ui: improved hover popup

this commit creates a custom hover handler which floats above all other
windows when trigged from the calltree ui.

Signed-off-by: ldelossa <louis.delos@gmail.com>

Author: ldelossa

lua/calltree/ui.lua

@@ -7,6 +7,7 @@ local help_buf = require('calltree.ui.help_buffer')
 local marshal = require('calltree.ui.marshal')
 local jumps = require('calltree.ui.jumps')
 local deets = require('calltree.ui.details')
+local hover = require('calltree.ui.hover')
 
 local M = {}
 
@@ -274,6 +275,7 @@ end
 -- hover will show LSP hover information for the symbol
 -- under the cursor.
 M.hover = function()
+    ui_buf.close_all_popups()
     local line = vim.api.nvim_get_current_line()
     local node = marshal.marshal_line(line)
     if node == nil then
@@ -288,12 +290,13 @@ M.hover = function()
             character = node.call_hierarchy_obj.range.start.character
         }
     }
-    lsp_util.multi_client_request(M.active_lsp_clients, "textDocument/hover", params, nil, M.buffer_handle)
+    lsp_util.multi_client_request(M.active_lsp_clients, "textDocument/hover", params, hover.hover_handler, M.buffer_handle)
 end
 
 -- details opens a popup window for the given symbol
 -- showing more information.
 M.details = function()
+    ui_buf.close_all_popups()
     local line = vim.api.nvim_get_current_line()
     local node = marshal.marshal_line(line)
     if node == nil then

lua/calltree/ui/buffer.lua

@@ -5,6 +5,11 @@ local direction_map = {
     to   = {method="callHierarchy/outgoingCalls", buf_name="outgoingCalls"}
 }
 
+function M.close_all_popups()
+    require('calltree.ui.hover').close_hover_popup()
+    require('calltree.ui.details').close_details_popup()
+end
+
 -- _setup_buffer performs an idempotent creation
 -- of the calltree buffer
 --
@@ -45,7 +50,7 @@ function M._setup_buffer(direction, buffer_handle)
     -- au to clear highlights on window close
     vim.cmd("au BufWinLeave <buffer=" .. buffer_handle .. "> lua require('calltree.ui.jumps').set_jump_hl(false)")
     -- au to close popup with cursor moves or buffer is closed.
-    vim.cmd("au CursorMoved,BufWinLeave,WinLeave <buffer=" .. buffer_handle .. "> lua require('calltree.ui.details').close_details_popup()")
+    vim.cmd("au CursorMoved,BufWinLeave,WinLeave <buffer=" .. buffer_handle .. "> lua require('calltree.ui.buffer').close_all_popups()")
 
     -- set buffer local keymaps
     local opts = {silent=true}

lua/calltree/ui/hover.lua

@@ -0,0 +1,71 @@
+local M = {}
+
+local float_win = nil
+
+-- close_hover_popups closes the created popup window
+-- if it exists.
+function M.close_hover_popup()
+    if float_win ~= nil and
+        vim.api.nvim_win_is_valid(float_win) then
+        vim.api.nvim_win_close(float_win, true)
+        float_win = nil
+    end
+end
+
+-- modified from neovim runtime/lua/vim/lsp/handlers.lua
+-- function conforms to client LSP handler signature.
+function M.hover_handler(_, result, ctx, config)
+    M.close_hover_popup()
+    -- get lines from result
+    config = config or {}
+    config.focus_id = ctx.method
+    if not (result and result.contents) then
+      -- return { 'No information available' }
+      return
+    end
+    local lines = vim.lsp.util.convert_input_to_markdown_lines(result.contents)
+    lines = vim.lsp.util.trim_empty_lines(lines)
+    if vim.tbl_isempty(lines) then
+      -- return { 'No information available' }
+      return
+    end
+
+    -- create buffer for popup
+    local buf = vim.api.nvim_create_buf(false, false)
+    if buf == 0 then
+        vim.api.nvim_err_writeln("details_popup: could not create details buffer")
+        return
+    end
+    vim.api.nvim_buf_set_option(buf, 'bufhidden', 'delete')
+    vim.api.nvim_buf_set_option(buf, 'syntax',    'markdown')
+    vim.api.nvim_buf_set_option(buf, 'filetype',  'markdown')
+
+    lines = vim.lsp.util.stylize_markdown(buf, lines, {})
+
+    local width = 20
+    for _, line in ipairs(lines) do
+        local line_width = vim.fn.strdisplaywidth(line)
+        if line_width > width then
+            width = line_width
+        end
+    end
+
+    vim.api.nvim_buf_set_option(buf, 'modifiable', true)
+    vim.api.nvim_buf_set_lines(buf, 0, #lines, false, lines)
+    vim.api.nvim_buf_set_option(buf, 'modifiable', false)
+    local popup_conf = vim.lsp.util.make_floating_popup_options(
+            width,
+            #lines,
+            {
+                border= "rounded",
+                focusable= false,
+                zindex = 99,
+            }
+    )
+    float_win = vim.api.nvim_open_win(buf, false, popup_conf)
+
+  return float_win
+end
+
+
+return M