feat: allow custom input provider, removing dressing.nvim (#2173)

Co-authored-by: pre-commit-ci-lite[bot] <117423508+pre-commit-ci-lite[bot]@users.noreply.github.com>
Co-authored-by: yetone <yetoneful@gmail.com>

lua/avante/ui/input/init.lua

@@ -0,0 +1,48 @@
+local Utils = require("avante.utils")
+
+---@class avante.ui.InputOption
+---@field provider avante.InputProvider
+---@field title string
+---@field default string | nil
+---@field completion string | nil
+---@field provider_opts table | nil
+---@field on_submit fun(result: string | nil)
+---@field conceal boolean | nil -- Whether to conceal input (for passwords)
+
+---@class avante.ui.Input
+---@field provider avante.InputProvider
+---@field title string
+---@field default string | nil
+---@field completion string | nil
+---@field provider_opts table | nil
+---@field on_submit fun(result: string | nil)
+---@field conceal boolean | nil
+local Input = {}
+Input.__index = Input
+
+---@param opts avante.ui.InputOption
+function Input:new(opts)
+  local o = {}
+  setmetatable(o, Input)
+  o.provider = opts.provider
+  o.title = opts.title
+  o.default = opts.default or ""
+  o.completion = opts.completion
+  o.provider_opts = opts.provider_opts or {}
+  o.on_submit = opts.on_submit
+  o.conceal = opts.conceal or false
+  return o
+end
+
+function Input:open()
+  if type(self.provider) == "function" then
+    self.provider(self)
+    return
+  end
+
+  local ok, provider = pcall(require, "avante.ui.input.providers." .. self.provider)
+  if not ok then Utils.error("Unknown input provider: " .. self.provider) end
+  provider.show(self)
+end
+
+return Input