import { isDashscopeCompatibleModeUrl } from "@oh-my-pi/pi-catalog/hosts";
import { isQwenModelId } from "@oh-my-pi/pi-catalog/identity";

import type { 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");
}

/**
 * Detect known text-only Qwen models served via Alibaba DashScope's consumer
 * `compatible-mode` endpoint that the upstream chat-completions API rejects
 * multimodal content arrays for. The compatible-mode endpoint also serves
 * multimodal Qwen SKUs without `vl` in the id (e.g. `qwen3.7-plus`), so this
 * guard only covers families verified to be text-only for issue #1859:
 * `qwen*-coder*` and `qwen*-max` up to and including `qwen3.7-max`.
 *
 * Qwen-Max became multimodal at `qwen3.8-max` (image input, issue #8019), so
 * `-max` SKUs at version 3.8 or newer are excluded — otherwise the override
 * would strip images from a genuinely vision-capable flagship (issue #8305).
 *
 * Used as a defensive override in `convertMessages` so a misconfigured custom
 * provider (issue #1859) can't drive the request into an unrecoverable 400.
 */
export function isDashscopeCompatibleModeTextOnlyQwen(model: Model<"openai-completions">): boolean {
	if (!isDashscopeCompatibleModeUrl(model.baseUrl)) {
		return false;
	}
	if (!isQwenModelId(model.id)) return false;
	const id = model.id.toLowerCase();
	if (/\bqwen(?:[\d.]+)?-coder\b/.test(id)) return true;
	const maxMatch = id.match(/\bqwen(?:(\d+)(?:\.(\d+))?)?-max\b/);
	if (!maxMatch) return false;
	// Bare `qwen-max` (no version) is the text-only 2.5-era flagship. Compare
	// major/minor component-wise, not as a decimal float, so `qwen3.10-max`
	// sorts after `qwen3.8-max`: text-only through 3.7, multimodal from 3.8 on.
	const major = maxMatch[1] ? Number.parseInt(maxMatch[1], 10) : 0;
	const minor = maxMatch[2] ? Number.parseInt(maxMatch[2], 10) : 0;
	return major < 3 || (major === 3 && minor < 8);
}