import { z } from "zod";
import type { DocxEditorRuntime } from "@docx-editor.dev/editor-api/browser";

export const proposalSchema = z.object({
  replacement: z.string().min(1).max(100),
  reason: z.string().trim().min(1).max(500),
}).strict();

export type PaymentTask = {
  clause: string;
  source: string;
  minDays: number;
  maxDays: number;
};

export function validatePaymentProposal(value: unknown, task: PaymentTask) {
  const result = proposalSchema.safeParse(value);
  if (!result.success) {
    throw new Error("Provide replacement text and a reason of 1–500 characters, with no extra fields.");
  }
  const proposal = result.data;
  const match = /^within ([1-9]\d*) days$/.exec(proposal.replacement);
  const days = match ? Number(match[1]) : NaN;
  if (!Number.isSafeInteger(days) || days < task.minDays || days > task.maxDays) {
    throw new Error(`Use a payment deadline between ${task.minDays} and ${task.maxDays} days.`);
  }
  return proposal;
}

export async function applyPaymentProposal(
  runtime: Pick<DocxEditorRuntime, "run">,
  value: unknown,
  task: PaymentTask,
) {
  const proposal = validatePaymentProposal(value, task);
  await runtime.run(async (context) => {
    const clauses = context.document.body.search(task.clause, { matchCase: true });
    clauses.load("items");
    await context.sync();
    if (clauses.items.length !== 1) {
      throw new Error("The payment clause changed or is not unique. Select it again.");
    }
    const matches = clauses.items[0]!.search(task.source, { matchCase: true });
    matches.load("items");
    await context.sync();
    if (matches.items.length !== 1) {
      throw new Error("The selected clause needs one matching deadline.");
    }
    context.document.changeTrackingMode = "TrackMineOnly";
    matches.items[0]!.insertText(proposal.replacement, "Replace");
    await context.sync();
  });
  return proposal;
}