{ pkgs, lib, ... }:

{
  programs.nixvim = {
    enable = true;
    defaultEditor = true;

    # scowl provides English word lists for completion on NixOS
    extraPackages = [ pkgs.scowl ];

    # Global settings
    globals.mapleader = " ";

    # Vim options
    opts = {
      number = true;
      relativenumber = false;
      expandtab = true;
      shiftwidth = 2;
      tabstop = 2;
      smartindent = true;
      wrap = false;
      linebreak = true;      # Don't break words when wrapping
      breakindent = true;    # Preserve indentation when wrapping
      termguicolors = true;
      autoread = true;       # Automatically reload files when changed externally
      clipboard = "unnamedplus";  # Use system clipboard by default
    };

    # Enable filetype detection
    viAlias = true;
    vimAlias = true;

    # Gruvbox colorscheme with hard contrast
    colorschemes.gruvbox = {
      enable = true;
      settings = {
        contrast = "hard";  # Makes background much darker (#1d2021 instead of #282828)
        background = "dark";
      };
    };

    # Plugins
    plugins = {

      bufferline = {
        enable = true;
        settings = {
          options = {
            separator_style = [ "" "" ];  # Remove gaps between tabs
            offsets = [
              {
                filetype = "NvimTree";
                text = "File Explorer";
                text_align = "left";
                separator = true;  # Remove separator line
              }
            ];
          };
        };
      };
      gitsigns.enable = true;
      indent-blankline = {
        enable = true;
        settings = {
          indent = {
            char = "▏";  # Thinner vertical line
          };
          scope = {
            enabled = false;  # Disable scope highlighting
          };
        };
      };

      # File explorer
      nvim-tree = {
        enable = true;
        # NixVim nvim-tree uses extraConfig for detailed settings
      };

      # Syntax highlighting
      treesitter = {
        enable = true;
        settings = {
          highlight = {
            enable = true;
            additional_vim_regex_highlighting = true;
          };
          indent = {
            enable = true;
          };
          ensure_installed = [];  # Managed by Nix
          auto_install = false;
        };
        grammarPackages = with pkgs.vimPlugins.nvim-treesitter.builtGrammars; [
          bash c cpp css dockerfile go html javascript json lua markdown nix python rust typescript yaml
        ];
      };

      # Status line with gruvbox theme and relative paths
      lualine = {
        enable = true;
        settings = {
          options = {
            theme = "gruvbox_dark";
            component_separators = { left = "|"; right = "|"; };
            section_separators = { left = " "; right = " "; };
          };
          sections = {
            lualine_c = [{ __unkeyed-1 = "filename"; path = 1; }];
          };
        };
      };

      # Web dev icons
      web-devicons = {
        enable = true;
      };

      # Basic auto-completion
      cmp = {
        enable = true;
        autoEnableSources = true;
        
        settings = {
          sources = [
            { name = "buffer"; }     # Words from open buffers
            { name = "path"; }       # File system paths
            { name = "dictionary"; keyword_length = 2; } # English dictionary words
          ];
          
          mapping = {
            "<C-Space>" = "cmp.mapping.complete()";          # Trigger completion manually
            "<C-e>" = "cmp.mapping.close()";                 # Close completion menu
            "<CR>" = "cmp.mapping.confirm({ select = true })"; # Accept selected completion
            "<Tab>" = "cmp.mapping.select_next_item()";      # Navigate down in menu
            "<S-Tab>" = "cmp.mapping.select_prev_item()";    # Navigate up in menu
          };
        };
      };

      # Telescope - Fuzzy finder
      telescope = {
        enable = true;
        keymaps = {
          # Find files using Telescope command-line sugar
          "<leader>t" = "find_files";
          "<leader>g" = "live_grep";
        };
        settings = {
          defaults = {
            vimgrep_arguments = [
              "rg"
              "--color=never"
              "--no-heading"
              "--with-filename"
              "--line-number"
              "--column"
              "--smart-case"
              "--hidden"
              "--no-ignore"
            ];
            file_ignore_patterns = [
              "^.git/"
              "^node_modules/"
              ".DS_Store"
            ];
            layout_config = {
              prompt_position = "bottom";
              horizontal = {
                preview_width = 0.55;
              };
            };
          };
          pickers = {
            find_files = {
              hidden = true;
              no_ignore = true;
            };
          };
        };
      };

      auto-session.enable = true;
    };

    # Extra plugins that don't have dedicated modules
    extraPlugins = with pkgs.vimPlugins; [
      vim-fugitive
      cmp-dictionary
      plenary-nvim
    ];

    # Keymaps
    keymaps = [
      # File explorer
      {
        mode = "n";
        key = "<leader>e";
        action = ":NvimTreeToggle<CR>";
        options = { desc = "Toggle file explorer"; };
      }

      # Basic keymaps
      {
        mode = "n";
        key = "<leader>w";
        action = ":w<CR>";
        options = { desc = "Save file"; };
      }
      {
        mode = "n";
        key = "<leader>q";
        action = ":q<CR>";
        options = { desc = "Quit"; };
      }
      {
        mode = "n";
        key = "<leader>r";
        action = ":e<CR>";
        options = { desc = "Refresh"; };
      }

      # Buffer/Tab navigation
      {
        mode = "n";
        key = "<S-h>";
        action = ":BufferLineCyclePrev<CR>";
        options = { desc = "Previous buffer"; };
      }
      {
        mode = "n";
        key = "<S-l>";
        action = ":BufferLineCycleNext<CR>";
        options = { desc = "Next buffer"; };
      }
      {
        mode = "n";
        key = "<leader>x";
        action = ":bp|bd #<CR>";
        options = { desc = "Close current buffer"; };
      }
      {
        mode = "n";
        key = "<leader>X";
        action = ":lua close_other_buffers()<CR>";
        options = { desc = "Close all buffers except current"; };
      }

