-- my_lsp.lua
local ok_cmp, cmp = pcall(require, "cmp")
local ok_kind, lspkind = pcall(require, "lspkind")
local ok_cmp_caps, cmp_caps = pcall(require, "cmp_nvim_lsp")
local has_lspconfig, lspconfig = pcall(require, "lspconfig")

-- ── completion (cmp) ───────────────────────────────────────────────────────────
vim.opt.completeopt = { "menu", "menuone", "noselect" }
vim.opt.shortmess:append("c")

if ok_kind then
  lspkind.init({
    symbol_map = {
      Text = "󰉿",
      Method = "󰊕",
      Function = "λ",
      Constructor = "",
      Field = "󰜢",
      Variable = "󰀫",
      Class = "󰠱",
      Interface = "",
      Module = "󰆧",
      Property = "󰜢",
      Unit = "󰑭",
      Value = "󰎠",
      Enum = "",
      Keyword = "󰌋",
      Snippet = "",
      Color = "󰏘",
      File = "󰈙",
      Reference = "󰈇",
      Folder = "󰉋",
      EnumMember = "",
      Constant = "󰏿",
      Struct = "󰙅",
      Event = "",
      Operator = "󰆕",
      TypeParameter = "τ",
    },
  })
end

local function has_words_before()
  local unpack = unpack or table.unpack
  local line, col = unpack(vim.api.nvim_win_get_cursor(0))
  if col == 0 then return false end
  local l = vim.api.nvim_buf_get_lines(0, line - 1, line, true)[1] or ""
  return l:sub(col, col):match("%s") == nil
end

local function feedkey(key, mode)
  vim.api.nvim_feedkeys(vim.api.nvim_replace_termcodes(key, true, true, true), mode, true)
end

if ok_cmp then
  cmp.setup({
    mapping = {
      ["<C-d>"] = cmp.mapping.scroll_docs(-4, { "i", "s" }),
      ["<C-u>"] = cmp.mapping.scroll_docs(4, { "i", "s" }),
      ["<C-e>"] = cmp.mapping.close(),
      ["<C-Space>"] = cmp.mapping(cmp.mapping.complete(), { "i", "c" }),
      ["<C-n>"] = cmp.mapping(function()
        cmp.select_next_item()
        pcall(vim.fn["vsnip#deactivate"])
      end, { "i", "s" }),
      ["<C-p>"] = cmp.mapping(function()
        cmp.select_prev_item()
        pcall(vim.fn["vsnip#deactivate"])
      end, { "i", "s" }),
      ["<Tab>"] = cmp.mapping(function(fallback)
        if vim.fn == 1 then
          feedkey("<Plug>(vsnip-expand-or-jump)", "")
        elseif cmp.visible() then
          cmp.mapping.confirm({ select = true })()
        elseif has_words_before() then
          cmp.complete()
        else
          fallback()
        end
      end, { "i", "s" }),
      ["<S-Tab>"] = cmp.mapping(function()
        if cmp.visible() then
          cmp.select_prev_item()
        elseif vim.fn["vsnip#jumpable"](-1) == 1 then
          feedkey("<Plug>(vsnip-jump-prev)", "")
        end
      end, { "i", "s" }),
    },
    formatting = ok_kind and {
      format = lspkind.cmp_format({
        mode = "symbol_text",
        maxwidth = 50,
        ellipsis_char = "...",
        show_labelDetails = true,
        before = function(_, item)
          local function split_args(s)
            if #s == 0 or not s:find("%(") then return s, "" end
            local i = s:find("%(") - 1
            return s:sub(1, i), s:sub(i + 1)
          end
          local verbosity = (vim.bo.filetype == "java") and 2 or 1
          if vim.bo.filetype == "java" and item.kind == "Method" then
            local name, args = split_args(item.abbr)
            item.abbr = name
            item.menu = (args or "") .. (item.menu or "")
          end
          item.abbr = item.abbr:sub(1, 20 * verbosity)
          item.menu = (item.menu or ""):sub(1, 20 * verbosity)
          return item
        end,
      }),
    } or nil,
    sources = {
      { name = "nvim_lsp" },
      { name = "path" },
      { name = "vim_vsnip" },
      { name = "buffer",   keyword_length = 5 },
    },
    sorting = { comparators = {} }, -- let LSP decide
    snippet = {
      expand = function(args) vim.fn["vsnip#anonymous"](args.body) end,
    },
    experimental = { native_menu = false, ghost_text = true },
  })

  -- zsh source on zsh buffers
  vim.api.nvim_create_augroup("CmpZsh", { clear = true })
  vim.api.nvim_create_autocmd("FileType", {
    group = "CmpZsh",
    pattern = "zsh",
    callback = function()
      require("cmp").setup.buffer { sources = { { name = "zsh" } } }
    end,
  })
end

-- ── LSP shared on_attach & capabilities ───────────────────────────────────────
local M = {}

