MOVINGBRICKS

package mainimport (    "encoding/json"    "fmt"    "io/ioutil"    "net/http"    "net/url"    "sort"    "strconv"    "strings"    "time"    "github.com/davecgh/go-spew/spew")const defProxy = "https://usr:psswd@192.168.1.148:8080"var (    KnownSymbols = []string{        "BTC",        "ETH",        "USDT",        "ETC",    })func findSuffix(pairname string) string {    for _, suf := range KnownSymbols {        if strings.HasSuffix(pairname, suf) {            return suf        }    }    return ""}func splitPair(pairname string) (string, string) {    s := findSuffix(pairname)    return pairname[:len(s)], pairname[len(pairname)-len(s):]}var (    ExcludedSymbols = []string{        "123456",    })func isExcludedSymbol(name string) bool {    for _, v := range ExcludedSymbols {        if v == name {            return true        }    }    return false}type BaItem struct {    Symbol string `json:"symbol"`    Price  string `json:"price"`    Numerator   string    Denominator string    Rate        float64}type baItem BaItemfunc (b *BaItem) UnmarshalJSON(bytes []byte) (err error) {    j := baItem{}    err = json.Unmarshal(bytes, &j)    if err == nil {        *b = BaItem(j)        b.Numerator, b.Denominator = splitPair(b.Symbol)        b.Rate, _ = strconv.ParseFloat(b.Price, 64)    }    return}func (b *BaItem) String() string {    return fmt.Sprintf("%v=>%v:%f", b.Numerator, b.Denominator, b.Rate)}type TSnapshot []BaItemtype BaAgent struct {    client *http.Client}type TsEntry struct {    Timestamp time.Time    Tsa       TSnapshot}func newConn() *http.Client {    tr := &http.Transport{        MaxIdleConns:       10,        IdleConnTimeout:    10 * time.Second,        DisableCompression: true,        DisableKeepAlives:  false, //    }    url, eUrl := url.Parse(defProxy)    if eUrl != nil {        panic(eUrl)    }    tr.Proxy = http.ProxyURL(url)    //tr.Proxy = http.ProxyFromEnvironment    return &http.Client{        Transport: tr,    }}func NewBaAgent() *BaAgent {    return &BaAgent{        client: newConn(),    }}func (b *BaAgent) GetSnapshot() (*TsEntry, error) {    //~ As long as it could be made new from `make`    const ticker_uri = "https://www.binance.com/api/v1/ticker/allPrices"    resp, err := b.client.Get(ticker_uri)    if err != nil {        return nil, err    }    defer resp.Body.Close() // must do    chunk, eChunk := ioutil.ReadAll(resp.Body)    if eChunk != nil {        return nil, eChunk    }    var tsa TSnapshot    if e := json.Unmarshal(chunk, &tsa); e != nil {        return nil, e    }    return &TsEntry{        Timestamp: time.Now(),        Tsa:       tsa,    }, nil}type ExchangeItem struct {    Name       string    EthBtcPair float64}type ExchangeItemArr []ExchangeItemfunc (s ExchangeItemArr) Len() int {    return len(s)}func (s ExchangeItemArr) Swap(i, j int) {    s[i], s[j] = s[j], s[i]}func (s ExchangeItemArr) Less(i, j int) bool {    return s[i].EthBtcPair < s[j].EthBtcPair}func Traverse(snap TsEntry) {    fmt.Printf("start analyzing %v\n", snap.Timestamp.Format(time.RFC822))    fromMap := make(map[string]map[string]float64) // all initialized.    // ico - to main-stream    for _, ent := range snap.Tsa {        if nil == fromMap[ent.Numerator] {            fromMap[ent.Numerator] = make(map[string]float64)        }        fromMap[ent.Numerator][ent.Denominator] = ent.Rate    }    spew.Dump(fromMap)    var exi []ExchangeItem    stdR := fromMap["ETH"]["BTC"]    //_ = stdR    for kind, ent := range fromMap {        b_rate, btcOK := ent["BTC"]        e_rate, ethOK := ent["ETH"]        if btcOK && ethOK {            esteR := 1 / e_rate * b_rate            //fmt.Printf("%v => %v\n", kind, esteR/stdR)            exi = append(exi, ExchangeItem{kind, esteR / stdR})        }    }    sort.Sort(ExchangeItemArr(exi))    fmt.Println("******************************")    spew.Dump(exi)}func main() {    ba := NewBaAgent()    if snap, e := ba.GetSnapshot(); nil == e {        //fmt.Printf("%+v\n", snap)        //spew.Dump(snap)        for _, snap := range snap.Tsa {            if isExcludedSymbol(snap.Symbol) {                continue            }            found := false            for _, n := range KnownSymbols {                if strings.HasSuffix(snap.Symbol, n) {                    found = true                    break                }            }            if !found {                fmt.Printf("Unknown symbol: %v\n", snap.Symbol)            }        }        fmt.Println()        Traverse(*snap)    } else {        fmt.Printf("Error: %v\n", e)    }    //fmt.Println("bye")}