add Lua API to override default settings (#111)

10 files changed, 172 insertions, 51 deletions

diff --git a/CUSTOM_SERVERS.md b/CUSTOM_SERVERS.md
index bcf4dd0a..c68ba305 100644
--- a/CUSTOM_SERVERS.md
+++ b/CUSTOM_SERVERS.md
@@ -1,5 +1,8 @@
 # Custom servers
 
+*Note that there may be breaking changes introduced over time that may have an impact on the functionality of custom
+servers. These breaking changes should generally be easy to address.*
+
 You may create your own server installers by using the same APIs that nvim-lsp-installer itself uses.
 
 Each installable LSP server is represented as an instance of the `Server` class. This class is responsible for
diff --git a/README.md b/README.md
index fa59b5fb..ff320a00 100644
--- a/README.md
+++ b/README.md
@@ -93,6 +93,56 @@ if ok then
 end
 ```
 
+### Configuration
+
+You can configure certain behavior of nvim-lsp-installer by calling the `.settings()` function.
+Refer to the [default configuration](#default-configuration) for all available settings.
+
+Example:
+
+```lua
+require("nvim-lsp-installer").settings {
+    ui = {
+        icons = {
+            server_installed = "✓",
+            server_pending = "➜",
+            server_uninstalled = "✗"
+        }
+    }
+}
+```
+
+#### Default configuration
+
+```lua
+local DEFAULT_SETTINGS = {
+    ui = {
+        icons = {
+            -- The list icon to use for installed servers.
+            server_installed = "◍",
+            -- The list icon to use for servers that are pending installation.
+            server_pending = "◍",
+            -- The list icon to use for servers that are not installed.
+            server_uninstalled = "◍",
+        },
+    },
+
+    -- Controls to which degree logs are written to the log file. For example, it's useful to set this to
+    -- vim.log.levels.TRACE when debugging issues with server installations.
+    log_level = vim.log.levels.WARN,
+
+    -- Whether to allow LSP servers to share the same installation directory.
+    -- For some servers, this effectively causes more than one server to be
+    -- installed (and uninstalled) when executing `:LspInstall` and
+    -- `:LspUninstall`.
+
+    -- For example, installing `cssls` will also install both `jsonls` and `html`
+    -- (and the other ways around), as these all share the same underlying
+    -- package.
+    allow_federated_servers = true,
+}
+```
+
 ## Available LSPs
 
 | Language                            | Server name              |
@@ -163,6 +213,6 @@ Illustrations in the logo are derived from [@Kaligule](https://schauderbasis.de/
 
 ## Roadmap
 
--   Managed versioning of installed servers
 -   Command (and corresponding Lua API) to update outdated servers (e.g., `:LspUpdate {server}`)
+-   More helpful metadata displayed in the UI window
 -   Cross-platform CI for all server installers
diff --git a/doc/nvim-lsp-installer.txt b/doc/nvim-lsp-installer.txt
index 49189054..44b57b83 100644
--- a/doc/nvim-lsp-installer.txt
+++ b/doc/nvim-lsp-installer.txt
@@ -104,28 +104,57 @@ Prints all installed language servers.
 
 
 ==============================================================================
-OPTIONS                                         *nvim-lsp-installer-options*
+SETTINGS                                       *nvim-lsp-installer-settings*
 
-                                   *g:lsp_installer_allow_federated_servers*
-                               *vim.g.lsp_installer_allow_federated_servers*
-VimL: g:lsp_installer_allow_federated_servers
-Lua:  vim.g.lsp_installer_allow_federated_servers
+You can configure certain behavior of nvim-lsp-installer by calling the
+`.settings()` function.
 
-    Type: |Boolean|
-    Default: `true` (`v:true`)
+Refer to the |nvim-lsp-installer-default-settings| for all available settings.
 
-    Whether to allow LSP servers to share the same installation directory.
-    For some servers, this effectively causes more than one server to be
-    installed (and uninstalled) when executing `:LspInstall` and
-    `:LspUninstall`.
