import * as z from "zod";

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

const extraSheetId = z.string().min(1).max(128);

export const extraSheetSchema = z.strictObject({
  columns: z.array(z.strictObject({
    id: extraSheetId,
    label: z.string().trim().min(1).max(120),
  })).min(1),
  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({}),
  })).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" });
  }
  sheet.rows.forEach((row, rowIndex) => {
    [...Object.keys(row.cells), ...Object.keys(row.backgrounds ?? {})].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 };
export type ExtraSheetMatrix = Array<Array<ExtraSheetCell | undefined>>;
type SheetPoint = { row: number; column: number };

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 = [1, 2].map((index) => ({
    id: createId("extra-sheet-column"),
    label: `คอลัมน์ ${index}`,
  }));
  return {
    columns,
    rows: [1, 2].map(() => ({
      id: createId("extra-sheet-row"),
      cells: Object.fromEntries(columns.map((column) => [column.id, ""])),
      backgrounds: {},
    })),
  };
}

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],
    })),
  );
}

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),
    });
  }
  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]] : [];
    })),
  }));
  return { columns, rows };
}

export function addExtraSheetColumn(
  sheet: ExtraSheet,
  label: string,
  id: string,
): ExtraSheet {
  return {
    columns: [...sheet.columns, { id, label }],
    rows: sheet.rows.map((row) => ({ ...row, cells: { ...row.cells, [id]: "" } })),
  };
}

export function addExtraSheetRow(sheet: ExtraSheet, id: string): ExtraSheet {
  return {
    ...sheet,
    rows: [...sheet.rows, {
      id,
      cells: Object.fromEntries(sheet.columns.map((column) => [column.id, ""])),
      backgrounds: {},
    }],
  };
}

export function moveExtraSheetColumn(
  sheet: ExtraSheet,
  from: number,
  to: number,
): ExtraSheet {
  if (to < 0 || to >= sheet.columns.length || from === to) return sheet;
  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;
  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;
  return {
    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)),
    })),
  };
}

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

export function updateExtraSheetCell(
  sheet: ExtraSheet,
  rowIndex: number,
  columnIndex: number,
  value: string,
): ExtraSheet {
  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 },
): ExtraSheet {
  const selected = new Set(Array.from(points, ({ row, column }) => `${row}:${column}`));
  return {
    ...sheet,
    rows: sheet.rows.map((row, rowIndex) => {
      const cells = { ...row.cells };
      const backgrounds = { ...(row.backgrounds ?? {}) };
      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;
      });
      return { ...row, cells, backgrounds };
    }),
  };
}

export function styleExtraSheetCells(
  sheet: ExtraSheet,
  points: Iterable<SheetPoint>,
  patch: RichTextStylePatch,
): ExtraSheet {
  const selected = new Set(Array.from(points, ({ row, column }) => `${row}:${column}`));
  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),
      ])),
    })),
  };
}