feat: cycle previewers

- new git previewers
- jump to line in bcommit previewer
- vimdiff for bcommits
- dynamic preview window titles

Co-authored-by: Thore Strassburg <thore@weilbier.net>

lua/telescope/actions/init.lua

@@ -202,7 +202,9 @@ actions._close = function(prompt_bufnr, keepinsert)
   local original_win_id = picker.original_win_id
 
   if picker.previewer then
-    picker.previewer:teardown()
+    for _, v in ipairs(picker.all_previewers) do
+      v:teardown()
+    end
   end
 
   actions.close_pum(prompt_bufnr)
@@ -375,11 +377,10 @@ actions.git_checkout = function(prompt_bufnr)
   end
 end
 
--- TODO: add this function header back once the treesitter max-query bug is resolved
--- Switch to git branch
--- If the branch already exists in local, switch to that.
--- If the branch is only in remote, create new branch tracking remote and switch to new one.
---@param prompt_bufnr number: The prompt bufnr
+--- Switch to git branch
+--- If the branch already exists in local, switch to that.
+--- If the branch is only in remote, create new branch tracking remote and switch to new one.
+---@param prompt_bufnr number: The prompt bufnr
 actions.git_switch_branch = function(prompt_bufnr)
   local cwd = action_state.get_current_picker(prompt_bufnr).cwd
   local selection = action_state.get_selected_entry()
@@ -419,9 +420,8 @@ actions.git_track_branch = function(prompt_bufnr)
   end
 end
 
--- TODO: add this function header back once the treesitter max-query bug is resolved
--- Delete the currently selected branch
--- @param prompt_bufnr number: The prompt bufnr
+--- Delete the currently selected branch
+---@param prompt_bufnr number: The prompt bufnr
 actions.git_delete_branch = function(prompt_bufnr)
   local cwd = action_state.get_current_picker(prompt_bufnr).cwd
   local selection = action_state.get_selected_entry()
@@ -442,9 +442,8 @@ actions.git_delete_branch = function(prompt_bufnr)
   end
 end
 
--- TODO: add this function header back once the treesitter max-query bug is resolved
--- Rebase to selected git branch
--- @param prompt_bufnr number: The prompt bufnr
+--- Rebase to selected git branch
+---@param prompt_bufnr number: The prompt bufnr
 actions.git_rebase_branch = function(prompt_bufnr)
   local cwd = action_state.get_current_picker(prompt_bufnr).cwd
   local selection = action_state.get_selected_entry()
@@ -465,9 +464,15 @@ actions.git_rebase_branch = function(prompt_bufnr)
   end
 end
 
--- TODO: add this function header back once the treesitter max-query bug is resolved
--- Stage/unstage selected file
--- @param prompt_bufnr number: The prompt bufnr
+--- Stage/unstage selected file
+---@param prompt_bufnr number: The prompt bufnr
+actions.git_checkout_current_buffer = function(prompt_bufnr)
+  local cwd = actions.get_current_picker(prompt_bufnr).cwd
+  local selection = actions.get_selected_entry()
+  actions.close(prompt_bufnr)
+  utils.get_os_command_output({ 'git', 'checkout', selection.value, '--', selection.file }, cwd)
+end
+
 actions.git_staging_toggle = function(prompt_bufnr)
   local cwd = action_state.get_current_picker(prompt_bufnr).cwd
   local selection = action_state.get_selected_entry()
@@ -597,6 +602,14 @@ actions.open_qflist = function(_)
   vim.cmd [[copen]]
 end
 
