import * as z from "zod";

import {
  applyRichTextStylePatch,
  clearRichTextFormatting,
  extraRichTextToPlainText,
  normalizeExtraRichText,
  type RichTextStylePatch,
} from "@/lib/rich-text";

const extraSheetId = z.string().min(1).max(128);
export const DEFAULT_EXTRA_SHEET_COLUMN_WIDTH = 140;
export const MIN_EXTRA_SHEET_COLUMN_WIDTH = 96;
export const MAX_EXTRA_SHEET_COLUMN_WIDTH = 480;
export const extraSheetAlignmentSchema = z.enum(["left", "center", "right"]);
export type ExtraSheetAlignment = z.infer<typeof extraSheetAlignmentSchema>;
export const extraSheetVerticalAlignmentSchema = z.enum(["top", "middle", "bottom"]);
export type ExtraSheetVerticalAlignment = z.infer<typeof extraSheetVerticalAlignmentSchema>;

export const extraSheetSchema = z.strictObject({
  columns: z.array(z.strictObject({
    id: extraSheetId,
    label: z.string().trim().min(1).max(120),
    width: z.number().int().min(MIN_EXTRA_SHEET_COLUMN_WIDTH).max(MAX_EXTRA_SHEET_COLUMN_WIDTH)
      .default(DEFAULT_EXTRA_SHEET_COLUMN_WIDTH),
  })).min(1),
  merges: z.array(z.strictObject({
    rowIds: z.array(extraSheetId).min(1),
    columnIds: z.array(extraSheetId).min(1),
  })).optional(),
  rows: z.array(z.strictObject({
    id: extraSheetId,
    cells: z.record(z.string(), z.string().max(10_000)),
    backgrounds: z.record(z.string(), z.string().regex(/^#[0-9A-Fa-f]{6}$/)).default({}),
    alignments: z.record(z.string(), extraSheetAlignmentSchema).default({}),
    verticalAlignments: z.record(z.string(), extraSheetVerticalAlignmentSchema).default({}),
  })).min(1),
}).superRefine((sheet, context) => {
  const columnIds = new Set(sheet.columns.map((column) => column.id));
  if (columnIds.size !== sheet.columns.length) {
    context.addIssue({ code: "custom", path: ["columns"], message: "รหัสคอลัมน์ต้องไม่ซ้ำกัน" });
  }
  const columnLabels = new Set(sheet.columns.map((column) => column.label.toLocaleLowerCase()));
  if (columnLabels.size !== sheet.columns.length) {
    context.addIssue({ code: "custom", path: ["columns"], message: "ชื่อคอลัมน์ต้องไม่ซ้ำกัน" });
  }
  const rowIds = new Set(sheet.rows.map((row) => row.id));
  if (rowIds.size !== sheet.rows.length) {
    context.addIssue({ code: "custom", path: ["rows"], message: "รหัสแถวต้องไม่ซ้ำกัน" });
  }
  const occupied = new Set<string>();
  sheet.merges?.forEach((merge, index) => {
    const consecutive = (ids: string[], axis: { id: string }[]) => {
      const start = axis.findIndex((item) => item.id === ids[0]);
      return start >= 0 && ids.every((id, offset) => axis[start + offset]?.id === id);
    };
    if (merge.rowIds.length * merge.columnIds.length < 2
      || !consecutive(merge.rowIds, sheet.rows)
      || !consecutive(merge.columnIds, sheet.columns)) {
      context.addIssue({ code: "custom", path: ["merges", index], message: "ช่วงเซลล์ที่ผสานต้องเป็นสี่เหลี่ยมต่อเนื่องและมีอย่างน้อยสองเซลล์" });
    }
    for (const rowId of merge.rowIds) {
      for (const columnId of merge.columnIds) {
        const key = JSON.stringify([rowId, columnId]);
        if (occupied.has(key)) {
          context.addIssue({ code: "custom", path: ["merges", index], message: "ช่วงเซลล์ที่ผสานต้องไม่ซ้อนกัน" });
        }
        occupied.add(key);
      }
    }
  });
  sheet.rows.forEach((row, rowIndex) => {
    [
      ...Object.keys(row.cells),
      ...Object.keys(row.backgrounds ?? {}),
      ...Object.keys(row.alignments ?? {}),
      ...Object.keys(row.verticalAlignments ?? {}),
    ].forEach((columnId) => {
      if (!columnIds.has(columnId)) {
        context.addIssue({
          code: "custom",
          path: ["rows", rowIndex, "cells", columnId],
          message: "ไม่พบคอลัมน์ของเซลล์นี้",
        });
      }
    });
  });
});

