local M = {}

function M.show_line_diagnostics()
  local opts = {
    focusable = false,
    close_events = { "BufLeave", "CursorMoved", "InsertEnter", "FocusLost" },
    border = 'single'
  }
  vim.lsp.diagnostic.show_line_diagnostics(opts)
end

local custom_attach = function(client, bufnr)
  local function buf_set_keymap(...)
    vim.api.nvim_buf_set_keymap(bufnr, ...)
  end
  local function buf_set_option(...)
    vim.api.nvim_buf_set_option(bufnr, ...)
  end

  buf_set_option("omnifunc", "v:lua.vim.lsp.omnifunc")

  -- Mappings.
  local opts = { noremap = true, silent = true }
  buf_set_keymap("n", "gd", "<Cmd>lua vim.lsp.buf.definition()<CR>", opts)
  buf_set_keymap("n", "<C-]>", "<Cmd>lua vim.lsp.buf.definition()<CR>", opts)
  buf_set_keymap("n", "K", "<Cmd>lua vim.lsp.buf.hover()<CR>", opts)
  buf_set_keymap("n", "<C-k>", "<cmd>lua vim.lsp.buf.signature_help()<CR>", opts)
  buf_set_keymap("n", "<space>wa", "<cmd>lua vim.lsp.buf.add_workspace_folder()<CR>", opts)
  buf_set_keymap("n", "<space>wr", "<cmd>lua vim.lsp.buf.remove_workspace_folder()<CR>", opts)
  buf_set_keymap("n", "<space>wl", "<cmd>lua print(vim.inspect(vim.lsp.buf.list_workspace_folders()))<CR>", opts)
  buf_set_keymap("n", "<space>rn", "<cmd>lua vim.lsp.buf.rename()<CR>", opts)
  buf_set_keymap("n", "gr", "<cmd>lua vim.lsp.buf.references()<CR>", opts)
  buf_set_keymap("n", "[d", "<cmd>lua vim.lsp.diagnostic.goto_prev()<CR>", opts)
  buf_set_keymap("n", "]d", "<cmd>lua vim.lsp.diagnostic.goto_next()<CR>", opts)
  buf_set_keymap("n", "<space>q", "<cmd>lua vim.lsp.diagnostic.set_loclist()<CR>", opts)
  buf_set_keymap("n", "<space>ca", "<cmd>lua vim.lsp.buf.code_action()<CR>", opts)

  vim.cmd([[
    autocmd CursorHold <buffer> lua require('config.lsp').show_line_diagnostics()
  ]])

  -- Set some key bindings conditional on server capabilities
  if client.resolved_capabilities.document_formatting then
    buf_set_keymap("n", "<space>f", "<cmd>lua vim.lsp.buf.formatting()<CR>", opts)
  end
  if client.resolved_capabilities.document_range_formatting then
    buf_set_keymap("x", "<space>f", "<cmd>lua vim.lsp.buf.range_formatting()<CR><ESC>", opts)
  end

  -- The blow command will highlight the current variable and its usages in the buffer.
  if client.resolved_capabilities.document_highlight then
    vim.cmd([[
      hi link LspReferenceRead Visual
      hi link LspReferenceText Visual
      hi link LspReferenceWrite Visual
      augroup lsp_document_highlight
        autocmd! * <buffer>
        autocmd CursorHold <buffer> lua vim.lsp.buf.document_highlight()
        autocmd CursorMoved <buffer> lua vim.lsp.buf.clear_references()
      augroup END
    ]])
  end

  local msg = string.format("Language server %s started!", client.name)
  vim.api.nvim_echo({ { msg, "MoreMsg" } }, false, {})
  -- vim.notify(msg, 'info', {title = 'Nvim-config', timeout = 2500})
end

local capabilities = vim.lsp.protocol.make_client_capabilities()
capabilities.textDocument.completion.completionItem.snippetSupport = true

local lspconfig = require("lspconfig")

lspconfig.pylsp.setup({
  on_attach = custom_attach,
  settings = {
    pylsp = {
      plugins = {
        pylint = { enabled = true, executable = "pylint" },
        pyflakes = { enabled = false },
        pycodestyle = { enabled = false },
        jedi_completion = { fuzzy = true },
        pyls_isort = { enabled = true },
        pylsp_mypy = { enabled = true },
      },
    },
  },
  flags = {
    debounce_text_changes = 200,
  },
})

