import type { Plugin } from "@opencode-ai/plugin";

/** All OpenCode hook event names — single source of truth. */
export const HOOK_EVENT_NAMES = [
  "tool",
  "config",
  "chat.message",
  "chat.params",
  "chat.headers",
  "event",
  "tool.execute.before",
  "tool.execute.after",
  "experimental.chat.messages.transform",
  "experimental.chat.system.transform",
  "tool.definition",
  "permission.ask",
  "command.execute.before",
  "shell.env",
  "experimental.session.compacting",
  "experimental.text.complete",
] as const;

/** All OpenCode hook event names. */
export type HookEventName = (typeof HOOK_EVENT_NAMES)[number];

/** Generic hook handler signature fallback. */
export type HookHandler = (input: unknown, output: unknown) => Promise<void> | void;

/** Raw plugin instance shape returned to OpenCode. */
type OpenCodePluginInstance = Awaited<ReturnType<Plugin>>;

/** Resolves the concrete OpenCode hook handler type for a hook name. */
type HookHandlerFor<Name extends HookEventName> =
  NonNullable<OpenCodePluginInstance[Name]> extends (...args: infer Args) => infer Return
    ? (...args: Args) => Return
    : HookHandler;

/** Hook contributions mapped by event name. */
export type PluginHookContributions = {
  [Name in HookEventName]: HookHandlerFor<Name>;
};

/** Priority for hook execution ordering (lower values run first). */
export type HookPriority = number;