Merge pull request #33 from grapp-dev/feature/buffer-component

feat: add Buffer component

docs/pages/docs/components/buffer.mdx

@@ -0,0 +1,100 @@
+import { Callout } from 'nextra/components';
+import { Property } from '../../../components/Property'
+
+## Buffer
+
+`Buffer` is a component that handles window layout only and renders the contents of a given buffer.
+
+![](/gifs/buffer-1.gif)
+
+### Usage Example
+
+<Callout type="info">
+  The code example is using the [`gen.nvim`](https://github.com/David-Kunz/gen.nvim) plugin.
+</Callout>
+
+```lua
+local renderer = n.create_renderer({
+  width = 60,
+  height = 3,
+})
+
+local signal = n.create_signal({
+  chat = "",
+  is_preview_visible = false,
+})
+
+local buf = vim.api.nvim_create_buf(false, true)
+
+local body = function()
+  return n.rows(
+    n.text_input({
+      border_label = "Chat",
+      autofocus = true,
+      wrap = true,
+      on_change = function(value)
+        signal.chat = value
+      end,
+    }),
+    n.buffer({
+      id = "preview",
+      flex = 1,
+      buf = buf,
+      autoscroll = true,
+      border_label = "Preview",
+      hidden = signal.is_preview_visible:negate(),
+    })
+  )
+end
+
+renderer:add_mappings({
+  {
+    mode = { "n", "i" },
+    key = "<D-CR>",
+    handler = function()
+      local gen = require("gen")
+      local state = signal:get_value()
+
+      renderer:set_size({ height = 20 })
+      signal.is_preview_visible = true
+
+      renderer:schedule(function()
+        gen.float_win = renderer:get_component_by_id("preview").winid
+        gen.result_buffer = buf
+        gen.exec({ prompt = state.chat })
+      end)
+    end,
+  },
+})
+
+renderer:render(body)
+```
+
+### Properties
+
+#### buf
+
+<Property 
+  required={true}
+  types={['number']}
+/>
+
+#### autoscroll
+
+<Property 
+  defaultValue="false"
+  types={['boolean']}
+/>
+
+#### filetype
+
+<Property 
+  types={['string']}
+/>
+
+#### linebreak
+
+<Property 
+  defaultValue="true"
+  types={['boolean']}
+/>

lua/nui-components/buffer.lua

@@ -0,0 +1,86 @@
+local Component = require("nui-components.component")
+local buf_storage = require("nui.utils.buf_storage")
+
+local fn = require("nui-components.utils.fn")
+
+local Buffer = Component:extend("Buffer")
+
+function Buffer:init(props, popup_options)
+  Buffer.super.init(
+    self,
+    fn.merge({
+      buf = nil,
+      autoscroll = false,
+    }, props),
+    fn.deep_merge({
+      buf_options = {
+        filetype = props.filetype or "",
+      },
+      win_options = {
+        linebreak = fn.default_to(props.linebreak, true),
+      },
+    }, popup_options)
+  )
+end
+
+function Buffer:prop_types()
+  return {
+    buf = "number",
+    autoscroll = "boolean",
+    filetype = { "string", "nil" },
+  }
+end
+
+function Buffer:_buf_create()
+  local props = self:get_props()
+
+  self.bufnr = props.buf
+
+  if props.autoscroll then
+    self._private.autoscroll_id = vim.api.nvim_create_autocmd("TextChanged", {
+      buffer = self.bufnr,
+      callback = function()
+        if not self.winid or not vim.api.nvim_win_is_valid(self.winid) then
+          return
+        end
+
+        if not self.bufnr or not vim.api.nvim_buf_is_valid(self.bufnr) then
+          return true
+        end
+
+        vim.api.nvim_win_set_cursor(self.winid, {
+          vim.api.nvim_buf_line_count(self.bufnr),
+          9999,
+        })
+      end,
+    })
+  end
+end
+
+function Buffer:_buf_destroy()
+  buf_storage.cleanup(self.bufnr)
+
+  if self._private.autoscroll_id then
+    pcall(vim.api.nvim_del_autocmd, self._private.autoscroll_id)
+    self._private.autoscroll_id = nil
+  end
+
+  self.bufnr = nil
+end
+
+function Buffer:on_update()
+  local props = self:get_props()
+
+  if props.buf and self.bufnr ~= props.buf and self._.layout_ready then
+    local is_focused = vim.api.nvim_get_current_win() == self.winid
+
+    self:unmount()
+    self:mount()
+
+    if is_focused then
+      vim.api.nvim_set_current_win(self.winid)
+    end
+  end
+end
+
+return Buffer

lua/nui-components/init.lua

@@ -66,6 +66,7 @@ M.checkbox = require("nui-components.checkbox")
 M.paragraph = require("nui-components.paragraph")
 M.spinner = require("nui-components.spinner")
 M.animated_text = require("nui-components.animated-text")
+M.buffer = require("nui-components.buffer")
 
 M.tabs = add_children_prop(Tabs)
 M.tab = add_children_prop(Tab)