Add --json and --count flag to list-modes command

[MikaelCarpenter]

I've tried to implement the --json command as specified in the issue. I was looking at list-apps as a reference and decided to add --count as well, because it seemed simple enough.

Happy to make any adjustments necessary, just let me know!

🧪 Testing Outputs

❯ ./.debug/aerospace list-modes
main
service

❯ ./.debug/aerospace list-modes --current
main

❯ ./.debug/aerospace list-modes --json
[
  {
    "mode-id" : "main"
  },
  {
    "mode-id" : "service"
  }
]

❯ ./.debug/aerospace list-modes --count
2

❯ ./.debug/aerospace list-modes --current --json
[
  {
    "mode-id" : "main"
  }
]

❯ ./.debug/aerospace list-modes --count --json
ERROR: Conflicting options: --count, --json

❯ ./.debug/aerospace list-modes --count --current
ERROR: Conflicting options: --count, --current

[nikitabobko]

The PR is functional, thanks.

Merged with the following cosmetic + shell completion changes from me:

diff --git a/Sources/AppBundle/command/impl/ListModesCommand.swift b/Sources/AppBundle/command/impl/ListModesCommand.swift
index 74f1ebcf..c154aea0 100644
--- a/Sources/AppBundle/command/impl/ListModesCommand.swift
+++ b/Sources/AppBundle/command/impl/ListModesCommand.swift
@@ -6,23 +6,15 @@ struct ListModesCommand: Command {
     /*conforms*/ var shouldResetClosedWindowsCache = false
 
     func run(_ env: CmdEnv, _ io: CmdIo) -> Bool {
-        if args.outputOnlyCount {
-            let count = args.current ? 1 : config.modes.count
-            return io.out("\(count)")
-        }
-
-        if args.json {
-            let modeNames = args.current ? [activeMode ?? mainModeId] : config.modes.keys.sorted()
-            let modeData = modeNames.map { ["mode-id": $0] }
-            return JSONEncoder.aeroSpaceDefault.encodeToString(modeData).map(io.out)
-                ?? io.err("Failed to encode JSON")
-        }
-
-        if args.current {
-            return io.out(activeMode ?? mainModeId)
-        } else {
-            let modeNames: [String] = config.modes.keys.sorted()
-            return io.out(modeNames)
+        let modes: [String] = args.current ? [activeMode ?? mainModeId] : config.modes.keys.sorted()
+        return switch () {
+            case _ where args.outputOnlyCount:
+                io.out("\(modes.count)")
+            case _ where args.json:
+                JSONEncoder.aeroSpaceDefault.encodeToString(modes.map { ["mode-id": $0] }).map(io.out)
+                    ?? io.err("Failed to encode JSON")
+            default:
+                io.out(modes)
         }
     }
 }
diff --git a/grammar/commands-bnf-grammar.txt b/grammar/commands-bnf-grammar.txt
index 31ee5963..5cb61dcd 100644
--- a/grammar/commands-bnf-grammar.txt
+++ b/grammar/commands-bnf-grammar.txt
@@ -91,7 +91,7 @@ aerospace -h;
 
     | list-exec-env-vars
 
-    | list-modes [--current]
+    | list-modes [--current|--json|--count]
 
     | list-monitors [--focused [no] | --mouse [no] | --format <output_format> | --count | --json]...