package services

import (
	"cmii-uav-watchdog-common/models"
	"fmt"
	"strconv"
	"strings"
	"syscall"
)

// GetDiskInfo retrieves disk information similar to df -Th.
func GetDiskInfo() []models.DiskInfo {
	var diskInfos []models.DiskInfo

	// Read /proc/mounts to get mounted filesystems
	mountsData, err := readFileWithWarning("/proc/mounts")
	if err != nil {
		return diskInfos
	}

	mounts := strings.Split(string(mountsData), "\n")

	// Read /proc/partitions to get physical disks
	partitionsData, err := readFileWithWarning("/proc/partitions")
	if err != nil {
		return diskInfos
	}

	partitions := strings.Split(string(partitionsData), "\n")
	physicalDevices := make(map[string]uint64)

	// Map physical devices to their sizes
	for _, line := range partitions {
		fields := strings.Fields(line)
		if len(fields) < 4 {
			continue
		}
		device := fields[3]                               // The device name is in the 4th column
		size, err := strconv.ParseUint(fields[2], 10, 64) // 读取大小
		if err != nil {
			continue
		}
		physicalDevices[device] = size * 1024 // 转换为字节
	}

	for _, mount := range mounts {
		if mount == "" {
			continue
		}
		fields := strings.Fields(mount)
		if len(fields) < 3 {
			continue
		}
		logicalDevice := fields[0] // 逻辑分区设备名
		mountPoint := fields[1]    // 挂载点
		fstype := fields[2]        // 文件系统类型

		// Skip NFS mounts
		if fstype == "nfs" {
			continue
		}

		// Skip overlay mounts
		if fstype == "overlay" {
			continue
		}

		// Get disk usage information using stat
		var stat syscall.Statfs_t
		if err := syscall.Statfs(mountPoint, &stat); err != nil {
			fmt.Printf("Warning: error getting statfs for %s: %v\n", mountPoint, err)
			continue
		}

		// Calculate total, used, and available space
		total := stat.Blocks * uint64(stat.Bsize)
		available := stat.Bavail * uint64(stat.Bsize)
		used := total - available

		// Skip if size is 0
		if total == 0 {
			continue
		}

		// Calculate percentage used
		usePercent := "0%"
		if total > 0 {
			usePercent = fmt.Sprintf("%.1f%%", float64(used)/float64(total)*100)
		}

		// Determine the physical device and its size
		physicalDevice := ""
		physicalSize := uint64(0)

		// Check if the logical device is a partition (e.g., /dev/sda1)
		if strings.HasPrefix(logicalDevice, "/dev/") {
			// Get the corresponding physical device (e.g., /dev/sda)
			physicalDevice = strings.TrimSuffix(logicalDevice, "1") // 假设逻辑分区是 /dev/sda1
			if size, exists := physicalDevices[physicalDevice]; exists {
				physicalSize = size
			}
		}

		// If not found, use the logical device as the physical device
		if physicalDevice == "" || physicalSize == 0 {
			physicalDevice = logicalDevice
			if size, exists := physicalDevices[physicalDevice]; exists {
				physicalSize = size
			}
		}

		diskInfos = append(diskInfos, models.DiskInfo{
			Device:         logicalDevice,  // 设置逻辑分区的设备名称
			Filesystem:     logicalDevice,  // 逻辑分区
			Type:           fstype,         // 文件系统类型
			Size:           total,          // 总大小
			Used:           used,           // 已用空间
			Available:      available,      // 可用空间
			UsePercent:     usePercent,     // 使用百分比
			MountPoint:     mountPoint,     // 挂载点
			PhysicalDevice: physicalDevice, // 物理设备名称
			PhysicalSize:   physicalSize,   // 物理盘大小
		})
	}

	return diskInfos
}

/*
Device: sda, Total: 500107862016 bytes, Used: 250000000000 bytes, Available: 200000000000 bytes
Device: sdb, Total: 400107862016 bytes, Used: 150000000000 bytes, Available: 250000000000 bytes
Device: sdc, Total: 100107862016 bytes, Used: 50000000000 bytes, Available: 50000000000 bytes
Device: unknown, Total: 0 bytes, Used: 0 bytes, Available: 0 bytes
*/