From 41c14b206c83197c5095faf47be2d8eb04386a92 Mon Sep 17 00:00:00 2001
From: Robin Jarry <robin@jarry.cc>
Date: Tue, 18 Oct 2022 08:55:02 +0200
Subject: [PATCH] filters/colorize: various fixes

Diff chunks can occur in the middle of email conversations followed by
regular and/or quoted text. Handle that properly.

Change diff meta lines inside quotes to bold. Update the meta lines with
more combination for renamed, copied and deleted files.

Fix the diff_chunk invalid color code, only colorize the chunk
characters, not the whole line.

Remove redundant variable resets to 0.

Signed-off-by: Robin Jarry <robin@jarry.cc>
Acked-on-irc-by: Tim Culverhouse <tim@timculverhouse.com>
---
 filters/colorize | 46 +++++++++++++++++++---------------------------
 1 file changed, 19 insertions(+), 27 deletions(-)

diff --git a/filters/colorize b/filters/colorize
index 322caa4..77f2603 100755
--- a/filters/colorize
+++ b/filters/colorize
@@ -7,7 +7,7 @@ BEGIN {
 	header = "\033[38;2;175;135;255m" # purple
 	signature = "\033[38;2;175;135;255m" # purple
 	diff_meta = "\033[1;38;2;255;255;255m" # bold white
-	diff_chunk = "\033[38;205;0;205m" # cyan
+	diff_chunk = "\033[38;2;0;205;205m" # cyan
 	diff_add = "\033[38;2;0;205;0m" # green
 	diff_del = "\033[38;2;205;0;0m" # red
 	quote_1 = "\033[38;2;95;175;255m"  # blue
@@ -15,6 +15,7 @@ BEGIN {
 	quote_3 = "\033[38;2;175;135;255m" # purple
 	quote_4 = "\033[38;2;255;95;215m" # pink
 	quote_x = "\033[38;2;128;128;128m" # gray
+	bold = "\033[1m"
 	reset = "\033[0m"
 	# state
 	in_diff = 0
@@ -24,6 +25,7 @@ BEGIN {
 	# patterns
 	header_pattern = @/^[A-Z][[:alnum:]-]+:/
 	url_pattern = @/[a-z]{2,6}:\/\/[[:graph:]]+|(mailto:)?[[:alnum:]_\+\.~\/-]*[[:alnum:]_]@[[:lower:]][[:alnum:]\.-]*[[:lower:]]/
+	meta_pattern = @/^(diff --git|(new|deleted) file|similarity index|(rename|copy) (to|from)|index|---|\+\+\+) /
 }
 function color_quote(line) {
 	level = 0
@@ -48,7 +50,9 @@ function color_quote(line) {
 	} else {
 		color = quote_x
 	}
-	if (line ~ /^\+/) {
+	if (line ~ meta_pattern) {
+		return color quotes bold line reset
+	} else if (line ~ /^\+/) {
 		return color quotes diff_add line reset
 	} else if (line ~ /^-/) {
 		return color quotes diff_del line reset
@@ -62,27 +66,31 @@ function color_quote(line) {
 
 	if (in_diff) {
 		if ($0 ~ /^-- ?$/) {
-			in_signature = 1
 			in_diff = 0
-			in_headers = 0
-			in_body = 0
+			in_signature = 1
 			$0 = signature $0 reset
 		} else if ($0 ~ /^@@ /) {
-			$0 = diff_chunk $0 reset
-		} else if ($0 ~ /^(diff --git|index|---|\+\+\+) /) {
+			gsub(/^@@[^@]+@@/, diff_chunk "&" reset)
+		} else if ($0 ~ meta_pattern) {
 			$0 = diff_meta $0 reset
 		} else if ($0 ~ /^\+/) {
 			$0 = diff_add $0 reset
 		} else if ($0 ~ /^-/) {
 			$0 = diff_del $0 reset
+		} else if ($0 !~ /^ / && $0 !~ /^$/) {
+			in_diff = 0
+			in_body = 1
+			if ($0 ~ /^>/) {
+				$0 = color_quote($0)
+			} else {
+				gsub(url_pattern, url "&" reset)
+			}
 		}
 	} else if (in_signature) {
 		gsub(url_pattern, url "&" signature)
 		$0 = signature $0 reset
 	} else if (in_headers) {
 		if ($0 ~ /^$/) {
-			in_signature = 0
-			in_diff = 0
 			in_headers = 0
 			in_body = 1
 		} else {
@@ -93,43 +101,27 @@ function color_quote(line) {
 		if ($0 ~ /^>/) {
 			$0 = color_quote($0)
 		} else if ($0 ~ /^diff --git /) {
-			in_signature = 0
-			in_diff = 1
-			in_headers = 0
 			in_body = 0
+			in_diff = 1
 			$0 = diff_meta $0 reset
 		} else if ($0 ~ /^-- ?$/) {
-			in_signature = 1
-			in_diff = 0
-			in_headers = 0
 			in_body = 0
+			in_signature = 1
 			$0 = signature $0 reset
 		} else {
 			gsub(url_pattern, url "&" reset)
 		}
 	} else if ($0 ~ /^diff --git /) {
-		in_signature = 0
 		in_diff = 1
-		in_headers = 0
-		in_body = 0
 		$0 = diff_meta $0 reset
 	} else if ($0 ~ /^-- ?$/) {
 		in_signature = 1
-		in_diff = 0
-		in_headers = 0
-		in_body = 0
 		$0 = signature $0 reset
 	} else if ($0 ~ header_pattern) {
-		in_signature = 0
-		in_diff = 0
 		in_headers = 1
-		in_body = 0
 		sub(header_pattern, header "&" reset)
 		gsub(url_pattern, url "&" reset)
 	} else {
-		in_signature = 0
-		in_diff = 0
-		in_headers = 0
 		in_body = 1
 		if ($0 ~ /^>/) {
 			$0 = color_quote($0)