Add oauth2 like auth service

Signed-off-by: Asai Neko <sugar@sne.moe>

service/auth/redirect.go

@@ -1,7 +1,122 @@
 package auth
 
-import "github.com/gin-gonic/gin"
+import (
+	"net/url"
+	"nixcn-cms/data"
+	"nixcn-cms/pkgs/authcode"
+
+	"github.com/gin-gonic/gin"
+	"github.com/google/uuid"
+	"gorm.io/gorm"
+)
 
 func Redirect(c *gin.Context) {
+	clientId := c.Query("client_id")
+	if clientId == "" {
+		c.JSON(400, gin.H{"status": "invalid request"})
+		return
+	}
 
+	redirectUri := c.Query("redirect_uri")
+	if redirectUri == "" {
+		c.JSON(400, gin.H{"status": "invalid request"})
+		return
+	}
+
+	state := c.Query("state")
+	if state == "" {
+		c.JSON(400, gin.H{"status": "invalid request"})
+		return
+	}
+
+	code := c.Query("code")
+	if code == "" {
+		userIdOrig, ok := c.Get("user_id")
+		if !ok || userIdOrig == "" {
+			c.JSON(401, gin.H{"status": "unauthorized"})
+			return
+		}
+
+		userId, err := uuid.Parse(userIdOrig.(string))
+		if err != nil {
+			c.JSON(500, gin.H{"status": "failed to parse uuid"})
+			return
+		}
+
+		userData := new(data.User)
+		user, err := userData.GetByUserId(userId)
+		if err != nil {
+			c.JSON(500, gin.H{"status": "failed to get user id"})
+			return
+		}
+
+		code, err := authcode.NewAuthCode(user.Email)
+		if err != nil {
+			c.JSON(500, gin.H{"status": "code gen failed"})
+			return
+		}
+
+		url, err := url.Parse(redirectUri)
+		if err != nil {
+			c.JSON(400, gin.H{"status": "invalid redirect uri"})
+			return
+		}
+		query := url.Query()
+		query.Set("code", code)
+		url.RawQuery = query.Encode()
+
+		c.Redirect(302, url.String())
+	}
+
+	// Verify email token
+	email, ok := authcode.VerifyAuthCode(code)
+	if !ok {
+		c.JSON(403, gin.H{"status": "invalid or expired token"})
+		return
+	}
+
+	// Verify if user exists
+	userData := new(data.User)
+	user, err := userData.GetByEmail(email)
+
+	if err != nil {
+		if err == gorm.ErrRecordNotFound {
+			// Create user
+			user.UUID = uuid.New()
+			user.UserId = uuid.New()
+			user.Email = email
+			user.PermissionLevel = 10
+			if err := user.Create(); err != nil {
+				c.JSON(500, gin.H{"status": "internal server error"})
+				return
+			}
+		} else {
+			c.JSON(500, gin.H{"status": "internal server error"})
+			return
+		}
+	}
+
+	clientData := new(data.Client)
+	client, err := clientData.GetClientByClientId(clientId)
+	if err != nil {
+		c.JSON(400, gin.H{"status": "client not found"})
+		return
+	}
+
+	err = client.ValidateRedirectURI(redirectUri)
+	if err != nil {
+		c.JSON(400, gin.H{"status": "redirect uri not match"})
+		return
+	}
+
+	url, err := url.Parse(redirectUri)
+	if err != nil {
+		c.JSON(400, gin.H{"status": "invalid redirect uri"})
+		return
+	}
+	query := url.Query()
+	query.Set("code", code)
+	url.RawQuery = query.Encode()
+
+	c.Redirect(302, url.String())
 }