+actions.cycle_previewers_next = function(prompt_bufnr)
+  actions.get_current_picker(prompt_bufnr):cycle_previewers(1)
+end
+
+actions.cycle_previewers_prev = function(prompt_bufnr)
+  actions.get_current_picker(prompt_bufnr):cycle_previewers(-1)
+end
+
 -- ==================================================
 -- Transforms modules and sets the corect metatables.
 -- ==================================================

lua/telescope/builtin/git.lua

@@ -6,6 +6,7 @@ local pickers = require('telescope.pickers')
 local previewers = require('telescope.previewers')
 local utils = require('telescope.utils')
 local entry_display = require('telescope.pickers.entry_display')
+local path = require('telescope.path')
 
 local conf = require('telescope.config').values
 
@@ -48,7 +49,12 @@ git.commits = function(opts)
       results = results,
       entry_maker = opts.entry_maker or make_entry.gen_from_git_commits(opts),
     },
-    previewer = previewers.git_commit_diff.new(opts),
+    previewer = {
+      previewers.git_commit_diff_to_parent.new(opts),
+      previewers.git_commit_diff_to_head.new(opts),
+      previewers.git_commit_diff_as_was.new(opts),
+      previewers.git_commit_message.new(opts),
+    },
     sorter = conf.file_sorter(opts),
     attach_mappings = function()
       actions.select_default:replace(actions.git_checkout)
@@ -76,9 +82,17 @@ git.stash = function(opts)
     end
   }):find()
 end
+
+local get_current_buf_line = function(winnr)
+  local lnum = vim.api.nvim_win_get_cursor(winnr)[1]
+  return vim.trim(vim.api.nvim_buf_get_lines(vim.api.nvim_win_get_buf(winnr), lnum - 1, lnum, false)[1])
+end
+
 git.bcommits = function(opts)
+  opts.current_line = (not opts.current_file) and get_current_buf_line(0) or nil
+  opts.current_file = opts.current_file or vim.fn.expand('%')
   local results = utils.get_os_command_output({
-    'git', 'log', '--pretty=oneline', '--abbrev-commit', vim.fn.expand('%')
+    'git', 'log', '--pretty=oneline', '--abbrev-commit', opts.current_file
   }, opts.cwd)
 
   pickers.new(opts, {
@@ -87,10 +101,62 @@ git.bcommits = function(opts)
       results = results,
       entry_maker = opts.entry_maker or make_entry.gen_from_git_commits(opts),
     },
-    previewer = previewers.git_commit_diff.new(opts),
+    previewer = {
+      previewers.git_commit_diff_to_parent.new(opts),
+      previewers.git_commit_diff_to_head.new(opts),
+      previewers.git_commit_diff_as_was.new(opts),
+      previewers.git_commit_message.new(opts),
+    },
     sorter = conf.file_sorter(opts),
     attach_mappings = function()
-      actions.select_default:replace(actions.git_checkout)
+      actions.select_default:replace(actions.git_checkout_current_buffer)
+      local transfrom_file = function()
+        return opts.current_file and path.make_relative(opts.current_file, opts.cwd)
+      end
+
+      local get_buffer_of_orig = function(selection)
+        local value = selection.value .. ':' .. transfrom_file()
+        local content = utils.get_os_command_output({ 'git', '--no-pager', 'show', value }, opts.cwd)
+
+        local bufnr = vim.api.nvim_create_buf(false, true)
+        vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, content)
+        vim.api.nvim_buf_set_name(bufnr, 'Original')
+        return bufnr
+      end
+
+      local vimdiff = function(selection, command)
+        local ft = vim.bo.filetype
+        vim.cmd("diffthis")
+
+        local bufnr = get_buffer_of_orig(selection)
+        vim.cmd(string.format("%s %s", command, bufnr))
+        vim.bo.filetype = ft
+        vim.cmd("diffthis")
+
+        vim.cmd(string.format(
+          "autocmd WinClosed <buffer=%s> ++nested ++once :lua vim.api.nvim_buf_delete(%s, { force = true })",
+          bufnr,
+          bufnr))
+      end
+
+      actions.select_vertical:replace(function(prompt_bufnr)
+        actions.close(prompt_bufnr)
+        local selection = action_state.get_selected_entry()
+        vimdiff(selection, 'leftabove vert sbuffer')
+      end)
+
+      actions.select_horizontal:replace(function(prompt_bufnr)
+        actions.close(prompt_bufnr)
+        local selection = action_state.get_selected_entry()
+        vimdiff(selection, 'belowright sbuffer')
+      end)
+
+      actions.select_tab:replace(function(prompt_bufnr)
+        actions.close(prompt_bufnr)
+        local selection = action_state.get_selected_entry()
+        vim.cmd('tabedit ' .. transfrom_file())
+        vimdiff(selection, 'leftabove vert sbuffer')
+      end)
       return true
     end
   }):find()

lua/telescope/config.lua

@@ -159,6 +159,14 @@ function config.set_defaults(defaults)
 
   set("file_ignore_patterns", nil)
 
