From fa19f99d27744e39a8ad6fc89e089149c85566d9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Th=C3=A9ophile=20Bastian?= <contact@tobast.fr>
Date: Sat, 9 May 2020 19:35:59 +0200
Subject: [PATCH] Vim session: better movement tracking

---
 patch2vimedit/vim_session.py | 58 ++++++++++++++++++++++++++++++++----
 1 file changed, 52 insertions(+), 6 deletions(-)

diff --git a/patch2vimedit/vim_session.py b/patch2vimedit/vim_session.py
index f535752..207e967 100644
--- a/patch2vimedit/vim_session.py
+++ b/patch2vimedit/vim_session.py
@@ -1,6 +1,32 @@
 import sys
 
 
+class LineMovement:
+    """ A movement to a given line, absolute or relative """
+
+    def __init__(self, absolute=None, relative=None):
+        self.absolute = absolute
+        self.relative = relative
+        if self.absolute and self.relative:
+            raise Exception("Cannot move both absolutely and relatively")
+
+    def __add__(self, num):
+        if not isinstance(num, type(0)):
+            raise Exception("Can only add an integer")
+        if self.absolute is not None:
+            return self.__class__(absolute=self.absolute + num)
+        if self.relative is not None:
+            return self.__class__(relative=self.relative + num)
+
+    def do(self, tmux_session):
+        if self.relative:
+            tmux_session.type_keys("escape", "{}j".format(self.relative))
+        elif self.absolute:
+            tmux_session.type_keys("escape", "{}G".format(self.absolute))
+        self.relative = 0
+        self.absolute = None
+
+
 class VimSession:
     """ A Vim session instrumented through tmux """
 
@@ -38,17 +64,37 @@ class VimSession:
 
         self.tmux_session.type_keys("escape", ":w", "enter")
 
+    def write_line(self, line):
+        """ Write a line to the vim buffer, assuming everything is set up for it and it
+        must be insterted above. """
+
+        if line.startswith(" "):
+            lead_spaces = 0
+            while lead_spaces < len(line) and line[lead_spaces] == " ":
+                lead_spaces += 1
+            line = line.strip()
+
+            self.tmux_session.type_keys(
+                "O", "escape", "{}a ".format(lead_spaces), "escape", "A", line, "escape"
+            )
+        else:
+            self.tmux_session.type_keys("O", line, "escape")
+
     def apply_hunk(self, hunk):
         # So far, very naive.
-        self.tmux_session.type_keys("escape", "{}G0".format(hunk.starttgt))
+        line_mvt = LineMovement(absolute=hunk.starttgt)
+
         for b_line in hunk.text:
             line = b_line.decode("utf8")
             if line[0] == " ":
-                self.tmux_session.type_keys("j")
-            elif line[0] == "-":
-                self.tmux_session.type_keys("dd")
-            elif line[0] == "+":
-                self.tmux_session.type_keys("O", line.strip()[1:], "escape", "j")
+                line_mvt += 1
+            else:
+                line_mvt.do(self.tmux_session)
+                if line[0] == "-":
+                    self.tmux_session.type_keys("dd")
+                elif line[0] == "+":
+                    self.write_line(line.strip()[1:])
+                    line_mvt += 1
 
     def quit(self):
         self.tmux_session.type_keys("escape", ":q", "enter")