+Example: >
 
-    For example, installing `cssls` will also install both `jsonls` and `html`
-    (and the other ways around), as these all share the same underlying
-    package.
+    require("nvim-lsp-installer").settings {
+        ui = {
+            icons = {
+                server_installed = "✓",
+                server_pending = "➜",
+                server_uninstalled = "✗"
+            }
+        }
+    }
+<
+
+                                       *nvim-lsp-installer-default-settings*
+
+The following settings are applied by default.
+
+>
+    local DEFAULT_SETTINGS = {
+        ui = {
+            icons = {
+                -- The list icon to use for installed servers.
+                server_installed = "◍",
+                -- The list icon to use for servers that are pending installation.
+                server_pending = "◍",
+                -- The list icon to use for servers that are not installed.
+                server_uninstalled = "◍",
+            },
+        },
+
+        -- Controls to which degree logs are written to the log file. For example, it's useful to set this to
+        -- vim.log.levels.TRACE when debugging issues with server installations.
+        log_level = vim.log.levels.WARN,
+
+        -- Whether to allow LSP servers to share the same installation directory.
+        -- For some servers, this effectively causes more than one server to be
+        -- installed (and uninstalled) when executing `:LspInstall` and
+        -- `:LspUninstall`.
 
-    Example: >
-        let g:lsp_installer_allow_federated_servers = v:false
-        vim.g.lsp_installer_allow_federated_servers = false
+        -- For example, installing `cssls` will also install both `jsonls` and `html`
+        -- (and the other ways around), as these all share the same underlying
+        -- package.
+        allow_federated_servers = true,
+    }
 <
 
 ==============================================================================
@@ -223,8 +252,7 @@ class: Server
                     Sets up the language server. This has the same function
                     signature as the setup function in nvim-lspconfig.
 
-                    See |lspconfig-custom-config| for more information on
-                    {opts}.
+                    Refer to nvim-lspconfig for more information on {opts}.
 
             - get_default_options()
                     Returns a deep copy of the default options provided to
diff --git a/lua/nvim-lsp-installer.lua b/lua/nvim-lsp-installer.lua
index 58b909dd..b05ac31c 100644
--- a/lua/nvim-lsp-installer.lua
+++ b/lua/nvim-lsp-installer.lua
@@ -3,9 +3,12 @@ local dispatcher = require "nvim-lsp-installer.dispatcher"
 local process = require "nvim-lsp-installer.process"
 local status_win = require "nvim-lsp-installer.ui.status-win"
 local servers = require "nvim-lsp-installer.servers"
+local settings = require "nvim-lsp-installer.settings"
 
 local M = {}
 
+M.settings = settings.set
+
 function M.display()
     status_win().open()
 end
diff --git a/lua/nvim-lsp-installer/log.lua b/lua/nvim-lsp-installer/log.lua
index 1fa3209e..8aa2e16e 100644
--- a/lua/nvim-lsp-installer/log.lua
+++ b/lua/nvim-lsp-installer/log.lua
@@ -1,3 +1,5 @@
+local settings = require "nvim-lsp-installer.settings"
+
 local config = {
     -- Name of the plugin. Prepended to log messages
     name = "lsp-installer",
@@ -28,9 +30,6 @@ local config = {
 
 local log = {}
 
--- Default log level is warn.
-vim.g.lsp_installer_log_level = vim.g.lsp_installer_log_level or vim.log.levels.WARN
-
 local unpack = unpack or table.unpack
 
 do
@@ -62,7 +61,7 @@ do
 
     local log_at_level = function(level, level_config, message_maker, ...)
