package auth

import (
	"CatsOfMastodonBotGo/internal/config"
	"bytes"
	"encoding/json"
	"io"
	"net/http"
	"net/url"
)

type GiteaOAuth2Handler struct {
	ClientID     string
	ClientSecret string
	InstanceUrl  string
}

var GiteaOauth2HandlerInstance *GiteaOAuth2Handler

func InitGiteaOauth2Token() {
	GiteaOauth2HandlerInstance = &GiteaOAuth2Handler{
		ClientID: config.Config.GiteaOauthClientID,
		ClientSecret: config.Config.GiteaOauthClientSecret,
		InstanceUrl: config.Config.GiteaOauthInstance,
	}
}

func (g *GiteaOAuth2Handler) GetGiteaLoginURL (redirectHost string) (string) {
	authUrl := g.InstanceUrl + "/login/oauth/authorize?client_id=" + g.ClientID + "&redirect_uri=" + redirectHost + "/oath/gitea&scope=openid&response_type=code&response_mode=form_post"
	return authUrl
}

func (g *GiteaOAuth2Handler) GetGiteaUserEmailByCode(code string) (string, error) {
    accessToken, err := getGiteaAccessTokenByCode(code)
    if err != nil {
        return "", err
    }

    req, err := http.NewRequest("POST", g.InstanceUrl+"/login/oauth/userinfo", nil)
    if err != nil {
        return "", err
    }
    req.Header.Set("Authorization", "Bearer " + accessToken)
    req.Header.Set("Accept", "application/json")

    resp, err := http.DefaultClient.Do(req)
    if err != nil {
        return "", err
    }
    defer resp.Body.Close()

    body, err := io.ReadAll(resp.Body)
    if err != nil {
        return "", err
    }

    var userInfo struct {
        Email string `json:"email"`
    }
    if err := json.Unmarshal(body, &userInfo); err != nil {
        return "", err
    }

    return userInfo.Email, nil
}



func getGiteaAccessTokenByCode(code string) (string, error) {
    form := url.Values{}
    form.Add("client_id", GiteaOauth2HandlerInstance.ClientID)
    form.Add("client_secret", GiteaOauth2HandlerInstance.ClientSecret)
    form.Add("code", code)
    form.Add("grant_type", "authorization_code")

    req, err := http.NewRequest("POST", GiteaOauth2HandlerInstance.InstanceUrl+"/login/oauth/access_token", bytes.NewBufferString(form.Encode()))
    if err != nil {
        return "", err
    }
    req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
    req.Header.Set("Accept", "application/json")

    resp, err := http.DefaultClient.Do(req)
    if err != nil {
        return "", err
    }
    defer resp.Body.Close()

    body, _ := io.ReadAll(resp.Body)
    var tokenResp struct {
        AccessToken string `json:"access_token"`
    }
    if err := json.Unmarshal(body, &tokenResp); err != nil {
        return "", err
    }

    return tokenResp.AccessToken, nil
}