-- The MIT License (MIT)
--
-- Copyright © 2026 Scott E. Graves <scott.e.graves@protonmail.com>
--
-- Permission is hereby granted, free of charge, to any person obtaining a copy of this software
-- and associated documentation files (the “Software”), to deal in the Software without restriction,
-- including without limitation the rights to use, copy, modify, merge, publish, distribute,
-- sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
-- furnished to do so, subject to the following conditions:
--
-- The above copyright notice and this permission notice shall be included in all copies or
-- substantial portions of the Software.
--
-- THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
-- BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
-- NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
-- DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-- OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
--
local M = {}

local focus_id = "textDocument/signatureHelp"
local timers = {}

local config = {
  delay = 50,
  border = "rounded",
  max_height = 25,
  max_width = 120,
  wrap = true
}

local function normalize_bufnr(bufnr)
  if bufnr == nil or bufnr == 0 then
    return vim.api.nvim_get_current_buf()
  end
  return bufnr
end

local function cancel_timer(bufnr)
  local timer = timers[bufnr]
  timers[bufnr] = nil
  if timer and not timer:is_closing() then
    timer:stop()
    timer:close()
  end
end

local function close_float(bufnr)
  for _, win in ipairs(vim.api.nvim_list_wins()) do
    local ok, owner = pcall(vim.api.nvim_win_get_var, win, focus_id)
    if ok and owner == bufnr then
      pcall(vim.api.nvim_win_close, win, true)
    end
  end
end

function M.close(bufnr)
  bufnr = normalize_bufnr(bufnr)
  cancel_timer(bufnr)
  close_float(bufnr)
end

function M.update(bufnr)
  bufnr = normalize_bufnr(bufnr)
  if
    not vim.api.nvim_buf_is_valid(bufnr) or
      bufnr ~= vim.api.nvim_get_current_buf()
   then
    return
  end

  local clients = vim.lsp.get_clients(
    {bufnr = bufnr, method = "textDocument/signatureHelp"}
  )
  if #clients == 0 then
    close_float(bufnr)
    return
  end

  vim.lsp.buf.signature_help(
    {
      anchor_bias = "above",
      border = config.border,
      focusable = false,
      max_height = config.max_height,
      max_width = config.max_width,
      silent = true,
      wrap = config.wrap
    }
  )
end

function M.schedule(args)
  local bufnr = normalize_bufnr(args and args.buf)
  cancel_timer(bufnr)
  timers[bufnr] = vim.defer_fn(
    function()
      timers[bufnr] = nil
      M.update(bufnr)
    end,
    config.delay
  )
end

function M.setup(opts)
  config = vim.tbl_deep_extend("force", config, opts or {})

  local group = vim.api.nvim_create_augroup("DarculaLspSignature", {clear = true})
  vim.api.nvim_create_autocmd(
    {"TextChangedI", "TextChangedP", "CursorHoldI"},
    {
      callback = M.schedule,
      group = group
    }
  )
  vim.api.nvim_create_autocmd(
    {"InsertLeave", "WinLeave"},
    {
      callback = function(args)
        M.close(args.buf)
      end,
      group = group
    }
  )
  vim.api.nvim_create_autocmd(
    "BufWipeout",
    {
      callback = function(args)
        cancel_timer(args.buf)
      end,
      group = group
    }
  )
end

return M