feat: Better border configuration.

Started adding `resolve` which will allow you to do some really nice
stuff easily with options to get the window options from a variety of
inputs.

You can see how we do it in pickers.lua for borders & borderchars
currently.

4 files changed, 127 insertions, 8 deletions

diff --git a/lua/telescope/pickers/config_collapse.lua b/lua/telescope/config/resolve.lua
index ee59c10..5aa9c84 100644
--- a/lua/telescope/pickers/config_collapse.lua
+++ b/lua/telescope/config/resolve.lua
@@ -79,8 +79,12 @@ That's the next step to scrolling.
     width = ...
 }
 
+
+
 --]]
 
+local get_default = require('telescope.utils').get_default
+
 local resolver = {}
 
 local percentage_resolver = function(selector, percentage)
@@ -100,4 +104,52 @@ resolver.resolve_percentage_width = function(percentage)
   return percentage_resolver(2, percentage)
 end
 
+--- Win option always returns a table with preview, results, and prompt.
+--- It handles many different ways. Some examples are as follows:
+--
+-- -- Disable
+-- borderschars = false
+--
+-- -- All three windows share the same
+-- borderchars = { '─', '│', '─', '│', '┌', '┐', '┘', '└'},
+--
+-- -- Each window gets it's own configuration
+-- borderchars = {
+--   preview = {...},
+--   results = {...},
+--   prompt = {...},
+-- }
+--
+-- -- Default to [1] but override with specific items
+-- borderchars = {
+--   {...}
+--   prompt = {...},
+-- }
+resolver.win_option = function(val, default)
+  if type(val) ~= 'table' or vim.tbl_islist(val) then
+    if val == nil then
+      val = default
+    end
+
+    return {
+      preview = val,
+      results = val,
+      prompt = val,
+    }
+  elseif type(val) == 'table' then
+    assert(not vim.tbl_islist(val))
+
+    local val_to_set = val[1]
+    if val_to_set == nil then
+      val_to_set = default
+    end
+
+    return {
+      preview = get_default(val.preview, val_to_set),
+      results = get_default(val.results, val_to_set),
+      prompt = get_default(val.prompt, val_to_set),
+    }
+  end
+end
+
 return resolver
diff --git a/lua/telescope/pickers.lua b/lua/telescope/pickers.lua
index cd83b3c..d402b39 100644
--- a/lua/telescope/pickers.lua
+++ b/lua/telescope/pickers.lua
@@ -3,6 +3,7 @@ local popup = require('popup')
 
 local actions = require('telescope.actions')
 local config = require('telescope.config')
+local resolve = require('telescope.config.resolve')
 local layout_strategies = require('telescope.pickers.layout_strategies')
 local log = require('telescope.log')
 local mappings = require('telescope.mappings')
@@ -134,28 +135,28 @@ function Picker:new(opts)
 end
 
 function Picker:_get_initial_window_options(prompt_title)
-  local popup_border = self.window.border
-  local popup_borderchars = self.window.borderchars
+  local popup_border = resolve.win_option(self.window.border)
+  local popup_borderchars = resolve.win_option(self.window.borderchars)
 
   local preview = {
     title = 'Preview',
-    border = popup_border,
-    borderchars = popup_borderchars,
+    border = popup_border.preview,
+    borderchars = popup_borderchars.preview,
     enter = false,
     highlight = false
   }
 
   local results = {
     title = 'Results',
-    border = popup_border,
-    borderchars = popup_borderchars,
+    border = popup_border.results,
+    borderchars = popup_borderchars.results,
     enter = false,
   }
 
   local prompt = {
     title = prompt_title,
-    border = popup_border,
-    borderchars = popup_borderchars,
+    border = popup_border.prompt,
+    borderchars = popup_borderchars.prompt,
     enter = true
   }
 
diff --git a/lua/tests/manual/resolver_spec.lua b/lua/tests/manual/resolver_spec.lua
new file mode 100644
index 0000000..b71e560
--- /dev/null
+++ b/lua/tests/manual/resolver_spec.lua
@@ -0,0 +1,58 @@
+RELOAD('telescope')
+
+local resolve = require('telescope.config.resolve')
+
+local eq = function(a, b)
+  if a ~= b then
+    error(string.format(
+      "Expected a == b, got: %s and %s", vim.inspect(a), vim.inspect(b)
+    ))
+  end
+end
+
+local opt = nil
+
+local height_config = 0.8
+opt = resolve.win_option(height_config)
+
+eq(height_config, opt.preview)
+eq(height_config, opt.prompt)
+eq(height_config, opt.results)
+
+opt = resolve.win_option(nil, height_config)
+
+eq(height_config, opt.preview)
+eq(height_config, opt.prompt)
+eq(height_config, opt.results)
+
+local table_val = {'a'}
+opt = resolve.win_option(nil, table_val)
+eq(table_val, opt.preview)
+eq(table_val, opt.prompt)
+eq(table_val, opt.results)
+
+local prompt_override = {'a', prompt = 'b'}
+opt = resolve.win_option(prompt_override)
+eq('a', opt.preview)
+eq('a', opt.results)
+eq('b', opt.prompt)
+
+local all_specified = {preview = 'a', prompt = 'b', results = 'c'}
+opt = resolve.win_option(all_specified)
+eq('a', opt.preview)
+eq('b', opt.prompt)
+eq('c', opt.results)
+
+local some_specified = {prompt = 'b', results = 'c'}
+opt = resolve.win_option(some_specified, 'a')
+eq('a', opt.preview)
+eq('b', opt.prompt)
+eq('c', opt.results)
+
+-- local true_table = {true}
+-- opt = resolve.win_option(some_specified, 'a')
+-- eq('a', opt.preview)
+-- eq('b', opt.prompt)
+-- eq('c', opt.results)
+
+print("DONE!")
diff --git a/plugin/telescope.vim b/plugin/telescope.vim
index 3a333c9..0361f3e 100644
--- a/plugin/telescope.vim
+++ b/plugin/telescope.vim
@@ -5,6 +5,14 @@ highlight default link TelescopeSelection Visual
 " "Normal" in the floating windows created by telescope.
 highlight default link TelescopeNormal Normal
 
+" Border highlight groups.
+"   Use TelescopeBorder to override the default.
+"   Otherwise set them specifically
+highlight default link TelescopeBorder TelescopeNormal
+highlight default link TelescopePromptBorder TelescopeBorder
+highlight default link TelescopeResultsBorder TelescopeBorder
+highlight default link TelescopePreviewBorder TelescopeBorder
+
 
 " This is like "<C-R>" in your terminal.
 "   To use it, do `cmap <C-R> <Plug>(TelescopeFuzzyCommandSearch)