From caf355f1428747c2485dd2cc7f55604825d73407 Mon Sep 17 00:00:00 2001
From: Chris Lane <chris@chris-allen-lane.com>
Date: Mon, 4 Feb 2019 11:56:00 -0500
Subject: [PATCH] Issue #349

Implements support for terminals with light backgrounds via a new
`CHEAT_COLORSCHEME` envvar.
---
 README.md              |  7 +++++++
 cheat/colorize.py      |  5 ++++-
 cheat/configuration.py | 13 +++++++++++++
 config/cheat           |  7 ++++---
 4 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/README.md b/README.md
index 4579d5e..8d67e00 100644
--- a/README.md
+++ b/README.md
@@ -118,6 +118,13 @@ export CHEAT_COLORS=true
 
 Note that [pygments][] must be installed on your system for this to work.
 
+`cheat` ships with both light and dark colorschemes to support terminals with
+different background colors. A colorscheme may be selected via the
+`CHEAT_COLORSCHEME` envvar:
+
+```sh
+export CHEAT_COLORSCHEME=light # must be 'light' (default) or 'dark'
+```
 
 #### Specifying a Syntax Highlighter ####
 You may manually specify which syntax highlighter to use for each cheatsheet by
diff --git a/cheat/colorize.py b/cheat/colorize.py
index 7b18beb..1d24d7c 100644
--- a/cheat/colorize.py
+++ b/cheat/colorize.py
@@ -59,4 +59,7 @@ class Colorize:
             except Exception:
                 pass
 
-        return highlight(sheet_content, lexer, TerminalFormatter())
+        return highlight(
+               sheet_content,
+               lexer,
+               TerminalFormatter(bg=self._config.cheat_colorscheme))
diff --git a/cheat/configuration.py b/cheat/configuration.py
index 4358a2f..bd97297 100644
--- a/cheat/configuration.py
+++ b/cheat/configuration.py
@@ -41,6 +41,13 @@ class Configuration:
             True,
         ])
 
+        # self.cheat_colorscheme
+        self.cheat_colorscheme = self._select([
+            os.environ.get('CHEAT_COLORSCHEME'),
+            config.get('CHEAT_COLORSCHEME'),
+            'light',
+        ]).strip().lower()
+
         # self.cheat_user_dir
         self.cheat_user_dir = self._select([
             os.environ.get('CHEAT_USER_DIR'),
@@ -104,4 +111,10 @@ class Configuration:
             Utils.die("%s %s" %
                       ('CHEAT_HIGHLIGHT must be one of:', highlights))
 
+        # assert that the color scheme is valid
+        colorschemes = ['light', 'dark']
+        if self.cheat_colorscheme not in colorschemes:
+            Utils.die("%s %s" %
+                      ('CHEAT_COLORSCHEME must be one of:', colorschemes))
+
         return True
diff --git a/config/cheat b/config/cheat
index bb18291..fcbcbbd 100644
--- a/config/cheat
+++ b/config/cheat
@@ -1,5 +1,6 @@
 {
-  "CHEAT_COLORS" : true,
-  "CHEAT_EDITOR" : "vi",
-  "CHEAT_PATH"   : "/usr/share/cheat"
+  "CHEAT_COLORS"      : true,
+  "CHEAT_COLORSCHEME" : "light",
+  "CHEAT_EDITOR"      : "vi",
+  "CHEAT_PATH"        : "/usr/share/cheat"
 }