local M = {}

local function map(buf, mode, lhs, rhs, opts)
  local options = { noremap = true, silent = true }
  if opts then options = vim.tbl_extend('force', options, opts) end
  vim.api.nvim_buf_set_keymap(buf, mode, lhs, rhs, options)
end

function M.on_attach(client, bufnr)
  -- Enable completion triggered by <c-x><c-o>
  vim.api.nvim_buf_set_option(bufnr, 'omnifunc', 'v:lua.vim.lsp.omnifunc')


  if client.server_capabilities.documentFormattingProvider then
    print("Initializing formatter...")

    vim.api.nvim_create_autocmd("BufWritePre", {
      group = vim.api.nvim_create_augroup("LspFormatting", {}),
      callback = vim.lsp.buf.formatting_sync
    })
  end

  print("Setting up keybinds...")
  -- Go to declaration / definition / implementation
  map(bufnr, "n", 'gD', '<cmd>lua vim.lsp.buf.declaration()<CR>')
  map(bufnr, "n", 'gd', '<cmd>lua vim.lsp.buf.definition()<CR>')
  map(bufnr, 'n', 'gi', '<cmd>lua vim.lsp.buf.implementation()<CR>')

  -- Hover
  map(bufnr, 'n', 'J', "<cmd>lua vim.diagnostic.open_float()<CR>")
  map(bufnr, 'n', 'K', '<cmd>lua vim.lsp.buf.hover()<CR>')
  map(bufnr, 'n', 'L', '<cmd>lua vim.lsp.buf.signature_help()<CR>')

  -- Workspace stuff
  -- map(bufnr, 'n', '<leader>wa',
  --     '<cmd>lua vim.lsp.buf.add_workspace_folder()<CR>')
  -- map(bufnr, 'n', '<leader>wr',
  --     '<cmd>lua vim.lsp.buf.remove_workspace_folder()<CR>')
  -- map(bufnr, 'n', '<leader>wl',
  --     '<cmd>lua print(vim.inspect(vim.lsp.buf.list_workspace_folders()))<CR>')

  -- Code actions
  map(bufnr, 'n', '<leader>D', '<cmd>lua vim.lsp.buf.type_definition()<CR>')
  map(bufnr, 'n', '<leader>rn', '<cmd>lua vim.lsp.buf.rename()<CR>')
  map(bufnr, 'n', '<space>ca', '<cmd>lua vim.lsp.buf.code_action()<CR>')
  map(bufnr, 'n', 'gr', '<cmd>lua vim.lsp.buf.references()<CR>')
  map(bufnr, 'n', '<leader>f',
    '<cmd>lua vim.lsp.buf.format({async = true})<CR>')

  print("Initialized language server!")
end

local function on_attach_typescript(client, bufnr)
  -- We handle formatting using null-ls and prettierd
  client.server_capabilities.documentFormattingProvider = false

  M.on_attach(client, bufnr)
end

-- General server config
local servers = {
  tsserver = { on_attach = on_attach_typescript },
  dhall_lsp_server = {},
  sumneko_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 }
      }
    },
    cmd = { "lua-language-server" }
  },
  purescriptls = {
    settings = {
      purescript = {
        censorWarnings = {
          "UnusedName", "ShadowedName", "UserDefinedWarning"
        },
        formatter = "purs-tidy"
      }
    }
  },
  hls = {
    haskell = {
      -- set formatter
      formattingProvider = "ormolu"
    }
  },
  rnix = {},
  cssls = {},
  kotlin_language_server = {}
  -- agda = {}, Haven't gotten this one to work yet
}

function M.setup()
  local capabilities = require('cmp_nvim_lsp').update_capabilities(vim.lsp
    .protocol
    .make_client_capabilities())

  -- Setup basic language servers
  for lsp, details in pairs(servers) do
    if details.on_attach == nil then
      -- Default setting for on_attach
      details.on_attach = M.on_attach
    end

    require('lspconfig')[lsp].setup {
      on_attach = details.on_attach,
      settings = details.settings, -- Specific per-language settings
      flags = {
        debounce_text_changes = 150 -- This will be the default in neovim 0.7+
      },
      cmd = details.cmd,
      capabilities = capabilities
    }
  end
end

return M