import { useMemo, useState } from "react";
import Link from "next/link";

export default function AppealStatusDashboard({ statusObj = [] }) {
    const [openSections, setOpenSections] = useState({});

    const sortedAppeals = useMemo(
        () =>
            [...statusObj].sort(
                (a, b) => (b.caseCount || 0) - (a.caseCount || 0)
            ),
        [statusObj]
    );

    const percentageOf = (value, total) =>
        total ? `${(((value || 0) / total) * 100).toFixed(1)}%` : "0.0%";

    const totalCases = sortedAppeals.reduce(
        (sum, appeal) => sum + (appeal.caseCount || 0),
        0
    );

    const largestAppeal = sortedAppeals[0];

    const allStatuses = sortedAppeals.flatMap((appeal) =>
        (appeal.statuses || []).map((status) => ({
            ...status,
            appealType: appeal.value
        }))
    );

    const statusTotals = allStatuses.reduce((acc, status) => {
        if (!acc[status.statuscode]) {
            acc[status.statuscode] = {
                value: status.value,
                statuscode: status.statuscode,
                caseCount: 0
            };
        }

        acc[status.statuscode].caseCount += status.caseCount || 0;
        return acc;
    }, {});

    const mostCommonStatus = Object.values(statusTotals).sort(
        (a, b) => b.caseCount - a.caseCount
    )[0];

    const maxAppealCount = largestAppeal?.caseCount || 1;

    const allExpanded =
        sortedAppeals.length > 0 &&
        sortedAppeals.every((_, index) => openSections[index]);

    const toggleSection = (index) => {
        setOpenSections((current) => ({
            ...current,
            [index]: !current[index]
        }));
    };

    const showAll = () => {
        const allOpen = {};
        sortedAppeals.forEach((_, index) => {
            allOpen[index] = true;
        });
        setOpenSections(allOpen);
    };

    const hideAll = () => {
        setOpenSections({});
    };

    return (
        <div className="govuk-grid-row">
            <div className="govuk-grid-column-full">
                <h1>Appeal case status dashboard</h1>

                <div className="govuk-grid-row">
                    <DashboardCard title="Total cases" value={totalCases} />
                    <DashboardCard
                        title="Appeal types"
                        value={sortedAppeals.length}
                    />
                    <DashboardCard
                        title="Largest appeal type"
                        value={largestAppeal?.caseCount || 0}
                        caption={largestAppeal?.value}
                    />
                    <DashboardCard
                        title="Most common status"
                        value={mostCommonStatus?.caseCount || 0}
                        caption={mostCommonStatus?.value}
                    />
                </div>

                <section className="govuk-!-margin-top-8">
                    <h2 className="govuk-heading-m">
                        Case counts and stage breakdown by appeal type
                    </h2>

                    <p className="govuk-body-s">
                        Select an appeal type row to show the case stage
                        breakdown.
                    </p>

                    <div className="govuk-accordion__controls">
                        <button
                            type="button"
                            className="govuk-accordion__show-all"
                            onClick={allExpanded ? hideAll : showAll}
                        >
                            <span className="govuk-accordion__show-all-text">
                                {allExpanded
                                    ? "Hide all sections"
                                    : "Show all sections"}
                            </span>
                        </button>
                    </div>

                    <div
                        className="govuk-accordion appeal-stage-chart"
                        id="appeals-with-status-accordion"
                    >
                        {sortedAppeals.map((appeal, index) => {
                            const isOpen = !!openSections[index];

                            const barWidth =
                                ((appeal.caseCount || 0) / maxAppealCount) *
                                100;

                            const sortedStatuses = [...(appeal.statuses || [])]
                                .filter((status) => (status.caseCount || 0) > 0)
                                .sort(
                                    (a, b) =>
                                        (b.caseCount || 0) - (a.caseCount || 0)
                                );

