# Function for creating a Neovim derivation
{
  pkgs,
  lib,
  stdenv,
  # Set by the overlay to ensure we use a compatible version of `wrapNeovimUnstable`
  pkgs-wrapNeovim ? pkgs,
}:
with lib;
  {
    # NVIM_APPNAME - Defaults to 'nvim' if not set.
    # If set to something else, this will also rename the binary.
    appName ? null,
    # The Neovim package to wrap
    neovim-unwrapped ? pkgs-wrapNeovim.neovim-unwrapped,
    plugins ? [], # List of plugins
    # List of dev plugins (will be bootstrapped) - useful for plugin developers
    # { name = <plugin-name>; url = <git-url>; }
    devPlugins ? [],
    # Regexes for config files to ignore, relative to the nvim directory.
    # e.g. [ "^plugin/neogit.lua" "^ftplugin/.*.lua" ]
    ignoreConfigRegexes ? [],
    extraPackages ? [], # Extra runtime dependencies (e.g. ripgrep, ...)
    # The below arguments can typically be left as their defaults
    # Additional lua packages (not plugins), e.g. from luarocks.org.
    # e.g. p: [p.jsregexp]
    extraLuaPackages ? p: [],
    extraPython3Packages ? p: [], # Additional python 3 packages
    withPython3 ? true, # Build Neovim with Python 3 support?
    withRuby ? false, # Build Neovim with Ruby support?
    withNodeJs ? false, # Build Neovim with NodeJS support?
    withSqlite ? true, # Add sqlite? This is a dependency for some plugins
    # You probably don't want to create vi or vim aliases
    # if the appName is something different than "nvim"
    # Add a "vi" binary to the build output as an alias?
    viAlias ? appName == null || appName == "nvim",
    # Add a "vim" binary to the build output as an alias?
    vimAlias ? appName == null || appName == "nvim",
  }: let
    # This is the structure of a plugin definition.
    # Each plugin in the `plugins` argument list can also be defined as this attrset
    defaultPlugin = {
      plugin = null; # e.g. nvim-lspconfig
      config = null; # plugin config
      # If `optional` is set to `false`, the plugin is installed in the 'start' packpath
      # set to `true`, it is installed in the 'opt' packpath, and can be lazy loaded with
      # ':packadd! {plugin-name}
      optional = false;
      runtime = {};
    };

    externalPackages = extraPackages ++ (optionals withSqlite [pkgs.sqlite]);

    # Map all plugins to an attrset { plugin = <plugin>; config = <config>; optional = <tf>; ... }
    normalizedPlugins = map (x:
      defaultPlugin
      // (
        if x ? plugin
        then x
        else {plugin = x;}
      ))
    plugins;

    # This nixpkgs util function creates an attrset
    # that pkgs.wrapNeovimUnstable uses to configure the Neovim build.
    neovimConfig = pkgs-wrapNeovim.neovimUtils.makeNeovimConfig {
      inherit extraPython3Packages withPython3 withRuby withNodeJs viAlias vimAlias;
      plugins = normalizedPlugins;
    };

    # This uses the ignoreConfigRegexes list to filter
    # the nvim directory
    nvimRtpSrc = let
      src = ../nvim;
    in
      lib.cleanSourceWith {
        inherit src;
        name = "nvim-rtp-src";
        filter = path: tyoe: let
          srcPrefix = toString src + "/";
          relPath = lib.removePrefix srcPrefix (toString path);
        in
          lib.all (regex: builtins.match regex relPath == null) ignoreConfigRegexes;
      };

    # Split runtimepath into 3 directories:
    # - lua, to be prepended to the rtp at the beginning of init.lua
    # - nvim, containing plugin, ftplugin, ... subdirectories
    # - after, to be sourced last in the startup initialization
    # See also: https://neovim.io/doc/user/starting.html
    nvimRtp = stdenv.mkDerivation {
      name = "nvim-rtp";
      src = nvimRtpSrc;

      buildPhase = ''
        mkdir -p $out/nvim
        mkdir -p $out/lua
        rm init.lua
      '';

      installPhase = ''
        cp -r lua $out/lua
        rm -r lua
        # Copy nvim/after only if it exists
        if [ -d "after" ]; then
            cp -r after $out/after
            rm -r after
        fi
        # Copy rest of nvim/ subdirectories only if they exist
        if [ ! -z "$(ls -A)" ]; then
            cp -r -- * $out/nvim
        fi
      '';
    };

