nvim/ftplugin/cpp.lua

vim.opt_local.cinoptions = vim.opt_local.cinoptions + '0{1' -- Places opening brace on the same line as function signature
vim.opt_local.smartindent = true -- Automatically adds indentation where needed
vim.opt_local.tabstop = 4 -- Set tab stop to 4 spaces
vim.opt_local.shiftwidth = 4 -- Set shift width to 4 spaces
vim.opt_local.softtabstop = 4 -- Use spaces instead of tabs

vim.api.nvim_create_user_command('RunCpp', function(opts)
  vim.cmd('w') -- Save the current file
  local filename = vim.fn.expand('%') -- Get current file name
  local output = 'bin/' .. vim.fn.expand('%:r'):match('([^/]+)$') .. '.out' -- Output file with .out extension

  -- Use provided compiler or default to 'clang++'
  local compiler = opts.args ~= '' and opts.args or 'clang++'

  -- Ensure the output directory exists
  vim.fn.mkdir('bin', 'p')

  -- Compile and run the C++ code
  vim.cmd('!' .. compiler .. ' ' .. filename .. ' -o ' .. output .. ' && ./' .. output)
end, { nargs = '?' }) -- Accepts one optional argument for the compiler

local function cmake_build_dir(name)
  local dir = vim.fn.getcwd() .. '/' .. (name or 'build')
  if vim.fn.isdirectory(dir) == 0 then
    vim.fn.mkdir(dir, 'p')
  end
  return dir
end

local function cmake_configure(build_dir, extra_args)
  local args = extra_args or ''
  local bin_dir = vim.fn.getcwd() .. '/bin'
  vim.fn.mkdir(bin_dir, 'p')
  local out_args =
    ' -DCMAKE_RUNTIME_OUTPUT_DIRECTORY=' .. vim.fn.shellescape(bin_dir) .. ' -DCMAKE_LIBRARY_OUTPUT_DIRECTORY='
    .. vim.fn.shellescape(bin_dir)
    .. ' -DCMAKE_ARCHIVE_OUTPUT_DIRECTORY='
    .. vim.fn.shellescape(bin_dir)
  vim.cmd('!cmake -S . -B ' .. vim.fn.fnameescape(build_dir) .. out_args .. ' ' .. args)
end

local function cmake_build(build_dir, extra_args)
  local args = extra_args or ''
  vim.cmd('!cmake --build ' .. vim.fn.fnameescape(build_dir) .. ' ' .. args)
end

local function cmake_ctest(build_dir)
  vim.cmd('!ctest --test-dir ' .. vim.fn.fnameescape(build_dir) .. ' --output-on-failure')
end

local function select_cmake_preset()
  local lines = vim.fn.systemlist('cmake --list-presets')
  local presets = {}
  for _, line in ipairs(lines) do
    local name = line:match('^%s*"([^"]+)"')
    if name then
      table.insert(presets, name)
    end
  end
  if #presets == 0 then
    return
  end
  vim.ui.select(presets, { prompt = 'CMake preset' }, function(choice)
    if choice then
      vim.g.cmake_preset = choice
    end
  end)
end

local function cmake_configure_with_preset()
  local preset = vim.g.cmake_preset
  if preset and preset ~= '' then
    vim.cmd('!cmake --preset ' .. preset)
    return true
  end
  return false
end

local function cmake_build_with_preset()
  local preset = vim.g.cmake_preset
  if preset and preset ~= '' then
    vim.cmd('!cmake --build --preset ' .. preset)
    return true
  end
  return false
end

local function toggle_debugger_repl()
  local dbg = vim.__cpp_dbg_term
  if dbg and dbg.is_open and dbg:is_open() then
    dbg:close()
    return
  end

  local ok_term, term_mod = pcall(require, 'toggleterm.terminal')
  if not ok_term then
    return
  end

  local cmd
  if vim.fn.has('mac') == 1 then
    cmd = 'lldb'
  else
    cmd = 'gdb'
  end

  if not vim.__cpp_dbg_term then
    vim.__cpp_dbg_term = term_mod.Terminal:new({
      cmd = cmd,
      direction = 'vertical',
      size = function()
        return math.floor(vim.o.columns * 0.4)
      end,
      hidden = true,
      on_open = function(term)
        vim.api.nvim_buf_set_keymap(term.bufnr, 'n', 'q', '<cmd>close<CR>', { noremap = true, silent = true })
        vim.api.nvim_buf_set_keymap(term.bufnr, 't', '<Esc><Esc>', '<C-\\><C-n>', { noremap = true, silent = true })
      end,
    })
  end

  vim.__cpp_dbg_term:open()
  vim.cmd('wincmd p')
end

local opts = { buffer = true, silent = true }

local function switch_source_header()
  local bufnr = vim.api.nvim_get_current_buf()
  local function edit_file(fname)
    if not fname or fname == '' then
      return
    end
    vim.cmd('edit ' .. vim.fn.fnameescape(fname))
  end

