3 files changed, 111 insertions, 13 deletions

diff --git a/helix-view/src/commands.rs b/helix-view/src/commands.rs
index 6dd1101c..19853c37 100644
--- a/helix-view/src/commands.rs
+++ b/helix-view/src/commands.rs
@@ -13,6 +13,8 @@ use crate::view::View;
 /// state (usually by creating and applying a transaction).
 pub type Command = fn(view: &mut View, count: usize);
 
+const PADDING: usize = 5;
+
 pub fn move_char_left(view: &mut View, count: usize) {
     // TODO: use a transaction
     let selection = view
@@ -117,6 +119,74 @@ pub fn move_next_word_end(view: &mut View, count: usize) {
     view.state.selection = Selection::single(pos, pos);
 }
 
+pub fn move_file_start(view: &mut View, _count: usize) {
+    // TODO: use a transaction
+    view.state.selection = Selection::single(0, 0);
+
+    view.state.mode = Mode::Normal;
+}
+
+pub fn move_file_end(view: &mut View, _count: usize) {
+    // TODO: use a transaction
+    let text = &view.state.doc;
+    let last_line = text.line_to_char(text.len_lines().saturating_sub(2));
+    view.state.selection = Selection::single(last_line, last_line);
+
+    view.state.mode = Mode::Normal;
+}
+
+pub fn check_cursor_in_view(view: &mut View) -> bool {
+    let cursor = view.state.selection().cursor();
+    let line = view.state.doc().char_to_line(cursor);
+    let document_end = view.first_line + view.size.1.saturating_sub(1) as usize;
+
+    if (line > document_end.saturating_sub(PADDING)) | (line < view.first_line + PADDING) {
+        return false;
+    }
+    true
+}
+
+pub fn page_up(view: &mut View, _count: usize) {
+    view.first_line = view.first_line.saturating_sub(view.size.1 as usize);
+
+    if !check_cursor_in_view(view) {
+        let text = view.state.doc();
+        let pos = text.line_to_char(view.last_line().saturating_sub(PADDING as usize));
+        view.state.selection = Selection::single(pos, pos);
+    }
+}
+
+pub fn page_down(view: &mut View, _count: usize) {
+    view.first_line += view.size.1 as usize + PADDING;
+
+    if view.first_line < view.state.doc().len_lines() {
+        let text = view.state.doc();
+        let pos = text.line_to_char(view.first_line as usize);
+        view.state.selection = Selection::single(pos, pos);
+    }
+}
+
+pub fn half_page_up(view: &mut View, _count: usize) {
+    view.first_line = view.first_line.saturating_sub(view.size.1 as usize / 2);
+
+    if !check_cursor_in_view(view) {
+        let text = &view.state.doc;
+        let pos = text.line_to_char(view.last_line() - PADDING as usize);
+        view.state.selection = Selection::single(pos, pos);
+    }
+}
+
+pub fn half_page_down(view: &mut View, _count: usize) {
+    let lines = view.state.doc().len_lines();
+    if view.first_line < lines.saturating_sub(view.size.1 as usize) {
+        view.first_line += view.size.1 as usize / 2;
+    }
+    if !check_cursor_in_view(view) {
+        let text = view.state.doc();
+        let pos = text.line_to_char(view.first_line as usize);
+        view.state.selection = Selection::single(pos, pos);
+    }
+}
 // avoid select by default by having a visual mode switch that makes movements into selects
 
 pub fn extend_char_left(view: &mut View, count: usize) {
@@ -292,6 +362,10 @@ pub fn normal_mode(view: &mut View, _count: usize) {
     }
 }
 
+pub fn goto_mode(view: &mut View, _count: usize) {
+    view.state.mode = Mode::Goto;
+}
+
 // TODO: insert means add text just before cursor, on exit we should be on the last letter.
 pub fn insert_char(view: &mut View, c: char) {
     let c = Tendril::from_char(c);
diff --git a/helix-view/src/keymap.rs b/helix-view/src/keymap.rs
index ef23ff2a..72fc0e79 100644
--- a/helix-view/src/keymap.rs
+++ b/helix-view/src/keymap.rs
@@ -108,6 +108,15 @@ macro_rules! shift {
     };
 }
 
