package main

import ( "fmt"
         "log"
         "os"
         "strconv" )

// http://go-database-sql.org/importing.html
//    _ "github.com/mattn/go-sqlite3"
//    _ "code.google.com/p/gosqlite/sqlite3"
import (
    "database/sql"
    _ "github.com/mattn/go-sqlite3"
    "github.com/pborman/getopt"
)

func ethers(db *sql.DB, vlan int) {
    var (
        mac string
        ipv4 string
    )

    // CREATE TABLE devices (name, mac, interface);
    // CREATE TABLE addresses (mac, vlan, ipv4);

    rows, err := db.Query("SELECT mac, ipv4 FROM addresses WHERE vlan=?", vlan)
    if err != nil {
        log.Fatal(err)
    }
    for rows.Next() {
        err := rows.Scan(&mac, &ipv4)
        if err != nil {
            log.Fatal(err)
        }
        fmt.Println(mac, " ", ipv4)
    }
}

func hosts(db *sql.DB, vlan int) {
    var (
        ipv4 string
        name string
        suffix *string
        alias string
        hostpart string
    )

    // CREATE TABLE devices (name, mac, interface);
    // CREATE TABLE addresses (mac, vlan, ipv4);

    rows, err := db.Query("SELECT a.ipv4, d.name, d.suffix " +
        "FROM addresses AS a JOIN devices AS d ON a.mac=d.mac WHERE vlan=?",
        vlan)
    if err != nil {
        log.Fatal(err)
    }
    for rows.Next() {
        err := rows.Scan(&ipv4, &name, &suffix)
        if err != nil {
            log.Fatal(err)
        }
        if suffix != nil {
            hostpart = name + "-" + *suffix
        } else {
            hostpart = name
        }
        fmt.Print(ipv4, "\t", hostpart)

        // CREATE TABLE aliases (alias, target);
        rows, err := db.Query("SELECT alias FROM aliases WHERE target=?", hostpart)
        if err != nil {
            log.Fatal(err)
        }
        for rows.Next() {
            err := rows.Scan(&alias)
            if err != nil {
                log.Fatal(err)
            }
            fmt.Print(" ", alias)
        }
        fmt.Println()
    }
}

func main() {
    var (
        description string
        ipv4 string
    )

    optDatabase := getopt.StringLong("database", 'd', "",
        "Path to SQLite3 database file with device addresses")
    optHelp := getopt.BoolLong("help", 0, "Help")
    getopt.SetParameters("{ethers|hosts} list_of_networks")
    getopt.Parse()

    if *optHelp {
        getopt.Usage()
        os.Exit(0)
    }
    args := getopt.Args()

    db, err := sql.Open("sqlite3", *optDatabase)
    if err != nil {
        log.Fatal(err)
    }

    for _, arg := range args[1:] {
        vlan, _ := strconv.Atoi(arg)
        rows, err := db.Query(
            "SELECT description, ipv4 FROM networks WHERE vlan=?", vlan)
        if err != nil {
            log.Fatal(err)
        }
        for rows.Next() {
            err := rows.Scan(&description, &ipv4)
            if err != nil {
                log.Fatal(err)
            }
            fmt.Print("\n# ", description, ", ", ipv4, "\n")
            fmt.Println("# vlan:", vlan)
            switch args[0] {
            case "ethers":
                ethers(db, vlan)
            case "hosts":
                hosts(db, vlan)
            default:
                os.Exit(1)
            }
        }
    }
    db.Close()
}