                            return (
                                <div
                                    className={
                                        isOpen
                                            ? "govuk-accordion__section govuk-accordion__section--expanded appeal-stage-chart__accordion-section"
                                            : "govuk-accordion__section appeal-stage-chart__accordion-section"
                                    }
                                    key={appeal.appealType || index}
                                >
                                    <div className="govuk-accordion__section-header">
                                        <h2 className="govuk-accordion__section-heading">
                                            <button
                                                type="button"
                                                className="govuk-accordion__section-button appeal-stage-chart__button"
                                                id={`appeal-status-heading-${index}`}
                                                aria-expanded={isOpen}
                                                aria-controls={`appeal-status-content-${index}`}
                                                onClick={() =>
                                                    toggleSection(index)
                                                }
                                            >
                                                <span className="appeal-stage-chart__row">
                                                    <span className="appeal-stage-chart__label">
                                                        {appeal.value} (
                                                        {percentageOf(
                                                            appeal.caseCount,
                                                            totalCases
                                                        )}
                                                        )
                                                    </span>

                                                    <span className="appeal-stage-chart__bar-wrapper">
                                                        <span
                                                            className="appeal-stage-chart__bar"
                                                            style={{
                                                                width: `${barWidth}%`
                                                            }}
                                                            aria-hidden="true"
                                                        >
                                                            {sortedStatuses.map(
                                                                (
                                                                    status,
                                                                    statusIndex
                                                                ) => (
                                                                    <span
                                                                        key={`${status.statuscode}-${statusIndex}`}
                                                                        className={`appeal-stage-chart__segment appeal-stage-chart__segment--${
                                                                            statusIndex %
                                                                            6
                                                                        }`}
                                                                        style={{
                                                                            width: `${
                                                                                ((status.caseCount ||
                                                                                    0) /
                                                                                    (appeal.caseCount ||
                                                                                        1)) *
                                                                                100
                                                                            }%`
                                                                        }}
                                                                        title={`${status.value}: ${status.caseCount}`}
                                                                    />
                                                                )
                                                            )}
                                                        </span>

                                                        <span className="appeal-stage-chart__count">
                                                            {appeal.caseCount ||
                                                                0}{" "}
                                                            cases
                                                        </span>
                                                    </span>
                                                </span>
                                            </button>
                                        </h2>
                                    </div>

                                    <div
                                        id={`appeal-status-content-${index}`}
                                        className="govuk-accordion__section-content"
                                        aria-labelledby={`appeal-status-heading-${index}`}
                                        hidden={!isOpen}
                                    >
                                        <dl className="govuk-summary-list">
                                            {sortedStatuses.map((status) => (
                                                <div
                                                    className="govuk-summary-list__row"
                                                    key={status.statuscode}
                                                >
                                                    <dt className="govuk-summary-list__key">
                                                        <Link
                                                            target="_blank"
                                                            href={`/advancedsearchresults?apt=${appeal.appealType}&statuscode=${status.statuscode}`}
                                                        >
                                                            {status.value}
                                                        </Link>
                                                    </dt>

                                                    <dd className="govuk-summary-list__value">
                                                        {status.caseCount || 0}{" "}
                                                        cases (
                                                        {percentageOf(
                                                            status.caseCount,
                                                            appeal.caseCount
                                                        )}{" "}
                                                        of this appeal type)
                                                    </dd>
                                                </div>
                                            ))}
                                        </dl>
                                    </div>
                                </div>
                            );
                        })}
                    </div>
                </section>
            </div>
        </div>
    );
}

function DashboardCard({ title, value, caption }) {
    return (
        <div className="govuk-grid-column-one-quarter">
            <div className="dashboard-card">
                <p className="govuk-body-s dashboard-card__title">{title}</p>
                <p className="govuk-heading-l dashboard-card__value">{value}</p>
                {caption && (
                    <p className="govuk-body-s dashboard-card__caption">
                        {caption}
                    </p>
                )}
            </div>
        </div>
    );
}