misc: update docs and handle errors

HANDLERS.md

@@ -0,0 +1,68 @@
+# Handlers
+
+Satellite provides an API to implement handlers for the scrollbar.
+
+The API for the handler is as follows:
+
+```lua
+--- @class Handler
+---
+--- @field name string
+--- Name of the handler
+---
+--- @field setup fun(config: HandlerConfig, update: fun())
+--- Setup the handler and autocmds that are required to trigger the handler.
+---
+--- @field update fun(bufnr: integer, winid: integer): SatelliteMark[]
+--- This function is called when the handler needs to update. It must return
+--- a list of SatelliteMark's
+---
+--- @field enabled fun(): boolean
+--- Whether the handler is enabled or not.
+```
+
+Handlers can accept any configuration but must also support the following
+base class:
+
+```lua
+--- @class HandlerConfig
+---
+--- @field enable boolean
+--- Whether the handler is enabled
+---
+--- @field overlap boolean
+--- If `true` decorations are rendered on top of the scrollbar. If `false` the
+--- decorations are rendered in a separate column to the right of the scrollbar.
+---
+--- @field priority integer
+--- Priority of the decorations from the handler.
+```
+
+The handlers `update()` method returns a list of `SatelliteMark`'s which is defined as:
+
+```lua
+--- @class SatelliteMark
+---
+--- @field pos integer
+--- Row of the mark, use `require('satellite.util').row_to_barpos(winid, lnum)`
+--- to translate an `lnum` from window `winid` to its respective scrollbar row.
+---
+--- @field highlight string
+--- Highlight group of the mark.
+---
+--- @field symbol string
+--- Symbol of the mark. Must be a single character.
+---
+--- @field unique boolean
+--- By default, for each position in the scrollbar, Satellite will only use the
+--- last mark with that position. This field indicates the mark is special and
+--- must be rendered even if there is another mark at the same position from the
+--- handler.
+```
+
+To register a handler call:
+```lua
+require('satellite.handlers').register(handler)
+```
+
+Please see the [cursor handler](lua/satellite/handlers/cursor.lua) as an example.

README.md

@@ -1,5 +1,3 @@
-# 🚧 WIP and EXPERIMENTAL 🚧
-
 # satellite.nvim
 
 `satellite.nvim` is a Neovim plugin that displays decorated scrollbars.
@@ -8,7 +6,6 @@
 
 **NOTE**: Many API's required to implement a decorated scrollbar in Neovim do not yet exist,
 and because of this, this plugin implements fairly unideal and unoptimised workarounds to get desired behaviours.
-Therefore, this plugin is highly experimental and currently serves as a platform to experiment, investigate and design the required API's that are needed to be implemented in Neovim core.
 
 ## Features
 
@@ -84,7 +81,7 @@ for details.
 
 ## Handlers
 
-TODO
+Satellite provides an API to implement handlers for the scrollbar, see [HANDLERS](HANDLERS.md) for more details.
 
 ## Documentation
 

lua/satellite/config.lua

@@ -22,7 +22,7 @@
 ---@field marks MarksConfig
 
 ---@class SatelliteConfig
----@field handlers HandlerConfigs
+---@field handlers HandlerConfigs ssss
 ---@field current_only boolean
 ---@field winblend integer
 ---@field zindex integer

lua/satellite/view.lua

@@ -83,73 +83,79 @@ end
 ---@param bbufnr integer
 ---@param handler Handler
 local function render_handler(bufnr, winid, bbufnr, handler)
-  local name = handler.name
-
   if not handler:enabled() then
     return
   end
 
+  if not api.nvim_buf_is_loaded(bbufnr) then
+    return
+  end
+
+  local max_pos = api.nvim_buf_line_count(bbufnr) - 1
+  local name = handler.name
   local handler_config = user_config.handlers[name] or {}
 
   api.nvim_buf_clear_namespace(bbufnr, handler.ns, 0, -1)
   for _, m in ipairs(handler.update(bufnr, winid)) do
     local pos, symbol = m.pos, m.symbol
 
-    local opts = {
-      id = not m.unique and pos + 1 or nil,
-      priority = handler_config.priority,
-    }
-
-    if handler_config.overlap ~= false then
-      opts.virt_text = { { symbol, m.highlight } }
-      opts.virt_text_pos = 'overlay'
-      opts.hl_mode = 'combine'
-    else
-      -- Signs are 2 chars so fill the first char with whitespace
-      opts.sign_text = ' ' .. symbol
-      opts.sign_hl_group = m.highlight
-    end
+    if pos <= max_pos then
+      local opts = {
+        id = not m.unique and pos + 1 or nil,
+        priority = handler_config.priority,
+      }
+
+      if handler_config.overlap ~= false then
+        opts.virt_text = { { symbol, m.highlight } }
+        opts.virt_text_pos = 'overlay'
+        opts.hl_mode = 'combine'
+      else
+        -- Signs are 2 chars so fill the first char with whitespace
+        opts.sign_text = ' ' .. symbol
+        opts.sign_hl_group = m.highlight
+      end
 
-    local ok, err = pcall(api.nvim_buf_set_extmark, bbufnr, handler.ns, pos, 0, opts)
-    if not ok then
-      print(
-        string.format(
-          'error(satellite.nvim): handler=%s buf=%d row=%d opts=%s, err="%s"',
-          handler.name,
-          bbufnr,
-          pos,
-          vim.inspect(opts, { newline = ' ', indent = '' }),
-          err
+      local ok, err = pcall(api.nvim_buf_set_extmark, bbufnr, handler.ns, pos, 0, opts)
+      if not ok then
+        print(
+          string.format(
+            'error(satellite.nvim): handler=%s buf=%d row=%d opts=%s, err="%s"',
+            handler.name,
+            bbufnr,
+            pos,
+            vim.inspect(opts, { newline = ' ', indent = '' }),
+            err
+          )
         )
-      )
+      end
     end
   end
 end
 
----@param winid integer
----@param bar_winid integer
----@param toprow integer
-local function reposition_bar(winid, bar_winid, toprow)
-  local winwidth = api.nvim_win_get_width(winid)
-  local wininfo = vim.fn.getwininfo(bar_winid)[1]
-
-  --- @type integer
-  local signwidth = wininfo.textoff
-
-  local cfg = {
-    relative = 'win',
-    win = winid,
-    row = 0,
-    col = winwidth - signwidth - 1,
-    width = 1 + signwidth,
-  }
-
-  api.nvim_win_set_config(bar_winid, cfg)
-
-  vim.w[bar_winid].col = cfg.col
-  vim.w[bar_winid].width = cfg.width
-  vim.w[bar_winid].row = toprow
-end
+-----@param winid integer
+-----@param bar_winid integer
+-----@param toprow integer
+--local function reposition_bar(winid, bar_winid, toprow)
+--  local winwidth = api.nvim_win_get_width(winid)
+--  local wininfo = vim.fn.getwininfo(bar_winid)[1]
+
+--  --- @type integer
+--  local signwidth = wininfo.textoff
+
+--  local cfg = {
+--    relative = 'win',
+--    win = winid,
+--    row = 0,
+--    col = winwidth - signwidth - 1,
+--    width = 1 + signwidth,
+--  }
+
+--  api.nvim_win_set_config(bar_winid, cfg)
+
+--  vim.w[bar_winid].col = cfg.col
+--  vim.w[bar_winid].width = cfg.width
+--  vim.w[bar_winid].row = toprow
+--end
 
 ---@param bbufnr integer
 ---@param winid integer