTP configuration: %w", err)
		}

		// Move to final location using sudo (requires root privileges)
		cmd := exec.CommandContext(ctx, "sh", "-c", fmt.Sprintf("mv %s %s", tmpPath, configPath))
		output, err := cmd.CombinedOutput()
		if err != nil {
			s.logger.Error("Failed to move NTP config", "error", err, "output", string(output))
			os.Remove(tmpPath) // Clean up temp file
			return fmt.Errorf("failed to move NTP configuration: %w", err)
		}

		// Restart systemd-timesyncd to apply changes
		cmd = exec.CommandContext(ctx, "systemctl", "restart", "systemd-timesyncd")
		output, err = cmd.CombinedOutput()
		if err != nil {
			s.logger.Error("Failed to restart systemd-timesyncd", "error", err, "output", string(output))
			return fmt.Errorf("failed to restart systemd-timesyncd: %w", err)
		}

		s.logger.Info("NTP servers configured", "servers", settings.NTPServers)
	}

	return nil
}

// GetNTPSettings retrieves current NTP configuration from the OS
func (s *Service) GetNTPSettings(ctx context.Context) (*NTPSettings, error) {
	settings := &NTPSettings{
		NTPServers: []string{},
	}

	// Get current timezone using timedatectl
	cmd := exec.CommandContext(ctx, "timedatectl", "show", "--property=Timezone", "--value")
	output, err := cmd.Output()
	if err != nil {
		s.logger.Warn("Failed to get timezone", "error", err)
		settings.Timezone = "Etc/UTC" // Default fallback
	} else {
		settings.Timezone = strings.TrimSpace(string(output))
		if settings.Timezone == "" {
			settings.Timezone = "Etc/UTC"
		}
	}

	// Read NTP servers from systemd-timesyncd config
	configPath := "/etc/systemd/timesyncd.conf"
	data, err := os.ReadFile(configPath)
	if err != nil {
		s.logger.Warn("Failed to read NTP config", "error", err)
		// Default NTP servers if config file doesn't exist
		settings.NTPServers = []string{"pool.ntp.org", "time.google.com"}
	} else {
		// Parse NTP servers from config file
		lines := strings.Split(string(data), "\n")
		for _, line := range lines {
			line = strings.TrimSpace(line)
			if strings.HasPrefix(line, "NTP=") {
				ntpLine := strings.TrimPrefix(line, "NTP=")
				if ntpLine != "" {
					servers := strings.Fields(ntpLine)
					settings.NTPServers = servers
					break
				}
			}
		}
		// If no NTP servers found in config, use defaults
		if len(settings.NTPServers) == 0 {
			settings.NTPServers = []string{"pool.ntp.org", "time.google.com"}
		}
	}

	return settings, nil
}