1 files changed, 206 insertions, 0 deletions
diff --git a/.config/vis/plugins/vis-lspc/settings.lua b/.config/vis/plugins/vis-lspc/settings.lua
new file mode 100644
index 0000000..ed753d4
--- /dev/null
+++ b/.config/vis/plugins/vis-lspc/settings.lua
@@ -0,0 +1,206 @@
+--- Collect all effective settings.
+-- There are three kinds of settings:
+--
+-- 1. Global settings explicitly set by the user in its vis configuration in the
+--    language server configuration's `settings` member.
+--
+-- 2. Project specific settings stored in .vis-lspc-settings.json files.
+--
+-- 3. Settings stored by vis-lspc in its settings.json file.
+--    The user settings are stored for each language server and each file path.
+--    Settings for a more specific file path override settings defined for
+--    a parent directory.
+--
+-- All settings are organized in sections which are their top-level organization.
+-- Commonly a language server expects its settings to be stored in a section with
+-- its name.
+-- Additionally, settings can be scoped which correspond with the local file
+-- system. The scoped settings are merged with more specific ones taking priority.
+--
+-- TODO: Implement commands to change the client settings and store them
+--       permanently.
+--
+-- @module settings
+-- @author Florian Fischer
+-- @license GPL-3
+-- @copyright Florian Fischer 2024
+local settings = {}
+
+local util
+
+local lspc
+
+--- Initialize the settings module
+-- @param the lspc module table
+-- @return the settings module table
+function settings.init(lspc_)
+  lspc = lspc_
+  local source_str = debug.getinfo(1, 'S').source:sub(2)
+  local source_path = source_str:match('(.*/)')
+
+  util = dofile(source_path .. 'util.lua').init(lspc)
+
+  return settings
+end
+
+--- Read a JSON settings file from disk
+-- @param settings_path the path to the settings file
+-- @return the settings table
+local function read_settings(settings_path)
+  local loaded_settings = {}
+  local settings_file = io.open(settings_path)
+  if settings_file then
+    loaded_settings = lspc.json.decode(settings_file:read('*a'))
+    settings_file:close()
+    lspc:log('read settings from ' .. settings_path .. ': ' .. lspc.json.encode(loaded_settings))
+  end
+  return loaded_settings
+end
+
+--- Read the user's local settings file
+--
+-- Local user settings are stored at $XDG_CONFIG_HOME/vis-lspc/settings.json.
+-- @return the user's local settings table
+local function read_local_settings()
+  local xdg_conf_dir = os.getenv('XDG_CONFIG_HOME') or os.getenv('HOME') .. '/.config'
+  local settings_path = xdg_conf_dir .. '/vis-lspc/settings.json'
+  return read_settings(settings_path)
+end
+
+--- Get a specific section from a settings table
+-- @param tbl the settings table
+-- @param section the dot-separated section name
+-- @return the settings table for the requested section
+function settings.get_section(tbl, section)
+  local t = tbl
+  -- iterate the dot-separated section components
+  for k in section:gmatch('[^.]+') do
+    if not t then
+      break
+    end
+    t = t[k]
+  end
+
+  return t or {}
+end
+
+--- Merge settings along the scope of their file path
+--
+-- The settings are merged from the top most directory to the
+-- actual file path.
+-- @param path_specific_settings the path specific settings table
+-- @param project_root path to the project
+-- @return a table containing the effective settings
+local function merge_path_specific(path_specific_settings, project_root)
+  local merged_settings = {}
+  local path = ''
+  local file_path_components = util.split_path_into_components(project_root)
+
+  for _, comp in ipairs(file_path_components) do
+    path = path .. '/' .. comp
+    if path_specific_settings[path] then
+      merged_settings = util.table.merge(merged_settings, path_specific_settings[path])
+    end
+  end
+
+  return merged_settings
+end
+
+--- Load the client local settings.
+-- @param section the section of the settings
+-- @param scope the scope of the local settings
+-- @return a table containing the local settings
+function settings.local_settings(section, scope)
+  local local_settings = read_local_settings()
+  local local_ls_settings = local_settings[section]
+  if not local_ls_settings then
+    return {}
+  end
+  return merge_path_specific(local_ls_settings, scope)
+end
+
+--- Load the project local settings.
+-- @param section the section of the settings
+-- @param scope the scope of the project local settings
+-- @return a table containing the local settings
+function settings.project_local_settings(section, scope)
+  local merged_settings = {}
+  local settings_name = '.vis-lspc-settings.json'
+
+  while true do
+    local settings_dir = util.find_upwards(settings_name .. '\n', scope)
+    if not settings_dir or settings_dir == '/' then
+      return merged_settings
+    end
+
+    scope = settings_dir
+
+    local settings_path = settings_dir .. '/' .. settings_name
+    lspc:log('settings: found project specific settings at "' .. settings_path)
+    local ls_settings = read_settings(settings_path) or {}
+    if section then
+      ls_settings = ls_settings[section] or {}
+    end
+    -- The settings found later have less priority than the settings found earlier
+    merged_settings = util.table.merge(ls_settings, merged_settings)
+
+  end
+end
+
+--- Get the effective settings for a language server and an active file
+-- @param section the section name of settings
+-- @param scope the scope of where the settings should have effect
+-- @return a table containing the effective settings
+function settings.effective_settings(ls, section, scope)
+  lspc:log('get effective settings (' .. tostring(section) .. ', ' .. tostring(scope) .. ') for ' ..
+               ls.name)
+  local effective_settings = {}
+  if ls.conf.settings then
+    lspc:log('global settings ' .. lspc.json.encode(ls.conf.settings))
+    effective_settings = util.table.deep_copy(ls.conf.settings)
+    if section then
+      effective_settings = settings.get_section(effective_settings, section)
+    end
+    lspc:log('-> ' .. lspc.json.encode(effective_settings))
+  end
+
+  if scope then
+    local project_local_settings = settings.project_local_settings(section, scope)
+    lspc:log('project local settings ' .. lspc.json.encode(project_local_settings))
+    util.table.merge(effective_settings, project_local_settings)
+    lspc:log('-> ' .. lspc.json.encode(effective_settings))
+  end
+
+  local local_settings = settings.local_settings(section, scope)
+  lspc:log('local settings ' .. lspc.json.encode(local_settings))
+  util.table.merge(effective_settings, local_settings)
+
+  lspc:log('-> settings ' .. lspc.json.encode(effective_settings))
+  return effective_settings
+end
+
+vis:command_register('lspc-settings-reload', function(argv)
+  local ls, err = lspc.get_running_ls(vis.win, argv[1])
+  if err then
+    lspc:err(err)
+    return
+  end
+  assert(ls)
+
+  ls:send_default_settings()
+end, 'reload language server settings')
+
+vis:command_register('lspc-settings-show', function(argv)
+  local ls, err = lspc.get_running_ls(vis.win, argv[1])
+  if err then
+    lspc:err(err)
+    return
+  end
+  assert(ls)
+
+  local scope = ls.rootUri or vis.win.file and vis.win.file.path
+  local effective_ls_settings = settings.effective_settings(ls, nil, scope)
+  vis:message(lspc.json.encode(effective_ls_settings))
+end, 'show the language server settings')
+
+return settings