import React, { useState, useMemo } from "react";
import { useSelector } from "react-redux";
import ReactApexChart from "react-apexcharts";
import { useAttendanceOverviewData } from "../../hooks/useDashboard_Data";
import flatColors from "../Charts/flatColor";
import ChartSkeleton from "../Charts/Skelton";
import { useSelectedProject } from "../../slices/apiDataManager";
import { formatDate_DayMonth } from "../../utils/dateUtils";



const AttendanceOverview = () => {
  const [dayRange, setDayRange] = useState(7);
  const [view, setView] = useState("chart");
  const selectedProject = useSelectedProject();

  const { data: attendanceOverviewData, isLoading, isError, error } = useAttendanceOverviewData(
    selectedProject,
    dayRange
  );

  // Use empty array while loading
  const attendanceData = attendanceOverviewData || [];

  const { tableData, roles, dates } = useMemo(() => {
    if (!attendanceData || attendanceData.length === 0) {
      return { tableData: [], roles: [], dates: [] };
    }

    const map = new Map();

    attendanceData.forEach((entry) => {
      const date = formatDate_DayMonth(entry.date);
      if (!map.has(date)) map.set(date, {});
      map.get(date)[entry.role.trim()] = entry.present;
    });

    const uniqueRoles = [...new Set(attendanceData.map((e) => e.role.trim()))];
    const sortedDates = [...map.keys()];

    const tableData = sortedDates.map((date) => {
      const row = { date };
      uniqueRoles.forEach((role) => {
        row[role] = map.get(date)?.[role] ?? 0;
      });
      return row;
    });

    return { tableData, roles: uniqueRoles, dates: sortedDates };
  }, [attendanceData]);

  const chartSeries = roles.map((role) => ({
    name: role,
    data: tableData.map((row) => row[role]),
  }));

  const chartOptions = {
    chart: { type: "bar", stacked: true, height: 400, toolbar: { show: false } },
    plotOptions: { bar: { borderRadius: 2, columnWidth: "60%" } },
    xaxis: { categories: tableData.map((row) => row.date) },
    yaxis: { show: true, axisBorder: { show: true, color: "#78909C" }, axisTicks: { show: true, color: "#78909C", width: 6 } },
    legend: { position: "bottom" },
    fill: { opacity: 1 },
    colors: roles.map((_, i) => flatColors[i % flatColors.length]),
  };

  return (
    <div className="bg-white p-4 rounded shadow d-flex flex-column position-relative">
      {/* Optional subtle loading overlay */}
      {isLoading && (
        <div className="position-absolute w-100 h-100 d-flex align-items-center justify-content-center bg-white bg-opacity-50 z-index-1">
          <span>Loading...</span>
        </div>
      )}

      {/* Header */}
      <div className="d-flex justify-content-between align-items-center mb-3">
        <div className="card-title mb-0 text-start">
          <h5 className="mb-1 fw-bold">Attendance Overview</h5>
          <p className="card-subtitle">Role-wise present count</p>
        </div>
        <div className="d-flex gap-2">
          <select className="form-select form-select-sm" value={dayRange} onChange={(e) => setDayRange(Number(e.target.value))}>
            <option value={7}>Last 7 Days</option>
            <option value={15}>Last 15 Days</option>
            <option value={30}>Last 30 Days</option>
          </select>
          <button className={`btn btn-sm p-1 ${view === "chart" ? "btn-primary" : "btn-outline-primary"}`} onClick={() => setView("chart")} title="Chart View">
            <i className="bx bx-bar-chart-alt-2"></i>
          </button>
          <button className={`btn btn-sm p-1 ${view === "table" ? "btn-primary" : "btn-outline-primary"}`} onClick={() => setView("table")} title="Table View">
            <i className="bx bx-list-ul fs-5"></i>
          </button>
        </div>
      </div>

      {/* Content */}
      <div className="flex-grow-1 d-flex align-items-center justify-content-center">
        {view === "chart" ? (
          <div className="w-100">
            <ReactApexChart options={chartOptions} series={chartSeries} type="bar" height={400} />
          </div>
        ) : (
          <div className="table-responsive w-100" style={{ maxHeight: "350px", overflowY: "auto" }}>
            <table className="table table-bordered table-sm text-start align-middle mb-0">
              <thead className="table-light" style={{ position: "sticky", top: 0, zIndex: 1 }}>
                <tr>
                  <th style={{ background: "#f8f9fa", textTransform: "none" }}>Role</th>
                  {dates.map((date, idx) => (
                    <th key={idx} style={{ background: "#f8f9fa", textTransform: "none" }}>{date}</th>
                  ))}
                </tr>
              </thead>
              <tbody>
                {roles.map((role) => (
                  <tr key={role}>
                    <td>{role}</td>
                    {tableData.map((row, idx) => {
                      const value = row[role];
                      return <td key={idx} style={value > 0 ? { backgroundColor: "#d5d5d5" } : {}}>{value}</td>;
                    })}
                  </tr>
                ))}
              </tbody>
            </table>
          </div>
        )}
      </div>
    </div>
  );
};

export default AttendanceOverview;