package fourbytegithub

import (
	"errors"
	"fmt"
	"io/ioutil"
	"net/http"
	"regexp"
	"strings"
	"time"

	"github.com/ethereum/go-ethereum/accounts/abi"
	"github.com/status-im/status-go/services/wallet/thirdparty"
)

type Signature struct {
	ID   int    `json:"id"`
	Text string `json:"text_signature"`
}

type ByID []Signature

func (s ByID) Len() int           { return len(s) }
func (s ByID) Less(i, j int) bool { return s[i].ID > s[j].ID }
func (s ByID) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }

type SignatureList struct {
	Count   int         `json:"count"`
	Results []Signature `json:"results"`
}

type Client struct {
	Client *http.Client
	URL    string
}

func NewClient() *Client {
	return &Client{Client: &http.Client{Timeout: time.Minute}, URL: "https://raw.githubusercontent.com"}
}

func (c *Client) DoQuery(url string) (*http.Response, error) {
	resp, err := c.Client.Get(url)

	if err != nil {
		return nil, err
	}
	return resp, nil
}

func (c *Client) Run(data string) (*thirdparty.DataParsed, error) {
	if len(data) < 10 || !strings.HasPrefix(data, "0x") {
		return nil, errors.New("input is badly formatted")
	}
	methodSigData := data[2:10]
	url := fmt.Sprintf("%s/ethereum-lists/4bytes/master/signatures/%s", c.URL, methodSigData)
	resp, err := c.DoQuery(url)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	body, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}
	signature := string(body)
	rgx := regexp.MustCompile(`\((.*?)\)`)

	id := fmt.Sprintf("0x%s", methodSigData)
	name := strings.Split(signature, "(")[0]
	rs := rgx.FindStringSubmatch(signature)

	inputs := make([]string, 0)
	rawInputs := strings.Split(rs[1], ",")
	for index, typ := range rawInputs {
		if index == len(rawInputs)-1 && typ == "bytes" {
			continue
		}
		inputs = append(inputs, fmt.Sprintf("{\"name\":\"%d\",\"type\":\"%s\"}", index, typ))
	}

	functionABI := fmt.Sprintf("[{\"constant\":true,\"inputs\":[%s],\"payable\":false,\"stateMutability\":\"view\",\"type\":\"function\", \"name\": \"%s\"}], ", strings.Join(inputs, ","), name)
	contractABI, err := abi.JSON(strings.NewReader(functionABI))
	if err != nil {
		return nil, err
	}
	method := contractABI.Methods[name]
	inputsMap := make(map[string]interface{})
	if err := method.Inputs.UnpackIntoMap(inputsMap, []byte(data[10:])); err != nil {
		return nil, err
	}
	inputsMapString := make(map[string]string)
	for key, value := range inputsMap {
		inputsMapString[key] = fmt.Sprintf("%v", value)
	}

	return &thirdparty.DataParsed{
		Name:      name,
		ID:        id,
		Signature: signature,
		Inputs:    inputsMapString,
	}, nil
}