BREAKING CHANGE: Delta Pager + Large Refactor (#43)

BREAKING CHANGE: This MR addresses an underlying issue with the original implementation in regards to detecting line numbers for comments. 

As such, this is a major breaking change. The setup function signature has changed, please review the `README.md` for the new arguments. The delta pager has also been added as a dependency: https://github.com/dandavison/delta

There will be future work to implement a native solution for parsing changes and line numbers.

lua/gitlab/reviewer/delta.lua

@@ -0,0 +1,202 @@
+-- This Module contains all of the code specific to the Delta reviewer.
+local state                   = require("gitlab.state")
+local u                       = require("gitlab.utils")
+
+local M                       = {
+  bufnr = nil
+}
+
+-- Public Functions
+-- These functions are exposed externally and are used
+-- when the reviewer is consumed by other code. They must follow the specification
+-- outlined in the reviewer/init.lua file
+M.open                        = function()
+  local current_buf = vim.api.nvim_get_current_buf()
+  if current_buf == state.discussion_buf then
+    vim.api.nvim_command("wincmd w")
+  end
+
+  vim.cmd.enew()
+  if M.bufnr ~= nil then
+    vim.api.nvim_set_current_buf(M.bufnr)
+    return
+  end
+
+  local term_command_template =
+  "GIT_PAGER='delta --hunk-header-style omit --line-numbers --paging never --file-added-label %s --file-removed-label %s --file-modified-label %s' git diff %s...HEAD"
+
+  local term_command = string.format(term_command_template,
+    state.settings.review_pane.delta.added_file,
+    state.settings.review_pane.delta.removed_file,
+    state.settings.review_pane.delta.modified_file,
+    state.INFO.target_branch)
+
+  vim.fn.termopen(term_command) -- Calls delta and sends the output to the currently blank buffer
+  M.bufnr = vim.api.nvim_get_current_buf()
+end
+
+M.jump                        = function(file_name, new_line, old_line)
+  local linnr, error = M.get_jump_location(file_name, new_line, old_line)
+  if error ~= nil then
+    vim.notify(error, vim.log.levels.ERROR)
+    return
+  end
+
+  vim.api.nvim_command("wincmd w")
+  u.jump_to_buffer(M.bufnr, linnr)
+end
+
+M.get_location                = function()
+  if M.bufnr == nil then return nil, nil, "Delta reviewer must be initialized first" end
+
+  local bufnr = vim.api.nvim_get_current_buf()
+  if bufnr ~= M.bufnr then return nil, nil, "Line location can only be determined within reviewer window" end
+
+  local line_num = u.get_current_line_number()
+  local file_name = M.get_file_from_review_buffer(u.get_current_line_number())
+
+  local range, error = M.get_review_buffer_range(file_name)
+
+  if error ~= nil then return nil, nil, error end
+  if range == nil then return nil, nil, "Review buffer range could not be identified" end
+
+  -- In case the comment is left on a line without change information, we
+  -- iterate backward until we find it within the range of the changes
+  local current_line_changes = nil
+  local num = line_num
+  while range ~= nil and num >= range[1] and current_line_changes == nil do
+    local content = u.get_line_content(M.bufnr, num)
+    local change_nums = M.get_change_nums(content)
+    current_line_changes = change_nums
+    num = num - 1
+  end
+
+  if current_line_changes == nil then
+    return nil, nil, "Could not find current line change information"
+  end
+
+  local new_line_num = line_num + 1
+  local next_line_changes = nil
+  while range ~= nil and new_line_num <= range[2] and next_line_changes == nil do
+    local content = u.get_line_content(M.bufnr, new_line_num)
+    local change_nums = M.get_change_nums(content)
+    next_line_changes = change_nums
+    new_line_num = new_line_num + 1
+  end
+
+  if next_line_changes == nil then
+    return nil, nil, "Could not find next line change information"
+  end
+
+  -- This is actually a modified line if these conditions are met
+  if (current_line_changes.old_line and not current_line_changes.new_line and not next_line_changes.old_line and next_line_changes.new_line) then
+    do
+      current_line_changes = {
+        old_line = current_line_changes.old,
+        new_line = next_line_changes.new_line
+      }
+    end
+  end
+
+  return file_name, current_line_changes