export type ExtraSheet = z.output<typeof extraSheetSchema>;

export type ExtraSheetCell = {
  value: string;
  backgroundColor?: string;
  alignment?: ExtraSheetAlignment;
  verticalAlignment?: ExtraSheetVerticalAlignment;
};
export type ExtraSheetMatrix = Array<Array<ExtraSheetCell | undefined>>;
type SheetPoint = { row: number; column: number };

export type ExtraSheetRange = { start: SheetPoint; end: SheetPoint };
export type ExtraSheetMerge = NonNullable<ExtraSheet["merges"]>[number];

export function extraSheetMergeRange(sheet: ExtraSheet, merge: ExtraSheetMerge): ExtraSheetRange {
  const row = sheet.rows.findIndex((item) => item.id === merge.rowIds[0]);
  const column = sheet.columns.findIndex((item) => item.id === merge.columnIds[0]);
  return {
    start: { row, column },
    end: { row: row + merge.rowIds.length - 1, column: column + merge.columnIds.length - 1 },
  };
}

function contains(range: ExtraSheetRange, point: SheetPoint): boolean {
  return point.row >= range.start.row && point.row <= range.end.row
    && point.column >= range.start.column && point.column <= range.end.column;
}

function intersects(a: ExtraSheetRange, b: ExtraSheetRange): boolean {
  return a.start.row <= b.end.row && a.end.row >= b.start.row
    && a.start.column <= b.end.column && a.end.column >= b.start.column;
}

export function extraSheetMergeAt(sheet: ExtraSheet, point: SheetPoint): ExtraSheetRange | undefined {
  const merge = sheet.merges?.find((item) => contains(extraSheetMergeRange(sheet, item), point));
  return merge ? extraSheetMergeRange(sheet, merge) : undefined;
}

export function extraSheetMergeMap(sheet: ExtraSheet): Map<string, ExtraSheetRange> {
  const map = new Map<string, ExtraSheetRange>();
  for (const merge of sheet.merges ?? []) {
    const range = extraSheetMergeRange(sheet, merge);
    for (const point of extraSheetRangePoints(range)) map.set(`${point.row}:${point.column}`, range);
  }
  return map;
}

export function extraSheetAnchor(sheet: ExtraSheet, point: SheetPoint): SheetPoint {
  return extraSheetMergeAt(sheet, point)?.start ?? point;
}

export function nextExtraSheetPoint(
  sheet: ExtraSheet, point: SheetPoint, direction: SheetPoint, wrap = false,
): SheetPoint | undefined {
  const merge = extraSheetMergeAt(sheet, point);
  const anchor = merge?.start ?? point;
  let next = {
    row: direction.row > 0 && merge ? merge.end.row + 1 : point.row + direction.row,
    column: direction.column > 0 && merge ? merge.end.column + 1 : point.column + direction.column,
  };
  while (true) {
    if (wrap && next.column >= sheet.columns.length) next = { row: next.row + 1, column: 0 };
    if (wrap && next.column < 0) next = { row: next.row - 1, column: sheet.columns.length - 1 };
    if (!sheet.rows[next.row] || !sheet.columns[next.column]) return undefined;
    const target = extraSheetAnchor(sheet, next);
    if (target.row !== anchor.row || target.column !== anchor.column) return target;
    if (!direction.row && !direction.column) return undefined;
    next = { row: next.row + direction.row, column: next.column + direction.column };
  }
}

export function extraSheetRangePoints(range: ExtraSheetRange): SheetPoint[] {
  return Array.from({ length: range.end.row - range.start.row + 1 }, (_, row) =>
    Array.from({ length: range.end.column - range.start.column + 1 }, (_, column) => ({
      row: range.start.row + row, column: range.start.column + column,
    })),
  ).flat();
}