-- lspconfig.pyright.setup{
--   on_attach = custom_attach,
-- }

lspconfig.clangd.setup({
  on_attach = custom_attach,
  capabilities = capabilities,
  filetypes = { "c", "cpp", "cc" },
  flags = {
    debounce_text_changes = 500,
  },
})

-- set up vim-language-server
lspconfig.vimls.setup({
  on_attach = custom_attach,
  flags = {
    debounce_text_changes = 500,
  },
})

local sumneko_binary_path = vim.fn.exepath("lua-language-server")
if vim.g.is_mac or vim.g.is_linux and sumneko_binary_path ~= "" then
  local sumneko_root_path = vim.fn.fnamemodify(sumneko_binary_path, ":h:h:h")

  local runtime_path = vim.split(package.path, ";")
  table.insert(runtime_path, "lua/?.lua")
  table.insert(runtime_path, "lua/?/init.lua")

  require("lspconfig").sumneko_lua.setup({
    on_attach = custom_attach,
    cmd = { sumneko_binary_path, "-E", sumneko_root_path .. "/main.lua" },
    settings = {
      Lua = {
        runtime = {
          -- Tell the language server which version of Lua you're using (most likely LuaJIT in the case of Neovim)
          version = "LuaJIT",
          -- Setup your lua path
          path = runtime_path,
        },
        diagnostics = {
          -- Get the language server to recognize the `vim` global
          globals = { "vim" },
        },
        workspace = {
          -- Make the server aware of Neovim runtime files
          library = vim.api.nvim_get_runtime_file("", true),
        },
        -- Do not send telemetry data containing a randomized but unique identifier
        telemetry = {
          enable = false,
        },
      },
    },
  })
end

-- Change diagnostic signs.
vim.fn.sign_define("LspDiagnosticsSignError", { text = "✗", texthl = "LspDiagnosticsDefaultError" })
vim.fn.sign_define("LspDiagnosticsSignWarning", { text = "!", texthl = "LspDiagnosticsDefaultWarning" })
vim.fn.sign_define("LspDiagnosticsSignInformation", { text = "", texthl = "LspDiagnosticsDefaultInformation" })
vim.fn.sign_define("LspDiagnosticsSignHint", { text = "", texthl = "LspDiagnosticsDefaultHint" })

vim.lsp.handlers["textDocument/publishDiagnostics"] = vim.lsp.with(vim.lsp.diagnostic.on_publish_diagnostics, {
  underline = false,
  virtual_text = false,
  signs = true,
  update_in_insert = false,
})

-- Refs: https://github.com/neovim/nvim-lspconfig/wiki/UI-customization#show-source-in-diagnostics
vim.lsp.handlers["textDocument/publishDiagnostics"] = function(_, _, params, client_id, _)
  local uri = params.uri
  local bufnr = vim.uri_to_bufnr(uri)

  if not bufnr then
    return
  end

  if not vim.api.nvim_buf_is_loaded(bufnr) then
    return
  end

  local diagnostics = params.diagnostics
  for i, v in ipairs(diagnostics) do
    diagnostics[i].message = string.format("%s: %s", v.source, v.message)
  end
  vim.lsp.diagnostic.save(diagnostics, bufnr, client_id)

  local config = {
    underline = false,
    virtual_text = false,
    signs = true,
    update_in_insert = false,
  }
  vim.lsp.diagnostic.display(diagnostics, bufnr, client_id, config)
end

-- The following settings works with the bleeding edge neovim.
-- See https://github.com/neovim/neovim/pull/13998.
vim.lsp.handlers["textDocument/hover"] = vim.lsp.with(vim.lsp.handlers.hover, {
  border = "rounded",
})

return M