M.on_attach = function(client, bufnr)
  -- omnifunc, tagfunc, formatexpr
  vim.bo[bufnr].omnifunc = "v:lua.vim.lsp.omnifunc"
  if vim.lsp.formatexpr then vim.bo[bufnr].formatexpr = "v:lua.vim.lsp.formatexpr" end
  if vim.lsp.tagfunc then vim.bo[bufnr].tagfunc = "v:lua.vim.lsp.tagfunc" end

  local map = function(mode, lhs, rhs)
    vim.keymap.set(mode, lhs, rhs, { buffer = bufnr, silent = true, noremap = true })
  end
  map("n", "<leader>rn", vim.lsp.buf.rename)
  map("n", "<leader>ca", vim.lsp.buf.code_action)
  map("n", "<M-k>", vim.lsp.buf.hover)
  map("n", "g0", vim.lsp.buf.document_symbol)
  map("n", "gW", vim.lsp.buf.workspace_symbol)
  map("n", "gd", vim.lsp.buf.definition)
  map("n", "gD", vim.lsp.buf.declaration)
  map("n", "gi", vim.lsp.buf.implementation)
  map("n", "gr", vim.lsp.buf.references)
  map("n", "<C-k>", vim.lsp.buf.signature_help)
  map("n", "g<space>", vim.lsp.buf.type_definition)
  map("n", "[d", vim.diagnostic.goto_prev)
  map("n", "]d", vim.diagnostic.goto_next)

  -- document highlight (only if server supports it)
  if client.server_capabilities.documentHighlightProvider then
    local gid = vim.api.nvim_create_augroup("LspDocumentHighlight" .. bufnr, { clear = true })
    vim.api.nvim_create_autocmd({ "CursorHold", "CursorHoldI" }, {
      group = gid, buffer = bufnr, callback = vim.lsp.buf.document_highlight,
    })
    vim.api.nvim_create_autocmd("CursorMoved", {
      group = gid, buffer = bufnr, callback = vim.lsp.buf.clear_references,
    })
  end

  vim.opt_local.signcolumn = "yes"
end

local capabilities = vim.lsp.protocol.make_client_capabilities()
if ok_cmp_caps then
  capabilities = cmp_caps.default_capabilities(capabilities)
end

-- nice diagnostics styling
vim.cmd [[hi DiagnosticUnderlineError gui=undercurl guisp=salmon]]
vim.cmd [[hi DiagnosticUnderlineWarn  gui=undercurl guisp=gold]]
for type, icon in pairs({ Error = " ", Warn = " ", Hint = " ", Info = " " }) do
  local hl = "DiagnosticSign" .. type
  vim.fn.sign_define(hl, { text = icon, texthl = hl, numhl = "" })
end

-- ── Servers (one table to rule them all) ──────────────────────────────────────
local servers = {
  bashls        = { filetypes = { "bash", "sh" } },
  clangd        = { filetypes = { "c", "cpp", "objc", "objcpp", "cuda" } },
  jqls          = { filetypes = { "jq" } },
  lua_ls        = { filetypes = { "lua" } },
  ocamllsp      = {},
  perlpls       = {},
  rust_analyzer = {
    settings = {
      semantic_tokens = {
        modifiers = {
          disabled = { "dead" },
        },
      },
    }
  },
  verible       = {},
  vimls         = {},
  zls           = {},
  texlab        = {},
  hls           = {
    settings = { haskell = { plugin = { semanticTokens = { globalOn = true } } } }
  },
  pylsp         = {
    settings = { pylsp = { plugins = { pycodestyle = { enabled = false } } } }
  },
}

-- Fallback command guesses for native start (used only if lspconfig is absent)
local default_cmd = {
  bashls        = { "bash-language-server", "start" },
  clangd        = { "clangd" },
  jqls          = { "jq-lsp" },
  lua_ls        = { "lua-language-server" },
  ocamllsp      = { "ocamllsp" },
  perlpls       = { "perlpls" },
  rust_analyzer = { "rust-analyzer" },
  verible       = { "verible-verilog-ls" },
  vimls         = { "vim-language-server", "--stdio" },
  zls           = { "zls" },
  texlab        = { "texlab" },
  hls           = { "haskell-language-server-wrapper", "--lsp" },
  pylsp         = { "pylsp" },
}

-- ── Setup: prefer native vim.lsp.config, fallback to lspconfig ───────────────
local has_native = (vim.lsp and vim.lsp.config and vim.lsp.start)

local function setup_with_native(name, opts)
  -- Build a vim.lsp.config() object and start per-filetype
  local cfg = vim.lsp.config(name, {
    name         = name,
    cmd          = opts.cmd or default_cmd[name],
    root_dir     = opts.root_dir, -- optional; can rely on server defaults
    filetypes    = opts.filetypes,
    settings     = opts.settings,
    capabilities = capabilities,
    on_attach    = M.on_attach,
  })

  vim.lsp.enable(name);

  -- if cfg.cmd == nil then
  --   vim.notify(("LSP %s: no cmd found; skipping native start."):format(name), vim.log.levels.WARN)
  --   return
  -- end

  -- Start when a matching buffer opens
  -- local pat = opts.filetypes or "*"
  -- vim.api.nvim_create_autocmd("FileType", {
  --   pattern = pat,
  --   callback = function(args)
  --     -- Only start if ft matches the server's filetypes (or none specified)
  --     if not cfg.filetypes or vim.tbl_contains(cfg.filetypes, vim.bo[args.buf].filetype) then
  --       vim.lsp.start(cfg, { bufnr = args.buf })
  --     end
  --   end,
  -- })
end

local function setup_with_lspconfig(name, opts)
  if not has_lspconfig then
    vim.notify(("lspconfig not found; cannot setup %s"):format(name), vim.log.levels.WARN)
    return
  end
  local final = vim.tbl_deep_extend("force", {
    capabilities = capabilities,
    on_attach = M.on_attach,
  }, opts or {})
  lspconfig[name].setup(final)
end

for name, opts in pairs(servers) do
  if has_native then
    setup_with_native(name, opts)
  else
    setup_with_lspconfig(name, opts)
  end
end

return M