+macro_rules! ctrl {
+    ($ch:expr) => {
+        Key {
+            code: KeyCode::Char($ch),
+            modifiers: Modifiers::CONTROL,
+        }
+    };
+}
+
 pub fn default() -> Keymaps {
     hashmap!(
         state::Mode::Normal =>
@@ -126,6 +135,7 @@ pub fn default() -> Keymaps {
                 vec![key!('w')] => commands::move_next_word_start,
                 vec![key!('b')] => commands::move_prev_word_start,
                 vec![key!('e')] => commands::move_next_word_end,
+                vec![key!('g')] => commands::goto_mode,
                 vec![key!('i')] => commands::insert_mode,
                 vec![shift!('I')] => commands::prepend_to_line,
                 vec![key!('a')] => commands::append_mode,
@@ -139,6 +149,16 @@ pub fn default() -> Keymaps {
                     code: KeyCode::Esc,
                     modifiers: Modifiers::NONE
                 }] => commands::normal_mode,
+                vec![Key {
+                    code: KeyCode::PageUp,
+                    modifiers: Modifiers::NONE
+                }] => commands::page_up,
+                vec![Key {
+                    code: KeyCode::PageDown,
+                    modifiers: Modifiers::NONE
+                }] => commands::page_down,
+                vec![ctrl!('u')] => commands::half_page_up,
+                vec![ctrl!('d')] => commands::half_page_down,
             ),
             state::Mode::Insert => hashmap!(
                 vec![Key {
@@ -161,6 +181,14 @@ pub fn default() -> Keymaps {
                     code: KeyCode::Tab,
                     modifiers: Modifiers::NONE
                 }] => commands::insert_tab,
+            ),
+            state::Mode::Goto => hashmap!(
+                vec![Key {
+                    code: KeyCode::Esc,
+                    modifiers: Modifiers::NONE
+                }] => commands::normal_mode as Command,
+                vec![key!('g')] => commands::move_file_start as Command,
+                vec![key!('e')] => commands::move_file_end as Command,
             )
     )
 }
diff --git a/helix-view/src/view.rs b/helix-view/src/view.rs
index 09cd4c65..887c45a2 100644
--- a/helix-view/src/view.rs
+++ b/helix-view/src/view.rs
@@ -11,7 +11,7 @@ use tui::layout::Rect;
 
 pub struct View {
     pub state: State,
-    pub first_line: u16,
+    pub first_line: usize,
     pub size: (u16, u16),
     pub theme: Theme, // TODO: share one instance
 }
@@ -33,10 +33,10 @@ impl View {
 
     pub fn ensure_cursor_in_view(&mut self) {
         let cursor = self.state.selection().cursor();
-        let line = self.state.doc().char_to_line(cursor) as u16;
-        let document_end = self.first_line + self.size.1.saturating_sub(1) - 1;
+        let line = self.state.doc().char_to_line(cursor);
+        let document_end = self.first_line + (self.size.1 as usize).saturating_sub(1);
 
-        let padding = 5u16;
+        let padding = 5usize;
 
         // TODO: side scroll
 
@@ -51,9 +51,10 @@ impl View {
 
     /// Calculates the last visible line on screen
     #[inline]
-    pub fn last_line(&self, viewport: Rect) -> usize {
+    pub fn last_line(&self) -> usize {
+        let viewport = Rect::new(6, 0, self.size.0, self.size.1 - 1); // - 1 for statusline
         std::cmp::min(
-            (self.first_line + viewport.height) as usize,
+            self.first_line + (viewport.height as usize),
             self.state.doc().len_lines() - 1,
         )
     }
@@ -61,15 +62,10 @@ impl View {
     /// Translates a document position to an absolute position in the terminal.
     /// Returns a (line, col) position if the position is visible on screen.
     // TODO: Could return width as well for the character width at cursor.
-    pub fn screen_coords_at_pos(
-        &self,
-        text: &RopeSlice,
-        pos: usize,
-        viewport: Rect,
-    ) -> Option<Position> {
+    pub fn screen_coords_at_pos(&self, text: &RopeSlice, pos: usize) -> Option<Position> {
         let line = text.char_to_line(pos);
 
-        if line < self.first_line as usize || line > self.last_line(viewport) {
+        if line < self.first_line as usize || line > self.last_line() {
             // Line is not visible on screen
             return None;
         }