3 files changed, 131 insertions, 10 deletions
diff --git a/lua/git-yodel.lua b/lua/git-yodel.lua
index 5f9a711..e0e8e80 100644
--- a/lua/git-yodel.lua
+++ b/lua/git-yodel.lua
@@ -1,21 +1,118 @@
 local buf = require('modules.buf')
+local win = require('modules.win')
 local sim = require('utils.simple')
 
 local M = {}
+local C = {}
 
-local function commitdiff()
-  local bufa = buf.create(true, false, 'Commit Diff')
-  local conta = sim.cmdcontent('git diff --cached')
-  if conta == nil then return end -- make sure we're setting from nothing
-  vim.api.nvim_buf_set_option(bufa, 'ft', 'diff')
-  vim.api.nvim_buf_set_lines(bufa, 0, -1, false, conta)
-  buf.lock(bufa)
+function M.setup(c)
+  c = c or {}
+
+  C.diffpreview = {
+    border = c.diffpreview.border or 'single',
+    width = c.diffpreview.width or 'auto',
+    height = c.diffpreview.height or 'auto',
+  }
+end
+
+-- window columns offset
+local function winc()
+  local a = 0
+  local num = vim.o.number or vim.o.relativenumber
+
+  -- if numberline or relativenumbers are enabled make sure we account for it
+  if num then a = vim.o.numberwidth end
+  -- same for signcolumn
+  if vim.o.signcolumn then a = a + string.match(vim.o.signcolumn, '[0-9]') end
+  -- if both we will have some spacing room between them
+  if num and vim.o.signcolumn then a = a + 1 end
+  -- if we have either we need to account for padding next to the buffer
+  if num or vim.o.signcolumn then a = a + 1 end
+
+  return sim.longbufl(0) + a
+end
+
+-- set window width
+local function winw(b)
+  if C.diffpreview.width == 'auto' then
+    return sim.lower(
+      sim.longbufl(b),
+      vim.o.columns - winc() - 2
+    )
+  else
+    return C.diffpreview.width
+  end
+end
+
+-- set window height
+local function winh(b, x)
+  x = x or 0
+  if C.diffpreview.height == 'auto' then
+    return sim.lower(
+      -- lines in buffer - cmd height - statusline
+      vim.o.lines - vim.o.cmdheight - x - 4,
+      vim.api.nvim_buf_line_count(b)
+    )
+  else
+    return C.diffpreview.height
+  end
 end
 
 vim.api.nvim_create_autocmd('FileType', {
-  group = 'bufcheck',
-  papttern = { 'gitcommit', 'gitrebase' },
-  callback =  commitdiff()
+  pattern = { 'gitcommit', 'gitrebase' },
+  callback = function()
+    local bufa = buf.create(true, false, 'Commit Diff')
+    local conta = sim.cmdcontent('git diff --cached')
+    if conta == nil then return end -- make sure we're setting from nothing
+    vim.api.nvim_buf_set_option(bufa, 'ft', 'diff')
+    vim.api.nvim_buf_set_lines(bufa, 0, -1, false, conta)
+    buf.lock(bufa)
+
+    local winopts = {
+      row = 1,
+      col = winc(),
+      width = winw(bufa),
+      height = winh(bufa),
+      border = C.diffpreview.border,
+      relative = 'win',
+      style = 'minimal',
+    }
+
+    local wina = win.create(bufa, false, winopts)
+    -- NOTE: we monitor a few events to make sure the window changes positions
+    -- properly
+    vim.api.nvim_create_autocmd({
+      'VimResized',
+      'CursorMovedI',
+      'CursorMoved',
+    }, {
+      callback = function()
+        if vim.o.columns < 100 then
+          win.hide(wina)
+          wina = win.create(bufa, false, {
+            row = vim.api.nvim_buf_line_count(0) + 1,
+            col = 2,
+            width = vim.o.columns - 4,
+            height = winh(bufa, vim.api.nvim_buf_line_count(0)),
+            border = C.diffpreview.border,
+            relative = 'win',
+            style = 'minimal',
+          })
+        else
+          win.hide(wina)
+          wina = win.create(bufa, false, {
+            row = 1,
+            col = winc(),
+            width = winw(bufa),
+            height = winh(bufa),
+            border = C.diffpreview.border,
+            relative = 'win',
+            style = 'minimal',
+          })
+        end
+      end
+    })
+  end
 })
 
 return M
diff --git a/lua/modules/win.lua b/lua/modules/win.lua
new file mode 100644
index 0000000..fd79d12
--- /dev/null
+++ b/lua/modules/win.lua
@@ -0,0 +1,13 @@
+local M = {}
+
+function M.create(buf, a, b)
+  local win = vim.api.nvim_open_win(buf, a, b)
+
+  return win
+end
+
+function M.hide(buf)
+  vim.api.nvim_win_hide(buf)
+end
+
+return M
diff --git a/lua/utils/simple.lua b/lua/utils/simple.lua
index 637dcde..bf158a7 100644
--- a/lua/utils/simple.lua
+++ b/lua/utils/simple.lua
@@ -19,4 +19,15 @@ function M.cmdcontent(cmd)
   return b
 end
 
+function M.longbufl(buf)
+  local a = vim.api.nvim_buf_get_lines(buf, 0, -1, true)
+  local greatest = 0
+  for i, l in ipairs(a) do
+    if string.len(a[i]) > greatest then
+      greatest = string.len(a[i])
+    end
+  end
+  return greatest
+end
+
 return M