local DEFAULT_INSTALLER_LABEL = 'TrapOS Installer';
local DEFAULT_INSTALL_URL = 'https://trapos.trapcloud.fr/install';
local DEFAULT_SETTINGS_SOURCE_PATH = '/.settings';

local function writeFile(path, body)
  local file = fs.open(path, 'w');
  if not file then return false; end
  file.write(body);
  file.close();
  return true;
end

local function createInstallerDisk(opts)
  opts = opts or {};
  local peripheralApi = opts.peripheral or peripheral;
  local settingsApi = opts.settings or settings;
  local settingsSourcePath = opts.settingsSourcePath or DEFAULT_SETTINGS_SOURCE_PATH;
  local installerLabel = opts.installerLabel or DEFAULT_INSTALLER_LABEL;
  local installUrl = opts.installUrl or DEFAULT_INSTALL_URL;

  local api = {};

  function api.buildAutorun()
    return '-- TrapOS installer disk autorun (generated; do not edit)\n'
      .. "local INSTALLER_LABEL = '" .. installerLabel .. "';\n"
      .. "local INSTALL_URL = '" .. installUrl .. "';\n"
      .. '\n'
      .. "if fs.exists('/trapos') then return; end\n"
      .. '\n'
      .. 'local function installerMount()\n'
      .. '  for _, name in ipairs(peripheral.getNames()) do\n'
      .. "    if peripheral.getType(name) == 'drive' then\n"
      .. '      local drive = peripheral.wrap(name);\n'
      .. '      if drive.isDiskPresent() and drive.getDiskLabel() == INSTALLER_LABEL then\n'
      .. '        return drive.getMountPath();\n'
      .. '      end\n'
      .. '    end\n'
      .. '  end\n'
      .. 'end\n'
      .. '\n'
      .. 'local mount = installerMount();\n'
      .. 'if mount then\n'
      .. "  local src = fs.combine(mount, '.settings');\n"
      .. '  if fs.exists(src) then\n'
      .. "    fs.delete('/.settings');\n"
      .. "    fs.copy(src, '/.settings');\n"
      .. '    settings.load();\n'
      .. '  end\n'
      .. 'end\n'
      .. '\n'
      .. "print('TrapOS Installer: installing TrapOS...');\n"
      .. "shell.run('wget', 'run', INSTALL_URL);\n";
  end

  function api.findTargetDrive()
    local names = peripheralApi.getNames and peripheralApi.getNames() or {};
    local presentCount = 0;
    local nonEmptyCount = 0;
    local empty = {};

    for _, name in ipairs(names) do
      if peripheralApi.getType(name) == 'drive' then
        local drive = peripheralApi.wrap(name);
        if drive.isDiskPresent() and drive.hasData() then
          presentCount = presentCount + 1;
          local mountPath = drive.getMountPath();
          if mountPath and #fs.list(mountPath) == 0 then
            empty[#empty + 1] = { name = name, mountPath = mountPath, drive = drive };
          else
            nonEmptyCount = nonEmptyCount + 1;
          end
        end
      end
    end

    if #empty > 1 then
      return false, 'multiple blank disks found, remove all but one';
    end
    if #empty == 1 then
      return true, empty[1];
    end
    if presentCount > 0 or nonEmptyCount > 0 then
      return false, 'disk not empty; insert a blank floppy';
    end
    return false, 'insert a blank floppy';
  end

  function api.create()
    local ok, target = api.findTargetDrive();
    if not ok then return false, target; end

    target.drive.setDiskLabel(installerLabel);

    local result = {
      name = target.name,
      mountPath = target.mountPath,
      label = installerLabel,
      settingsCopied = false,
      settingsWarning = false,
    };

    if fs.exists(settingsSourcePath) then
      settingsApi.save();
      local dest = fs.combine(target.mountPath, '.settings');
      fs.delete(dest);
      fs.copy(settingsSourcePath, dest);
      result.settingsCopied = true;
    else
      result.settingsWarning = true;
    end

    local startupPath = fs.combine(target.mountPath, 'startup.lua');
    fs.delete(startupPath);
    if not writeFile(startupPath, api.buildAutorun()) then
      return false, 'failed to write ' .. startupPath;
    end

    return true, result;
  end

  return api;
end

return createInstallerDisk;