Folder API support (#168)

# Description
This PR adds support for folders

# License
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license and that I have the authority necessary to make this
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src/main/kotlin/com/nylas/NylasClient.kt

@@ -119,6 +119,14 @@ class NylasClient(
     return Events(this)
   }
 
+  /**
+   * Access the Folders API
+   * @return The Folders API
+   */
+  fun folders(): Folders {
+    return Folders(this)
+  }
+
   /**
    * Access the Messages API
    * @return The Messages API

src/main/kotlin/com/nylas/models/CreateFolderRequest.kt

@@ -0,0 +1,75 @@
+package com.nylas.models
+
+/**
+ * Class representation of the Nylas folder creation request.
+ */
+data class CreateFolderRequest(
+  /**
+   * The name of the folder.
+   */
+  val name: String,
+  /**
+   * The parent ID of the folder. (Microsoft only)
+   */
+  val parentId: String? = null,
+  /**
+   * The background color of the folder. (Google only)
+   */
+  val backgroundColor: String? = null,
+  /**
+   * The text color of the folder. (Google only)
+   */
+  val textColor: String? = null,
+) {
+  /**
+   * Builder for [CreateFolderRequest].
+   * @param name The name of the folder.
+   */
+  data class Builder(
+    private val name: String,
+  ) {
+    private var parentId: String? = null
+    private var backgroundColor: String? = null
+    private var textColor: String? = null
+
+    /**
+     * Set the parent ID of the folder. (Microsoft only)
+     * @param parentId The parent ID of the folder.
+     * @return The builder.
+     */
+    fun parentId(parentId: String) = apply { this.parentId = parentId }
+
+    /**
+     * Set the background color of the folder. (Google only)
+     *
+     * The background color of the folder in the hexadecimal format `#0099EE`.
+     * See Google Defined Values for more information.
+     *
+     * @param backgroundColor The background color of the folder.
+     * @return The builder.
+     */
+    fun backgroundColor(backgroundColor: String) = apply { this.backgroundColor = backgroundColor }
+
+    /**
+     * Set the text color of the folder. (Google only)
+     *
+     * The text color of the folder in the hexadecimal format `#0099EE`.
+     * See Google Defined Values for more information.
+     *
+     * @param textColor The text color of the folder.
+     * @return The builder.
+     */
+    fun textColor(textColor: String) = apply { this.textColor = textColor }
+
+    /**
+     * Build the [CreateFolderRequest].
+     * @return The [CreateFolderRequest].
+     */
+    fun build() = CreateFolderRequest(
+      name = name,
+      parentId = parentId,
+      backgroundColor = backgroundColor,
+      textColor = textColor,
+    )
+  }
+}

src/main/kotlin/com/nylas/models/Folder.kt

@@ -0,0 +1,70 @@
+package com.nylas.models
+
+import com.squareup.moshi.Json
+
+/**
+ * Class representation of the Nylas folder response.
+ */
+data class Folder(
+  /**
+   * A globally unique object identifier.
+   */
+  @Json(name = "id")
+  val id: String,
+  /**
+   * A Grant ID of the Nylas account.
+   */
+  @Json(name = "grant_id")
+  val grantId: String,
+  /**
+   * Folder name
+   */
+  @Json(name = "name")
+  val name: String? = null,
+  /**
+   * The type of object.
+   */
+  @Json(name = "object")
+  val obj: String = "folder",
+  /**
+   * ID of the parent folder. (Microsoft only)
+   */
+  @Json(name = "parent_id")
+  val parentId: String? = null,
+  /**
+   * Folder background color. (Google only)
+   */
+  @Json(name = "background_color")
+  val backgroundColor: String? = null,
+  /**
+   * Folder text color. (Google only)
+   */
+  @Json(name = "text_color")
+  val textColor: String? = null,
+  /**
+   * Indicates if the folder is user created or system created. (Google Only)
+   */
+  @Json(name = "system_folder")
+  val systemFolder: Boolean? = null,
+  /**
+   * The number of immediate child folders in the current folder. (Microsoft only)
+   */
+  @Json(name = "child_count")
+  val childCount: Int? = null,
+  /**
+   * The number of unread items inside of a folder.
+   */
+  @Json(name = "unread_count")
+  val unreadCount: Int? = null,
+  /**
+   * The number of items inside of a folder.
+   */
+  @Json(name = "total_count")
+  val totalCount: Int? = null,
+) {
+  /**
+   * Get the type of object.
+   * @return The type of object.
+   */
+  fun getObject() = obj
+}

