From b0bf51b90bc233024f1b82bf3f050d26f677b935 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gustav=20S=C3=B6rn=C3=A4s?= <gustav@sornas.net>
Date: Mon, 3 May 2021 22:57:49 +0200
Subject: scroll window

Closes #3
---
 src/buffer/threads.rs |  2 ++
 src/window.rs         | 17 +++++++++++++++--
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/src/buffer/threads.rs b/src/buffer/threads.rs
index 49d9924..893b4ec 100644
--- a/src/buffer/threads.rs
+++ b/src/buffer/threads.rs
@@ -92,6 +92,8 @@ impl Threads {
                 } else {
                     self.i - 1
                 },
+            Key::Char('e') => window.scroll_down(),
+            Key::Char('y') => window.scroll_up(),
             Key::Char('i') => {
                 self.threads[self.i].remove_tag("inbox");
                 self.i += 1;
diff --git a/src/window.rs b/src/window.rs
index f01cfe9..68fc258 100644
--- a/src/window.rs
+++ b/src/window.rs
@@ -1,7 +1,7 @@
 //! A window is an abstraction for the UI. Buffers (like [Threads]) draw "to" windows.
 
 use std::io::Write;
-use termion::{clear, color, cursor};
+use termion::{color, cursor};
 
 #[derive(Clone, Copy)]
 pub struct Area {
@@ -18,18 +18,20 @@ pub enum Line {
 
 pub struct Window {
     pub lines: Vec<Line>,
+    scroll: usize,
 }
 
 impl Window {
     pub fn new() -> Self {
         Self {
             lines: Vec::new(),
+            scroll: 0,
         }
     }
 
     pub fn draw<W: Write>(&mut self, out: &mut W, area: Area) -> Result<(), std::io::Error> {
         let mut y = area.y;
-        let mut lines = self.lines.iter();
+        let mut lines = self.lines.iter().skip(self.scroll);
         while y < area.h + 1 {
             match lines.next() {
                 Some(line) => {
@@ -54,4 +56,15 @@ impl Window {
         self.lines.clear();
         Ok(())
     }
+
+    pub fn scroll_down(&mut self) {
+        //TODO check if we're at bottom
+        self.scroll += 1;
+    }
+
+    pub fn scroll_up(&mut self) {
+        if self.scroll != 0 {
+            self.scroll -= 1;
+        }
+    }
 }
-- 
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