Feat: Add and Remove Labels from an MR (#159)

This MR adds the ability to add or remove labels to a merge request. These labels are visible in the summary panel and are colored the same way as they would be in the Gitlab UI.

This is a MINOR release.

lua/gitlab/actions/labels.lua

@@ -0,0 +1,83 @@
+-- This module is responsible for the creation, deletion,
+-- and assignment and removeal of labels.
+local u = require("gitlab.utils")
+local job = require("gitlab.job")
+local state = require("gitlab.state")
+local M = {}
+
+M.add_label = function()
+  M.add_popup("label")
+end
+
+M.delete_label = function()
+  M.delete_popup("label")
+end
+
+local refresh_label_state = function(labels)
+  local new_labels = ""
+  for _, label in ipairs(labels) do
+    new_labels = new_labels .. "," .. label
+  end
+  state.INFO.labels = new_labels
+end
+
+local get_current_labels = function()
+  local label_string = state.INFO.labels
+  local current_labels = {}
+  for value in label_string:gmatch("[^,]+") do
+    table.insert(current_labels, value)
+  end
+  return current_labels
+end
+
+local get_all_labels = function()
+  local labels = {}
+  for _, label in ipairs(state.LABELS) do -- How can we use the colors??
+    table.insert(labels, label.Name)
+  end
+  return labels
+end
+
+M.add_popup = function(type)
+  local all_labels = get_all_labels()
+  local current_labels = get_current_labels()
+  local unused_labels = u.difference(all_labels, current_labels)
+  vim.ui.select(unused_labels, {
+    prompt = "Choose label to add",
+  }, function(choice)
+    if not choice then
+      return
+    end
+    local label_string = state.INFO.labels
+    local new_labels = {}
+    for value in label_string:gmatch("[^,]+") do
+      table.insert(new_labels, value)
+    end
+
+    table.insert(new_labels, choice)
+    local body = { labels = new_labels }
+    job.run_job("/mr/" .. type, "PUT", body, function(data)
+      u.notify(data.message, vim.log.levels.INFO)
+      refresh_label_state(data.labels)
+    end)
+  end)
+end
+
+M.delete_popup = function(type)
+  local current_labels = get_current_labels()
+  vim.ui.select(current_labels, {
+    prompt = "Choose label to delete",
+  }, function(choice)
+    if not choice then
+      return
+    end
+    local filtered_labels = u.filter(current_labels, choice)
+    local body = { labels = filtered_labels }
+    job.run_job("/mr/" .. type, "PUT", body, function(data)
+      u.notify(data.message, vim.log.levels.INFO)
+      refresh_label_state(data.labels)
+    end)
+  end)
+end
+
+return M