Add a way to review room highlights - Fixes #1673

This new features is available with M-p and M-n (previous/next).
It saves the last highlight viewed, meaning that if you scroll in the
buffer, M-n or M-p will take you to the next or previous hl compared to
the one before you started scrolling.

For convenience, going to the previous highlight of the first highlight
will take you to the bottom of the buffer, and going to the next
highlight of the last highlight will do *the same*.

If there are several highlights in one message, only the first line will
be considered a highlight.

1 files changed, 77 insertions, 4 deletions

diff --git a/src/windows.py b/src/windows.py
index 7185346e..ae79fb74 100644
--- a/src/windows.py
+++ b/src/windows.py
@@ -622,6 +622,8 @@ class TextWin(Win):
         # on resize, we rebuild all the messages
         self.lock = False
         self.lock_buffer = []
+        self.highlights = []
+        self.hl_pos = -1
 
     def toggle_lock(self):
         if self.lock:
@@ -637,6 +639,74 @@ class TextWin(Win):
             self.built_lines.append(line)
         self.lock = False
 
+    def next_highlight(self):
+        """
+        Go to the next highlight in the buffer.
+        (depending on which highlight was selected before)
+        if the buffer is already positionned on the last, of if there are no
+        highlights, scroll to the end of the buffer.
+        """
+        log.debug('Going to the next highlight…')
+        if not self.highlights or self.hl_pos == -1 or \
+                self.hl_pos == len(self.highlights)-1:
+            self.hl_pos = -1
+            self.pos = 0
+            return
+        hl_size = len(self.highlights) - 1
+        if self.hl_pos < hl_size:
+            self.hl_pos += 1
+        else:
+            self.hl_pos = hl_size
+
+        hl = self.highlights[self.hl_pos]
+        pos = None
+        while not pos:
+            try:
+                pos = self.built_lines.index(hl)
+            except ValueError:
+                self.highlights = self.highlights[self.hl_pos+1:]
+                if not self.highlights:
+                    self.hl_pos = -1
+                    self.pos = 0
+                    return
+                hl = self.highlights[0]
+        self.pos =  len(self.built_lines) - pos - self.height
+        if self.pos < 0 or self.pos >= len(self.built_lines):
+            self.pos = 0
+
+    def previous_highlight(self):
+        """
+        Go to the previous highlight in the buffer.
+        (depending on which highlight was selected before)
+        if the buffer is already positionned on the first, or if there are no
+        highlights, scroll to the end of the buffer.
+        """
+        log.debug('Going to the previous highlight…')
+        if not self.highlights or self.hl_pos == 0:
+            self.hl_pos = -1
+            self.pos =  0
+            return
+        if self.hl_pos < 0:
+            self.hl_pos = len(self.highlights) - 1
+        elif self.hl_pos > 0:
+            self.hl_pos -= 1
+
+        hl = self.highlights[self.hl_pos]
+        pos = None
+        while not pos:
+            try:
+                pos = self.built_lines.index(hl)
+            except ValueError:
+                self.highlights = self.highlights[self.hl_pos+1:]
+                if not self.highlights:
+                    self.hl_pos = -1
+                    self.pos = 0
+                    return
+                hl = self.highlights[0]
+        self.pos = len(self.built_lines) - pos - self.height
+        if self.pos < 0 or self.pos >= len(self.built_lines):
+            self.pos = 0
+
     def scroll_up(self, dist=14):
         self.pos += dist
         if self.pos + self.height > len(self.built_lines):
@@ -676,7 +746,7 @@ class TextWin(Win):
         if None not in self.built_lines:
             self.built_lines.append(None)
 
-    def build_new_message(self, message, history=None, clean=True):
+    def build_new_message(self, message, history=None, clean=True, highlight=False):
         """
         Take one message, build it and add it to the list
         Return the number of lines that are built for the given
@@ -703,10 +773,13 @@ class TextWin(Win):
                                              start_pos=line[0],
                                              end_pos=line[1]))
         else:
+
             for line in lines:
-                self.built_lines.append(Line(msg=message,
-                                             start_pos=line[0],
-                                             end_pos=line[1]))
+                saved_line = Line(msg=message,start_pos=line[0],end_pos=line[1])
+                self.built_lines.append(saved_line)
+                if highlight:
+                    highlight = False
+                    self.highlights.append(saved_line)
         if clean:
             while len(self.built_lines) > self.lines_nb_limit:
                 self.built_lines.pop(0)