feat: replay pi transcript as CLI input

src/agent/claude-code/transcript.ts

@@ -0,0 +1,75 @@
+import type { ImageContent, Message, TextContent, Tool } from "@earendil-works/pi-ai";
+import { getCurrentSystemPrompt, getCurrentTools } from "@earendil-works/pi-ai/utils/transcript";
+
+export type ClaudeContentBlock = { type: "text"; text: string } | { type: "image"; source: { type: "base64"; media_type: string; data: string } };
+
+export type ClaudeInput = {
+	systemPrompt: string;
+	tools: Tool[];
+	userContent: ClaudeContentBlock[];
+};
+
+type ReplayPart = string | ImageContent;
+
+function toImageBlock(image: ImageContent): ClaudeContentBlock {
+	return { type: "image", source: { type: "base64", media_type: image.mimeType, data: image.data } };
+}
+
+function getLabelledParts(label: string, content: string | (TextContent | ImageContent)[]): ReplayPart[] {
+	if (typeof content === "string") return [`${label}\n${content}`];
+	const text = content.flatMap((block) => (block.type === "text" ? [block.text] : [])).join("\n");
+	const images = content.filter((block) => block.type === "image");
+	return [text ? `${label}\n${text}` : label, ...images];
+}
+
+function getReplayParts(message: Message): ReplayPart[] {
+	switch (message.role) {
+		case "system":
+			return [];
+		case "user":
+			return getLabelledParts("[user]", message.content);
+		case "assistant":
+			return message.content.flatMap((block) => {
+				if (block.type === "text") return [`[assistant]\n${block.text}`];
+				if (block.type === "toolCall") return [`[tool call ${block.name}] ${JSON.stringify(block.arguments)}`];
+				return [];
+			});
+		case "toolResult":
+			return getLabelledParts(message.isError ? `[tool result ${message.toolName} error]` : `[tool result ${message.toolName}]`, message.content);
+	}
+}
+
+function toContentBlocks(parts: ReplayPart[]): ClaudeContentBlock[] {
+	const blocks: ClaudeContentBlock[] = [];
+	let pendingText: string[] = [];
+	const flushText = () => {
+		if (pendingText.length > 0) blocks.push({ type: "text", text: pendingText.join("\n\n") });
+		pendingText = [];
+	};
+	for (const part of parts) {
+		if (typeof part === "string") {
+			pendingText.push(part);
+		} else {
+			flushText();
+			blocks.push(toImageBlock(part));
+		}
+	}
+	flushText();
+	return blocks;
+}
+
+function toUnlabelledBlocks(content: string | (TextContent | ImageContent)[]): ClaudeContentBlock[] {
+	if (typeof content === "string") return [{ type: "text", text: content }];
+	return content.map((block) => (block.type === "text" ? { type: "text", text: block.text } : toImageBlock(block)));
+}
+
+export function toClaudeInput(messages: Message[]): ClaudeInput {
+	const conversation = messages.filter((message) => message.role !== "system");
+	const onlyMessage = conversation.length === 1 ? conversation[0] : null;
+	const userContent = onlyMessage?.role === "user" ? toUnlabelledBlocks(onlyMessage.content) : toContentBlocks(conversation.flatMap(getReplayParts));
+	return { systemPrompt: getCurrentSystemPrompt(messages), tools: getCurrentTools(messages), userContent };
+}
+
+export function toStreamJsonLine(content: ClaudeContentBlock[]): string {
+	return JSON.stringify({ type: "user", message: { role: "user", content } });
+}