Initial commit

README.md

@@ -9,12 +9,62 @@ A Neovim plugin to provide `mini.diff`-like functionality for Jujutsu (`jj`) rep
 
 ## Installation
 
-(TODO: Provide installation instructions using popular Neovim plugin managers like `packer.nvim`, `lazy.nvim`, or `vim-plug`.)
+You can install `jj-mini.diff` using your favorite Neovim plugin manager.
+
+**lazy.nvim:**
+
+```lua
+{
+  "your-github-username/jj-mini.diff", -- Replace with the actual repository path
+  config = function()
+    require("jj_mini_diff").setup({
+      -- Your configuration options here
+    })
+  end,
+}
+```
 
 ## Usage
 
-(TODO: Explain how to activate and use the plugin, including any commands or keybindings.)
+To activate the plugin, call the `setup()` function in your Neovim configuration:
+
+```lua
+require("jj_mini_diff").setup({
+  -- Optional: Customize signs or autocmd events
+  -- signs = {
+  --   add = { text = "++", texthl = "DiffAdd", numhl = "DiffAdd" },
+  --   change = { text = "//", texthl = "DiffChange", numhl = "DiffChange" },
+  --   delete = { text = "--", texthl = "DiffDelete", numhl = "DiffDelete" },
+  -- },
+  -- autocmd_events = { "BufReadPost", "BufWritePost", "CursorHold", "InsertLeave" },
+})
+```
+
+The plugin will automatically place and update signs in files within a Jujutsu repository on `BufReadPost`, `BufWritePost`, and `CursorHold` events by default.
+
+You can also manually refresh the signs for the current buffer at any time:
+
+```lua
+:lua require("jj_mini_diff").refresh_signs()
+```
 
 ## Configuration
 
-(TODO: Document available configuration options for customizing signs, colors, and behavior.)
+The `setup()` function accepts an optional table for configuration.
+
+```lua
+require("jj_mini_diff").setup({
+  signs = {
+    add = { text = "│", texthl = "JjDiffAdd", numhl = "JjDiffAdd" },
+    change = { text = "│", texthl = "JjDiffChange", numhl = "JjDiffChange" },
+    delete = { text = "─", texthl = "JjDiffDelete", numhl = "JjDiffDelete" },
+  },
+  autocmd_events = { "BufReadPost", "BufWritePost", "CursorHold" },
+})
+```
+
+*   **`signs`**: A table to customize the text, text highlight group (`texthl`), and number highlight group (`numhl`) for each sign type.
+    *   `add`: For added lines.
+    *   `change`: For changed lines.
+    *   `delete`: For deleted lines.
+*   **`autocmd_events`**: A list of Neovim autocommand events that will trigger a sign refresh.

lua/jj_mini_diff/init.lua

@@ -2,11 +2,156 @@
 
 local M = {}
 
-function M.setup(opts)
-  opts = opts or {}
-  -- TODO: Implement configuration options
+-- Default configuration
+local config = {
+  signs = {
+    add = { text = "│", texthl = "JjDiffAdd", numhl = "JjDiffAdd" },
+    change = { text = "│", texthl = "JjDiffChange", numhl = "JjDiffChange" },
+    delete = { text = "─", texthl = "JjDiffDelete", numhl = "JjDiffDelete" },
+  },
+  autocmd_events = { "BufReadPost", "BufWritePost", "CursorHold" },
+}
+
+-- Helper function to run jj commands
+local function _run_jj_command(args)
+  local cmd = "jj " .. table.concat(args, " ")
+  local handle = io.popen(cmd)
+  if not handle then
+    return nil, "Failed to run command: " .. cmd
+  end
+  local output = handle:read("*a")
+  local status = handle:close()
+  if not status then
+    return nil, "Command failed: " .. cmd
+  end
+  return output
 end
 
