/**
 * EmbedHelpers — utilities for working within Discord embed limits
 * and controlling inline field grid layout.
 *
 * Usage:
 *   import { EmbedHelpers } from "@ui/embed-helpers";
 *
 *   EmbedHelpers.chunkRows(rows)
 *   EmbedHelpers.addNationFields(embed, header, rows, inline)
 *   EmbedHelpers.addPerPlayerGrid(embed, [{ header, rows }, { header, rows }])
 */

 interface EmbedLike {
  addFields: (...fields: { name: string; value: string; inline: boolean }[]) => any;
}

// ─── Chunking (for non-inline / single-field cases) ──────────────────────────

function chunkRows(rows: string[], separator: string = "\n", maxLen: number = 1024): string[] {
  if (rows.length === 0) return [];

  const chunks: string[] = [];
  let current = "";

  for (const row of rows) {
    const candidate = current ? `${current}${separator}${row}` : row;
    if (candidate.length > maxLen && current) {
      chunks.push(current);
      current = row;
    } else {
      current = candidate;
    }
  }
  if (current) chunks.push(current);
  console.log(`[EmbedHelpers] chunkRows: ${rows.length} rows -> ${chunks.length} chunk(s), lengths: ${chunks.map(c => c.length).join(", ")}`);
  return chunks;
}

function addNationFields(
  embed: EmbedLike,
  header: string,
  rows: string[],
  inline: boolean = false
): void {
  const chunks = chunkRows(rows);

  if (chunks.length === 0) {
    embed.addFields({ name: header, value: "—", inline });
    return;
  }

  chunks.forEach((chunk, i) => {
    embed.addFields({
      name:  i === 0 ? header : "\u200b",
      value: chunk,
      inline,
    });
  });
}

// ─── Per-player grid ──────────────────────────────────────────────────────────

/**
 * Render two columns as a clean 2-column grid, one player per field row.
 * The nation header is embedded as bold text at the top of the first
 * player's field (not a separate field) to avoid an extra header-to-content gap.
 */
function addPerPlayerGrid(
  embed: EmbedLike,
  columns: { header: string; rows: string[] }[]
): void {
  if (columns.length !== 2) {
    for (const col of columns) {
      addNationFields(embed, col.header, col.rows, true);
    }
    return;
  }

  const [left, right] = columns;
  const maxLen = Math.max(left.rows.length, right.rows.length, 1);

  for (let i = 0; i < maxLen; i++) {
    const leftRow  = left.rows[i];
    const rightRow = right.rows[i];

    const leftValue = i === 0
      ? `**${left.header}**\n${leftRow ?? "—"}`
      : (leftRow ?? "\u200b");

    const rightValue = i === 0
      ? `**${right.header}**\n${rightRow ?? "—"}`
      : (rightRow ?? "\u200b");

    embed.addFields(
      { name: "\u200b", value: leftValue,  inline: true },
      { name: "\u200b", value: rightValue, inline: true },
      { name: "\u200b", value: "\u200b",   inline: true },
    );
  }
}

// ─── Single-column per-player fields ──────────────────────────────────────────

/**
 * Render a single-column list, one player per field (no chunking needed —
 * each field only holds one row, well under the 1024 char limit regardless
 * of padding/content length). Header embedded as bold text in the first
 * player's field to avoid an extra header-to-content gap.
 */
function addPerPlayerColumn(
  embed: EmbedLike,
  header: string,
  rows: string[]
): void {
  if (rows.length === 0) {
    embed.addFields({ name: header, value: "—", inline: false });
    return;
  }

  rows.forEach((row, i) => {
    const value = i === 0 ? `**${header}**\n\u200b\n${row}` : row;
    embed.addFields({ name: "\u200b", value, inline: false });
  });
}

// ─── Namespace ────────────────────────────────────────────────────────────────

export const EmbedHelpers = {
  chunkRows,
  addNationFields,
  addPerPlayerGrid,
  addPerPlayerColumn,
};