package raid

import (
	"errors"
	"fmt"
	"log"
	"os"
	"os/exec"
	"sort"
	"strconv"
	"strings"

	"imuslab.com/arozos/mod/utils"
)

/*
	mdadm manager

	This script handles the interaction with mdadm
*/

// Storage Device meta was generated by lsblk
type StorageDeviceMeta struct {
	Name       string
	Size       int64
	RO         bool
	DevType    string
	MountPoint string
}

// RAIDDevice represents information about a RAID device.
type RAIDMember struct {
	Name string
	Seq  int
}

type RAIDDevice struct {
	Name    string
	Status  string
	Level   string
	Members []*RAIDMember
}

// List all the storage device in the system, set minSize to 0 for no filter
func (m *Manager) ListAllStorageDevices(minSize int64) ([]*StorageDeviceMeta, error) {
	cmd := exec.Command("sudo", "lsblk", "-b")

	output, err := cmd.CombinedOutput()
	if err != nil {
		return nil, fmt.Errorf("lsblk error: %v", err)
	}

	// Split the output into lines
	lines := strings.Split(string(output), "\n")

	var devices []*StorageDeviceMeta

	// Parse each line to extract device information
	for _, line := range lines[1:] { // Skip the header line
		fields := strings.Fields(line)
		if len(fields) < 7 {
			continue
		}

		size, err := strconv.ParseInt(fields[3], 10, 64)
		if err != nil {
			return nil, fmt.Errorf("error parsing device size: %v", err)
		}

		ro := fields[4] == "1"

		device := &StorageDeviceMeta{
			Name:       fields[0],
			Size:       size,
			RO:         ro,
			DevType:    fields[5],
			MountPoint: fields[6],
		}

		// Filter devices based on minimum size
		if size >= minSize {
			devices = append(devices, device)
		}
	}

	return devices, nil
}

// Return the uuid of the disk by its path name (e.g. /dev/sda)
func (m *Manager) GetDiskUUIDByPath(devicePath string) (string, error) {
	cmd := exec.Command("sudo", "blkid", devicePath)

	output, err := cmd.CombinedOutput()
	if err != nil {
		return "", fmt.Errorf("blkid error: %v", err)
	}

	// Parse the output to extract the UUID
	fields := strings.Fields(string(output))
	for _, field := range fields {
		if strings.HasPrefix(field, "UUID=") {
			uuid := strings.TrimPrefix(field, "UUID=\"")
			uuid = strings.TrimSuffix(uuid, "\"")
			return uuid, nil
		}
	}

	return "", fmt.Errorf("UUID not found for device %s", devicePath)
}

// CreateRAIDDevice creates a RAID device using the mdadm command.
func (m *Manager) CreateRAIDDevice(devName string, raidName string, raidLevel int, raidDeviceIds []string, spareDeviceIds []string) error {
	//Calculate the size of the raid devices
	raidDev := len(raidDeviceIds)
	spareDevice := len(spareDeviceIds)

	//Validate if raid level
	if !IsValidRAIDLevel("raid" + strconv.Itoa(raidLevel)) {
		return fmt.Errorf("invalid or unsupported raid level given: raid" + strconv.Itoa(raidLevel))
	}

	//Validate the number of disk is enough for the raid
	if raidLevel == 0 && raidDev < 2 {
		return fmt.Errorf("not enough disks for raid0")
	} else if raidLevel == 1 && raidDev < 2 {
		return fmt.Errorf("not enough disks for raid1")
	} else if raidLevel == 5 && raidDev < 3 {
		return fmt.Errorf("not enough disk for raid5")
	} else if raidLevel == 6 && raidDev < 4 {
		return fmt.Errorf("not enough disk for raid6")
	}

	//Append /dev to the name if missing
	if !strings.HasPrefix(devName, "/dev/") {
		devName = "/dev/" + devName
	}

	if utils.FileExists(devName) {
		//RAID device already exists
		return errors.New(devName + " already been used")
	}

	// Concatenate RAID and spare device arrays
	allDeviceIds := append(raidDeviceIds, spareDeviceIds...)

	// Build the mdadm command
	cmd := exec.Command("bash", "-c", fmt.Sprintf("yes | sudo mdadm --create %s --name %s --level=%d --raid-devices=%d --spare-devices=%d %s",
		devName, raidName, raidLevel, raidDev, spareDevice, strings.Join(allDeviceIds, " ")))

	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr

	err := cmd.Run()
	if err != nil {
		return fmt.Errorf("error running mdadm command: %v", err)
	}

	return nil
}

// GetRAIDDevicesFromProcMDStat retrieves information about RAID devices from /proc/mdstat.
// if your RAID array is in auto-read-only mode, it is (usually) brand new
func (m *Manager) GetRAIDDevicesFromProcMDStat() ([]RAIDDevice, error) {
	// Execute the cat command to read /proc/mdstat
	cmd := exec.Command("cat", "/proc/mdstat")

	// Run the command and capture its output
	output, err := cmd.Output()
	if err != nil {
		return nil, fmt.Errorf("error running cat command: %v", err)
	}

	// Convert the output to a string and split it into lines
	lines := strings.Split(string(output), "\n")

	// Initialize an empty slice to store RAID devices
	raidDevices := make([]RAIDDevice, 0)

	// Iterate over the lines, skipping the first line (Personalities)
	// Lines usually looks like this
	// md0 : active raid1 sdc[1] sdb[0]
	for _, line := range lines[1:] {
		// Skip empty lines
		if line == "" {
			continue
		}

		// Split the line by colon (:)
		parts := strings.SplitN(line, " : ", 2)
		if len(parts) != 2 {
			continue
		}

		// Extract device name and status
		deviceName := parts[0]

		// Split the members string by space to get individual member devices
		info := strings.Fields(parts[1])
		if len(info) < 4 {
			//Malform output
			continue
		}

		deviceStatus := info[0]

		//Raid level usually appears at position 1 - 2, check both
		raidLevel := ""
		if strings.HasPrefix(info[1], "raid") {
			raidLevel = info[1]
		} else if strings.HasPrefix(info[2], "raid") {
			raidLevel = info[2]
		}

		//Get the members (disks) of the array
		members := []*RAIDMember{}
		for _, disk := range info[2:] {
			if !strings.HasPrefix(disk, "sd") {
				//Probably not a storage device
				continue
			}

			//In sda[0] format, we need to split out the number from the disk seq
			tmp := strings.Split(disk, "[")
			if len(tmp) != 2 {
				continue
			}

			//Convert the sequence to id
			seqInt, err := strconv.Atoi(strings.TrimSuffix(strings.TrimSpace(tmp[1]), "]"))
			if err != nil {
				//Not an integer?
				log.Println("[RAID] Unable to parse " + disk + " sequence ID")
				continue
			}
			member := RAIDMember{
				Name: strings.TrimSpace(tmp[0]),
				Seq:  seqInt,
			}

			members = append(members, &member)
		}

		//Sort the member disks
		sort.Slice(members[:], func(i, j int) bool {
			return members[i].Seq < members[j].Seq
		})

		// Create a RAIDDevice struct and append it to the slice
		raidDevice := RAIDDevice{
			Name:    deviceName,
			Status:  deviceStatus,
			Level:   raidLevel,
			Members: members,
		}
		raidDevices = append(raidDevices, raidDevice)
	}

	return raidDevices, nil
}