         -- Return early if we're below the current_log_level
-        if level < vim.g.lsp_installer_log_level then
+        if level < settings.current.log_level then
             return
         end
         local nameupper = level_config.name:upper()
diff --git a/lua/nvim-lsp-installer/opts.lua b/lua/nvim-lsp-installer/opts.lua
deleted file mode 100644
index 71128808..00000000
--- a/lua/nvim-lsp-installer/opts.lua
+++ /dev/null
@@ -1,16 +0,0 @@
-local M = {}
-
-local function boolean_val(val, default)
-    if type(val) == "nil" then
-        return default
-    elseif type(val) == "number" then
-        return val == 1
-    end
-    return val and true or false
-end
-
-function M.allow_federated_servers()
-    return boolean_val(vim.g.lsp_installer_allow_federated_servers, true)
-end
-
-return M
diff --git a/lua/nvim-lsp-installer/servers/init.lua b/lua/nvim-lsp-installer/servers/init.lua
index 497d5375..f0ed0533 100644
--- a/lua/nvim-lsp-installer/servers/init.lua
+++ b/lua/nvim-lsp-installer/servers/init.lua
@@ -1,17 +1,18 @@
 local Data = require "nvim-lsp-installer.data"
 local path = require "nvim-lsp-installer.path"
 local fs = require "nvim-lsp-installer.fs"
-local opts = require "nvim-lsp-installer.opts"
+local settings = require "nvim-lsp-installer.settings"
 
 local M = {}
 
 local function vscode_langservers_extracted(name)
-    return opts.allow_federated_servers() and "vscode-langservers-extracted" or "vscode-langservers-extracted_" .. name
+    return settings.current.allow_federated_servers and "vscode-langservers-extracted"
+        or "vscode-langservers-extracted_" .. name
 end
 
 -- By default the install dir will be the same as the server's name.
 -- There are two cases when servers should install to a different location:
---  1. federated server installations, (see :help vim.g.lsp_installer_allow_federated_servers)
+--  1. federated server installations, (see :help nvim-lsp-installer-settings)
 --  2. legacy reasons, where some servers were previously installed to a location different than their name
 local INSTALL_DIRS = {
     ["bashls"] = "bash",
diff --git a/lua/nvim-lsp-installer/settings.lua b/lua/nvim-lsp-installer/settings.lua
new file mode 100644
index 00000000..ec7f622b
--- /dev/null
+++ b/lua/nvim-lsp-installer/settings.lua
@@ -0,0 +1,36 @@
+local DEFAULT_SETTINGS = {
+    ui = {
+        icons = {
+            -- The list icon to use for installed servers.
+            server_installed = "◍",
+            -- The list icon to use for servers that are pending installation.
+            server_pending = "◍",
+            -- The list icon to use for servers that are not installed.
+            server_uninstalled = "◍",
+        },
+    },
+
+    -- Controls to which degree logs are written to the log file. For example, it's useful to set this to
+    -- vim.log.levels.TRACE when debugging issues with server installations.
+    log_level = vim.log.levels.WARN,
+
+    -- Whether to allow LSP servers to share the same installation directory.
+    -- For some servers, this effectively causes more than one server to be
+    -- installed (and uninstalled) when executing `:LspInstall` and
+    -- `:LspUninstall`.
+
+    -- For example, installing `cssls` will also install both `jsonls` and `html`
+    -- (and the other ways around), as these all share the same underlying
+    -- package.
