From c1aef1106eb537d94041ef502174ba0dc97887c0 Mon Sep 17 00:00:00 2001
From: Jonathan Daugherty <cygnus@foobox.com>
Date: Fri, 3 Nov 2023 17:25:12 -0700
Subject: [PATCH] Add Brick.Main.customMainWithDefaultVty (fixes #488)

---
 brick.cabal                 |  1 -
 programs/CustomEventDemo.hs |  7 ++-----
 programs/TailDemo.hs        |  3 +--
 src/Brick/Main.hs           | 26 ++++++++++++++++++++++----
 4 files changed, 25 insertions(+), 12 deletions(-)

diff --git a/brick.cabal b/brick.cabal
index 17c9c0f..29a7767 100644
--- a/brick.cabal
+++ b/brick.cabal
@@ -453,7 +453,6 @@ executable brick-custom-event-demo
   build-depends:       base,
                        brick,
                        vty,
-                       vty-crossplatform,
                        text,
                        microlens >= 0.3.0.0,
                        microlens-th,
diff --git a/programs/CustomEventDemo.hs b/programs/CustomEventDemo.hs
index 335d082..4693047 100644
--- a/programs/CustomEventDemo.hs
+++ b/programs/CustomEventDemo.hs
@@ -12,13 +12,12 @@ import Control.Concurrent (threadDelay, forkIO)
 import Data.Monoid
 #endif
 import qualified Graphics.Vty as V
-import Graphics.Vty.CrossPlatform (mkVty)
 
 import Brick.BChan
 import Brick.Main
   ( App(..)
   , showFirstCursor
-  , customMain
+  , customMainWithDefaultVty
   , halt
   )
 import Brick.AttrMap
@@ -83,6 +82,4 @@ main = do
         writeBChan chan Counter
         threadDelay 1000000
 
-    let buildVty = mkVty V.defaultConfig
-    initialVty <- buildVty
-    void $ customMain initialVty buildVty (Just chan) theApp initialState
+    void $ customMainWithDefaultVty (Just chan) theApp initialState
diff --git a/programs/TailDemo.hs b/programs/TailDemo.hs
index 7bd3a28..1cd0b18 100644
--- a/programs/TailDemo.hs
+++ b/programs/TailDemo.hs
@@ -143,10 +143,9 @@ randomVal as = do
 
 main :: IO ()
 main = do
-    vty <- mkVty V.defaultConfig
     chan <- newBChan 10
 
     -- Run thread to simulate incoming data
     void $ forkIO $ generateLines chan
 
-    void $ customMain vty (mkVty V.defaultConfig) (Just chan) app initialState
+    void $ customMainWithDefaultVty (Just chan) app initialState
diff --git a/src/Brick/Main.hs b/src/Brick/Main.hs
index 7f69e51..98fa33a 100644
--- a/src/Brick/Main.hs
+++ b/src/Brick/Main.hs
@@ -5,6 +5,7 @@ module Brick.Main
   , defaultMain
   , customMain
   , customMainWithVty
+  , customMainWithDefaultVty
   , simpleMain
   , resizeOrQuit
   , simpleApp
@@ -130,10 +131,8 @@ defaultMain :: (Ord n)
             -> s
             -- ^ The initial application state.
             -> IO s
-defaultMain app st = do
-    let builder = mkVty defaultConfig
-    initialVty <- builder
-    customMain initialVty builder Nothing app st
+defaultMain app st =
+    fst <$> customMainWithDefaultVty Nothing app st
 
 -- | A simple main entry point which takes a widget and renders it. This
 -- event loop terminates when the user presses any key, but terminal
@@ -235,6 +234,25 @@ customMain initialVty buildVty mUserChan app initialAppState = do
     restoreInitialState
     return s
 
+-- | Like 'customMainWithVty', except that Vty is initialized with the
+-- default configuration.
+customMainWithDefaultVty :: (Ord n)
+                         => Maybe (BChan e)
+                         -- ^ An event channel for sending custom
+                         -- events to the event loop (you write to this
+                         -- channel, the event loop reads from it).
+                         -- Provide 'Nothing' if you don't plan on
+                         -- sending custom events.
+                         -> App s e n
+                         -- ^ The application.
+                         -> s
+                         -- ^ The initial application state.
+                         -> IO (s, Vty)
+customMainWithDefaultVty mUserChan app initialAppState = do
+    let builder = mkVty defaultConfig
+    vty <- builder
+    customMainWithVty vty builder mUserChan app initialAppState
+
 -- | Like 'customMain', except the last 'Vty' handle used by the
 -- application is returned without being shut down with 'shutdown'. This
 -- allows the caller to re-use the 'Vty' handle for something else, such