// Bounded labels only: request fields and item types can otherwise contain private data.
export const WEBSOCKET_REQUEST_CHANGE_REASONS = {
	model: "model_changed",
	instructions: "instructions_changed",
	tools: "tools_changed",
	tool_choice: "tool_choice_changed",
	parallel_tool_calls: "parallel_tool_calls_changed",
	reasoning: "reasoning_changed",
	store: "store_changed",
	stream: "stream_changed",
	include: "include_changed",
	service_tier: "service_tier_changed",
	prompt_cache_key: "prompt_cache_key_changed",
	text: "text_changed",
	temperature: "temperature_changed",
	access_programs: "access_programs_changed",
} as const;

export const WEBSOCKET_CONTINUATION_DECISIONS = [
	"disabled", "no_session_cache_entry", "no_continuation", "body_mismatch",
	"input_shorter_than_baseline", "input_prefix_mismatch", "missing_previous_response_id", "delta",
	...Object.values(WEBSOCKET_REQUEST_CHANGE_REASONS),
] as const;

export type WebSocketContinuationDecision = typeof WEBSOCKET_CONTINUATION_DECISIONS[number];

const RESPONSE_ITEM_TYPES = [
	"additional_tools", "message", "agent_message", "reasoning", "local_shell_call",
	"function_call", "function_call_output", "custom_tool_call", "custom_tool_call_output",
	"tool_search_call", "tool_search_output", "web_search_call", "image_generation_call",
	"compaction", "context_compaction", "configuration_update", "compaction_trigger",
	"other", "none",
] as const;

type ResponseItemType = typeof RESPONSE_ITEM_TYPES[number];

export interface WebSocketContinuationMismatch {
	previousItemType: ResponseItemType;
	currentItemType: ResponseItemType;
}

export function continuationItemType(item: unknown): ResponseItemType {
	if (!item || typeof item !== "object") return "other";
	const value = item as Record<string, unknown>;
	// Responses also accepts message items with an omitted type.
	if (value["type"] === undefined && typeof value["role"] === "string"
		&& ["user", "assistant", "system", "developer"].includes(value["role"])) return "message";
	return RESPONSE_ITEM_TYPES.find(type => type !== "none" && type === value["type"]) ?? "other";
}

export function isWebSocketContinuationMismatch(value: unknown): value is WebSocketContinuationMismatch {
	if (!value || typeof value !== "object") return false;
	const mismatch = value as Record<string, unknown>;
	return RESPONSE_ITEM_TYPES.some(type => type === mismatch["previousItemType"])
		&& RESPONSE_ITEM_TYPES.some(type => type === mismatch["currentItemType"]);
}