local configs = require 'nvim_lsp/configs'
local util = require 'nvim_lsp/util'

-- https://clangd.llvm.org/extensions.html#switch-between-sourceheader
local function switch_source_header(bufnr)
  bufnr = util.validate_bufnr(bufnr)
  local params = { uri = vim.uri_from_bufnr(bufnr) }
  vim.lsp.buf_request(bufnr, 'textDocument/switchSourceHeader', params, function(err, _, result)
    if err then error(tostring(err)) end
    if not result then print ("Corresponding file can’t be determined") return end
    vim.api.nvim_command('edit '..vim.uri_to_fname(result))
  end)
end

local root_pattern = util.root_pattern("compile_commands.json", "compile_flags.txt", ".git")
configs.clangd = {
  default_config = util.utf8_config {
    cmd = {"clangd", "--background-index"};
    filetypes = {"c", "cpp", "objc", "objcpp"};
    root_dir = function(fname)
      local filename = util.path.is_absolute(fname) and fname
        or util.path.join(vim.loop.cwd(), fname)
      return root_pattern(filename) or util.path.dirname(filename)
    end;
    capabilities = {
      textDocument = {
        completion = {
          editsNearCursor = true
        }
      }
    },
  };
  commands = {
    ClangdSwitchSourceHeader = {
      function()
        switch_source_header(0)
      end;
      description = "Switch between source/header";
    };
  };
  docs = {
    description = [[
https://clang.llvm.org/extra/clangd/Installation.html

**NOTE:** Clang >= 9 is recommended! See [this issue for more](https://github.com/neovim/nvim-lsp/issues/23).

clangd relies on a [JSON compilation database](https://clang.llvm.org/docs/JSONCompilationDatabase.html) specified
as compile_commands.json or, for simpler projects, a compile_flags.txt.
For details on how to automatically generate one using CMake look [here](https://cmake.org/cmake/help/latest/variable/CMAKE_EXPORT_COMPILE_COMMANDS.html).
]];
    default_config = {
      root_dir = [[root_pattern("compile_commands.json", "compile_flags.txt", ".git") or dirname]];
      on_init = [[function to handle changing offsetEncoding]];
      capabilities = [[default capabilities, with offsetEncoding utf-8]];
    };
  };
}

configs.clangd.switch_source_header = switch_source_header
-- vim:et ts=2 sw=2