// System monitor adapter interface and implementations
// These adapters parse command output into structured metrics data.
// The actual command execution happens via IPC (netcatty:ssh:exec).

import type {
  CpuUsage,
  MemoryUsage,
  DiskUsage,
  NetworkTraffic,
  SystemLoad,
  ProcessInfo,
  DockerContainer,
  ListeningPort,
  SystemService,
  SystemMetricsSnapshot,
} from '../../domain/systemMonitor';

/**
 * Adapter interface for collecting system metrics from a remote host.
 * Each OS/device type has its own implementation.
 */
export interface SystemMonitorAdapter {
  /** OS family this adapter handles */
  readonly osFamily: 'linux' | 'windows' | 'network';

  /** Build a single command that collects all fast metrics (CPU, mem, load, uptime) */
  buildFastMetricsCommand(): string;

  /** Parse the output of fast metrics command */
  parseFastMetrics(output: string): Partial<SystemMetricsSnapshot>;

  /** Build command for disk usage */
  buildDiskCommand(): string;
  /** Parse disk usage output */
  parseDiskOutput(output: string): DiskUsage[];

  /** Build command for network traffic (current snapshot) */
  buildNetworkCommand(): string;
  /** Parse network output, needs prev snapshot for speed calc */
  parseNetworkOutput(output: string, prev?: NetworkTraffic[], intervalMs?: number): NetworkTraffic[];

  /** Build command for process list */
  buildProcessCommand(limit?: number): string;
  /** Parse process list output */
  parseProcessOutput(output: string): ProcessInfo[];

  /** Build command for docker containers */
  buildDockerCommand(): string;
  /** Parse docker output */
  parseDockerOutput(output: string): DockerContainer[];

  /** Build command for listening ports */
  buildPortsCommand(): string;
  /** Parse listening ports output */
  parsePortsOutput(output: string): ListeningPort[];

  /** Build command for system services */
  buildServicesCommand(): string;
  /** Parse services output */
  parseServicesOutput(output: string): SystemService[];
}

// ============================================================================
// Linux adapter
// ============================================================================

export class LinuxMonitorAdapter implements SystemMonitorAdapter {
  readonly osFamily = 'linux' as const;

  buildFastMetricsCommand(): string {
    // Collect CPU, memory, load, uptime, hostname in one shot
    // Using /proc for reliable parsing, plus uptime and hostname
    return `cat /proc/stat | head -1; echo "---MEM---"; cat /proc/meminfo; echo "---LOAD---"; cat /proc/loadavg; echo "---UPTIME---"; cat /proc/uptime; echo "---HOST---"; hostname; echo "---OS---"; cat /etc/os-release 2>/dev/null | head -5 || uname -r`;
  }

  parseFastMetrics(output: string): Partial<SystemMetricsSnapshot> {
    const result: Partial<SystemMetricsSnapshot> = {};
    const sections = output.split(/^---[A-Z]+---$/m);

    // CPU from /proc/stat (first line)
    const cpuLine = sections[0]?.trim().split('\n')[0];
    if (cpuLine) {
      const parts = cpuLine.trim().split(/\s+/);
      // cpu user nice system idle iowait irq softirq steal guest guest_nice
      if (parts.length >= 5) {
        const user = parseInt(parts[1]) || 0;
        const nice = parseInt(parts[2]) || 0;
        const system = parseInt(parts[3]) || 0;
        const idle = parseInt(parts[4]) || 0;
        const iowait = parts[5] ? parseInt(parts[5]) : 0;
        const total = user + nice + system + idle + iowait +
          (parts[6] ? parseInt(parts[6]) : 0) +
          (parts[7] ? parseInt(parts[7]) : 0) +
          (parts[8] ? parseInt(parts[8]) : 0);
        // We can't compute percentage without previous sample, so we store raw
        // For single snapshot, try to use more clever approach
        result.cpu = {
          totalPercent: 0, // will be calculated with delta
          cores: [],
          userPercent: 0,
          systemPercent: 0,
          idlePercent: 0,
        };
        (result.cpu as any)._rawTotal = total;
        (result.cpu as any)._rawIdle = idle;
        (result.cpu as any)._rawUser = user;
        (result.cpu as any)._rawSystem = system;
      }
    }

