import ExcelJS from "exceljs";
import { promises as fs } from "node:fs";
import path from "node:path";
import { register } from "../engine/registry";
import { RuntimeError, type CapabilityHandler } from "../engine/types";
import { defaultEngine } from "../engine/engine";
import { acquireWorkbook, publishWorkbook, releaseWorkbook } from "./excel-store";

interface ExcelHandle {
  id: string;
  path: string;
}

// 句柄 id → 工作簿；本体挂在引擎实例上（任务 1.3），此处委托 defaultEngine。
const workbooks = defaultEngine.excelHandles;

function value(args: Record<string, unknown>, keys: string[], fallback = ""): unknown {
  for (const key of keys) {
    if (args[key] !== undefined && args[key] !== null && args[key] !== "") return args[key];
  }
  return fallback;
}

function text(args: Record<string, unknown>, keys: string[], fallback = ""): string {
  return String(value(args, keys, fallback));
}

function bool(valueToRead: unknown, fallback = false): boolean {
  if (valueToRead === undefined || valueToRead === null || valueToRead === "") return fallback;
  if (typeof valueToRead === "string") return ["true", "1", "yes", "是", "开启"].includes(valueToRead.trim().toLowerCase());
  return [true, "true", "1", 1, "是", "开启"].includes(valueToRead as never);
}

function required(valueToRead: unknown, label: string, nodeId: string, componentId: string): string {
  const result = String(valueToRead || "").trim();
  if (!result) throw new RuntimeError("validation_error", `${label}为空`, { nodeId, componentId, recommendation: `请配置${label}` });
  return result;
}

function newHandle(filePath: string, workbook: ExcelJS.Workbook): ExcelHandle {
  const handle = { id: `excel_${Date.now().toString(36)}_${Math.random().toString(36).slice(2, 7)}`, path: filePath };
  workbooks.set(handle.id, workbook);
  publishWorkbook(filePath, workbook);
  return handle;
}

async function resolveWorkbook(args: Record<string, unknown>, nodeId: string, componentId: string): Promise<{ handle: ExcelHandle; workbook: ExcelJS.Workbook }> {
  const raw = value(args, ["workbook", "objExcel", "objExcelWorkBook", "file", "path"]);
  const id = typeof raw === "object" && raw !== null ? String((raw as Partial<ExcelHandle>).id || "") : String(raw || "");
  const existing = id ? workbooks.get(id) : undefined;
  // 直接返回流程变量持有的原始句柄对象：saveAs 等处理器对其 path 的改写需要
  // 同步反映到后续节点引用的同一个对象上
  if (existing) return { handle: raw as ExcelHandle, workbook: existing };
  const filePath = required(typeof raw === "object" ? (raw as Partial<ExcelHandle>).path : raw, "Excel文件路径", nodeId, componentId);
  const workbook = await acquireWorkbook(filePath);
  return { handle: { id, path: filePath }, workbook };
}

function sheetOf(workbook: ExcelJS.Workbook, name: string): ExcelJS.Worksheet {
  const sheet = name ? workbook.getWorksheet(name) : workbook.worksheets[0];
  if (!sheet) throw new Error(`Sheet 不存在：${name || "第一个 Sheet"}`);
  return sheet;
}

function parseRange(range: string, sheet: ExcelJS.Worksheet): { start: string; end?: string } {
  if (range.trim()) {
    const [start, end] = range.split(":").map((item) => item.trim());
    return { start, end };
  }
  const lastRow = Math.max(1, sheet.rowCount);
  const lastColumn = Math.max(1, sheet.columnCount);
  return { start: "A1", end: `${sheet.getColumn(lastColumn).letter}${lastRow}` };
}

function cellValue(valueToRead: ExcelJS.CellValue): unknown {
  if (valueToRead && typeof valueToRead === "object" && "text" in valueToRead) return valueToRead.text;
  if (valueToRead && typeof valueToRead === "object" && "result" in valueToRead) return valueToRead.result;
  return valueToRead ?? "";
}

function tableFromSheet(sheet: ExcelJS.Worksheet, range: string): unknown[][] {
  const target = parseRange(range, sheet);
  const startRow = Number(sheet.getCell(target.start).row);
  const endRow = target.end ? Number(sheet.getCell(target.end).row) : sheet.rowCount;
  const rows = sheet.getRows(startRow, Math.max(1, endRow - startRow + 1)) || [];
  const startColumn = Number(sheet.getCell(target.start).col);
  const endColumn = target.end ? Number(sheet.getCell(target.end).col) : sheet.columnCount;
  return rows.map((row) => {
    const values: unknown[] = [];
    for (let column = startColumn; column <= endColumn; column += 1) values.push(cellValue(row.getCell(column).value));
    return values;
  });
}

