Moved files around, tweaked content generators. Things are in a broken state atm.

rtv/page.py

@@ -0,0 +1,178 @@
+import curses
+
+class Navigator(object):
+    """
+    Handles math behind cursor movement and screen paging.
+    """
+
+    def __init__(
+            self,
+            valid_page_cb,
+            page_index=0,
+            cursor_index=0,
+            inverted=False):
+
+        self.page_index = page_index
+        self.cursor_index = cursor_index
+        self.inverted = inverted
+        self._page_cb = valid_page_cb
+        self._header_window = None
+        self._content_window = None
+
+    @property
+    def step(self):
+        return 1 if not self.inverted else -1
+
+    @property
+    def position(self):
+        return (self.page_index, self.cursor_index, self.inverted)
+
+    @property
+    def absolute_index(self):
+        return self.page_index + (self.step * self.cursor_index)
+
+    def move(self, direction, n_windows):
+        "Move the cursor down (positive direction) or up (negative direction)"
+
+        valid, redraw = True, False
+
+        # TODO: add variable movement
+        forward = ((direction*self.step) > 0)
+
+        if forward:
+            self.cursor_index += 1
+            if self.cursor_index >= n_windows - 1:
+                self.page_index += (self.step * self.cursor_index)
+                self.cursor_index = 0
+                self.inverted = not self.inverted
+                redraw = True
+        else:
+            if self.cursor_index > 0:
+                self.cursor_index -= 1
+            else:
+                if self._is_valid(self.page_index - self.step):
+                    self.page_index -= self.step
+                    redraw = True
+                else:
+                    valid = False
+
+        return valid, redraw
+
+    def _is_valid(self, page_index):
+        "Check if a page index will cause entries to fall outside valid range"
+
+        try:
+            self._page_cb(page_index)
+            self._page_cb(page_index + self.step * self.cursor_index)
+        except IndexError:
+            return False
+        else:
+            return True
+
+
+class BasePage(object):
+    """
+    Base terminal viewer incorperates a cursor to navigate content
+    """
+
+    def __init__(self, stdscr, content, **kwargs):
+
+        self.stdscr = stdscr
+        self.content = content
+
+        self.nav = Navigator(self.content.get, **kwargs)
+
+        self._subwindows = None
+
+    def draw(self):
+        raise NotImplementedError
+
+    def move_cursor_up(self):
+        self._move_cursor(-1)
+
+    def move_cursor_down(self):
+        self._move_cursor(1)
+
+    def add_cursor(self):
+        self._edit_cursor(curses.A_REVERSE)
+
+    def remove_cursor(self):
+        self._edit_cursor(curses.A_NORMAL)
+
+    def clear_input_queue(self):
+        "Clear excessive input caused by the scroll wheel or holding down a key"
+        self.stdscr.nodelay(1)
+        while self.stdscr.getch() != -1:
+            continue
+        self.stdscr.nodelay(0)
+
+    def draw_header(self):
+
+        n_rows, n_cols = self._header_window.getmaxyx()
+
+        self._header_window.erase()
+        self._header_window.addnstr(0, 0, self.content.display_name, n_cols-1)
+
+    def draw_content(self):
+        """
+        Loop through submissions and fill up the content page.
+        """
+
+        n_rows, n_cols = self._content_window.getmaxyx()
+        self._content_window.erase()
+        self._subwindows = []
+
+        page_index, cursor_index, inverted = self.nav.position
+        step = self.nav.step
+
+        # If not inverted, align the first submission with the top and draw
+        # downwards. If inverted, align the first submission with the bottom
+        # and draw upwards.
+        current_row = n_rows if inverted else 0
+        available_rows = n_rows
+        for data in self.content.iterate(page_index, step, n_cols-2):
+            window_rows = min(available_rows, data['n_rows'])
+            window_cols = n_cols - data['offset']
+            start = current_row - window_rows if inverted else current_row
+            subwindow = self._content_window.derwin(
+                window_rows, window_cols, start, data['offset'])
+            self.draw_item(subwindow, data, inverted)
+            self._subwindows.append(subwindow)
+            available_rows -= (window_rows + 1)  # Add one for the blank line
+            current_row += step * (window_rows + 1)
+            if available_rows <= 0:
+                break
+
+        self._content_window.refresh()
+
+    def draw_item(self, window, data, inverted):
+        raise NotImplementedError
+
+    def _move_cursor(self, direction):
+
+        self.remove_cursor()
+
+        valid, redraw = self.nav.move(direction, len(self._subwindows))
+        if not valid:
+            curses.flash()
+
+        # If we don't redraw, ACS_VLINE gets screwed up when changing the
+        # attr back to normal. There may be a way around this.
+        if True: #if redraw
+            self.draw_content()
+
+        self.add_cursor()
+
+    def _edit_cursor(self, attribute):
+
+        # Don't alow the cursor to go below page index 0
+        if self.nav.absolute_index == -1:
+            window = self._subwindows[self.nav.cursor_index + 1]
+        else:
+            window = self._subwindows[self.nav.cursor_index]
+
+        n_rows, _ = window.getmaxyx()
+        for row in xrange(n_rows):
+            window.chgat(row, 0, 1, attribute)
+
+        window.refresh()