    // Memory from /proc/meminfo
    const memSection = sections[1];
    if (memSection) {
      const memInfo = this.parseMemInfo(memSection);
      if (memInfo) result.memory = memInfo;
    }

    // Load average
    const loadSection = sections[2];
    if (loadSection) {
      const loadParts = loadSection.trim().split(/\s+/);
      if (loadParts.length >= 3) {
        result.load = {
          load1: parseFloat(loadParts[0]) || 0,
          load5: parseFloat(loadParts[1]) || 0,
          load15: parseFloat(loadParts[2]) || 0,
        };
      }
    }

    // Uptime
    const uptimeSection = sections[3];
    if (uptimeSection) {
      const uptimeVal = parseFloat(uptimeSection.trim().split(/\s+/)[0]);
      if (!isNaN(uptimeVal)) result.uptimeSeconds = Math.floor(uptimeVal);
    }

    // Hostname
    const hostSection = sections[4];
    if (hostSection) {
      result.hostname = hostSection.trim();
    }

    // OS info
    const osSection = sections[5];
    if (osSection) {
      const prettyMatch = osSection.match(/PRETTY_NAME="?([^"\n]+)"?/);
      if (prettyMatch) result.osName = prettyMatch[1];
    }

    return result;
  }

  private parseMemInfo(output: string): MemoryUsage | null {
    const lines = output.trim().split('\n');
    const info: Record<string, number> = {};
    for (const line of lines) {
      const m = line.match(/^(\S+):\s+(\d+)/);
      if (m) info[m[1]] = parseInt(m[2]) * 1024; // kB -> bytes
    }
    const total = info['MemTotal'] || 0;
    const free = info['MemFree'] || 0;
    const buffers = info['Buffers'] || 0;
    const cached = info['Cached'] || 0;
    const sreclaimable = info['SReclaimable'] || 0;
    const used = total - free - buffers - cached - sreclaimable;
    const percent = total > 0 ? (used / total) * 100 : 0;

    return {
      totalBytes: total,
      usedBytes: used,
      freeBytes: free + buffers + cached + sreclaimable,
      percent,
      cachedBytes: cached + buffers + sreclaimable,
      swapUsedBytes: (info['SwapTotal'] || 0) - (info['SwapFree'] || 0),
      swapTotalBytes: info['SwapTotal'] || 0,
    };
  }

  buildDiskCommand(): string {
    return `df -PT -x tmpfs -x devtmpfs -x overlay -x squashfs 2>/dev/null | tail -n +2`;
  }

  parseDiskOutput(output: string): DiskUsage[] {
    const lines = output.trim().split('\n').filter(l => l.trim());
    const disks: DiskUsage[] = [];
    for (const line of lines) {
      const parts = line.trim().split(/\s+/);
      // Filesystem Type Size Used Avail Use% Mounted on
      if (parts.length >= 7) {
        const total = parseInt(parts[2]) * 1024; // KB -> bytes
        const used = parseInt(parts[3]) * 1024;
        const avail = parseInt(parts[4]) * 1024;
        const usePercent = parseInt(parts[5]);
        const mountPoint = parts.slice(6).join(' ');
        disks.push({
          filesystem: parts[0],
          mountPoint,
          totalBytes: total,
          usedBytes: used,
          freeBytes: avail,
          percent: usePercent,
        });
      }
    }
    return disks;
  }

  buildNetworkCommand(): string {
    return `cat /proc/net/dev | tail -n +3`;
  }

  parseNetworkOutput(output: string, prev?: NetworkTraffic[], intervalMs: number = 2000): NetworkTraffic[] {
    const lines = output.trim().split('\n').filter(l => l.trim());
    const current: Map<string, { rx: number; tx: number }> = new Map();

    for (const line of lines) {
      const parts = line.trim().split(/[:\s]+/);
      if (parts.length >= 10) {
        const iface = parts[0];
        if (iface === 'lo' || !iface) continue;
        const rxBytes = parseInt(parts[1]) || 0;
        const txBytes = parseInt(parts[9]) || 0;
        current.set(iface, { rx: rxBytes, tx: txBytes });
      }
    }

