import type { Spec } from "@json-render/core";
import { formatDisplayText, withChartDisplayTimes } from "@/shared/utils/date-time-text";

const textFields = new Set(["title", "description", "summary", "text", "label", "value", "source", "observed_at"]);
const utcLabel = /UTC(?:\s*\+?0(?::00)?)?(?![\w+:-])/;
const timeAxis = (value: string) => formatDisplayText(value).replace(/UTC(?:\s*\+?0(?::00)?)?(?![\w+:-])/g, "UTC+8");
const bareTime = /^(?:\d{4}-\d{2}-\d{2}[T ])?\d{2}:\d{2}(?::\d{2}(?:\.\d{1,9})?)?$/;

function displayCell(value: string, heading: string): string {
  return formatDisplayText(utcLabel.test(heading) && bareTime.test(value) ? `${value} UTC` : value);
}

/** Render display fields in UTC8 while keeping the stored spec and identifiers intact. */
export function withAnswerDisplayTimes(spec: Spec): Spec {
  return { ...spec, elements: Object.fromEntries(Object.entries(spec.elements).map(([id, node]) => {
    const props = { ...node.props };
    for (const key of textFields) {
      if (typeof props[key] === "string") props[key] = formatDisplayText(props[key]);
    }
    if (node.type === "Table") {
      const columns = props.columns as string[];
      props.rows = (props.rows as string[][]).map((row) => row.map((cell, index) => displayCell(cell, columns[index] ?? "")));
      props.columns = columns.map(timeAxis);
    }
    if (node.type === "Chart") {
      Object.assign(props, withChartDisplayTimes(props as Parameters<typeof withChartDisplayTimes>[0]));
    }
    return [id, { ...node, props }];
  })) };
}