feat: json output

Author: beeemT

README.md

@@ -78,6 +78,47 @@ gw co -
 | `gw sync [--dry-run] [--force]` | `gw s` | Fetch + prune stale worktrees |
 | `gw list` | `gw ls` | List worktrees |
 
+## Global options
+
+| Flag | Description |
+|---|---|
+| `--format=json` | Output results as JSON to stderr |
+| `--help` | Show help |
+
+### JSON output
+
+When `--format=json` is passed, output is written to stderr as JSON:
+
+```bash
+gw --format=json list
+```
+
+Output format:
+
+```json
+{
+  "path": "/path/to/worktree",
+  "data": { ... },
+  "messages": [{"level": "info", "text": "..."}]
+}
+```
+
+Errors:
+
+```json
+{
+  "error": "error message",
+  "messages": [{"level": "error", "text": "error message"}]
+}
+```
+
+Example - list worktrees as JSON:
+
+```bash
+$ gw --format=json list
+{"data":{"worktrees":[{"dir":"main","branch":"main","current":true}]},"messages":[...]}
+```
+
 ## Command details
 
 ### `gw clone` / `gw cl`

lib/git_work/cli.ex

@@ -20,6 +20,8 @@ defmodule GitWork.CLI do
   }
 
   def run(args) do
+    {format, args} = extract_format(args)
+
     case args do
       ["--help"] ->
         print_help()
@@ -37,42 +39,63 @@ defmodule GitWork.CLI do
         if "--help" in rest or "-h" in rest do
           print_command_help(command)
         else
-          dispatch(command, rest)
+          dispatch(command, rest, format)
         end
 
       [] ->
         print_help()
     end
   end
 
-  defp dispatch(command, args) do
+  defp extract_format(args) do
+    case Enum.split_with(args, &(&1 == "--format=json")) do
+      {format_args, rest} when format_args != [] ->
+        {:json, rest}
+
+      _ ->
+        {:text, args}
+    end
+  end
+
+  defp dispatch(command, args, format) do
     case Map.get(@commands, command) do
       nil ->
-        IO.write(:stderr, "git-work: unknown command '#{command}'\n\n")
+        GitWork.Output.print_error("unknown command '#{command}'", format)
         print_help()
         System.halt(1)
 
       module ->
         result =
           try do
-            module.run(args)
+            module.run(args, format)
           rescue
             e ->
               {:error, "unexpected error: #{Exception.message(e)}"}
           end
 
-        handle_result(result)
+        handle_result(result, format)
     end
   end
 
-  defp handle_result({:ok, output}) when is_binary(output) and output != "" do
-    IO.puts(output)
+  defp handle_result({:ok, %GitWork.Output{} = output}, format) do
+    GitWork.Output.print(output, format)
+  end
+
+  defp handle_result({:ok, output}, format) when is_binary(output) and output != "" do
+    case format do
+      :json ->
+        json = JSON.encode!(%{path: output, messages: []})
+        IO.write(:stderr, json <> "\n")
+
+      :text ->
+        IO.puts(output)
+    end
   end
 
-  defp handle_result({:ok, _}), do: :ok
+  defp handle_result({:ok, _}, _format), do: :ok
 
-  defp handle_result({:error, message}) do
-    IO.write(:stderr, "git-work: #{message}\n")
+  defp handle_result({:error, message}, format) do
+    GitWork.Output.print_error(message, format)
     System.halt(1)
   end
 
@@ -89,7 +112,7 @@ defmodule GitWork.CLI do
 
   defp print_help do
     IO.write(:stderr, """
-    usage: git-work <command> [<args>]
+    usage: git-work [--format=json] <command> [<args>]
 
     Commands:
       activate <shell>       Print shell integration (bash, zsh, fish)
@@ -100,8 +123,9 @@ defmodule GitWork.CLI do
       sync (s) [--dry-run]        Fetch and prune stale worktrees
       list (ls)                   List all worktrees
 