    # The final init.lua content that we pass to the Neovim wrapper.
    # It wraps the user init.lua, prepends the lua lib directory to the RTP
    # and prepends the nvim and after directory to the RTP
    # It also adds logic for bootstrapping dev plugins (for plugin developers)
    initLua =
      ''
        vim.loader.enable()
        -- prepend lua directory
        vim.opt.rtp:prepend('${nvimRtp}/lua')
      ''
      # Wrap init.lua
      + (builtins.readFile ../nvim/init.lua)
      # Bootstrap/load dev plugins
      + optionalString (devPlugins != []) (
        ''
          local dev_pack_path = vim.fn.stdpath('data') .. '/site/pack/dev'
          local dev_plugins_dir = dev_pack_path .. '/opt'
          local dev_plugin_path
        ''
        + strings.concatMapStringsSep
        "\n"
        (plugin: ''
          dev_plugin_path = dev_plugins_dir .. '/${plugin.name}'
          if vim.fn.empty(vim.fn.glob(dev_plugin_path)) > 0 then
            vim.notify('Bootstrapping dev plugin ${plugin.name} ...', vim.log.levels.INFO)
            vim.cmd('!${pkgs.git}/bin/git clone ${plugin.url} ' .. dev_plugin_path)
          end
          vim.cmd('packadd! ${plugin.name}')
        '')
        devPlugins
      )
      # Prepend nvim and after directories to the runtimepath
      # NOTE: This is done after init.lua,
      # because of a bug in Neovim that can cause filetype plugins
      # to be sourced prematurely, see https://github.com/neovim/neovim/issues/19008
      # We prepend to ensure that user ftplugins are sourced before builtin ftplugins.
      + ''
        vim.opt.rtp:prepend('${nvimRtp}/nvim')
        vim.opt.rtp:prepend('${nvimRtp}/after')
      '';

    # Add arguments to the Neovim wrapper script
    extraMakeWrapperArgs = builtins.concatStringsSep " " (
      # Set the NVIM_APPNAME environment variable
      (optional (appName != "nvim" && appName != null && appName != "")
        ''--set NVIM_APPNAME "${appName}"'')
      # Add external packages to the PATH
      ++ (optional (externalPackages != [])
        ''--prefix PATH : "${makeBinPath externalPackages}"'')
      # Set the LIBSQLITE_CLIB_PATH if sqlite is enabled
      ++ (optional withSqlite
        ''--set LIBSQLITE_CLIB_PATH "${pkgs.sqlite.out}/lib/libsqlite3.so"'')
      # Set the LIBSQLITE environment variable if sqlite is enabled
      ++ (optional withSqlite
        ''--set LIBSQLITE "${pkgs.sqlite.out}/lib/libsqlite3.so"'')
    );

    luaPackages = neovim-unwrapped.lua.pkgs;
    resolvedExtraLuaPackages = extraLuaPackages luaPackages;

    # Native Lua libraries
    extraMakeWrapperLuaCArgs =
      optionalString (resolvedExtraLuaPackages != [])
      ''--suffix LUA_CPATH ";" "${concatMapStringsSep ";" luaPackages.getLuaCPath resolvedExtraLuaPackages}"'';

    # Lua libraries
    extraMakeWrapperLuaArgs =
      optionalString (resolvedExtraLuaPackages != [])
      ''--suffix LUA_PATH ";" "${concatMapStringsSep ";" luaPackages.getLuaPath resolvedExtraLuaPackages}"'';

    # wrapNeovimUnstable is the nixpkgs utility function for building a Neovim derivation.
    neovim-wrapped = pkgs-wrapNeovim.wrapNeovimUnstable neovim-unwrapped (neovimConfig
      // {
        luaRcContent = initLua;
        wrapperArgs =
          escapeShellArgs neovimConfig.wrapperArgs
          + " "
          + extraMakeWrapperArgs
          + " "
          + extraMakeWrapperLuaCArgs
          + " "
          + extraMakeWrapperLuaArgs;
        wrapRc = true;
      });

    isCustomAppName = appName != null && appName != "nvim";
  in
    neovim-wrapped.overrideAttrs (oa: {
      buildPhase =
        oa.buildPhase
        # If a custom NVIM_APPNAME has been set, rename the `nvim` binary
        + lib.optionalString isCustomAppName ''
          mv $out/bin/nvim $out/bin/${lib.escapeShellArg appName}
        '';
      meta.mainProgram =
        if isCustomAppName
        then appName
        else oa.meta.mainProgram;
    })