  local clangd
  for _, client in ipairs(vim.lsp.get_clients({ bufnr = bufnr })) do
    if client.name == 'clangd' then
      clangd = client
      break
    end
  end

  if clangd then
    clangd.request('textDocument/switchSourceHeader', { uri = vim.uri_from_bufnr(bufnr) }, function(err, result)
      if err then
        vim.notify('clangd: switchSourceHeader failed', vim.log.levels.WARN)
        return
      end
      if not result then
        vim.notify('No corresponding header/source found', vim.log.levels.INFO)
        return
      end
      vim.schedule(function()
        edit_file(vim.uri_to_fname(result))
      end)
    end, bufnr)
    return
  end

  local file = vim.api.nvim_buf_get_name(bufnr)
  if file == '' then
    return
  end

  local root = file:gsub('%.[^%.]+$', '')
  local ext = vim.fn.fnamemodify(file, ':e')
  local candidates

  if ext == 'h' or ext == 'hpp' or ext == 'hh' or ext == 'hxx' then
    candidates = { 'cpp', 'cc', 'cxx', 'c' }
  elseif ext == 'c' then
    candidates = { 'h' }
  else
    candidates = { 'h', 'hpp', 'hh', 'hxx' }
  end

  for _, e in ipairs(candidates) do
    local cand = root .. '.' .. e
    if vim.fn.filereadable(cand) == 1 then
      edit_file(cand)
      return
    end
  end

  vim.notify('No corresponding header/source found', vim.log.levels.INFO)
end

local function memory_profile_command(run_cmd)
  if vim.fn.has('mac') == 1 then
    return 'leaks --atExit -- ' .. run_cmd
  end
  return 'valgrind --leak-check=full --track-origins=yes ' .. run_cmd
end

vim.keymap.set('n', '<leader>cS', select_cmake_preset, vim.tbl_extend('force', opts, { desc = 'CMake: Select preset' }))

vim.keymap.set('n', '<leader>cb', function()
  if cmake_configure_with_preset() then
    cmake_build_with_preset()
    return
  end
  local build_dir = cmake_build_dir('build')
  cmake_configure(build_dir)
  cmake_build(build_dir)
end, vim.tbl_extend('force', opts, { desc = 'CMake: Build' }))

vim.keymap.set('n', '<leader>ct', function()
  local build_dir = cmake_build_dir('build')
  cmake_ctest(build_dir)
end, vim.tbl_extend('force', opts, { desc = 'CMake: Test' }))

vim.keymap.set('n', '<leader>cr', function()
  local cmd = vim.fn.input('Run command: ', './')
  if cmd == '' then
    return
  end
  vim.cmd('!' .. cmd)
end, vim.tbl_extend('force', opts, { desc = 'CMake: Run (prompt)' }))

vim.keymap.set('n', '<leader>ch', switch_source_header, vim.tbl_extend('force', opts, { desc = 'C++: Switch header/source' }))

vim.keymap.set('n', '<leader>cg', toggle_debugger_repl, vim.tbl_extend('force', opts, { desc = 'C++: Toggle debugger REPL' }))

vim.keymap.set('n', '<leader>cm', function()
  local cmd = vim.fn.input('Memory profile run: ', './bin/')
  if cmd == '' then
    return
  end
  vim.cmd('!' .. memory_profile_command(cmd))
end, vim.tbl_extend('force', opts, { desc = 'C++: Memory profile (leaks/valgrind)' }))

vim.keymap.set('n', '<leader>Rr', toggle_debugger_repl, vim.tbl_extend('force', opts, { desc = 'Run/REPL: Toggle' }))

vim.keymap.set('n', '<leader>Rf', function()
  local cmd = vim.fn.input('Run: ', './bin/')
  if cmd == '' then
    return
  end
  vim.cmd('!' .. cmd)
end, vim.tbl_extend('force', opts, { desc = 'Run/REPL: Run' }))

vim.keymap.set('n', '<leader>Ri', function()
  local dbg = vim.__cpp_dbg_term
  if dbg and dbg.send and dbg.is_open and dbg:is_open() then
    dbg:send('\x03')
  end
end, vim.tbl_extend('force', opts, { desc = 'Run/REPL: Interrupt' }))

vim.keymap.set('n', '<leader>ca', function()
  local build_dir = cmake_build_dir('build-asan')
  local flags = "-DCMAKE_BUILD_TYPE=Debug -DCMAKE_C_FLAGS='-fsanitize=address -fno-omit-frame-pointer' -DCMAKE_CXX_FLAGS='-fsanitize=address -fno-omit-frame-pointer'"
  cmake_configure(build_dir, flags)
  cmake_build(build_dir)
end, vim.tbl_extend('force', opts, { desc = 'CMake: Build (ASan)' }))