{
  config,
  lib,
  pkgs,
  ...
}:
with lib; let
  cfg = config.coding.agents.opencode;
in {
  options.coding.agents.opencode = {
    enable = mkEnableOption "OpenCode agent management via canonical agent.toml definitions";

    agentsInput = mkOption {
      type = types.nullOr types.anything;
      default = null;
      description = ''
        The `agents` flake input (your personal AGENTS repo).
        When set, agents are rendered from canonical agent.toml files
        and symlinked to ~/.config/opencode/agents/.
      '';
    };

    modelOverrides = mkOption {
      type = types.attrsOf types.str;
      default = {};
      description = ''
        Per-agent model overrides. Maps agent slug to model string.
        Example: { chiron = "anthropic/claude-sonnet-4"; }
      '';
      example = literalExpression ''
        {
          chiron = "anthropic/claude-sonnet-4";
          "chiron-forge" = "anthropic/claude-sonnet-4";
        }
      '';
    };

    externalSkills = mkOption {
      type = types.listOf (types.submodule {
        options = {
          src = mkOption {
            type = types.anything;
            description = "Flake input pointing to a skills repository root.";
          };
          skillsDir = mkOption {
            type = types.str;
            default = "skills";
            description = ''
              Subdirectory inside src that contains skill folders.
            '';
          };
          selectSkills = mkOption {
            type = types.nullOr (types.listOf types.str);
            default = null;
            description = ''
              List of skill names to cherry-pick from this source.
              null means include every skill found in skillsDir.
            '';
          };
        };
      });
      default = [];
      description = ''
        External skill sources passed to mkOpencodeSkills.
        Each entry maps directly to an element of the externalSkills
        list accepted by the AGENTS flake's lib.mkOpencodeSkills.
      '';
      example = literalExpression ''
        [
          { src = inputs.skills-anthropic; selectSkills = [ "claude-api" ]; }
          { src = inputs.skills-vercel; }
        ]
      '';
    };
  };

  config = mkIf cfg.enable {
    # Rendered agent files symlinked to ~/.config/opencode/agents/
    xdg.configFile."opencode/agents" = mkIf (cfg.agentsInput != null) {
      source = (import ../../../../lib {inherit lib;}).agents.renderForOpencode {
        inherit pkgs;
        canonical = cfg.agentsInput.lib.loadAgents;
        modelOverrides = cfg.modelOverrides;
      };
    };

    # Skills (merged from personal AGENTS repo + optional external skills)
    xdg.configFile."opencode/skills" = mkIf (cfg.agentsInput != null) {
      source = cfg.agentsInput.lib.mkOpencodeSkills {
        inherit pkgs;
        customSkills = "${cfg.agentsInput}/skills";
        externalSkills =
          map (
            entry:
              {inherit (entry) src skillsDir;}
              // optionalAttrs (entry.selectSkills != null) {inherit (entry) selectSkills;}
          )
          cfg.externalSkills;
      };
    };

    # Static config dirs from AGENTS repo
    xdg.configFile."opencode/context" = mkIf (cfg.agentsInput != null) {
      source = "${cfg.agentsInput}/context";
    };
    xdg.configFile."opencode/commands" = mkIf (cfg.agentsInput != null) {
      source = "${cfg.agentsInput}/commands";
    };
    xdg.configFile."opencode/prompts" = mkIf (cfg.agentsInput != null) {
      source = "${cfg.agentsInput}/prompts";
    };
  };
}