package nfs

import (
    "bufio"
    "log"
    "os"
    "strconv"
    "strings"
    "fmt"

    "github.com/influxdata/telegraf"
    "github.com/influxdata/telegraf/plugins/inputs"
)

type NFS struct {
    Iostat bool
    Fullstat bool
}

var sampleConfig = `
  # iostat = true
  # Read iostat metrics
  iostat = true
  # fullstat = true
  # Read all metrics
  fullstat = true
`

func (n *NFS) SampleConfig() string {
    return sampleConfig
}

func (n *NFS) Description() string {
    return "Read NFS metrics from /proc/self/mountstats"
}

var eventsFields = []string{
        "inoderevalidates",
        "dentryrevalidates",
        "datainvalidates",
        "attrinvalidates",
        "vfsopen",
        "vfslookup",
        "vfspermission",
        "vfsupdatepage",
        "vfsreadpage",
        "vfsreadpages",
        "vfswritepage",
        "vfswritepages",
        "vfsreaddir",
        "vfssetattr",
        "vfsflush",
        "vfsfsync",
        "vfslock",
        "vfsrelease",
        "congestionwait",
        "setattrtrunc",
        "extendwrite",
        "sillyrenames",
        "shortreads",
        "shortwrites",
        "delay",
        "pnfsreads",
        "pnfswrites",
}

var bytesFields = []string{
        "normalreadbytes",
        "normalwritebytes",
        "directreadbytes",
        "directwritebytes",
        "serverreadbytes",
        "serverwritebytes",
        "readpages",
        "writepages",
}

var xprtudpFields = []string{
//        "port",
        "bind_count",
        "rpcsends",
        "rpcreceives",
        "badxids",
        "inflightsends",
        "backlogutil",
}

var xprttcpFields = []string{
//        "port",
        "bind_count",
        "connect_count",
        "connect_time",
        "idle_time",
        "rpcsends",
        "rpcreceives",
        "badxids",
        "inflightsends",
        "backlogutil",
}

var nfs3Fields = []string{
        "NULL",
        "GETATTR",
        "SETATTR",
        "LOOKUP",
        "ACCESS",
        "READLINK",
        "READ",
        "WRITE",
        "CREATE",
        "MKDIR",
        "SYMLINK",
        "MKNOD",
        "REMOVE",
        "RMDIR",
        "RENAME",
        "LINK",
        "READDIR",
        "READDIRPLUS",
        "FSSTAT",
        "FSINFO",
        "PATHCONF",
        "COMMIT",
}

var nfs4Fields = []string{
        "NULL",
        "READ",
        "WRITE",
        "COMMIT",
        "OPEN",
        "OPEN_CONFIRM",
        "OPEN_NOATTR",
        "OPEN_DOWNGRADE",
        "CLOSE",
        "SETATTR",
        "FSINFO",
        "RENEW",
        "SETCLIENTID",
        "SETCLIENTID_CONFIRM",
        "LOCK",
        "LOCKT",
        "LOCKU",
        "ACCESS",
        "GETATTR",
        "LOOKUP",
        "LOOKUP_ROOT",
        "REMOVE",
        "RENAME",
        "LINK",
        "SYMLINK",
        "CREATE",
        "PATHCONF",
        "STATFS",
        "READLINK",
        "READDIR",
        "SERVER_CAPS",
        "DELEGRETURN",
        "GETACL",
        "SETACL",
        "FS_LOCATIONS",
        "RELEASE_LOCKOWNER",
        "SECINFO",
        "FSID_PRESENT",
        "EXCHANGE_ID",
        "CREATE_SESSION",
        "DESTROY_SESSION",
        "SEQUENCE",
        "GET_LEASE_TIME",
        "RECLAIM_COMPLETE",
        "LAYOUTGET",
        "GETDEVICEINFO",
        "LAYOUTCOMMIT",
        "LAYOUTRETURN",
        "SECINFO_NO_NAME",
        "TEST_STATEID",
        "FREE_STATEID",
        "GETDEVICELIST",
        "BIND_CONN_TO_SESSION",
        "DESTROY_CLIENTID",
        "SEEK",
        "ALLOCATE",
        "DEALLOCATE",
        "LAYOUTSTATS",
        "CLONE",
}