export function expandExtraSheetRange(sheet: ExtraSheet, start: SheetPoint, end: SheetPoint): ExtraSheetRange {
  const range = {
    start: { row: Math.min(start.row, end.row), column: Math.min(start.column, end.column) },
    end: { row: Math.max(start.row, end.row), column: Math.max(start.column, end.column) },
  };
  let changed = true;
  while (changed) {
    changed = false;
    for (const merge of sheet.merges ?? []) {
      const bounds = extraSheetMergeRange(sheet, merge);
      if (!intersects(range, bounds)) continue;
      if (contains(range, bounds.start) && contains(range, bounds.end)) continue;
      range.start.row = Math.min(range.start.row, bounds.start.row);
      range.start.column = Math.min(range.start.column, bounds.start.column);
      range.end.row = Math.max(range.end.row, bounds.end.row);
      range.end.column = Math.max(range.end.column, bounds.end.column);
      changed = true;
    }
  }
  return range;
}

export function canMergeExtraSheetRange(sheet: ExtraSheet, range: ExtraSheetRange): boolean {
  if (!sheet.rows[range.start.row] || !sheet.rows[range.end.row]
    || !sheet.columns[range.start.column] || !sheet.columns[range.end.column]) return false;
  if (range.end.row < range.start.row || range.end.column < range.start.column
    || (range.start.row === range.end.row && range.start.column === range.end.column)) return false;
  return !(sheet.merges ?? []).some((merge) => {
    const bounds = extraSheetMergeRange(sheet, merge);
    const identical = bounds.start.row === range.start.row && bounds.start.column === range.start.column
      && bounds.end.row === range.end.row && bounds.end.column === range.end.column;
    return identical || (intersects(range, bounds)
      && !(contains(range, bounds.start) && contains(range, bounds.end)));
  });
}

export function unmergeExtraSheetRange(sheet: ExtraSheet, range: ExtraSheetRange): ExtraSheet {
  if (!sheet.merges?.some((merge) => intersects(range, extraSheetMergeRange(sheet, merge)))) return sheet;
  return { ...sheet, merges: sheet.merges.filter((merge) => !intersects(range, extraSheetMergeRange(sheet, merge))) };
}

export function mergeExtraSheetRange(sheet: ExtraSheet, range: ExtraSheetRange): ExtraSheet {
  if (!canMergeExtraSheetRange(sheet, range)) return sheet;
  const points = extraSheetRangePoints(range);
  const text = points.flatMap(({ row, column }) => {
    const value = sheet.rows[row].cells[sheet.columns[column].id] ?? "";
    return extraRichTextToPlainText(value).trim() ? [normalizeExtraRichText(value)] : [];
  }).join("");
  if (text.length > 10_000) throw new Error("ข้อความที่ผสานต้องไม่เกิน 10,000 ตัวอักษร");
  const unmerged = unmergeExtraSheetRange(sheet, range);
  const cleared = updateExtraSheetCells(unmerged, points, { value: "" });
  const updated = updateExtraSheetCell(cleared, range.start.row, range.start.column, text);
  return {
    ...updated,
    merges: [...(updated.merges ?? []), {
      rowIds: sheet.rows.slice(range.start.row, range.end.row + 1).map((row) => row.id),
      columnIds: sheet.columns.slice(range.start.column, range.end.column + 1).map((column) => column.id),
    }],
  };
}

function anchorKeys(sheet: ExtraSheet, points: Iterable<SheetPoint>): Set<string> {
  const merges = extraSheetMergeMap(sheet);
  return new Set(Array.from(points, (point) => {
    const { row, column } = merges.get(`${point.row}:${point.column}`)?.start ?? point;
    return `${row}:${column}`;
  }));
}

// Remove only merges touched by a structural edit. Insertion at a boundary is outside a merge.
function unmergeExtraSheetAxis(
  sheet: ExtraSheet, axis: "row" | "column", from: number, to = from, insertion = false,
): ExtraSheet {
  if (!sheet.merges?.length) return sheet;
  return {
    ...sheet,
    merges: sheet.merges.filter((merge) => {
      const range = extraSheetMergeRange(sheet, merge);
      const start = range.start[axis];
      const end = range.end[axis];
      return insertion ? !(from > start && from <= end)
        : !(Math.min(from, to) <= end && Math.max(from, to) >= start);
    }),
  };
}

