import { $env } from "@oh-my-pi/pi-utils";
import type { Api, ImageContent, Model, TextContent } from "../types";

export const NON_VISION_IMAGE_PLACEHOLDER = "[image omitted: model does not support vision]";
export function partitionVisionContent(
	content: ReadonlyArray<TextContent | ImageContent>,
	supportsImages: boolean,
): {
	textBlocks: TextContent[];
	imageBlocks: ImageContent[];
	omittedImages: boolean;
} {
	const textBlocks = content.filter((block): block is TextContent => block.type === "text");
	const imageBlocks = content.filter((block): block is ImageContent => block.type === "image");
	return {
		textBlocks,
		imageBlocks: supportsImages ? imageBlocks : [],
		omittedImages: !supportsImages && imageBlocks.length > 0,
	};
}

export function joinTextWithImagePlaceholder(text: string, omittedImages: boolean): string {
	const parts: string[] = [];
	if (text.length > 0) {
		parts.push(text);
	}
	if (omittedImages) {
		parts.push(NON_VISION_IMAGE_PLACEHOLDER);
	}
	return parts.join("\n");
}

/**
 * Evaluates whether an OpenAI-compatible Chat Completions model genuinely
 * supports multimodal image inputs on the wire. Defensive guards override
 * misconfigured provider descriptors or user model entries (e.g. text-only
 * DashScope Qwen SKUs, DeepSeek models) whose endpoints reject `image_url`.
 */
export function isOpenAICompletionsVisionSupported(model: Model<"openai-completions" | "openrouter">): boolean {
	if (!model.input.includes("image")) return false;
	if (model.compat.stripImageInput) return false;
	return true;
}

/**
 * Whether the transport that will carry `model` sends image content on the wire.
 *
 * The `pi-native` transport forwards the original context (images included) to
 * the gateway, which resolves its own model server-side, so the Chat
 * Completions guard below never runs client-side and the declared input
 * applies. Otherwise the OpenAI Chat Completions path applies the text-only
 * guard, as does the OpenRouter chat fallback (`PI_OPENROUTER_RESPONSES=0`,
 * which dispatches `openrouter` models through `streamOpenAICompletions`);
 * every other API ships the modalities the model declares. Callers that report
 * or gate on the wire (for example the `omp models` table) read this
 * predicate; declared capability reads `model.input`.
 */
export function sendsImageInputOnWire(model: Model<Api>): boolean {
	if (model.transport === "pi-native") return model.input.includes("image");
	if (isGuardedCompletionsTransport(model)) return isOpenAICompletionsVisionSupported(model);
	return model.input.includes("image");
}

/** True for the transports that encode through the Chat Completions guard. */
function isGuardedCompletionsTransport(model: Model<Api>): model is Model<"openai-completions" | "openrouter"> {
	if (model.api === "openai-completions") return true;
	return model.api === "openrouter" && $env.PI_OPENROUTER_RESPONSES === "0";
}