made LoginHandler slightly less awful

Signed-off-by: ari melody <ari@arimelody.me>

discord/discord.go

@@ -1,44 +1,105 @@
 package discord
 
+import (
+    "encoding/json"
+    "errors"
+    "fmt"
+    "net/http"
+    "net/url"
+    "strings"
+)
+
 const API_ENDPOINT = "https://discord.com/api/v10"
 const CLIENT_ID = "1268013769578119208"
+
 // TODO: good GOD change this later please i beg you. we've already broken
 // the rules by doing this at all
 const CLIENT_SECRET = "JUEZnixhN7BxmLIHmbECiKETMP85VT0E"
 const REDIRECT_URI = "https://discord.com/oauth2/authorize?client_id=1268013769578119208&response_type=code&redirect_uri=http%3A%2F%2F127.0.0.1%3A8080%2Fapi%2Fv1%2Fadmin%2Flogin&scope=identify"
+
 // TODO: change before prod
 const MY_REDIRECT_URI = "http://127.0.0.1:8080/api/v1/admin/login"
 
 type (
     AccessTokenResponse struct {
-        TokenType string `json:"token_type"`
-        AccessToken string `json:"access_token"`
-        ExpiresIn int `json:"expires_in"`
+        TokenType    string `json:"token_type"`
+        AccessToken  string `json:"access_token"`
+        ExpiresIn    int    `json:"expires_in"`
         RefreshToken string `json:"refresh_token"`
-        Scope string `json:"scope"`
+        Scope        string `json:"scope"`
     }
 
     AuthInfoResponse struct {
         Application struct {
-            Id string
-            Name string
-            Icon string
-            Description string
-            Hook bool
-            BotPublic bool
+            Id                  string
+            Name                string
+            Icon                string
+            Description         string
+            Hook                bool
+            BotPublic           bool
             botRequireCodeGrant bool
-            VerifyKey bool
+            VerifyKey           bool
         }
-        Scopes []string
+        Scopes  []string
         Expires string
-        User struct {
-            Id string
-            Username string
-            Avatar string
-            Discriminator string
-            GlobalName string
-            PublicFlags int
-        }
+        User    DiscordUser
+    }
+
+    DiscordUser struct {
+        Id            string
+        Username      string
+        Avatar        string
+        Discriminator string
+        GlobalName    string
+        PublicFlags   int
     }
 )
 
+func GetOAuthTokenFromCode(code string) (string, error) {
+    // let's get an oauth token!
+    req, err := http.NewRequest(http.MethodPost, fmt.Sprintf("%s/oauth2/token", API_ENDPOINT),
+    strings.NewReader(url.Values{
+        "client_id":     {CLIENT_ID},
+        "client_secret": {CLIENT_SECRET},
+        "grant_type":    {"authorization_code"},
+        "code":          {code},
+        "redirect_uri":  {MY_REDIRECT_URI},
+    }.Encode()))
+    req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
+
+    res, err := http.DefaultClient.Do(req)
+    if err != nil {
+        return "", errors.New(fmt.Sprintf("Failed while contacting discord API: %s", err))
+    }
+
+    oauth := AccessTokenResponse{}
+
+    err = json.NewDecoder(res.Body).Decode(&oauth)
+    if err != nil {
+        return "", errors.New(fmt.Sprintf("Failed to parse OAuth response data from discord: %s\n", err))
+    }
+    res.Body.Close()
+
+    return oauth.AccessToken, nil
+}
+
+func GetDiscordUserFromAuth(token string) (DiscordUser, error) {
+    // let's get authorisation information!
+    req, err := http.NewRequest(http.MethodGet, fmt.Sprintf("%s/oauth2/@me", API_ENDPOINT), nil)
+    req.Header.Add("Authorization", "Bearer " + token)
+
+    res, err := http.DefaultClient.Do(req)
+    if err != nil {
+        return DiscordUser{}, errors.New(fmt.Sprintf("Failed to retrieve discord auth information: %s\n", err))
+    }
+
+    auth_info := AuthInfoResponse{}
+
+    err = json.NewDecoder(res.Body).Decode(&auth_info)
+    if err != nil {
+        return DiscordUser{}, errors.New(fmt.Sprintf("Failed to parse auth information from discord: %s\n", err))
+    }
+    defer res.Body.Close()
+
+    return auth_info.User, nil
+}