-    Options:
-      --help                 Show this help
+    Global options:
+      --format=json    Output results as JSON to stderr
+      --help           Show this help
 
     Run 'git-work <command> --help' for more information on a specific command.
     """)

lib/git_work/commands/activate.ex

@@ -24,19 +24,19 @@ defmodule GitWork.Commands.Activate do
     """
   end
 
-  def run([shell]) do
+  def run([shell], _format) do
     case ShellHook.generate(shell) do
       {:error, _} = err -> err
       code when is_binary(code) -> {:ok, code}
     end
   end
 
-  def run([]) do
+  def run([], _format) do
     {:error,
      "activate requires a shell argument (#{Enum.join(ShellHook.supported_shells(), ", ")})"}
   end
 
-  def run(_args) do
+  def run(_args, _format) do
     {:error, "activate takes exactly one argument: the shell name"}
   end
 end

lib/git_work/commands/checkout.ex

@@ -39,7 +39,7 @@ defmodule GitWork.Commands.Checkout do
     """
   end
 
-  def run(args) do
+  def run(args, _format) do
     case args do
       ["-b", branch] ->
         with {:ok, root} <- Project.find_root() do

lib/git_work/commands/clone.ex

@@ -22,7 +22,7 @@ defmodule GitWork.Commands.Clone do
     """
   end
 
-  def run(args) do
+  def run(args, _format) do
     case args do
       [url] ->
         dir = Project.dir_from_url(url)

lib/git_work/commands/init.ex

@@ -25,7 +25,7 @@ defmodule GitWork.Commands.Init do
     """
   end
 
-  def run(_args) do
+  def run(_args, _format) do
     cwd = File.cwd!()
     do_init(cwd)
   end

lib/git_work/commands/list.ex

@@ -19,7 +19,7 @@ defmodule GitWork.Commands.List do
     """
   end
 
-  def run(_args) do
+  def run(_args, format) do
     with {:ok, root} <- Project.find_root() do
       bare_dir = Project.bare_path(root)
 
@@ -30,16 +30,34 @@ defmodule GitWork.Commands.List do
             |> parse_porcelain(root)
             |> Enum.reject(fn e -> String.starts_with?(e.dir, ".") end)
 
-          formatted = format_table(entries, File.cwd!())
-          IO.write(:stderr, formatted)
-          {:ok, ""}
+          output_result = output_for_list(entries, File.cwd!())
+
+          case format do
+            :json -> {:ok, output_result}
+            :text -> GitWork.Output.print(output_result, :text); {:ok, ""}
+          end
 
         {:error, msg} ->
           {:error, "worktree list failed: #{msg}"}
       end
     end
   end
 
+  defp output_for_list(entries, cwd) do
+    %GitWork.Output{
+      data: %{
+        worktrees: Enum.map(entries, fn e ->
+          %{
+            dir: e.dir,
+            branch: e.branch,
+            current: e.path == cwd
+          }
+        end)
+      },
+      messages: [%{level: :info, text: format_table(entries, cwd)}]
+    }
+  end
+
   @doc false
   def parse_porcelain(output, project_root) do
     output

lib/git_work/commands/rm.ex

@@ -31,7 +31,7 @@ defmodule GitWork.Commands.Rm do
     """
   end
 
-  def run(args) do
+  def run(args, _format) do
     {opts, rest, _} = OptionParser.parse(args, strict: [force: :boolean, yes: :boolean])
     force? = Keyword.get(opts, :force, false)
     yes? = Keyword.get(opts, :yes, false)

lib/git_work/commands/sync.ex

@@ -25,7 +25,7 @@ defmodule GitWork.Commands.Sync do
     """
   end
 
-  def run(args) do
+  def run(args, _format) do
     {opts, _, _} =
       OptionParser.parse(args,
         strict: [dry_run: :boolean, force: :boolean],