From 828a9b589d1887f2186c38cf69067f74a7b08d57 Mon Sep 17 00:00:00 2001
From: Alexander Rosenberg <zanderpkg@pm.me>
Date: Sun, 5 Nov 2023 00:15:01 -0700
Subject: [PATCH] Add dedicated persistent documentation buffer

---
 acm/acm.el               | 12 ++++++------
 core/handler/__init__.py |  2 +-
 core/handler/hover.py    |  8 +++++++-
 lsp-bridge.el            | 26 ++++++++++++++++++++++++++
 4 files changed, 40 insertions(+), 8 deletions(-)

diff --git a/acm/acm.el b/acm/acm.el
index fcec39e8aa..b6adbb47f2 100644
--- a/acm/acm.el
+++ b/acm/acm.el
@@ -1128,7 +1128,7 @@ The key of candidate will change between two LSP results."
     ("dark" acm-frame-background-dark-color)
     ("light" acm-frame-background-light-color)))
 
-(defun acm-markdown-render-content ()
+(defun acm-markdown-render-content (&optional enable-decorations)
   (when (fboundp 'gfm-view-mode)
     (let ((inhibit-message t))
       ;; Enable `gfm-view-mode' first, otherwise `gfm-view-mode' will change attribute of face `markdown-code-face'.
@@ -1145,14 +1145,14 @@ The key of candidate will change between two LSP results."
   (setq prettify-symbols-compose-predicate (lambda (_start _end _match) t))
   (prettify-symbols-mode 1)
 
-  ;; Disable line number.
-  (display-line-numbers-mode -1)
-
   ;; Syntax Highlight.
   (font-lock-ensure)
 
-  ;; Disable mode line.
-  (setq-local mode-line-format nil))
+  (unless enable-decorations
+    ;; Disable line number.
+    (display-line-numbers-mode -1)
+    ;; Disable mode line.
+    (setq-local mode-line-format nil)))
 
 (defun acm-doc-markdown-render-content (doc)
   (when (and (acm-frame-visible-p acm-doc-frame)
diff --git a/core/handler/__init__.py b/core/handler/__init__.py
index 34d2fa4b28..e47f0bb080 100644
--- a/core/handler/__init__.py
+++ b/core/handler/__init__.py
@@ -50,7 +50,7 @@ def handle_response(self, request_id, response):
 from core.handler.find_implementation import FindImplementation
 from core.handler.find_references import FindReferences
 from core.handler.peek import PeekFindDefine, PeekFindReferences
-from core.handler.hover import Hover
+from core.handler.hover import Hover, Documentation
 from core.handler.signature_help import SignatureHelp
 from core.handler.prepare_rename import PrepareRename
 from core.handler.rename import Rename
diff --git a/core/handler/hover.py b/core/handler/hover.py
index 27697f140b..1eca1849f9 100644
--- a/core/handler/hover.py
+++ b/core/handler/hover.py
@@ -9,6 +9,7 @@ def make_code_block(language, string):
 class Hover(Handler):
     name = "hover"
     method = "textDocument/hover"
+    callback = "lsp-bridge-popup-documentation--show"
 
     def process_request(self, position) -> dict:
         return dict(position=position)
@@ -47,4 +48,9 @@ def process_response(self, response: dict) -> None:
         contents = response["contents"]
         render_string = self.parse_hover_contents(contents, [])
 
-        eval_in_emacs("lsp-bridge-popup-documentation--show", render_string)
+        eval_in_emacs(self.callback, render_string)
+
+class Documentation(Hover, Handler):
+    name = "documentation"
+    method = "textDocument/hover"
+    callback = "lsp-bridge-documentation-at-point--show"
diff --git a/lsp-bridge.el b/lsp-bridge.el
index 909f75b43d..0c2da33761 100644
--- a/lsp-bridge.el
+++ b/lsp-bridge.el
@@ -187,6 +187,12 @@ After set `lsp-bridge-completion-obey-trigger-characters-p' to nil, you need use
   :safe #'stringp
   :group 'lsp-bridge)
 
+(defcustom lsp-bridge-buffer-documentation-buffer "*lsp-bridge-doc*"
+  "Buffer for display documentation information."
+  :type 'string
+  :safe #'stringp
+  :group 'lsp-bridge)
+
 (defcustom lsp-bridge-disable-backup t
   "Default disable backup feature, include `make-backup-files' `auto-save-default' and `create-lockfiles'."
   :type 'boolean
@@ -1696,6 +1702,10 @@ Off by default."
                                  (acm-backend-lsp-position-to-point bound-start)
                                  (acm-backend-lsp-position-to-point bound-end))))
 
+(defun lsp-bridge-documentation-at-point ()
+  (interactive)
+  (lsp-bridge-call-file-api "documentation" (lsp-bridge--position)))
+
 (defun lsp-bridge-popup-documentation ()
   (interactive)
   (lsp-bridge-call-file-api "hover" (lsp-bridge--position)))
@@ -1783,6 +1793,22 @@ Off by default."
   ;; Flash define line.
   (lsp-bridge-flash-line))
 
+(defun lsp-bridge-switch-to-documentation-buffer (norecord)
+  (interactive)
+  (switch-to-buffer-other-window
+   (get-buffer-create lsp-bridge-buffer-documentation-buffer) norecord))
+
+(defun lsp-bridge-documentation-at-point--show (value)
+  (let ((buffer (get-buffer-create lsp-bridge-buffer-documentation-buffer)))
+    (with-current-buffer buffer
+      (read-only-mode -1)
+      (erase-buffer)
+      (insert value)
+      (setq-local truncate-lines nil)
+      (acm-markdown-render-content t)
+      (read-only-mode 1))
+    (display-buffer buffer 'display-buffer-reuse-window)))
+
 (defvar lsp-bridge-popup-documentation-frame nil)
 
 (defun lsp-bridge-popup-documentation-scroll-up (&optional arg)