export function extraSheetUsedRange(sheet: ExtraSheet): ExtraSheet | null {
  const usedPoints = sheet.rows.flatMap((row, rowIndex) =>
    sheet.columns.flatMap((column, columnIndex) => {
      const used = extraRichTextToPlainText(row.cells[column.id] ?? "").trim()
        || row.backgrounds?.[column.id]
        || row.alignments?.[column.id]
        || row.verticalAlignments?.[column.id];
      return used ? [{ row: rowIndex, column: columnIndex }] : [];
    }),
  );
  for (const merge of sheet.merges ?? []) {
    const range = extraSheetMergeRange(sheet, merge);
    usedPoints.push(range.start, range.end);
  }
  if (!usedPoints.length) return null;

  const rowIndexes = usedPoints.map((point) => point.row);
  const columnIndexes = usedPoints.map((point) => point.column);
  const firstRow = Math.min(...rowIndexes);
  const lastRow = Math.max(...rowIndexes);
  const firstColumn = Math.min(...columnIndexes);
  const lastColumn = Math.max(...columnIndexes);

  const columns = sheet.columns.slice(firstColumn, lastColumn + 1);
  return {
    ...sheet,
    columns,
    rows: sheet.rows.slice(firstRow, lastRow + 1).map((row) => ({
      ...row,
      cells: Object.fromEntries(columns.map((column) => [column.id, row.cells[column.id] ?? ""])),
      backgrounds: Object.fromEntries(columns.flatMap((column) =>
        row.backgrounds?.[column.id] ? [[column.id, row.backgrounds[column.id]]] : [],
      )),
      alignments: Object.fromEntries(columns.flatMap((column) =>
        row.alignments?.[column.id] ? [[column.id, row.alignments[column.id]]] : [],
      )),
      verticalAlignments: Object.fromEntries(columns.flatMap((column) =>
        row.verticalAlignments?.[column.id] ? [[column.id, row.verticalAlignments[column.id]]] : [],
      )),
    })),
  };
}

export function nextExtraSheetColumnLabel(columns: ExtraSheet["columns"]): string {
  const labels = new Set(columns.map((column) => column.label.toLocaleLowerCase()));
  let index = columns.length + 1;
  while (labels.has(`คอลัมน์ ${index}`.toLocaleLowerCase())) index += 1;
  return `คอลัมน์ ${index}`;
}

export function createExtraSheet(createId: (prefix: string) => string): ExtraSheet {
  const columns = Array.from({ length: 6 }, (_, index) => ({
    id: createId("extra-sheet-column"),
    label: `คอลัมน์ ${index + 1}`,
    width: DEFAULT_EXTRA_SHEET_COLUMN_WIDTH,
  }));
  return {
    columns,
    rows: Array.from({ length: 4 }, () => ({
      id: createId("extra-sheet-row"),
      cells: Object.fromEntries(columns.map((column) => [column.id, ""])),
      backgrounds: {},
      alignments: {},
      verticalAlignments: {},
    })),
  };
}

export function extraSheetToMatrix(sheet: ExtraSheet): ExtraSheetMatrix {
  return sheet.rows.map((row) =>
    sheet.columns.map((column) => ({
      value: row.cells[column.id] ?? "",
      backgroundColor: row.backgrounds?.[column.id],
      alignment: row.alignments?.[column.id],
      verticalAlignment: row.verticalAlignments?.[column.id],
    })),
  );
}

