package com.sshmanager.controller;

import com.sshmanager.entity.Connection;
import com.sshmanager.entity.User;
import com.sshmanager.repository.UserRepository;
import com.sshmanager.service.ConnectionService;
import com.sshmanager.service.SshService;
import org.springframework.http.ResponseEntity;
import org.springframework.security.core.Authentication;
import org.springframework.web.bind.annotation.*;

import java.util.HashMap;
import java.util.Map;

@RestController
@RequestMapping("/api/monitor")
public class MonitorController {

    private final ConnectionService connectionService;
    private final SshService sshService;
    private final UserRepository userRepository;

    public MonitorController(ConnectionService connectionService, SshService sshService, UserRepository userRepository) {
        this.connectionService = connectionService;
        this.sshService = sshService;
        this.userRepository = userRepository;
    }

    private Long getCurrentUserId(Authentication auth) {
        User user = userRepository.findByUsername(auth.getName()).orElseThrow(() -> new IllegalStateException("User not found"));
        return user.getId();
    }

    @GetMapping("/{connectionId}")
    public ResponseEntity<Map<String, Object>> getServerMetrics(@PathVariable Long connectionId, Authentication authentication) {
        try {
            Long userId = getCurrentUserId(authentication);
            Connection conn = connectionService.getConnectionForSsh(connectionId, userId);
            if (conn == null) {
                return ResponseEntity.notFound().build();
            }

            String password = connectionService.getDecryptedPassword(conn);
            String privateKey = connectionService.getDecryptedPrivateKey(conn);
            String passphrase = connectionService.getDecryptedPassphrase(conn);

            Map<String, Object> metrics = new HashMap<>();

            // 获取CPU使用率（兼容多种系统）
            try {
                double cpuUsage = 0;
                try {
                    // 优先使用top
                    String cpuOutput = sshService.executeCommand(conn, password, privateKey, passphrase, 
                        "top -bn1 2>/dev/null | grep 'Cpu(s)' | sed 's/.*, *\\([0-9.]*\\)%* id.*/\\1/' | awk '{print 100 - $1}'");
                    if (!cpuOutput.trim().isEmpty()) {
                        cpuUsage = Double.parseDouble(cpuOutput.trim());
                    } else {
                        throw new Exception("top command failed");
                    }
                } catch (Exception e) {
                    // 备用方案：使用/proc/stat计算（需要两次采样，这里简化处理用vmstat）
                    try {
                        String vmstatOutput = sshService.executeCommand(conn, password, privateKey, passphrase,
                            "vmstat 1 2 | tail -1 | awk '{print 100 - $15}'");
                        cpuUsage = Double.parseDouble(vmstatOutput.trim());
                    } catch (Exception e2) {
                        throw new Exception("Both top and vmstat failed");
                    }
                }
                metrics.put("cpuUsage", Math.round(cpuUsage * 10.0) / 10.0);
            } catch (Exception e) {
                metrics.put("cpuUsage", null);
            }

            // 获取内存信息（兼容多种系统）
            try {
                long totalMem = 0;
                long usedMem = 0;
                try {
                    // 优先使用free -b
                    String memOutput = sshService.executeCommand(conn, password, privateKey, passphrase,
                        "free -b 2>/dev/null | grep Mem");
                    if (!memOutput.trim().isEmpty()) {
                        String[] memParts = memOutput.trim().split("\\s+");
                        if (memParts.length >= 3) {
                            totalMem = Long.parseLong(memParts[1]);
                            usedMem = Long.parseLong(memParts[2]);
                        }
                    }
                } catch (Exception e) {
                    // 备用方案：从/proc/meminfo读取
                    String meminfoOutput = sshService.executeCommand(conn, password, privateKey, passphrase,
                        "cat /proc/meminfo | grep -E 'MemTotal|MemAvailable'");
                    String[] lines = meminfoOutput.trim().split("\n");
                    if (lines.length >= 2) {
                        totalMem = Long.parseLong(lines[0].replaceAll("\\D+", "")) * 1024;
                        long availableMem = Long.parseLong(lines[1].replaceAll("\\D+", "")) * 1024;
                        usedMem = totalMem - availableMem;
                    }
                }
                
                if (totalMem > 0 && usedMem >= 0) {
                    double memUsage = (double) usedMem / totalMem * 100;
                    metrics.put("memTotal", totalMem);
                    metrics.put("memUsed", usedMem);
                    metrics.put("memUsage", Math.round(memUsage * 10.0) / 10.0);
                } else {
                    throw new Exception("Failed to parse memory info");
                }
            } catch (Exception e) {
                metrics.put("memTotal", null);
                metrics.put("memUsed", null);
                metrics.put("memUsage", null);
            }

            // 获取磁盘使用率
            try {
                String diskOutput = sshService.executeCommand(conn, password, privateKey, passphrase,
                    "df -P / | tail -1");
                String[] diskParts = diskOutput.trim().split("\\s+");
                int diskUsage = Integer.parseInt(diskParts[4].replace("%", ""));
                metrics.put("diskUsage", diskUsage);
            } catch (Exception e) {
                metrics.put("diskUsage", null);
            }

            // 获取系统负载
            try {
                String loadOutput = sshService.executeCommand(conn, password, privateKey, passphrase,
                    "cat /proc/loadavg");
                String[] loadParts = loadOutput.trim().split("\\s+");
                double load1 = Double.parseDouble(loadParts[0]);
                metrics.put("load1", load1);
            } catch (Exception e) {
                metrics.put("load1", null);
            }

            // 获取CPU核数
            try {
                String cpuCountOutput = sshService.executeCommand(conn, password, privateKey, passphrase,
                    "grep -c ^processor /proc/cpuinfo");
                int cpuCores = Integer.parseInt(cpuCountOutput.trim());
                metrics.put("cpuCores", cpuCores);
            } catch (Exception e) {
                metrics.put("cpuCores", null);
            }

            // 获取系统运行时间
            try {
                String uptimeOutput = sshService.executeCommand(conn, password, privateKey, passphrase,
                    "uptime -p");
                metrics.put("uptime", uptimeOutput.trim().replace("up ", ""));
            } catch (Exception e) {
                // 尝试另一种uptime格式
                try {
                    String uptimeOutput = sshService.executeCommand(conn, password, privateKey, passphrase,
                        "cat /proc/uptime | awk '{print $1}'");
                    double uptimeSeconds = Double.parseDouble(uptimeOutput.trim());
                    long days = (long) (uptimeSeconds / 86400);
                    long hours = (long) ((uptimeSeconds % 86400) / 3600);
                    long minutes = (long) ((uptimeSeconds % 3600) / 60);
                    StringBuilder uptimeStr = new StringBuilder();
                    if (days > 0) uptimeStr.append(days).append("d ");
                    if (hours > 0) uptimeStr.append(hours).append("h ");
                    uptimeStr.append(minutes).append("m");
                    metrics.put("uptime", uptimeStr.toString().trim());
                } catch (Exception e2) {
                    metrics.put("uptime", null);
                }
            }

            return ResponseEntity.ok(metrics);
        } catch (Exception e) {
            Map<String, Object> error = new HashMap<>();
            error.put("error", e.getMessage());
            return ResponseEntity.badRequest().body(error);
        }
    }
}