    const results: NetworkTraffic[] = [];
    const intervalSec = intervalMs / 1000;

    for (const [iface, curr] of current) {
      const prevItem = prev?.find(p => p.interfaceName === iface);
      let rxSpeed = 0;
      let txSpeed = 0;
      if (prevItem && prevItem.rxTotalBytes !== undefined && prevItem.txTotalBytes !== undefined) {
        rxSpeed = Math.max(0, (curr.rx - prevItem.rxTotalBytes) / intervalSec);
        txSpeed = Math.max(0, (curr.tx - prevItem.txTotalBytes) / intervalSec);
      }
      results.push({
        interfaceName: iface,
        rxBytesPerSec: rxSpeed,
        txBytesPerSec: txSpeed,
        rxTotalBytes: curr.rx,
        txTotalBytes: curr.tx,
      });
    }

    return results;
  }

  buildProcessCommand(limit: number = 20): string {
    return `ps -eo pid,user,%cpu,%mem,rss,comm,stat --sort=-%cpu --no-headers | head -${limit}`;
  }

  parseProcessOutput(output: string): ProcessInfo[] {
    const lines = output.trim().split('\n').filter(l => l.trim());
    const processes: ProcessInfo[] = [];
    for (const line of lines) {
      const parts = line.trim().split(/\s+/);
      if (parts.length >= 7) {
        processes.push({
          pid: parseInt(parts[0]) || 0,
          user: parts[1],
          cpuPercent: parseFloat(parts[2]) || 0,
          memPercent: parseFloat(parts[3]) || 0,
          memBytes: (parseInt(parts[4]) || 0) * 1024, // KB -> bytes
          name: parts[5],
          status: parts[6],
        });
      }
    }
    return processes;
  }

  buildDockerCommand(): string {
    return `docker ps -a --format "{{.ID}}|{{.Names}}|{{.Image}}|{{.Status}}|{{.State}}" 2>/dev/null || echo "DOCKER_NOT_FOUND"`;
  }

  parseDockerOutput(output: string): DockerContainer[] {
    if (output.includes('DOCKER_NOT_FOUND') || output.trim() === '') return [];
    const lines = output.trim().split('\n').filter(l => l.trim());
    const containers: DockerContainer[] = [];
    for (const line of lines) {
      const parts = line.split('|');
      if (parts.length >= 5) {
        containers.push({
          id: parts[0],
          name: parts[1],
          image: parts[2],
          status: parts[3],
          state: (parts[4].toLowerCase() as DockerContainer['state']) || 'unknown',
        });
      }
    }
    return containers;
  }

  buildPortsCommand(): string {
    return `ss -tulnp 2>/dev/null || netstat -tulnp 2>/dev/null || echo "PORTS_NOT_AVAILABLE"`;
  }

  parsePortsOutput(output: string): ListeningPort[] {
    if (output.includes('PORTS_NOT_AVAILABLE')) return [];
    const lines = output.trim().split('\n').filter(l => l.trim());
    const ports: ListeningPort[] = [];
    const seen = new Set<string>();

    for (const line of lines) {
      if (line.startsWith('State') || line.startsWith('Proto')) continue;
      const parts = line.trim().split(/\s+/);
      if (parts.length < 5) continue;

      const proto = parts[0].toLowerCase().includes('tcp') ? 'tcp' :
                    parts[0].toLowerCase().includes('udp') ? 'udp' : 'tcp';
      const localAddr = parts.find(p => p.includes(':') && !p.startsWith('0x'));
      if (!localAddr) continue;

      const lastColonIdx = localAddr.lastIndexOf(':');
      const addr = localAddr.substring(0, lastColonIdx).replace(/^\[|\]$/g, '');
      const portStr = localAddr.substring(lastColonIdx + 1);
      const port = parseInt(portStr);
      if (!port || isNaN(port)) continue;

      const key = `${proto}:${port}:${addr}`;
      if (seen.has(key)) continue;
      seen.add(key);