+  set("dynamic_preview_title", false, [[
+    Will change the title of the preview window dynamically, where it
+    is supported. Means the preview window will for example show the
+    full filename.
+
+    Default: false
+  ]])
+
   set("file_previewer", function(...) return require('telescope.previewers').vim_buffer_cat.new(...) end)
   set("grep_previewer", function(...) return require('telescope.previewers').vim_buffer_vimgrep.new(...) end)
   set("qflist_previewer", function(...) return require('telescope.previewers').vim_buffer_qflist.new(...) end)

lua/telescope/make_entry.lua

@@ -255,7 +255,7 @@ function make_entry.gen_from_git_stash()
 end
 
 
-function make_entry.gen_from_git_commits()
+function make_entry.gen_from_git_commits(opts)
   local displayer = entry_display.create {
     separator = " ",
     items = {
@@ -287,7 +287,8 @@ function make_entry.gen_from_git_commits()
       value = sha,
       ordinal = sha .. ' ' .. msg,
       msg = msg,
-      display = make_display
+      display = make_display,
+      current_file = opts.current_file
     }
   end
 end

lua/telescope/pickers.lua

@@ -74,7 +74,10 @@ function Picker:new(opts)
 
     finder = opts.finder,
     sorter = opts.sorter or require('telescope.sorters').empty(),
-    previewer = opts.previewer,
+
+    all_previewers = opts.previewer,
+    current_previewer_index = 1,
+
     default_selection_index = opts.default_selection_index,
 
     cwd = opts.cwd,
@@ -124,6 +127,15 @@ function Picker:new(opts)
 
   obj.get_window_options = opts.get_window_options or p_window.get_window_options
 
+  if obj.all_previewers ~= nil and obj.all_previewers ~= false then
+    if obj.all_previewers[1] == nil then
+      obj.all_previewers = { obj.all_previewers }
+    end
+    obj.previewer = obj.all_previewers[1]
+  else
+    obj.previewer = false
+  end
+
   -- TODO: It's annoying that this is create and everything else is "new"
   obj.scroller = p_scroller.create(
     get_default(opts.scroll_strategy, config.values.scroll_strategy),
@@ -453,7 +465,9 @@ function Picker:find()
 
   self.prompt_bufnr = prompt_bufnr
 
-  local preview_border_win = preview_opts and preview_opts.border and preview_opts.border.win_id
+  local preview_border = preview_opts and preview_opts.border
+  self.preview_border = preview_border
+  local preview_border_win = (preview_border and preview_border.win_id) and preview_border.win_id
 
   state.set_status(prompt_bufnr, setmetatable({
     prompt_bufnr = prompt_bufnr,
@@ -758,9 +772,31 @@ function Picker:refresh_previewer()
       self._selection_entry,
       status
     )
+    if self.preview_border then
+      if config.values.dynamic_preview_title == true then
+        self.preview_border:change_title(self.previewer:dynamic_title(self._selection_entry))
+      else
+        self.preview_border:change_title(self.previewer:title())
+      end
+    end
   end
 end
 
+function Picker:cycle_previewers(next)
+  local size = table.getn(self.all_previewers)
+  if size == 1 then return end
+
+  self.current_previewer_index = self.current_previewer_index + next
+  if self.current_previewer_index > size then
+    self.current_previewer_index = 1
+  elseif self.current_previewer_index < 1 then
+    self.current_previewer_index = size
+  end
+
+  self.previewer = self.all_previewers[self.current_previewer_index]
+  self:refresh_previewer()
+end
+
 function Picker:entry_adder(index, entry, _, insert)
   if not entry then return end