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

{
  options.neovim = {
    enable = lib.mkEnableOption "Enables neovim";
    languages = {
      c.enable = lib.mkEnableOption "Enables c support";
      go.enable = lib.mkEnableOption "Enables go support";
      nix.enable = lib.mkEnableOption "Enables nix support";
      rust.enable = lib.mkEnableOption "Enables rust support";
      typescript.enable = lib.mkEnableOption "Enables typescript support";
    };
    themes = {
      catppuccin.enable = lib.mkEnableOption "Enables catppuccin theme";
    };
    plugins = {
      comments.enable = lib.mkOption { default = true; };
      fugitive.enable = lib.mkOption { default = true; };
      lualine.enable = lib.mkOption { default = true; };
      luasnip.enable = lib.mkOption { default = false; };
      nvimcmp.enable = lib.mkOption { default = true; };
      telescope = {
        enable = lib.mkOption { default = true; };
        fzf.enable = lib.mkOption { default = true; };
      };
      treesitter.enable = lib.mkOption { default = true; };
      wiki.enable = lib.mkOption { default = false; };
    };
  };

  config = lib.mkIf config.neovim.enable {
    home.sessionVariables = {
      EDITOR = "nvim";
      VISUAL = "nvim";
    };

    programs.nixvim = {
      enable = true;
      viAlias = true;
      vimAlias = true;
      vimdiffAlias = true;

      globals = {
        mapleader = " ";
        maplocalleader = " ";
        rust_recommended_style = 0;
      };

      options = {
        list = true;
        updatetime = 750;

        tabstop = 2;
        softtabstop = 0;
        shiftwidth = 2;
        smarttab = true;
        expandtab = true;

        colorcolumn = "81";
        showmatch = true;
        number = true;
        relativenumber = true;

        swapfile = false;
        backup = false;
        undofile = true;
        undodir = "${config.xdg.configHome}/nvim/undodir";

        smartcase = true;
      };

      keymaps = [
        {
          key = "<leader>d";
          mode = "n";
          action = "vim.diagnostic.open_float()";
        }
        # -- Easy Split Navigation
        # -- nnoremap <C-J> <C-W><C-J>
        # -- nnoremap <C-K> <C-W><C-K>
        # -- nnoremap <C-L> <C-W><C-L>
        # -- nnoremap <C-H> <C-W><C-H>
        #
        # -- Easy copy and pasting to external programs
        # -- map <C-y> "+yy
        # -- map <C-p> "+P
      ];
    };

    programs.nixvim.colorschemes = with config.neovim.themes; {
      catppuccin = lib.mkIf catppuccin.enable {
        enable = true;
        flavour = "mocha";
        integrations.vimwiki = lib.mkIf wiki.enable true;
      }
    };

    programs.nixvim.plugins = with config.neovim.plugins; {
      comment.enable = comments.enable;

      fugitive.enable = fugitive.enable;

      lualine = lib.mkIf lualine.enable {
        enable = true;
        icons_enabled = true;
      };
      web-devicons.enable = lualine.enable;

      luasnip.enable = luasnip.enable;
      friendly-snippets.enable = luasnip.enable;

      cmp = {
        enable = nvimcmp.enable;
        autoEnableSources = true;
        settings.sources = [
          { name = "nvim_lsp"; }
          { name = "path"; }
          { name = "buffer"; }
        ] + lib.options luasnip.enable { name = "cmp-luasnip" };

        mapping = {
          "<C-Space>" = "cmp.mapping.complete {}";
          "<CR>" = "cmp.mapping.confirm {
            behavior = cmp.ConfirmBehavior.Replace,
            select = true,
          }";
          "<Tab>" = {
            actions = ''
              function(fallback)
                if cmp.visible() then
                  cmp.select_next_item()
            '' + lib.optionalString luasnip.enable ''
                elseif luasnip.expand_or_locally_jumpable() then
                  luasnip.expand_or_jump()
            '' + ''
                else
                  fallback()
                end
              end
            '';
            modes = [ "i" "s" ];
          };
          "<S-Tab>" = {
            actions = ''
              function(fallback)
                if cmp.visible() then
                  cmp.select_prev_item()
            '' + lib.optionalString luasnip.enable ''
                elseif luasnip.locally_jumpable(-1) then
                  luasnip.jump(-1)
            '' + ''
                else
                  fallback()
                end
              end
            '';
            modes = [ "i" "s" ];
          };
        };
      };

      telescope = {
        enable = telescope.enable;
        keymaps = [
          { key = "<leader>ff"; action = "find_files"; }
          { key = "<leader>fg"; action = "git_files"; }
        ];
        extensions = {
          fzf = lib.mkIf telescope.fzf.enable {
            enable = true;
            fuzzy = true;
            override_generic_sorter = true;
            override_file_sorter = true;
            case_mode = "smart_case";
          };
        };
      };

      treesitter = {
        enable = treesiter.enable;
        highlight.enable = true;
        indent.enable = true;
        folding.enable = true;
      };

      vimwiki = {
        enable = wiki.enable;
        list = [
          {
            path = "${config.xdg.userDirs.documents}/wiki";
            links_space_char = "_";
            ext = ".md";
            syntax = "markdown";
          }
        ];
      };
    };

    programs.nixvim.plugins.nvim-lspconfig.enable = true;
    programs.nixvim.plugins = with config.neovim.languages; {
      nix.enable = nix.enable;
      rustaceanvim.enable = rust.enable;
      typsecript-tools.enable = typescript.enable;
    };
    programs.nixvim.lsp = {
      enable = true;
      servers = with config.neovim.languages; {
        clangd.enable = c.enable;
        gopls.enable = go.enable;
        nil_ls.enable = nix.enable;
        rust_analyzer.enable = rust.enable;
        tsserver.enable = typescript.enable;
      };
      keymaps = [
        { key = "gd"; lspBufAction = "definition"; }
        { key = "gD"; lspBufAction = "declaration"; }
        { key = "gi"; lspBufAction = "implementation"; }
        { key = "gt"; lspBufAction = "type_definition"; }
        { key = "K"; lspBufAction = "hover"; }
      ] + lib.options config.neovim.plugins.telescope.enable {
          key = "gr";
          action = lib.nixvim.mkRaw
            "require('telescope.builtin').lsp_references";
      };
    };
  };
}