/*
 * Markdown output layout is adapted from Incur's Formatter.
 * Copyright (c) 2025-present weth, LLC
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */
import { Formatter } from "incur";

/** Keep REA's Markdown layout compatible with Incur while owning table safety. */
export const formatCliOutput = (
  value: unknown,
  format: Formatter.Format,
): string =>
  format === "md" ? formatMarkdown(value) : Formatter.format(value, format);

const isScalar = (value: unknown): boolean =>
  value === null || value === undefined || typeof value !== "object";

const isFlatObject = (value: Record<string, unknown>): boolean =>
  Object.values(value).every(isScalar);

const isObjectArray = (value: unknown): value is Record<string, unknown>[] =>
  Array.isArray(value) &&
  value.length > 0 &&
  value.every(
    (item) => typeof item === "object" && item !== null && !Array.isArray(item),
  );

const escapeTableCell = (value: string): string =>
  value
    .replace(/&/g, "&amp;")
    .replace(/</g, "&lt;")
    .replace(/>/g, "&gt;")
    .replace(/\\/g, "\\\\")
    .replace(/\|/g, "\\|")
    .replace(/\r\n|\r|\n/g, "<br>");

const renderTable = (
  headers: readonly string[],
  rows: readonly string[][],
): string => {
  const escapedHeaders = headers.map(escapeTableCell);
  const widths = escapedHeaders.map((header) => header.length);
  for (const row of rows) {
    for (let index = 0; index < escapedHeaders.length; index += 1) {
      const width = escapeTableCell(row[index] ?? "").length;
      if (width > widths[index]!) widths[index] = width;
    }
  }

  const pad = (value: string, index: number): string =>
    value.padEnd(widths[index]!);
  const lines = [
    `| ${escapedHeaders.map(pad).join(" | ")} |`,
    `|${widths.map((width) => "-".repeat(width + 2)).join("|")}|`,
  ];
  for (const row of rows) {
    lines.push(
      `| ${escapedHeaders
        .map((_, index) => pad(escapeTableCell(row[index] ?? ""), index))
        .join(" | ")} |`,
    );
  }
  return lines.join("\n");
};

/** Keep nested JSON facts inside their owning table cell. */
const markdownCell = (value: unknown): string =>
  value !== null && typeof value === "object"
    ? JSON.stringify(value)
    : value === undefined
      ? ""
      : String(value);

const formatKeyValueTable = (value: Record<string, unknown>): string =>
  renderTable(
    ["Key", "Value"],
    Object.entries(value).map(([key, child]) => [key, markdownCell(child)]),
  );

const formatObjectTable = (
  items: readonly Record<string, unknown>[],
): string => {
  const headers: string[] = [];
  const seen = new Set<string>();
  for (const item of items)
    for (const key of Object.keys(item))
      if (!seen.has(key)) {
        seen.add(key);
        headers.push(key);
      }
  return renderTable(
    headers,
    items.map((item) =>
      headers.map((key) =>
        markdownCell(Object.hasOwn(item, key) ? item[key] : undefined),
      ),
    ),
  );
};

const formatMarkdown = (
  value: unknown,
  path: readonly string[] = [],
): string => {
  if (value == null && path.length === 0) return "";
  if (isScalar(value)) {
    if (path.length === 0) return String(value);
    return `## ${path.join(".")}\n\n${String(value)}`;
  }
  if (Array.isArray(value)) {
    if (isObjectArray(value)) {
      const table = formatObjectTable(value);
      return path.length === 0 ? table : `## ${path.join(".")}\n\n${table}`;
    }
    return formatMarkdown(markdownCell(value), path);
  }

  const object = value as Record<string, unknown>;
  const entries = Object.entries(object);
  if (path.length === 0 && isFlatObject(object))
    return formatKeyValueTable(object);

  const needsHeadings =
    path.length > 0 ||
    entries.length > 1 ||
    entries.some(([, child]) => !isScalar(child));
  if (!needsHeadings) return formatKeyValueTable(object);

  return entries
    .map(([key, child]) => {
      const childPath = [...path, key];
      const heading = `## ${childPath.join(".")}\n\n`;
      if (isScalar(child)) return `${heading}${String(child)}`;
      if (isObjectArray(child)) return `${heading}${formatObjectTable(child)}`;
      if (
        typeof child === "object" &&
        child !== null &&
        !Array.isArray(child)
      ) {
        const nested = child as Record<string, unknown>;
        return isFlatObject(nested)
          ? `${heading}${formatKeyValueTable(nested)}`
          : formatMarkdown(nested, childPath);
      }
      return `${heading}${markdownCell(child)}`;
    })
    .join("\n\n");
};