+    allow_federated_servers = true,
+}
+
+local M = {}
+
+function M.set(opts)
+    M.current = vim.tbl_deep_extend("force", DEFAULT_SETTINGS, opts)
+end
+
+M.current = DEFAULT_SETTINGS
+
+return M
diff --git a/lua/nvim-lsp-installer/ui/status-win/init.lua b/lua/nvim-lsp-installer/ui/status-win/init.lua
index a8bad050..76569352 100644
--- a/lua/nvim-lsp-installer/ui/status-win/init.lua
+++ b/lua/nvim-lsp-installer/ui/status-win/init.lua
@@ -1,5 +1,6 @@
 local Ui = require "nvim-lsp-installer.ui"
 local fs = require "nvim-lsp-installer.fs"
+local settings = require "nvim-lsp-installer.settings"
 local Log = require "nvim-lsp-installer.log"
 local Data = require "nvim-lsp-installer.data"
 local display = require "nvim-lsp-installer.ui.display"
@@ -23,9 +24,6 @@ local function Header()
     })
 end
 
--- TODO make configurable
-local LIST_ICON = "◍"
-
 local Seconds = {
     DAY = 86400, -- 60 * 60 * 24
     WEEK = 604800, -- 60 * 60 * 24 * 7
@@ -45,7 +43,7 @@ local function get_relative_install_time(time)
     elseif delta < (Seconds.MONTH * 2) then
         return "last month"
     elseif delta < Seconds.YEAR then
-        return ("%d months ago"):format(math.floor((delta / 2419200) + 0.5))
+        return ("%d months ago"):format(math.floor((delta / Seconds.MONTH) + 0.5))
     else
         return "more than a year ago"
     end
@@ -56,7 +54,7 @@ local function InstalledServers(servers)
         return Ui.Node {
             Ui.HlTextNode {
                 {
-                    { LIST_ICON, "LspInstallerGreen" },
+                    { settings.current.ui.icons.server_installed, "LspInstallerGreen" },
                     { " " .. server.name, "Normal" },
                     {
                         (" installed %s"):format(get_relative_install_time(server.creation_time)),
@@ -91,7 +89,10 @@ local function PendingServers(servers)
         return Ui.Node {
             Ui.HlTextNode {
                 {
-                    { LIST_ICON, has_failed and "LspInstallerError" or "LspInstallerOrange" },
+                    {
+                        settings.current.ui.icons.server_pending,
+                        has_failed and "LspInstallerError" or "LspInstallerOrange",
+                    },
                     { " " .. server.name, server.installer.is_running and "Normal" or "LspInstallerGray" },
                     { " " .. note, "Comment" },
                     {
@@ -118,7 +119,7 @@ local function UninstalledServers(servers)
         return Ui.Node {
             Ui.HlTextNode {
                 {
-                    { LIST_ICON, "LspInstallerGray" },
+                    { settings.current.ui.icons.server_uninstalled, "LspInstallerGray" },
                     { " " .. server.name, "Comment" },
                     { server.uninstaller.has_run and " (just uninstalled)" or "", "Comment" },
                 },
diff --git a/plugin/nvim-lsp-installer.vim b/plugin/nvim-lsp-installer.vim
index 2e2bc315..f8458f44 100644
--- a/plugin/nvim-lsp-installer.vim
+++ b/plugin/nvim-lsp-installer.vim
@@ -1,6 +1,5 @@
 if exists('g:loaded_nvim_lsp_installer') | finish | endif
 let g:loaded_nvim_lsp_installer = v:true
-let g:lsp_installer_allow_federated_servers = get(g:, "lsp_installer_allow_federated_servers", v:true)
 
 let s:save_cpo = &cpo
 set cpo&vim
@@ -52,3 +51,20 @@ autocmd User LspAttachBuffers lua require"nvim-lsp-installer".lsp_attach_proxy()
 
 let &cpo = s:save_cpo
 unlet s:save_cpo
+
+
+
+"""
+""" Backward compat for deprecated g:lsp_installer* options. Remove by 2021-12-01-ish.
+"""
+if exists("g:lsp_installer_allow_federated_servers")
+    " legacy global variable option
+    call luaeval("require('nvim-lsp-installer').settings { allow_federated_servers = _A }", g:lsp_installer_allow_federated_servers)
+    lua vim.notify("[Deprecation notice] Providing settings via global variables (g:lsp_installer_allow_federated_servers) is deprecated. Please refer to https://github.com/williamboman/nvim-lsp-installer#configuration.", vim.log.levels.WARN)
+endif
+
+if exists("g:lsp_installer_log_level")
+    " legacy global variable option
+    call luaeval("require('nvim-lsp-installer').settings { log_level = _A }", g:lsp_installer_log_level)
+    lua vim.notify("[Deprecation notice] Providing settings via global variables (g:lsp_installer_log_level) is deprecated. Please refer to https://github.com/williamboman/nvim-lsp-installer#configuration.", vim.log.levels.WARN)
+endif