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import type { AiChatMessage } from "@/worker/lib/ai/types";
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export interface RewritePromptInput {
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  action: "proofread" | "formal" | "casual" | "simplify" | "expand";
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  selectedText: string;
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  parentBlock: string;
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  beforeBlock: string;
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  afterBlock: string;
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  pageTitle: string;
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}
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export interface GeneratePromptInput {
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  intent: "continue" | "explain" | "brainstorm";
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  beforeBlock: string;
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  afterBlock: string;
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  pageTitle: string;
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}
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export interface AskHistoryTurn {
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  role: "user" | "assistant";
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  content: string;
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}
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export function buildRewriteMessages(data: RewritePromptInput): AiChatMessage[] {
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  const instructions: Record<RewritePromptInput["action"], string> = {
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    proofread: "Proofread the selection. Fix grammar, spelling, and punctuation. Preserve meaning and voice.",
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    formal: "Rewrite the selection in a more formal, professional tone.",
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    casual: "Rewrite the selection in a more casual, conversational tone.",
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    simplify: "Simplify the selection so it is easier to read without losing information.",
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    expand: "Expand the selection with more detail and supporting sentences while preserving voice.",
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  };
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  const system = [
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    "You are a writing assistant embedded in a document editor.",
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    instructions[data.action],
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    "Return only the rewritten replacement for the selection. Do not include the surrounding paragraphs, labels, quotes, or explanations.",
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  ].join(" ");
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  const parts: string[] = [];
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  if (data.pageTitle) parts.push(`Page title: ${data.pageTitle}`);
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  if (data.beforeBlock) parts.push(`Previous block: ${data.beforeBlock}`);
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  if (data.parentBlock) parts.push(`Current block: ${data.parentBlock}`);
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  if (data.afterBlock) parts.push(`Next block: ${data.afterBlock}`);
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  parts.push(`Selection to rewrite:\n${data.selectedText}`);
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  return [
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    { role: "system", content: system },
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    { role: "user", content: parts.join("\n\n") },
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  ];
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}
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export function buildGenerateMessages(data: GeneratePromptInput): AiChatMessage[] {
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  const instructions: Record<GeneratePromptInput["intent"], string> = {
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    continue:
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      "Continue writing the document from the cursor. Match the existing voice, tense, and style. Produce 1-3 paragraphs.",
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    explain: "Write a clear explanation that fits naturally at the cursor, grounded in the surrounding context.",
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    brainstorm: "Brainstorm a concise bulleted list of ideas that fit the current context.",
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  };
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  const system = [
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    "You are a writing assistant embedded in a document editor.",
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    instructions[data.intent],
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    "Return only the inserted text, with no preamble or labels.",
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  ].join(" ");
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  const parts: string[] = [];
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  if (data.pageTitle) parts.push(`Page title: ${data.pageTitle}`);
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  if (data.beforeBlock) parts.push(`Text before the cursor:\n${data.beforeBlock}`);
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  if (data.afterBlock) parts.push(`Text after the cursor:\n${data.afterBlock}`);
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  parts.push("Write the continuation at the cursor.");
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  return [
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    { role: "system", content: system },
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    { role: "user", content: parts.join("\n\n") },
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  ];
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}
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export function buildAskMessages(
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  pageTitle: string,
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  pageContext: string,
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  question: string,
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  history: AskHistoryTurn[],
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): AiChatMessage[] {
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  const system = [
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    "You are a helpful assistant answering questions about a document.",
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    "Use only the provided page content to answer. If the page does not contain the answer, say so.",
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    pageTitle ? `Page title: ${pageTitle}` : "",
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    pageContext ? `Page content:\n${pageContext}` : "Page content is empty.",
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  ]
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    .filter(Boolean)
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    .join("\n\n");
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  const messages: AiChatMessage[] = [{ role: "system", content: system }];
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  for (const turn of history) {
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    messages.push({ role: turn.role, content: turn.content });
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  }
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  messages.push({ role: "user", content: question });
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  return messages;
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}