package jsonem

import (
	"bytes"
	"encoding/json"
	"io"
	"io/ioutil"
	"net/http"
	"net/url"
	"strings"
	"time"

	"v2ray.com/core"
	"v2ray.com/core/common"
	"v2ray.com/core/common/buf"
	"v2ray.com/core/infra/conf"
	"v2ray.com/core/infra/conf/serial"
)

func init() {
	common.Must(core.RegisterConfigLoader(&core.ConfigFormat{
		Name:      "JSON",
		Extension: []string{"json"},
		Loader: func(input io.Reader) (*core.Config, error) {
			fns := []string{}
			data, _ := ioutil.ReadAll(input)
			json.Unmarshal(data, &fns)

			cf := &conf.Config{}
			for _, arg := range fns {
				r, err := LoadArg(arg)
				common.Must(err)
				c, err := serial.DecodeJSONConfig(r)
				common.Must(err)
				cf.Override(c, arg)
			}
			return cf.Build()
		}}))
}

func LoadArg(arg string) (out io.Reader, err error) {

	var data []byte
	if strings.HasPrefix(arg, "http://") || strings.HasPrefix(arg, "https://") {
		data, err = FetchHTTPContent(arg)
	} else {
		data, err = ioutil.ReadFile(arg)
	}

	if err != nil {
		return
	}
	out = bytes.NewBuffer(data)
	return
}

func FetchHTTPContent(target string) ([]byte, error) {

	parsedTarget, err := url.Parse(target)
	if err != nil {
		return nil, newError("invalid URL: ", target).Base(err)
	}

	if s := strings.ToLower(parsedTarget.Scheme); s != "http" && s != "https" {
		return nil, newError("invalid scheme: ", parsedTarget.Scheme)
	}

	client := &http.Client{
		Timeout: 30 * time.Second,
	}
	resp, err := client.Do(&http.Request{
		Method: "GET",
		URL:    parsedTarget,
		Close:  true,
	})
	if err != nil {
		return nil, newError("failed to dial to ", target).Base(err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != 200 {
		return nil, newError("unexpected HTTP status code: ", resp.StatusCode)
	}

	content, err := buf.ReadAllToBytes(resp.Body)
	if err != nil {
		return nil, newError("failed to read HTTP response").Base(err)
	}

	return content, nil
}