feat: refactor file structure

lua/cp/ui/highlight.lua

@@ -0,0 +1,156 @@
+---@class DiffHighlight
+---@field line number
+---@field col_start number
+---@field col_end number
+---@field highlight_group string
+
+---@class ParsedDiff
+---@field content string[]
+---@field highlights DiffHighlight[]
+
+local M = {}
+
+---@param text string Raw git diff output line
+---@return string cleaned_text, DiffHighlight[]
+local function parse_diff_line(text)
+  local result_text = ''
+  local highlights = {}
+  local pos = 1
+
+  while pos <= #text do
+    local removed_start, removed_end, removed_content = text:find('%[%-(.-)%-%]', pos)
+    if removed_start and removed_start == pos then
+      local highlight_start = #result_text
+      result_text = result_text .. removed_content
+      table.insert(highlights, {
+        line = 0,
+        col_start = highlight_start,
+        col_end = #result_text,
+        highlight_group = 'CpDiffRemoved',
+      })
+      pos = removed_end + 1
+    else
+      local added_start, added_end, added_content = text:find('{%+(.-)%+}', pos)
+      if added_start and added_start == pos then
+        local highlight_start = #result_text
+        result_text = result_text .. added_content
+        table.insert(highlights, {
+          line = 0,
+          col_start = highlight_start,
+          col_end = #result_text,
+          highlight_group = 'CpDiffAdded',
+        })
+        pos = added_end + 1
+      else
+        result_text = result_text .. text:sub(pos, pos)
+        pos = pos + 1
+      end
+    end
+  end
+
+  return result_text, highlights
+end
+
+---@param diff_output string
+---@return ParsedDiff
+function M.parse_git_diff(diff_output)
+  if diff_output == '' then
+    return { content = {}, highlights = {} }
+  end
+
+  local lines = vim.split(diff_output, '\n', { plain = true })
+  local content_lines = {}
+  local all_highlights = {}
+
+  local content_started = false
+  for _, line in ipairs(lines) do
+    if
+      content_started
+      or (
+        not line:match('^@@')
+        and not line:match('^%+%+%+')
+        and not line:match('^%-%-%-')
+        and not line:match('^index')
+        and not line:match('^diff %-%-git')
+      )
+    then
+      content_started = true
+
+      if line:match('^%+') then
+        local clean_line = line:sub(2)
+        local parsed_line, line_highlights = parse_diff_line(clean_line)
+
+        table.insert(content_lines, parsed_line)
+
+        local line_num = #content_lines
+        for _, highlight in ipairs(line_highlights) do
+          highlight.line = line_num - 1
+          table.insert(all_highlights, highlight)
+        end
+      elseif not line:match('^%-') and not line:match('^\\') then
+        local clean_line = line:match('^%s') and line:sub(2) or line
+        local parsed_line, line_highlights = parse_diff_line(clean_line)
+
+        if parsed_line ~= '' then
+          table.insert(content_lines, parsed_line)
+
+          local line_num = #content_lines
+          for _, highlight in ipairs(line_highlights) do
+            highlight.line = line_num - 1
+            table.insert(all_highlights, highlight)
+          end
+        end
+      end
+    end
+  end
+
+  return {
+    content = content_lines,
+    highlights = all_highlights,
+  }
+end
+
+---@param bufnr number
+---@param highlights DiffHighlight[]
+---@param namespace number
+function M.apply_highlights(bufnr, highlights, namespace)
+  vim.api.nvim_buf_clear_namespace(bufnr, namespace, 0, -1)
+
+  for _, highlight in ipairs(highlights) do
+    if highlight.col_start < highlight.col_end then
+      vim.api.nvim_buf_set_extmark(bufnr, namespace, highlight.line, highlight.col_start, {
+        end_col = highlight.col_end,
+        hl_group = highlight.highlight_group,
+        priority = 100,
+      })
+    end
+  end
+end
+
+---@return number
+function M.create_namespace()
+  return vim.api.nvim_create_namespace('cp_diff_highlights')
+end
+
+---@param bufnr number
+---@param diff_output string
+---@param namespace number
+---@return string[] content_lines
+function M.parse_and_apply_diff(bufnr, diff_output, namespace)
+  local parsed = M.parse_git_diff(diff_output)
+
+  local was_modifiable = vim.api.nvim_get_option_value('modifiable', { buf = bufnr })
+  local was_readonly = vim.api.nvim_get_option_value('readonly', { buf = bufnr })
+
+  vim.api.nvim_set_option_value('readonly', false, { buf = bufnr })
+  vim.api.nvim_set_option_value('modifiable', true, { buf = bufnr })
+  vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, parsed.content)
+  vim.api.nvim_set_option_value('modifiable', was_modifiable, { buf = bufnr })
+  vim.api.nvim_set_option_value('readonly', was_readonly, { buf = bufnr })
+
+  M.apply_highlights(bufnr, parsed.highlights, namespace)
+
+  return parsed.content
+end
+
+return M