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 { SpinnerLoader } from "../common/Loader";

const formatDate = (dateStr) => {
  const date = new Date(dateStr);
  return date.toLocaleDateString("en-GB", {
    day: "2-digit",
    month: "long",
  });
};

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

  const projectId = useSelector((store) => store.localVariables.projectId);
  const { attendanceOverviewData, loading, error } = useAttendanceOverviewData(
    projectId,
    dayRange
  );

  const { tableData, roles, dates } = useMemo(() => {
    const map = new Map();

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

    const uniqueRoles = [
      ...new Set(attendanceOverviewData.map((e) => e.role.trim())),
    ];
    const sortedDates = [...map.keys()];
    const data = sortedDates.map((date) => {
      const row = { date };
      uniqueRoles.forEach((role) => {
        row[role] = map.get(date)?.[role] ?? 0;
      });
      return row;
    });

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

  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",
        offsetX: 0,
        offsetY: 0,
      },
      axisTicks: {
        show: true,
        borderType: "solid",
        color: "#78909C",
        width: 6,
        offsetX: 0,
        offsetY: 0,
      },
    },
    legend: {
      position: "bottom",
    },
    fill: {
      opacity: 1,
    },
    colors: roles.map((_, i) => flatColors[i % flatColors.length]),
  };

  return (
    <div className="bg-white px-4 rounded shadow d-flex flex-column h-100" style={{ minHeight: "450px" }}>
      {/* Header */}
      <div className="d-flex mt-2 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">
        {loading ? (
          <SpinnerLoader />
        ) : error ? (
          <p className="text-danger">{error}</p>
        ) : attendanceOverviewData.length === 0 ||
          attendanceOverviewData.every((item) => item.present === 0) ? (
          <div className="text-center text-dark">No data found</div>
        ) : 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];
                      const cellStyle = value > 0 ? { backgroundColor: "#d5d5d5" } : {};
                      return (
                        <td key={idx} style={cellStyle}>
                          {value}
                        </td>
                      );
                    })}
                  </tr>
                ))}
              </tbody>
            </table>
          </div>
        )}
      </div>
    </div>
  );
};

export default AttendanceOverview;