var nfsopFields = []string {
        "ops",
        "trans",
        "timeouts",
        "bytes_sent",
        "bytes_recv",
        "queue_time",
        "response_time",
        "total_time",
}

func convert(line []string) []float64 {
    var nline []float64
    for _, l := range line[1:] {
        f, _ := strconv.ParseFloat(l, 64)
        nline = append(nline, f)
    }
    return nline
}

func In(list []string, val string) bool {
    for _, v := range list {
        if v == val {
            return true
        }
    }
    return false
}

func (n *NFS) parseStat(mountpoint string, version string, line []string, acc telegraf.Accumulator) error {
    tags := map[string]string{"mountpoint": mountpoint}
    nline := convert(line)
    first := strings.Replace(line[0], ":", "", 1)

    var fields = make(map[string]interface{})

    if version == "3" || version == "4" {
        if In(nfs3Fields, first) {
            if first == "READ" {
                fields["read_ops"] = nline[0]
                fields["read_retrans"] = (nline[1] - nline[0])
                fields["read_bytes"] = (nline[3] + nline[4])
                fields["read_rtt"] = nline[6]
                fields["read_exe"] = nline[7]
                acc.AddFields("nfsstat_read", fields, tags)
            } else if first == "WRITE" {
                fields["write_ops"] = nline[0]
                fields["write_retrans"] = (nline[1] - nline[0])
                fields["write_bytes"] = (nline[3] + nline[4])
                fields["write_rtt"] = nline[6]
                fields["write_exe"] = nline[7]
                acc.AddFields("nfsstat_write", fields, tags)
            }
        }
    }
    return nil
}

func (n *NFS) parseData(mountpoint string, version string, line []string, acc telegraf.Accumulator) error {
    tags := map[string]string{"mountpoint": mountpoint}
    nline := convert(line)
    first := strings.Replace(line[0], ":", "", 1)

    var fields = make(map[string]interface{})

    if first == "events" {
        for i,t := range eventsFields {
            fields[t] = nline[i]
        }
        acc.AddFields("nfs_events", fields, tags)
    } else if first == "bytes" {
        for i,t := range bytesFields {
            fields[t] = nline[i]
        }
        acc.AddFields("nfs_bytes", fields, tags)
    } else if first == "xprt" {
        switch line[1] {
            case "tcp": {
                for i,t := range xprttcpFields {
                    fields[t] = nline[i+2]
                }
                acc.AddFields("nfs_xprttcp", fields, tags)
            }
            case "udp": {
                for i,t := range xprtudpFields {
                    fields[t] = nline[i+2]
                }
                acc.AddFields("nfs_xprtudp", fields, tags)
            }
        }
    } else if version == "3" {
        if In(nfs3Fields, first) {
            for i , t := range nline {
                item := fmt.Sprintf("%s_%s", first, nfsopFields[i])
                fields[item] = t
            }
            acc.AddFields("nfs_ops", fields, tags)
        }
    } else if version == "4" {
        if In(nfs4Fields, first) {
            for i , t := range nline {
                item := fmt.Sprintf("%s_%s", first, nfsopFields[i])
                fields[item] = t
            }
            acc.AddFields("nfs_ops", fields, tags)
        }
    }
    return nil
}

func (n *NFS) processText(scanner *bufio.Scanner, acc telegraf.Accumulator) error {
    var device string
    var version string
    for scanner.Scan() {
        line := strings.Fields(scanner.Text())
        if In(line, "fstype") && In(line, "nfs") {
            device = fmt.Sprintf("%s %s", line[1], line[4])
        } else if In(line, "(nfs)") {
            version = strings.Split(line[5], "/")[1]
        }
        if (len(line) > 0) {
            if n.Iostat == true {
                n.parseStat(device, version, line, acc)
            }
            if n.Fullstat == true {
                n.parseData(device, version, line, acc)
            }
        }
    }
    return nil
}

func (n *NFS) Gather(acc telegraf.Accumulator) error {
    var outerr error

    file, err := os.Open("/proc/self/mountstats")
    if err != nil {
        log.Fatal(err)
    }
    defer file.Close()

    scanner := bufio.NewScanner(file)
    n.processText(scanner, acc)

    if err := scanner.Err(); err != nil {
        log.Fatal(err)
    }

    return outerr
}

func init() {
    inputs.Add("nfs", func() telegraf.Input {
        return &NFS{}
    })
}