From 36e636743b52c65de057a057de1a36a643a19e84 Mon Sep 17 00:00:00 2001
From: Don Alfons Nisnoni <donnisnoni.tid3@gmail.com>
Date: Sat, 8 Feb 2020 01:46:20 +0800
Subject: [PATCH] term: header()

---
 vlib/term/term.v      | 18 ++++++++++++--
 vlib/term/term_test.v | 57 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 73 insertions(+), 2 deletions(-)
 create mode 100644 vlib/term/term_test.v

diff --git a/vlib/term/term.v b/vlib/term/term.v
index 501f63e328..399df46fdb 100644
--- a/vlib/term/term.v
+++ b/vlib/term/term.v
@@ -6,7 +6,6 @@ const (
 	default_columns_size = 80
 	default_rows_size = 25
 )
-
 // can_show_color_on_stdout returns true if colors are allowed in stdout;
 // returns false otherwise.
 pub fn can_show_color_on_stdout() bool {
@@ -34,11 +33,26 @@ pub fn fail_message(s string) string {
 // h_divider returns a horizontal divider line with a dynamic width,
 // that depends on the current terminal settings.
 pub fn h_divider(divider string) string {
-	cols, _ := get_terminal_size()
+	cols,_ := get_terminal_size()
 	result := divider.repeat(1 + (cols / divider.len))
 	return result[0..cols]
 }
 
+// header returns a horizontal divider line with a centered text in the middle.
+// e.g: term.header('TEXT', '=')
+// =============== TEXT ===============
+pub fn header(text, divider string) string {
+	if text.len == 0 {
+		return h_divider(divider)
+	}
+	cols,_ := get_terminal_size()
+	tlimit := if cols > text.len + 2 + 2 * divider.len { text.len } else { cols - 3 - 2 * divider.len }
+	tlimit_alligned := if (tlimit % 2) != (cols % 2) { tlimit + 1 } else { tlimit }
+	tstart := (cols - tlimit_alligned) / 2
+	ln := divider.repeat(1 + cols / divider.len)[0..cols]
+	return ln[0..tstart] + ' ' + text[0..tlimit] + ' ' + ln[tstart + tlimit + 2..cols]
+}
+
 fn supports_escape_sequences(fd int) bool {
 	$if windows {
 		return (is_atty(fd) & 0x0004) > 0 && os.getenv('TERM') != 'dumb' // ENABLE_VIRTUAL_TERMINAL_PROCESSING
diff --git a/vlib/term/term_test.v b/vlib/term/term_test.v
new file mode 100644
index 0000000000..70a005c765
--- /dev/null
+++ b/vlib/term/term_test.v
@@ -0,0 +1,57 @@
+import term
+
+fn test_get_terminal_size() {
+	cols,_ := term.get_terminal_size()
+	assert cols > 0
+}
+
+fn test_h_divider() {
+	divider := term.h_divider('-')
+	assert divider.len > 0
+	assert divider[0] == `-`
+	assert divider[divider.len - 1] == `-`
+}
+
+fn test_h_divider_multiple_characters() {
+	xdivider := term.h_divider('abc')
+	assert xdivider.len > 0
+	assert xdivider.contains('abcabc')
+}
+
+fn test_header() {
+	divider := term.h_divider('-')
+	term_width := divider.len
+	assert term_width > 0
+	empty_header := term.header('', '-')
+	short_header := term.header('reasonable header', '-')
+	very_long_header := term.header(['abc'].repeat(500).join(' '), '-')
+	very_long_header_2 := term.header(['abcd'].repeat(500).join(' '), '-')
+	/*
+	eprintln(divider)
+	eprintln(empty_header)
+	eprintln(short_header)
+	eprintln(term.header('another longer header', '_-/\\'))
+	eprintln(term.header('another longer header', '-'))
+	eprintln(term.header('short', '-'))
+	eprintln(term.header('12345', '-'))
+	eprintln(term.header('1234', '-'))
+	eprintln(term.header('123', '-'))
+	eprintln(term.header('12', '-'))
+	eprintln(term.header('1', '-'))
+	eprintln(very_long_header)
+	eprintln(divider)
+	eprintln(very_long_header_2)
+	eprintln(term.header(['abcd'].repeat(500).join(' '), '_-/\\'))
+	eprintln(term.header(['abcd'].repeat(500).join(' '), '_-//'))
+	eprintln(term.header('1', '_-/\\\/'))
+	eprintln(term.header('12', '_-/\\\/'))
+	eprintln(term.header('123', '_-/\\\/'))
+	eprintln(term.header('1234', '_-/\\/\\'))
+	eprintln(term.header('', '-'))
+    */
+	assert term_width == empty_header.len
+	assert term_width == short_header.len
+	assert term_width == very_long_header.len
+	assert term_width == very_long_header_2.len
+	assert term_width == term.header('1234', '_-/\\/\\').len
+}