function rowsFrom(valueToRead: unknown): unknown[][] {
  if (Array.isArray(valueToRead)) {
    return valueToRead.map((row) => Array.isArray(row) ? row : [row]);
  }
  if (typeof valueToRead === "string") {
    try {
      return rowsFrom(JSON.parse(valueToRead));
    } catch {
      return [[valueToRead]];
    }
  }
  return [[valueToRead]];
}

const newExcel: CapabilityHandler = async (_ctx, node, args) => {
  const folder = required(value(args, ["filePath", "path", "folder"]), "文件路径", node.id, node.componentId);
  const name = text(args, ["name"], "新建工作簿.xlsx");
  const filePath = path.resolve(folder, path.extname(name) ? name : `${name}.xlsx`);
  const makedirs = bool(value(args, ["isMakedirs"]), true);
  if (!makedirs) {
    try {
      await fs.access(path.dirname(filePath));
    } catch {
      throw new RuntimeError("validation_error", `目录不存在：${path.dirname(filePath)}`, { nodeId: node.id, componentId: node.componentId, recommendation: "将「是否创建该路径」设为 True，或先创建目录" });
    }
  }
  if (!bool(value(args, ["override"]), true)) {
    try {
      await fs.access(filePath);
      throw new RuntimeError("validation_error", `文件已存在：${filePath}`, { nodeId: node.id, componentId: node.componentId, recommendation: "开启覆盖同名文件，或修改文件名称" });
    } catch (error) {
      if (error instanceof RuntimeError) throw error;
    }
  }
  const workbook = new ExcelJS.Workbook();
  workbook.addWorksheet("Sheet1");
  await fs.mkdir(path.dirname(filePath), { recursive: true });
  await workbook.xlsx.writeFile(filePath);
  return newHandle(filePath, workbook);
};

const openExcel: CapabilityHandler = async (_ctx, node, args) => {
  const filePath = path.resolve(required(value(args, ["file", "filePath", "path"]), "Excel文件", node.id, node.componentId));
  const workbook = await acquireWorkbook(filePath);
  return newHandle(filePath, workbook);
};

const readExcel: CapabilityHandler = async (_ctx, node, args) => {
  const { workbook } = await resolveWorkbook(args, node.id, node.componentId);
  const sheet = sheetOf(workbook, text(args, ["sheet", "sheetName"]));
  return tableFromSheet(sheet, text(args, ["range", "excelRng"]));
};

const writeCell: CapabilityHandler = async (_ctx, node, args) => {
  const { handle, workbook } = await resolveWorkbook(args, node.id, node.componentId);
  const sheet = sheetOf(workbook, text(args, ["sheet", "sheetName"]));
  const address = `${text(args, ["column"], "A")}${text(args, ["row"], "1")}`;
  sheet.getCell(address).value = value(args, ["content", "value"]) as ExcelJS.CellValue;
  if (bool(value(args, ["save"]), true)) await workbook.xlsx.writeFile(handle.path);
  return handle;
};

const writeRange: CapabilityHandler = async (_ctx, node, args) => {
  const { handle, workbook } = await resolveWorkbook(args, node.id, node.componentId);
  const sheet = sheetOf(workbook, text(args, ["sheet", "sheetName"]));
  const cellPos = text(args, ["cellPos"]);
  const cellMatch = cellPos.match(/^([A-Za-z]+)(\d+)$/);
  const column = cellMatch ? cellMatch[1] : text(args, ["column"], "A");
  const row = cellMatch ? cellMatch[2] : text(args, ["row"], "1");
  const start = `${column}${row}`;
  const startCell = sheet.getCell(start);
  const startRow = startCell.row;
  const startColumn = startCell.col;
  for (const [rowIndex, row] of rowsFrom(value(args, ["contents", "data", "table"])).entries()) {
    for (const [columnIndex, cell] of row.entries()) sheet.getCell(startRow + rowIndex, startColumn + columnIndex).value = cell as ExcelJS.CellValue;
  }
  if (bool(value(args, ["save", "isSave"]), true)) await workbook.xlsx.writeFile(handle.path);
  return handle;
};

const saveExcel: CapabilityHandler = async (_ctx, node, args) => {
  const { handle, workbook } = await resolveWorkbook(args, node.id, node.componentId);
  await workbook.xlsx.writeFile(handle.path);
  return handle.path;
};