      // Try to find process info
      let processName = '';
      let pid: number | undefined;
      const procMatch = line.match(/users:\(\("([^"]+)"/);
      const pidMatch = line.match(/pid=(\d+)/);
      if (procMatch) processName = procMatch[1];
      if (pidMatch) pid = parseInt(pidMatch[1]);

      ports.push({
        port,
        protocol: proto as 'tcp' | 'udp',
        address: addr || '0.0.0.0',
        process: processName || undefined,
        pid,
        state: parts[1] || undefined,
      });
    }

    return ports.sort((a, b) => a.port - b.port);
  }

  buildServicesCommand(): string {
    return `systemctl list-units --type=service --all --no-pager --no-legend 2>/dev/null || echo "SYSTEMD_NOT_FOUND"`;
  }

  parseServicesOutput(output: string): SystemService[] {
    if (output.includes('SYSTEMD_NOT_FOUND')) return [];
    const lines = output.trim().split('\n').filter(l => l.trim());
    const services: SystemService[] = [];
    for (const line of lines) {
      const parts = line.trim().split(/\s+/);
      if (parts.length < 4) continue;
      const name = parts[0];
      const load = parts[1];
      const active = parts[2];
      const sub = parts[3];
      const desc = parts.slice(4).join(' ');

      let state: SystemService['state'] = 'unknown';
      if (active === 'active' && (sub === 'running' || sub === 'exited')) state = 'running';
      else if (active === 'inactive' || active === 'failed') state = active === 'failed' ? 'failed' : 'stopped';

      services.push({
        name,
        state,
        description: desc,
      });
    }
    return services.slice(0, 50); // limit
  }
}

// ============================================================================
// Windows adapter (for SSH-connected Windows servers)
// ============================================================================

export class WindowsMonitorAdapter implements SystemMonitorAdapter {
  readonly osFamily = 'windows' as const;

  buildFastMetricsCommand(): string {
    return `powershell -NoProfile -Command "
      $cpu = Get-WmiObject Win32_Processor | Measure-Object -Property LoadPercentage -Average | Select-Object -ExpandProperty Average;
      $os = Get-WmiObject Win32_OperatingSystem;
      $memTotal = $os.TotalVisibleMemorySize * 1024;
      $memFree = $os.FreePhysicalMemory * 1024;
      $memUsed = $memTotal - $memFree;
      $memPct = if ($memTotal -gt 0) { [math]::Round(($memUsed / $memTotal) * 100, 1) } else { 0 };
      $uptime = (Get-Date) - $os.ConvertToDateTime($os.LastBootUpTime);
      $hostName = $env:COMPUTERNAME;
      $osName = $os.Caption;
      Write-Output \"CPU:$cpu\";
      Write-Output \"MEM_TOTAL:$memTotal\";
      Write-Output \"MEM_USED:$memUsed\";
      Write-Output \"MEM_FREE:$memFree\";
      Write-Output \"MEM_PCT:$memPct\";
      Write-Output \"UPTIME:$([int]$uptime.TotalSeconds)\";
      Write-Output \"HOSTNAME:$hostName\";
      Write-Output \"OS:$osName\";
    " 2>$null`;
  }

  parseFastMetrics(output: string): Partial<SystemMetricsSnapshot> {
    const result: Partial<SystemMetricsSnapshot> = {};
    const lines = output.trim().split('\n');

    for (const line of lines) {
      const trimmed = line.trim();
      if (trimmed.startsWith('CPU:')) {
        const val = parseFloat(trimmed.substring(4)) || 0;
        result.cpu = { totalPercent: val, cores: [] };
      } else if (trimmed.startsWith('MEM_TOTAL:')) {
        if (!result.memory) result.memory = { totalBytes: 0, usedBytes: 0, freeBytes: 0, percent: 0 };
        result.memory.totalBytes = parseInt(trimmed.substring(10)) || 0;
      } else if (trimmed.startsWith('MEM_USED:')) {
        if (!result.memory) result.memory = { totalBytes: 0, usedBytes: 0, freeBytes: 0, percent: 0 };
        result.memory.usedBytes = parseInt(trimmed.substring(9)) || 0;
      } else if (trimmed.startsWith('MEM_FREE:')) {
        if (!result.memory) result.memory = { totalBytes: 0, usedBytes: 0, freeBytes: 0, percent: 0 };
        result.memory.freeBytes = parseInt(trimmed.substring(9)) || 0;
      } else if (trimmed.startsWith('MEM_PCT:')) {
        if (!result.memory) result.memory = { totalBytes: 0, usedBytes: 0, freeBytes: 0, percent: 0 };
        result.memory.percent = parseFloat(trimmed.substring(8)) || 0;
      } else if (trimmed.startsWith('UPTIME:')) {
        result.uptimeSeconds = parseInt(trimmed.substring(7)) || 0;
      } else if (trimmed.startsWith('HOSTNAME:')) {
        result.hostname = trimmed.substring(9);
      } else if (trimmed.startsWith('OS:')) {
        result.osName = trimmed.substring(3);
      }
    }