export function matrixToExtraSheet(
  sheet: ExtraSheet,
  matrix: ExtraSheetMatrix,
  createId: (prefix: string) => string,
): ExtraSheet {
  const columnCount = Math.max(
    sheet.columns.length,
    ...matrix.map((row) => row.length),
  );
  const columns = [...sheet.columns];
  while (columns.length < columnCount) {
    columns.push({
      id: createId("extra-sheet-column"),
      label: nextExtraSheetColumnLabel(columns),
      width: DEFAULT_EXTRA_SHEET_COLUMN_WIDTH,
    });
  }
  const rowCount = Math.max(sheet.rows.length, matrix.length);
  const rows = Array.from({ length: rowCount }, (_, rowIndex) => ({
    id: sheet.rows[rowIndex]?.id ?? createId("extra-sheet-row"),
    cells: Object.fromEntries(columns.map((column, columnIndex) => [
      column.id,
      String(matrix[rowIndex]?.[columnIndex]?.value ?? ""),
    ])),
    backgrounds: Object.fromEntries(columns.flatMap((column, columnIndex) => {
      const backgroundColor = matrix[rowIndex]?.[columnIndex]?.backgroundColor
        ?? sheet.rows[rowIndex]?.backgrounds?.[column.id];
      return backgroundColor ? [[column.id, backgroundColor]] : [];
    })),
    alignments: Object.fromEntries(columns.flatMap((column, columnIndex) => {
      const alignment = matrix[rowIndex]?.[columnIndex]?.alignment
        ?? sheet.rows[rowIndex]?.alignments?.[column.id];
      return alignment ? [[column.id, alignment]] : [];
    })),
    verticalAlignments: Object.fromEntries(columns.flatMap((column, columnIndex) => {
      const alignment = matrix[rowIndex]?.[columnIndex]?.verticalAlignment
        ?? sheet.rows[rowIndex]?.verticalAlignments?.[column.id];
      return alignment ? [[column.id, alignment]] : [];
    })),
  }));
  return { ...sheet, columns, rows };
}

export function addExtraSheetColumn(
  sheet: ExtraSheet,
  label: string,
  id: string,
): ExtraSheet {
  return insertExtraSheetColumn(sheet, sheet.columns.length, label, id);
}

export function insertExtraSheetColumn(
  sheet: ExtraSheet,
  index: number,
  label: string,
  id: string,
): ExtraSheet {
  const position = Math.max(0, Math.min(index, sheet.columns.length));
  sheet = unmergeExtraSheetAxis(sheet, "column", position, position, true);
  const columns = [...sheet.columns];
  columns.splice(position, 0, {
    id,
    label,
    width: DEFAULT_EXTRA_SHEET_COLUMN_WIDTH,
  });
  return {
    ...sheet,
    columns,
    rows: sheet.rows.map((row) => ({ ...row, cells: { ...row.cells, [id]: "" } })),
  };
}

export function addExtraSheetRow(sheet: ExtraSheet, id: string): ExtraSheet {
  return insertExtraSheetRow(sheet, sheet.rows.length, id);
}

export function insertExtraSheetRow(
  sheet: ExtraSheet,
  index: number,
  id: string,
): ExtraSheet {
  const position = Math.max(0, Math.min(index, sheet.rows.length));
  sheet = unmergeExtraSheetAxis(sheet, "row", position, position, true);
  const rows = [...sheet.rows];
  rows.splice(position, 0, {
    id,
    cells: Object.fromEntries(sheet.columns.map((column) => [column.id, ""])),
    backgrounds: {},
    alignments: {},
    verticalAlignments: {},
  });
  return {
    ...sheet,
    rows,
  };
}

export function resizeExtraSheetColumn(
  sheet: ExtraSheet,
  index: number,
  width: number,
): ExtraSheet {
  if (!sheet.columns[index]) return sheet;
  const normalized = Math.round(Math.max(
    MIN_EXTRA_SHEET_COLUMN_WIDTH,
    Math.min(MAX_EXTRA_SHEET_COLUMN_WIDTH, width),
  ));
  return {
    ...sheet,
    columns: sheet.columns.map((column, columnIndex) =>
      columnIndex === index ? { ...column, width: normalized } : column),
  };
}

export function moveExtraSheetColumn(
  sheet: ExtraSheet,
  from: number,
  to: number,
): ExtraSheet {
  if (to < 0 || to >= sheet.columns.length || from === to) return sheet;
  sheet = unmergeExtraSheetAxis(sheet, "column", from, to);
  const columns = [...sheet.columns];
  const [column] = columns.splice(from, 1);
  columns.splice(to, 0, column);
  return { ...sheet, columns };
}

export function moveExtraSheetRow(
  sheet: ExtraSheet,
  from: number,
  to: number,
): ExtraSheet {
  if (to < 0 || to >= sheet.rows.length || from === to) return sheet;
  sheet = unmergeExtraSheetAxis(sheet, "row", from, to);
  const rows = [...sheet.rows];
  const [row] = rows.splice(from, 1);
  rows.splice(to, 0, row);
  return { ...sheet, rows };
}