+end
+
+-- Helper Functions 🤝
+-- These functions are not exported and should be private
+-- to the delta reviewer, they are used to support the public functions
+M.get_jump_location           = function(file_name, new_line, old_line)
+  local range, error = M.get_review_buffer_range(file_name)
+  if error ~= nil then return nil, error end
+  if range == nil then return nil, "Review buffer range could not be identified" end
+
+  local linnr = nil
+
+  local lines = M.get_review_buffer_lines(range)
+  for _, line in ipairs(lines) do
+    local line_data = M.get_change_nums(line.line_content)
+    if old_line == line_data.old_line and new_line == line_data.new_line then
+      linnr = line.line_number
+      break
+    end
+  end
+  if linnr == nil then return nil, "Could not find matching line" end
+  return linnr, nil
+end
+
+M.get_file_from_review_buffer = function(linenr)
+  for i = linenr, 0, -1 do
+    local line_content = u.get_line_content(M.bufnr, i)
+    if M.starts_with_file_symbol(line_content) then
+      local file_name = u.get_last_chunk(line_content)
+      return file_name
+    end
+  end
+end
+
+M.get_change_nums             = function(line)
+  local data, _ = line:match("(.-)" .. "│" .. "(.*)")
+  local line_data = {}
+  if data == nil then return nil end
+
+  if data ~= nil then
+    local old_line = u.trim(u.get_first_chunk(data, "[^" .. "⋮" .. "]+"))
+    local new_line = u.trim(u.get_last_chunk(data, "[^" .. "⋮" .. "]+"))
+    line_data.new_line = tonumber(new_line)
+    line_data.old_line = tonumber(old_line)
+  end
+
+  if line_data.new_line == nil and line_data.old_line == nil then return nil end
+
+  return line_data
+end
+
+
+M.get_review_buffer_range = function(file_name)
+  if M.bufnr == nil then return nil, "Delta reviewer must be initialized first" end
+  local lines = vim.api.nvim_buf_get_lines(M.bufnr, 0, -1, false)
+  local start = nil
+  local stop = nil
+
+  for i, line in ipairs(lines) do
+    if start ~= nil and stop ~= nil then return { start, stop } end
+    if M.starts_with_file_symbol(line) then
+      -- Check if the file name matches the node name
+      local delta_file_name = u.get_last_chunk(line)
+      if file_name == delta_file_name then
+        start = i
+      elseif start ~= nil then
+        stop = i
+      end
+    end
+  end
+
+  -- We've reached the end of the file, set "stop" in case we already found start
+  stop = #lines
+  if start ~= nil and stop ~= nil then return { start, stop } end
+end
+
+M.starts_with_file_symbol = function(line)
+  for _, substring in ipairs({
+    state.settings.review_pane.delta.added_file,
+    state.settings.review_pane.delta.removed_file,
+    state.settings.review_pane.delta.modified_file,
+  }) do
+    if string.sub(line, 1, string.len(substring)) == substring then
+      return true
+    end
+  end
+  return false
+end
+
+M.get_review_buffer_lines = function(review_buffer_range)
+  local lines = {}
+  for i = review_buffer_range[1], review_buffer_range[2], 1 do
+    local line_content = vim.api.nvim_buf_get_lines(M.bufnr, i - 1, i, false)[1]
+    if string.find(line_content, "⋮") then
+      table.insert(lines, { line_content = line_content, line_number = i })
+    end
+  end
+  return lines
+end
+
+return M

lua/gitlab/reviewer/init.lua

@@ -0,0 +1,36 @@
+-- This Module will pick the reviewer set in the user's
+-- settings and then map all of it's functions
+local state = require("gitlab.state")
+local delta = require("gitlab.reviewer.delta")
+
+local M = {
+  reviewer = nil,
+}
+
+local reviewer_map = {
+  delta = delta
+}
+
+M.init = function()
+  local reviewer = reviewer_map[state.settings.reviewer]
+  if reviewer == nil then
+    vim.notify(string.format("gitlab.nvim could not find reviewer %s", state.settings.reviewer), vim.log.levels.ERROR)
+    return
+  end
+
+  M.open = reviewer.open
+  -- Opens the reviewer window
+
+  M.jump = reviewer.jump
+  -- Jumps to the location provided in the reviewer window
+  -- Parameters:
+  --   • {file_name}      The name of the file to jump to
+  --   • {new_line}  The new_line of the change
+  --   • {interval}  The old_lien of the change
+
+  M.get_location = reviewer.get_location
+  -- Returns the current location (based on cursor) from the reviewer window
+end
+
+
+return M