const saveAsExcel: CapabilityHandler = async (_ctx, node, args) => {
  const { handle, workbook } = await resolveWorkbook(args, node.id, node.componentId);
  // CS 版（Excel_Cs_SaveAs）用 path=目录 + name=文件名；Legacy（Excel_SaveAs）用 filename=完整路径
  const rawName = text(args, ["name"]);
  const raw = rawName
    ? path.resolve(text(args, ["path", "file", "savePath"], ""), rawName)
    : required(value(args, ["path", "file", "savePath", "filename", "saveFilePath"]), "另存为路径", node.id, node.componentId);
  // Legacy Excel_SaveAs 用 isAbsolutePath 标记 filename 是否为绝对路径，相对路径基于原文件目录
  const absolute = rawName ? true : bool(value(args, ["isAbsolutePath"]), true);
  const previousPath = handle.path;
  handle.path = absolute ? path.resolve(raw) : path.resolve(path.dirname(previousPath), raw);
  await fs.mkdir(path.dirname(handle.path), { recursive: true });
  await workbook.xlsx.writeFile(handle.path);
  // 另存后同一实例以新路径登记，旧路径的缓存不再代表最新内容，释放之
  publishWorkbook(handle.path, workbook);
  if (path.resolve(previousPath) !== handle.path) releaseWorkbook(previousPath);
  return handle;
};

register(["Excel_Cs_NewV5", "Excel_Cs_New", "Excel_New"], newExcel);
register(["Excel_Cs_OpenV4", "Excel_Cs_Open", "Excel_Open"], openExcel);
register(["Excel_Cs_ReadContentV2", "Excel_Cs_ReadRangeV2", "Excel_ReadRange"], readExcel);
register(["Excel_Cs_WriteCell", "Excel_WriteCell"], writeCell);
register(["Excel_Cs_WriteRange", "Excel_WriteRange"], writeRange);
register(["Excel_Save", "Excel_Cs_Save", "Excel_SaveV2"], saveExcel);
register(["Excel_Cs_SaveAs", "Excel_SaveAs"], saveAsExcel);
register(["Excel_GetSheetsName", "Excel_GetSheetNames"], async (_ctx, node, args) => {
  const { workbook } = await resolveWorkbook(args, node.id, node.componentId);
  return workbook.worksheets.map((sheet) => sheet.name);
});
register(["Excel_Cs_Rename", "Excel_RenameSheet"], async (_ctx, node, args) => {
  const { handle, workbook } = await resolveWorkbook(args, node.id, node.componentId);
  const oldName = required(value(args, ["sheet", "oldName"]), "原 Sheet 名称", node.id, node.componentId);
  const newName = required(value(args, ["newSheet", "newName", "name", "sheetName"]), "新 Sheet 名称", node.id, node.componentId);
  const sheet = sheetOf(workbook, oldName);
  sheet.name = newName;
  await workbook.xlsx.writeFile(handle.path);
  return handle;
});
register(["Excel_Cs_Insert", "Excel_InsertSheet"], async (_ctx, node, args) => {
  const { handle, workbook } = await resolveWorkbook(args, node.id, node.componentId);
  const name = required(value(args, ["name", "sheetName"]), "Sheet名称", node.id, node.componentId);
  if (workbook.getWorksheet(name)) throw new RuntimeError("validation_error", `Sheet 已存在：${name}`, { nodeId: node.id, componentId: node.componentId });
  workbook.addWorksheet(name);
  if (bool(value(args, ["save"]), false)) await workbook.xlsx.writeFile(handle.path);
  return handle;
});
register("Excel_Cs_InsertRow", async (_ctx, node, args) => {
  const { handle, workbook } = await resolveWorkbook(args, node.id, node.componentId);
  const sheet = sheetOf(workbook, text(args, ["sheet", "sheetName"]));
  const index = Math.max(1, Number(value(args, ["index"], "1")) || 1);
  const count = Math.max(1, Number(value(args, ["count"], "1")) || 1);
  const rows = rowsFrom(value(args, ["contents"]));
  const inserts = Array.from({ length: count }, (_, rowIndex) => rows[rowIndex] || []);
  sheet.spliceRows(index, 0, ...inserts);
  if (bool(value(args, ["save"]), true)) await workbook.xlsx.writeFile(handle.path);
  return handle;
});
register("Excel_Cs_InsertColumn", async (_ctx, node, args) => {
  const { handle, workbook } = await resolveWorkbook(args, node.id, node.componentId);
  const sheet = sheetOf(workbook, text(args, ["sheet", "sheetName"]));
  const index = Math.max(1, Number(value(args, ["index"], "1")) || 1);
  const count = Math.max(1, Number(value(args, ["count"], "1")) || 1);
  const values = rowsFrom(value(args, ["contents"])).flat();
  const inserts = Array.from({ length: count }, (_, columnIndex) => [values[columnIndex] ?? ""]);
  sheet.spliceColumns(index, 0, ...inserts);
  if (bool(value(args, ["save"]), true)) await workbook.xlsx.writeFile(handle.path);
  return handle;
});