export function deleteExtraSheetColumn(sheet: ExtraSheet, index: number): ExtraSheet {
  if (sheet.columns.length === 1) return sheet;
  const columnId = sheet.columns[index]?.id;
  if (!columnId) return sheet;
  sheet = unmergeExtraSheetAxis(sheet, "column", index);
  return {
    ...sheet,
    columns: sheet.columns.filter((_, columnIndex) => columnIndex !== index),
    rows: sheet.rows.map((row) => ({
      ...row,
      cells: Object.fromEntries(Object.entries(row.cells).filter(([key]) => key !== columnId)),
      backgrounds: Object.fromEntries(Object.entries(row.backgrounds ?? {}).filter(([key]) => key !== columnId)),
      alignments: Object.fromEntries(Object.entries(row.alignments ?? {}).filter(([key]) => key !== columnId)),
      verticalAlignments: Object.fromEntries(Object.entries(row.verticalAlignments ?? {}).filter(([key]) => key !== columnId)),
    })),
  };
}

export function deleteExtraSheetRow(sheet: ExtraSheet, index: number): ExtraSheet {
  if (sheet.rows.length === 1) return sheet;
  sheet = unmergeExtraSheetAxis(sheet, "row", index);
  return { ...sheet, rows: sheet.rows.filter((_, rowIndex) => rowIndex !== index) };
}

export function updateExtraSheetCell(
  sheet: ExtraSheet,
  rowIndex: number,
  columnIndex: number,
  value: string,
): ExtraSheet {
  const anchor = extraSheetAnchor(sheet, { row: rowIndex, column: columnIndex });
  rowIndex = anchor.row;
  columnIndex = anchor.column;
  const row = sheet.rows[rowIndex];
  const column = sheet.columns[columnIndex];
  if (!row || !column) return sheet;
  return {
    ...sheet,
    rows: sheet.rows.map((candidate, index) => index === rowIndex
      ? { ...candidate, cells: { ...candidate.cells, [column.id]: value } }
      : candidate),
  };
}

export function updateExtraSheetCells(
  sheet: ExtraSheet,
  points: Iterable<SheetPoint>,
  update: {
    value?: string;
    backgroundColor?: string | null;
    alignment?: ExtraSheetAlignment | null;
    verticalAlignment?: ExtraSheetVerticalAlignment | null;
  },
): ExtraSheet {
  const selected = anchorKeys(sheet, points);
  return {
    ...sheet,
    rows: sheet.rows.map((row, rowIndex) => {
      const cells = { ...row.cells };
      const backgrounds = { ...(row.backgrounds ?? {}) };
      const alignments = { ...(row.alignments ?? {}) };
      const verticalAlignments = { ...(row.verticalAlignments ?? {}) };
      sheet.columns.forEach((column, columnIndex) => {
        if (!selected.has(`${rowIndex}:${columnIndex}`)) return;
        if (update.value !== undefined) cells[column.id] = update.value;
        if (update.backgroundColor === null) delete backgrounds[column.id];
        else if (update.backgroundColor !== undefined) backgrounds[column.id] = update.backgroundColor;
        if (update.alignment === null) delete alignments[column.id];
        else if (update.alignment !== undefined) alignments[column.id] = update.alignment;
        if (update.verticalAlignment === null) delete verticalAlignments[column.id];
        else if (update.verticalAlignment !== undefined) verticalAlignments[column.id] = update.verticalAlignment;
      });
      return { ...row, cells, backgrounds, alignments, verticalAlignments };
    }),
  };
}

export function clearExtraSheetCellFormatting(
  sheet: ExtraSheet,
  points: Iterable<SheetPoint>,
): ExtraSheet {
  const selected = anchorKeys(sheet, points);
  return {
    ...sheet,
    rows: sheet.rows.map((row, rowIndex) => {
      const cells = { ...row.cells };
      const backgrounds = { ...(row.backgrounds ?? {}) };
      const alignments = { ...(row.alignments ?? {}) };
      const verticalAlignments = { ...(row.verticalAlignments ?? {}) };
      sheet.columns.forEach((column, columnIndex) => {
        if (!selected.has(`${rowIndex}:${columnIndex}`)) return;
        cells[column.id] = clearRichTextFormatting(cells[column.id] ?? "");
        delete backgrounds[column.id];
        delete alignments[column.id];
        delete verticalAlignments[column.id];
      });
      return { ...row, cells, backgrounds, alignments, verticalAlignments };
    }),
  };
}

