package provider

import (
	"context"
	"net/http"

	json "github.com/json-iterator/go"
	"golang.org/x/oauth2"
	"golang.org/x/oauth2/github"
)

type GithubProvider struct {
	config oauth2.Config
}

func (p *GithubProvider) Init(ClientID, ClientSecret string, options ...Oauth2Option) {
	p.config.ClientID = ClientID
	p.config.ClientSecret = ClientSecret
	p.config.Scopes = []string{"user"}
	p.config.Endpoint = github.Endpoint
	for _, o := range options {
		o(&p.config)
	}
}

func (p *GithubProvider) Provider() OAuth2Provider {
	return "github"
}

func (p *GithubProvider) NewConfig(options ...Oauth2Option) *oauth2.Config {
	c := p.config
	for _, o := range options {
		o(&c)
	}
	return &c
}

func (p *GithubProvider) GetUserInfo(ctx context.Context, config *oauth2.Config, code string) (*UserInfo, error) {
	oauth2Token, err := config.Exchange(ctx, code)
	if err != nil {
		return nil, err
	}
	client := config.Client(ctx, oauth2Token)
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, "https://api.github.com/user", nil)
	if err != nil {
		return nil, err
	}
	resp, err := client.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	ui := githubUserInfo{}
	err = json.NewDecoder(resp.Body).Decode(&ui)
	if err != nil {
		return nil, err
	}
	return &UserInfo{
		Username:       ui.Login,
		ProviderUserID: ui.ID,
	}, nil
}

type githubUserInfo struct {
	Login string `json:"login"`
	ID    uint   `json:"id"`
}

func init() {
	registerProvider(new(GithubProvider))
}