      # System integration
      {
        mode = "n";
        key = "<leader>o";
        action = ":lua open_file_with_system_app()<CR>";
        options = { desc = "Open file with system default app"; };
      }
    ] ++ (if pkgs.stdenv.isDarwin then [
      {
        mode = "n";
        key = "<leader>f";
        action = ":lua show_file_in_file_manager()<CR>";
        options = { desc = "Show current file in Finder"; };
      }
    ] else [
      {
        mode = "n";
        key = "<leader>f";
        action = ":!thunar %:h &<CR><CR>";
        options = { desc = "Open current file directory in file manager"; };
      }
    ]);

    # Additional Lua configuration for plugins that need custom setup
    extraConfigLua = ''
      -- Nvim-tree setup with filters and auto-sync
      require("nvim-tree").setup({
        sync_root_with_cwd = true,
        respect_buf_cwd = true,
        update_focused_file = {
          enable = true,
          update_root = true,
          ignore_list = {},
        },
        filters = {
          dotfiles = true,      -- Hide dotfiles by default (H to toggle)
          git_ignored = true,  -- Show gitignored files by default (I to toggle)
          custom = {            -- Hide macOS system files
            ".DS_Store",
          },
        },
        view = {
          width = 30,
          side = "left",
        },
        renderer = {
          highlight_opened_files = "all",
          highlight_modified = "all",
        },
      })

      -- Dictionary completion setup
      ${lib.optionalString pkgs.stdenv.isDarwin ''
        require("cmp_dictionary").setup({
          paths = { "/usr/share/dict/words" },  -- Standard dictionary path on macOS
          exact_length = 2,                     -- Minimum length before completion
          first_case_insensitive = true,        -- Case insensitive matching
        })
      ''}
      ${lib.optionalString (!pkgs.stdenv.isDarwin) ''
        require("cmp_dictionary").setup({
          paths = { "${pkgs.scowl}/share/dict/wamerican.txt" },  -- Nix-provided dictionary on NixOS
          exact_length = 2,                                       -- Minimum length before completion
          first_case_insensitive = true,                          -- Case insensitive matching
        })
      ''}

      -- Telescope setup for better file finding
      local telescope = require('telescope')
      local actions = require('telescope.actions')

      telescope.setup{
        defaults = {
          mappings = {
            i = {
              ["<C-j>"] = actions.move_selection_next,
              ["<C-k>"] = actions.move_selection_previous,
              ["<C-q>"] = actions.send_selected_to_qflist + actions.open_qflist,
            }
          }
        }
      }

      -- OSC-52 clipboard integration (matches tmux setup, works with Ghostty)
      -- This enables clipboard functionality across SSH, tmux, and multi-platform
      -- Only enabled on Linux; macOS uses native clipboard with "unnamedplus"
      ${lib.optionalString (!pkgs.stdenv.isDarwin) ''
        vim.g.clipboard = {
          name = 'OSC 52',
          copy = {
            ['+'] = require('vim.ui.clipboard.osc52').copy('+'),
            ['*'] = require('vim.ui.clipboard.osc52').copy('*'),
          },
          paste = {
            ['+'] = require('vim.ui.clipboard.osc52').paste('+'),
            ['*'] = require('vim.ui.clipboard.osc52').paste('*'),
          },
        }
      ''}

      -- Close all buffers except current (preserving NvimTree and other special buffers)
      function close_other_buffers()
        local current_buf = vim.api.nvim_get_current_buf()
        local buffers = vim.api.nvim_list_bufs()

        for _, buf in ipairs(buffers) do
          if buf ~= current_buf and vim.api.nvim_buf_is_valid(buf) then
            local buftype = vim.api.nvim_buf_get_option(buf, 'buftype')
            local filetype = vim.api.nvim_buf_get_option(buf, 'filetype')

            -- Skip special buffers (NvimTree, terminals, quickfix, etc.)
            if buftype == "" and filetype ~= "NvimTree" then
              -- Only delete if it's a normal file buffer
              vim.api.nvim_buf_delete(buf, { force = false })
            end
          end
        end
      end

      -- Unicode-safe file operations (async to prevent blocking)
      function open_file_with_system_app()
        local filepath = vim.fn.expand('%:p')
        if filepath ~= "" then
          local escaped_path = vim.fn.shellescape(filepath)
          ${if pkgs.stdenv.isDarwin then
            "vim.fn.system('open ' .. escaped_path)"
          else
            "vim.fn.system('xdg-open ' .. escaped_path)"}
        else
          print("No file to open")
        end
      end

      -- Disable italic for code blocks and strings
      vim.api.nvim_set_hl(0, "@markup.raw", { italic = false })
      vim.api.nvim_set_hl(0, "@markup.raw.block", { italic = false })
      vim.api.nvim_set_hl(0, "@markup.raw.markdown_inline", { italic = false })
      vim.api.nvim_set_hl(0, "String", { fg = "#b8bb26", italic = false })

      ${lib.optionalString pkgs.stdenv.isDarwin ''
        function show_file_in_file_manager()
          local filepath = vim.fn.expand('%:p')
          if filepath ~= "" then
            local escaped_path = vim.fn.shellescape(filepath)
            vim.fn.system('open -R ' .. escaped_path)
          else
            print("No file to show")
          end
        end
      ''}
    '';
  };
}