    return result;
  }

  buildDiskCommand(): string {
    return `powershell -NoProfile -Command "Get-PSDrive -PSProvider FileSystem | Where-Object { $_.Used -gt 0 } | ForEach-Object { $total = $_.Used + $_.Free; $pct = if ($total -gt 0) { [math]::Round(($_.Used / $total) * 100, 1) } else { 0 }; Write-Output '$($_.Name)|$total|$($_.Used)|$($_.Free)|$pct|$($_.Root)' }" 2>$null`;
  }

  parseDiskOutput(output: string): DiskUsage[] {
    const lines = output.trim().split('\n').filter(l => l.trim());
    const disks: DiskUsage[] = [];
    for (const line of lines) {
      const parts = line.trim().split('|');
      if (parts.length >= 6) {
        disks.push({
          filesystem: parts[0],
          mountPoint: parts[5],
          totalBytes: parseInt(parts[1]) || 0,
          usedBytes: parseInt(parts[2]) || 0,
          freeBytes: parseInt(parts[3]) || 0,
          percent: parseFloat(parts[4]) || 0,
        });
      }
    }
    return disks;
  }

  buildNetworkCommand(): string {
    return `powershell -NoProfile -Command "Get-NetAdapterStatistics -ErrorAction SilentlyContinue | ForEach-Object { Write-Output '$($_.Name)|$($_.ReceivedBytes)|$($_.SentBytes)' }" 2>$null`;
  }

  parseNetworkOutput(output: string, prev?: NetworkTraffic[], intervalMs: number = 2000): NetworkTraffic[] {
    const lines = output.trim().split('\n').filter(l => l.trim());
    const current: Map<string, { rx: number; tx: number }> = new Map();

    for (const line of lines) {
      const parts = line.trim().split('|');
      if (parts.length >= 3) {
        current.set(parts[0], {
          rx: parseInt(parts[1]) || 0,
          tx: parseInt(parts[2]) || 0,
        });
      }
    }

    const results: NetworkTraffic[] = [];
    const intervalSec = intervalMs / 1000;

    for (const [iface, curr] of current) {
      const prevItem = prev?.find(p => p.interfaceName === iface);
      let rxSpeed = 0;
      let txSpeed = 0;
      if (prevItem && prevItem.rxTotalBytes !== undefined && prevItem.txTotalBytes !== undefined) {
        rxSpeed = Math.max(0, (curr.rx - prevItem.rxTotalBytes) / intervalSec);
        txSpeed = Math.max(0, (curr.tx - prevItem.txTotalBytes) / intervalSec);
      }
      results.push({
        interfaceName: iface,
        rxBytesPerSec: rxSpeed,
        txBytesPerSec: txSpeed,
        rxTotalBytes: curr.rx,
        txTotalBytes: curr.tx,
      });
    }
    return results;
  }

  buildProcessCommand(limit: number = 20): string {
    return `powershell -NoProfile -Command "Get-Process | Sort-Object CPU -Descending | Select-Object -First ${limit} | ForEach-Object { $cpuPct = if ($_.CPU -ne $null) { [math]::Round($_.CPU, 1) } else { 0 }; $memPct = 0; $name = $_.ProcessName; Write-Output '$($_.Id)|$($_.UserName ?? '')|$cpuPct|$memPct|$($_.WorkingSet64)|$name|$($_.StartTime)' }" 2>$null`;
  }