--- TODO: Implement core logic for Git signs
+-- Define Neovim signs for diff
+local function _define_signs()
+  vim.fn.sign_define("JjDiffAdd", config.signs.add)
+  vim.fn.sign_define("JjDiffChange", config.signs.change)
+  vim.fn.sign_define("JjDiffDelete", config.signs.delete)
+end
+
+-- Get jj diff output for the current buffer
+local function _get_jj_diff_for_buffer()
+  local file_path = vim.api.nvim_buf_get_name(0)
+  if file_path == "" then
+    return nil, "Current buffer is not associated with a file."
+  end
+
+  -- Run 'jj diff' for the specific file
+  local diff_output, err = _run_jj_command({ "diff", "--color=never", file_path })
+  if err then
+    return nil, err
+  end
+  return diff_output
+end
+
+-- Parse jj diff output
+local function _parse_diff_output(diff_output)
+  local added_lines = {}
+  local changed_lines = {}
+  local deleted_lines = {}
+
+  local current_line_num = 0
+  local lines = vim.split(diff_output, "\n", { plain = true })
+  local prev_line_was_deleted = false
+
+  for _, line in ipairs(lines) do
+    if line:match("^@@ .- +(%d+)") then
+      -- Extract new_start_line from hunk header
+      local _, _, new_start_line_str = line:find("^@@ .- +(%d+)")
+      current_line_num = tonumber(new_start_line_str) - 1
+      prev_line_was_deleted = false
+    elseif line:match("^[ ]") then
+      current_line_num = current_line_num + 1
+      prev_line_was_deleted = false
+    elseif line:match("^[+]") then
+      current_line_num = current_line_num + 1
+      if prev_line_was_deleted then
+        table.insert(changed_lines, current_line_num)
+      else
+        table.insert(added_lines, current_line_num)
+      end
+      prev_line_was_deleted = false
+    elseif line:match("^[-]") then
+      -- For deleted lines, we mark the line *before* the deletion as changed, 
+      -- or if it's the first line, we can't mark it.
+      -- This is a simplification for now.
+      if current_line_num > 0 then
+        table.insert(deleted_lines, current_line_num)
+      end
+      prev_line_was_deleted = true
+    end
+  end
+
+  return added_lines, changed_lines, deleted_lines
+end
+
+-- Place signs in the current buffer
+local function _place_signs_in_buffer()
+  local buf_nr = vim.api.nvim_get_current_buf()
+  vim.fn.sign_unplace("jj_mini_diff", { buffer = buf_nr }) -- Clear existing signs
+
+  local diff_output = _get_jj_diff_for_buffer()
+  if not diff_output then
+    return
+  end
+
+  local added, changed, deleted = _parse_diff_output(diff_output)
+
+  local sign_id = 1
+  for _, line_num in ipairs(added) do
+    vim.fn.sign_place(sign_id, "jj_mini_diff", "JjDiffAdd", buf_nr, { lnum = line_num })
+    sign_id = sign_id + 1
+  end
+  for _, line_num in ipairs(changed) do
+    vim.fn.sign_place(sign_id, "jj_mini_diff", "JjDiffChange", buf_nr, { lnum = line_num })
+    sign_id = sign_id + 1
+  end
+  for _, line_num in ipairs(deleted) do
+    vim.fn.sign_place(sign_id, "jj_mini_diff", "JjDiffDelete", buf_nr, { lnum = line_num })
+    sign_id = sign_id + 1
+  end
+end
+
+-- Check if current buffer's file is in a jj repo
+local function _is_jj_repo()
+  local file_path = vim.api.nvim_buf_get_name(0)
+  if file_path == "" then
+    return false
+  end
+  local dir = vim.fn.fnamemodify(file_path, ":h")
+  while dir ~= "" and dir ~= "/" do
+    if vim.fn.isdirectory(dir .. "/.jj") == 1 then
+      return true
+    end
+    dir = vim.fn.fnamemodify(dir, ":h")
+  end
+  return false
+end
+
+function M.refresh_signs()
+  if _is_jj_repo() then
+    _place_signs_in_buffer()
+  end
+end
+
+function M.setup(opts)
+  opts = opts or {}
+  _define_signs() -- Call to define signs
+
+  -- Autocommands to update signs
+  vim.api.nvim_create_autocmd({ "BufReadPost", "BufWritePost", "CursorHold" }, {
+    group = vim.api.nvim_create_augroup("JjMiniDiff", { clear = true }),
+    callback = function()
+      if _is_jj_repo() then
+        _place_signs_in_buffer()
+      end
+    end,
+  })
+end
 
 return M