function quoteTsvValue(value: string): string {
  return /[\t\r\n"]/.test(value) ? `"${value.replaceAll('"', '""')}"` : value;
}

export function extraSheetRangeToTsv(
  sheet: ExtraSheet,
  start: SheetPoint,
  end: SheetPoint,
): string {
  const range = expandExtraSheetRange(sheet, start, end);
  const { row: top, column: left } = range.start;
  const { row: bottom, column: right } = range.end;
  return sheet.rows.slice(top, bottom + 1).map((row) =>
    sheet.columns.slice(left, right + 1).map((column) =>
      quoteTsvValue(extraRichTextToPlainText(row.cells[column.id] ?? "")),
    ).join("\t"),
  ).join("\n");
}

export function parseExtraSheetTsv(value: string): string[][] {
  const rows: string[][] = [[]];
  let field = "";
  let quoted = false;
  for (let index = 0; index < value.length; index += 1) {
    const character = value[index];
    if (character === '"') {
      if (quoted && value[index + 1] === '"') {
        field += '"';
        index += 1;
      } else quoted = !quoted;
    } else if (character === "\t" && !quoted) {
      rows.at(-1)!.push(field);
      field = "";
    } else if ((character === "\n" || character === "\r") && !quoted) {
      if (character === "\r" && value[index + 1] === "\n") index += 1;
      rows.at(-1)!.push(field);
      rows.push([]);
      field = "";
    } else field += character;
  }
  rows.at(-1)!.push(field);
  return rows.length > 1 && rows.at(-1)?.length === 1 && rows.at(-1)?.[0] === ""
    ? rows.slice(0, -1)
    : rows;
}

export function pasteExtraSheetText(
  sheet: ExtraSheet,
  start: SheetPoint,
  text: string,
  createId: (prefix: string) => string,
): ExtraSheet {
  const pasted = parseExtraSheetTsv(text);
  if (!pasted.length) return sheet;
  if (pasted.length === 1 && pasted[0].length === 1) {
    return updateExtraSheetCell(sheet, start.row, start.column, normalizeExtraRichText(pasted[0][0]));
  }
  let next = unmergeExtraSheetRange(sheet, {
    start,
    end: { row: start.row + pasted.length - 1, column: start.column + Math.max(...pasted.map((row) => row.length)) - 1 },
  });
  const requiredRows = start.row + pasted.length;
  const requiredColumns = start.column + Math.max(...pasted.map((row) => row.length));
  while (next.rows.length < requiredRows) {
    next = addExtraSheetRow(next, createId("extra-sheet-row"));
  }
  while (next.columns.length < requiredColumns) {
    next = addExtraSheetColumn(
      next,
      nextExtraSheetColumnLabel(next.columns),
      createId("extra-sheet-column"),
    );
  }
  return {
    ...next,
    rows: next.rows.map((row, rowIndex) => {
      const pastedRow = pasted[rowIndex - start.row];
      if (!pastedRow) return row;
      const cells = { ...row.cells };
      pastedRow.forEach((cell, offset) => {
        const column = next.columns[start.column + offset];
        if (column) cells[column.id] = normalizeExtraRichText(cell);
      });
      return { ...row, cells };
    }),
  };
}

export function styleExtraSheetCells(
  sheet: ExtraSheet,
  points: Iterable<SheetPoint>,
  patch: RichTextStylePatch,
): ExtraSheet {
  const selected = anchorKeys(sheet, points);
  return {
    ...sheet,
    rows: sheet.rows.map((row, rowIndex) => ({
      ...row,
      cells: Object.fromEntries(Object.entries(row.cells).map(([columnId, value]) => {
        const columnIndex = sheet.columns.findIndex((column) => column.id === columnId);
        return [
          columnId,
          selected.has(`${rowIndex}:${columnIndex}`)
            ? applyRichTextStylePatch(value, patch)
            : value,
        ];
      })),
    })),
  };
}

export function normalizeExtraSheetRichText(sheet: ExtraSheet): ExtraSheet {
  return {
    ...sheet,
    rows: sheet.rows.map((row) => ({
      ...row,
      cells: Object.fromEntries(Object.entries(row.cells).map(([columnId, value]) => [
        columnId,
        normalizeExtraRichText(value),
      ])),
    })),
  };
}