Implement document PATCH operation

api/handlers/documents.go

@@ -1,11 +1,14 @@
 package handlers
 
 import (
+	"encoding/json"
 	"fmt"
 	"net/http"
 
+	jsonpatch "github.com/evanphx/json-patch/v5"
 	"github.com/gin-gonic/gin"
 	"github.com/pikami/cosmium/internal/constants"
+	"github.com/pikami/cosmium/internal/logger"
 	"github.com/pikami/cosmium/internal/repositories"
 	repositorymodels "github.com/pikami/cosmium/internal/repository_models"
 )
@@ -100,6 +103,82 @@ func ReplaceDocument(c *gin.Context) {
 	c.IndentedJSON(http.StatusInternalServerError, gin.H{"message": "Unknown error"})
 }
 
+func PatchDocument(c *gin.Context) {
+	databaseId := c.Param("databaseId")
+	collectionId := c.Param("collId")
+	documentId := c.Param("docId")
+
+	document, status := repositories.GetDocument(databaseId, collectionId, documentId)
+	if status == repositorymodels.StatusNotFound {
+		c.IndentedJSON(http.StatusNotFound, gin.H{"message": "NotFound"})
+		return
+	}
+
+	var requestBody map[string]interface{}
+	if err := c.BindJSON(&requestBody); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"message": err.Error()})
+		return
+	}
+
+	operations := requestBody["operations"]
+	operationsBytes, err := json.Marshal(operations)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"message": "Could not decode operations"})
+		return
+	}
+
+	patch, err := jsonpatch.DecodePatch(operationsBytes)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"message": err.Error()})
+		return
+	}
+
+	currentDocumentBytes, err := json.Marshal(document)
+	if err != nil {
+		logger.Error("Failed to marshal existing document:", err)
+		c.JSON(http.StatusInternalServerError, gin.H{"message": "Failed to marshal existing document"})
+		return
+	}
+
+	modifiedDocumentBytes, err := patch.Apply(currentDocumentBytes)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"message": err.Error()})
+		return
+	}
+
+	var modifiedDocument map[string]interface{}
+	err = json.Unmarshal(modifiedDocumentBytes, &modifiedDocument)
+	if err != nil {
+		logger.Error("Failed to unmarshal modified document:", err)
+		c.JSON(http.StatusInternalServerError, gin.H{"message": "Failed to unmarshal modified document"})
+		return
+	}
+
+	if modifiedDocument["id"] != document["id"] {
+		c.JSON(http.StatusUnprocessableEntity, gin.H{"message": "The ID field cannot be modified"})
+		return
+	}
+
+	status = repositories.DeleteDocument(databaseId, collectionId, documentId)
+	if status == repositorymodels.StatusNotFound {
+		c.IndentedJSON(http.StatusNotFound, gin.H{"message": "NotFound"})
+		return
+	}
+
+	createdDocument, status := repositories.CreateDocument(databaseId, collectionId, modifiedDocument)
+	if status == repositorymodels.Conflict {
+		c.IndentedJSON(http.StatusConflict, gin.H{"message": "Conflict"})
+		return
+	}
+
+	if status == repositorymodels.StatusOk {
+		c.IndentedJSON(http.StatusCreated, createdDocument)
+		return
+	}
+
+	c.IndentedJSON(http.StatusInternalServerError, gin.H{"message": "Unknown error"})
+}
+
 func DocumentsPost(c *gin.Context) {
 	databaseId := c.Param("databaseId")
 	collectionId := c.Param("collId")