src/main/kotlin/com/nylas/models/UpdateFolderRequest.kt

@@ -0,0 +1,80 @@
+package com.nylas.models
+
+/**
+ * Class representation of the Nylas folder update request.
+ */
+data class UpdateFolderRequest(
+  /**
+   * The name of the folder.
+   */
+  val name: String? = null,
+  /**
+   * The parent ID of the folder. (Microsoft only)
+   */
+  val parentId: String? = null,
+  /**
+   * The background color of the folder. (Google only)
+   */
+  val backgroundColor: String? = null,
+  /**
+   * The text color of the folder. (Google only)
+   */
+  val textColor: String? = null,
+) {
+  /**
+   * Builder for [UpdateFolderRequest].
+   */
+  class Builder {
+    private var name: String? = null
+    private var parentId: String? = null
+    private var backgroundColor: String? = null
+    private var textColor: String? = null
+
+    /**
+     * Set the name of the folder.
+     * @param name The name of the folder.
+     * @return The builder.
+     */
+    fun name(name: String) = apply { this.name = name }
+
+    /**
+     * Set the parent ID of the folder. (Microsoft only)
+     * @param parentId The parent ID of the folder.
+     * @return The builder.
+     */
+    fun parentId(parentId: String) = apply { this.parentId = parentId }
+
+    /**
+     * Set the background color of the folder. (Google only)
+     *
+     * The background color of the folder in the hexadecimal format `#0099EE`.
+     * See Google Defined Values for more information.
+     *
+     * @param backgroundColor The background color of the folder.
+     * @return The builder.
+     */
+    fun backgroundColor(backgroundColor: String) = apply { this.backgroundColor = backgroundColor }
+
+    /**
+     * Set the text color of the folder. (Google only)
+     *
+     * The text color of the folder in the hexadecimal format `#0099EE`.
+     * See Google Defined Values for more information.
+     *
+     * @param textColor The text color of the folder.
+     * @return The builder.
+     */
+    fun textColor(textColor: String) = apply { this.textColor = textColor }
+
+    /**
+     * Build the [UpdateFolderRequest].
+     * @return The [UpdateFolderRequest].
+     */
+    fun build() = UpdateFolderRequest(
+      name = name,
+      parentId = parentId,
+      backgroundColor = backgroundColor,
+      textColor = textColor,
+    )
+  }
+}

src/main/kotlin/com/nylas/resources/Folders.kt

@@ -0,0 +1,71 @@
+package com.nylas.resources
+
+import com.nylas.NylasClient
+import com.nylas.models.*
+import com.nylas.util.JsonHelper
+
+class Folders(client: NylasClient) : Resource<Folder>(client, Folder::class.java) {
+  /**
+   * Return all Folders
+   * @param identifier Grant ID or email account to query.
+   * @return The list of Folders
+   */
+  @Throws(NylasApiError::class, NylasSdkTimeoutError::class)
+  fun list(identifier: String): ListResponse<Folder> {
+    val path = String.format("v3/grants/%s/folders", identifier)
+    return listResource(path)
+  }
+
+  /**
+   * Return a Folder
+   * @param identifier Grant ID or email account to query.
+   * @param folderId The id of the folder to retrieve.
+   * @return The folder
+   */
+  @Throws(NylasApiError::class, NylasSdkTimeoutError::class)
+  fun find(identifier: String, folderId: String): Response<Folder> {
+    val path = String.format("v3/grants/%s/folders/%s", identifier, folderId)
+    return findResource(path)
+  }
+
+  /**
+   * Create a Folder
+   * @param identifier Grant ID or email account in which to create the object.
+   * @param requestBody The values to create the folder with
+   * @return The created folder
+   */
+  @Throws(NylasApiError::class, NylasSdkTimeoutError::class)
+  fun create(identifier: String, requestBody: CreateFolderRequest): Response<Folder> {
+    val path = String.format("v3/grants/%s/folders", identifier)
+    val adapter = JsonHelper.moshi().adapter(CreateFolderRequest::class.java)
+    val serializedRequestBody = adapter.toJson(requestBody)
+    return createResource(path, serializedRequestBody)
+  }
+
+  /**
+   * Update a Folder
+   * @param identifier Grant ID or email account in which to update an object.
+   * @param folderId The id of the folder to update.
+   * @param requestBody The values to update the folder with
+   * @return The updated folder
+   */
+  @Throws(NylasApiError::class, NylasSdkTimeoutError::class)
+  fun update(identifier: String, folderId: String, requestBody: UpdateFolderRequest): Response<Folder> {
+    val path = String.format("v3/grants/%s/folders/%s", identifier, folderId)
+    val adapter = JsonHelper.moshi().adapter(UpdateFolderRequest::class.java)
+    val serializedRequestBody = adapter.toJson(requestBody)
+    return updateResource(path, serializedRequestBody)
+  }
+
+  /**
+   * Delete a Folder
+   * @param identifier Grant ID or email account from which to delete an object.
+   * @param folderId The id of the folder to delete.
+   * @return The deletion response
+   */
+  @Throws(NylasApiError::class, NylasSdkTimeoutError::class)
+  fun destroy(identifier: String, folderId: String): DeleteResponse {
+    val path = String.format("v3/grants/%s/folders/%s", identifier, folderId)
+    return destroyResource(path)
+  }
+}