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

with lib;

let
  cfg = config.programs.zsh.syntax-highlighting;
in
  {
    options = {
      programs.zsh.syntax-highlighting = {
        enable = mkOption {
          default = false;
          type = types.bool;
          description = ''
            Enable zsh-syntax-highlighting.
          '';
        };

        highlighters = mkOption {
          default = [ "main" ];

          # https://github.com/zsh-users/zsh-syntax-highlighting/blob/master/docs/highlighters.md
          type = types.listOf(types.enum([
            "main"
            "brackets"
            "pattern"
            "cursor"
            "root"
            "line"
          ]));

          description = ''
            Specifies the highlighters to be used by zsh-syntax-highlighting.

            The following defined options can be found here:
            https://github.com/zsh-users/zsh-syntax-highlighting/blob/master/docs/highlighters.md
          '';
        };

        patterns = mkOption {
          default = [];
          type = types.listOf(types.listOf(types.string));

          example = literalExample ''
            [
              ["rm -rf *" "fg=white,bold,bg=red"]
            ]
          '';

          description = ''
            Specifies custom patterns to be highlighted by zsh-syntax-highlighting.

            Please refer to the docs for more information about the usage:
            https://github.com/zsh-users/zsh-syntax-highlighting/blob/master/docs/highlighters/pattern.md
          '';
        };
      };
    };

    config = mkIf cfg.enable {
      environment.systemPackages = with pkgs; [ zsh-syntax-highlighting ];

      programs.zsh.interactiveShellInit = with pkgs; with builtins; ''
        source ${zsh-syntax-highlighting}/share/zsh-syntax-highlighting/zsh-syntax-highlighting.zsh

        ${optionalString (length(cfg.highlighters) > 0)
          "ZSH_HIGHLIGHT_HIGHLIGHTERS=(${concatStringsSep " " cfg.highlighters})"
        }

        ${optionalString (length(cfg.patterns) > 0)
          (assert(elem "pattern" cfg.highlighters); (foldl (
            a: b:
              assert(length(b) == 2); ''
                ${a}
                ZSH_HIGHLIGHT_PATTERNS+=('${elemAt b 0}' '${elemAt b 1}')
              ''
          ) "") cfg.patterns)
        }
      '';
    };
  }