{ config, lib, pkgs, ... }:

with lib;
with import ./lib.nix { inherit lib; };
let
  cfg = config.programs.neovim.lazy;

  luaList = values: "{" + (concatStringsSep ", " values) + "}";

  keybinding = { key, cmd, func, mode, desc }:
    let
      cmdString =
        if cmd != null then toLua cmd else
        if func != null then func else
        abort "Either cmd or function must be set";
      descString = optionalString (desc != null) "desc = ${toLua desc},";
    in
    ''{ ${toLua key}, ${cmdString}, mode = ${toLua mode}, ${descString} }'';

  lazySpecFromPlugin =
    { cmd
    , conf
    , dependencies
    , enabled
    , event
    , ft
    , init
    , keys
    , lazy
    , opts
    , plugin
    , priority
    }:

    luaList
      ([
        "dir = ${string plugin}"
        "name = ${toLua (getName plugin)}"
      ]
      ++ (optional (opts != null) "opts = ${toLua opts}")
      ++ (optional (lazy != null) "lazy = ${toLua lazy}")
      ++ (optional (!enabled) "enabled = ${toLua enabled}")
      ++ (optional (dependencies != [ ]) "dependencies = ${luaList (map lazySpecFromPlugin dependencies)}")
      ++ (optional (init != null) "init = function(spec)\n${init}\nend")
      ++ (optional (conf != null) "config = function(spec, opts)\n${conf}\nend")
      ++ (optional (keys != [ ]) "keys = ${luaList (map keybinding keys)}")
      ++ (optional (event != [ ]) "event = ${toLua event}")
      ++ (optional (cmd != [ ]) "cmd = ${toLua cmd}")
      ++ (optional (ft != [ ]) "ft = ${toLua ft}")
      ++ (optional (priority != null) "priority = ${toLua priority}")
      );
  lazySpecs = luaList (map lazySpecFromPlugin cfg.plugins);
  text = /* lua */ ''
    require("lazy").setup(${lazySpecs})
  '';

  formatted =
    pkgs.runCommand "lazy.lua" { inherit text; } ''
      touch $out
      echo -n "$text" > $out
      ${getExe pkgs.stylua} $out
    '';

  lazy = if cfg.format then readFile formatted else text;
in
{
  options.programs.neovim.lazy = {
    enable = mkEnableOption "lazy.nvim";
    format = mkEnableOption "format";
    plugins = mkOption
      {
        default = [ ];
        description = ''
          List of plugins with config.
        '';
        type = with types; listOf (
          let
            sub = submodule {
              options = {
                conf = mkOption {
                  type = nullOr str;
                  default = null;
                  description = ''
                    Lua function to be executed when the plugin is loaded.
                  '';
                };
                opts = mkOption {
                  type =
                    let
                      valueType = nullOr
                        (oneOf [
                          str
                          bool
                          int
                          float
                          (listOf valueType)
                          (attrsOf valueType)
                        ]) // {
                        description = "Lua value";
                      };
                    in
                    nullOr (attrsOf valueType);
                  default = null;
                  description = ''
                    Lua table to be passed to te plugin config function.
                  '';
                };
                dependencies = mkOption {
                  type = listOf sub;
                  default = [ ];
                  description = ''
                    List of plugins this plugin depends on.
                  '';
                };
                init = mkOption {
                  type = nullOr str;
                  default = null;
                  description = ''
                    Lua code to be executed when the plugin is initialized.
                  '';
                };
                event = mkOption {
                  type = listOf str;
                  default = [ ];
                  description = ''
                    Event to load the plugin on.
                  '';
                };
                lazy = mkOption {
                  type = nullOr bool;
                  default = null;
                  description = ''
                    Whether to load the plugin lazily.
                  '';
                };
                plugin = mkOption {
                  type = package;
                  description = ''
                    The plugin package.
                  '';
                };
                enabled = mkOption {
                  type = bool;
                  default = true;
                  description = ''
                    Whether to enable the plugin.
                  '';
                };
                cmd = mkOption {
                  type = listOf str;
                  default = [ ];
                  description = ''
                    Command to load the plugin.
                  '';
                };
                ft = mkOption {
                  type = listOf str;
                  default = [ ];
                  description = ''
                    Filetype to load the plugin on.
                  '';
                };
                priority = mkOption {
                  type = nullOr int;
                  default = null;
                  description = ''
                    Priority to load the plugin.
                  '';
                };
                keys = mkOption {
                  default = [ ];
                  description = ''
                    List of keybindings.
                  '';
                  type = listOf (submodule {
                    options = {
                      key = mkOption {
                        type = str;
                        description = ''
                          Key to bind.
                        '';
                      };
                      cmd = mkOption {
                        type = nullOr str;
                        default = null;
                        description = ''
                          Command to execute.
                        '';
                      };
                      func = mkOption {
                        type = nullOr str;
                        default = null;
                        description = ''
                          Function to execute.
                        '';
                      };
                      mode = mkOption {
                        type = listOf str;
                        default = [ "n" ];
                        description = ''
                          Mode to bind the key in.
                        '';
                      };
                      desc = mkOption {
                        type = nullOr str;
                        default = null;
                        description = ''
                          Description of the keybinding.
                        '';
                      };
                    };
                  });
                };
              };
            };
          in
          sub
        );
      };
  };

  config = mkIf cfg.enable {
    programs.neovim = {
      extraLuaConfig = lazy;
      extraPython3Packages = ps:
        let
          plugins = map (getAttr "plugin") cfg.plugins;
          depAttrName = "python3Dependencies";
          filtered = filter (hasAttr depAttrName) plugins;
          funcs = map (getAttr depAttrName) filtered;
        in
        foldl (list: f: list ++ (f ps)) [ ] funcs;
      plugins = [
        pkgs.vimPlugins.lazy-nvim
      ];
    };
  };
}