  parseProcessOutput(output: string): ProcessInfo[] {
    const lines = output.trim().split('\n').filter(l => l.trim());
    const processes: ProcessInfo[] = [];
    for (const line of lines) {
      const parts = line.trim().split('|');
      if (parts.length >= 6) {
        processes.push({
          pid: parseInt(parts[0]) || 0,
          user: parts[1] || undefined,
          cpuPercent: parseFloat(parts[2]) || 0,
          memPercent: parseFloat(parts[3]) || 0,
          memBytes: parseInt(parts[4]) || 0,
          name: parts[5],
        });
      }
    }
    return processes;
  }

  buildDockerCommand(): string {
    return `docker ps -a --format "{{.ID}}|{{.Names}}|{{.Image}}|{{.Status}}|{{.State}}" 2>$null`;
  }

  parseDockerOutput(output: string): DockerContainer[] {
    if (output.trim() === '' || output.includes('not found')) return [];
    const lines = output.trim().split('\n').filter(l => l.trim());
    const containers: DockerContainer[] = [];
    for (const line of lines) {
      const parts = line.split('|');
      if (parts.length >= 5) {
        containers.push({
          id: parts[0],
          name: parts[1],
          image: parts[2],
          status: parts[3],
          state: (parts[4].toLowerCase().trim() as DockerContainer['state']) || 'unknown',
        });
      }
    }
    return containers;
  }

  buildPortsCommand(): string {
    return `powershell -NoProfile -Command "Get-NetTCPConnection -State Listen -ErrorAction SilentlyContinue | ForEach-Object { Write-Output '$($_.LocalAddress)|$($_.LocalPort)|TCP|$($_.OwningProcess)' }; Get-NetUDPEndpoint -ErrorAction SilentlyContinue | ForEach-Object { Write-Output '$($_.LocalAddress)|$($_.LocalPort)|UDP|$($_.OwningProcess)' }" 2>$null`;
  }

  parsePortsOutput(output: string): ListeningPort[] {
    const lines = output.trim().split('\n').filter(l => l.trim());
    const ports: ListeningPort[] = [];
    const seen = new Set<string>();

    for (const line of lines) {
      const parts = line.trim().split('|');
      if (parts.length >= 4) {
        const addr = parts[0].replace(/^\[|\]$/g, '');
        const port = parseInt(parts[1]);
        const proto = parts[2].toLowerCase() as 'tcp' | 'udp';
        const pid = parseInt(parts[3]);

        const key = `${proto}:${port}:${addr}`;
        if (seen.has(key) || !port) continue;
        seen.add(key);

        ports.push({
          port,
          protocol: proto,
          address: addr || '0.0.0.0',
          pid: pid || undefined,
        });
      }
    }
    return ports.sort((a, b) => a.port - b.port);
  }

  buildServicesCommand(): string {
    return `powershell -NoProfile -Command "Get-Service | ForEach-Object { $state = switch ($_.Status) { 'Running' { 'running' } 'Stopped' { 'stopped' } default { 'unknown' } }; $startType = switch ($_.StartType) { 'Automatic' { 'auto' } 'Manual' { 'manual' } 'Disabled' { 'disabled' } default { 'manual' } }; Write-Output '$($_.Name)|$state|$($_.DisplayName)|$startType' }" 2>$null`;
  }

  parseServicesOutput(output: string): SystemService[] {
    const lines = output.trim().split('\n').filter(l => l.trim());
    const services: SystemService[] = [];
    for (const line of lines) {
      const parts = line.trim().split('|');
      if (parts.length >= 4) {
        services.push({
          name: parts[0],
          state: parts[1] as SystemService['state'],
          description: parts[2],
          startupType: parts[3] as SystemService['startupType'],
        });
      }
    }
    return services.slice(0, 50);
  }
}

/**
 * Get the appropriate monitor adapter based on OS type.
 */
export function getMonitorAdapter(osType: 'linux' | 'windows' | 'macos' | string): SystemMonitorAdapter {
  switch (osType) {
    case 'windows':
      return new WindowsMonitorAdapter();
    case 'linux':
    case 'macos':
    default:
      return new LinuxMonitorAdapter();
  }
}