import { diff } from 'deep-diff';
import type { IEvent } from 'interfaces/event';
import { useTheme } from '@mui/system';
import type { JSX, CSSProperties } from 'react';

const DIFF_PREFIXES: Record<string, string> = {
    A: ' ',
    E: ' ',
    D: '-',
    N: '+',
};

interface IEventDiffResult {
    key: string;
    value: JSX.Element;
    index: number;
}

interface IEventDiffProps {
    entry: Partial<IEvent>;
    sort?: (a: IEventDiffResult, b: IEventDiffResult) => number;
}

const EventDiff = ({
    entry,
    sort = (a, b) => a.key.localeCompare(b.key),
}: IEventDiffProps) => {
    const theme = useTheme();

    const styles: Record<string, CSSProperties> = {
        A: { color: theme.palette.eventLog.edited }, // array edited
        E: { color: theme.palette.eventLog.edited }, // edited
        D: { color: theme.palette.eventLog.diffSub }, // deleted
        N: { color: theme.palette.eventLog.diffAdd }, // added
    };

    const diffs =
        entry.data && entry.preData
            ? diff(entry.preData, entry.data)
            : undefined;

    const buildItemDiff = (diff: any, key: string) => {
        let change: JSX.Element | undefined;
        if (diff.lhs !== undefined) {
            change = (
                <div style={styles.D}>
                    - {key}: {JSON.stringify(diff.lhs)}
                </div>
            );
        } else if (diff.rhs !== undefined) {
            change = (
                <div style={styles.N}>
                    + {key}: {JSON.stringify(diff.rhs)}
                </div>
            );
        }

        return change;
    };

    const buildDiff = (diff: any, index: number): IEventDiffResult => {
        let change: JSX.Element | undefined;
        const key = diff.path?.join('.') ?? diff.index;

        if (diff.item) {
            change = buildItemDiff(diff.item, key);
        } else if (diff.lhs !== undefined && diff.rhs !== undefined) {
            change = (
                <div>
                    <div style={styles.D}>
                        - {key}: {JSON.stringify(diff.lhs)}
                    </div>
                    <div style={styles.N}>
                        + {key}: {JSON.stringify(diff.rhs)}
                    </div>
                </div>
            );
        } else {
            const changeValue = JSON.stringify(diff.rhs || diff.item);
            change = (
                <div style={styles[diff.kind]}>
                    {DIFF_PREFIXES[diff.kind]} {key}
                    {changeValue
                        ? `: ${changeValue}`
                        : diff.kind === 'D'
                          ? ' (deleted)'
                          : ''}
                </div>
            );
        }

        return {
            key: key.toString(),
            value: <div key={index}>{change}</div>,
            index,
        };
    };

    let changes: any[] = [];

    if (diffs) {
        changes = diffs
            .map(buildDiff)
            .sort(sort)
            .map(({ value }) => value);
    } else if (entry.data == null || entry.preData == null) {
        // Just show the data if there is no diff yet.
        const data = entry.data || entry.preData;
        changes = [
            <div key={0} style={entry.data ? styles.N : styles.D}>
                {JSON.stringify(data, null, 2)}
            </div>,
        ];
    }

    return (
        // biome-ignore lint/a11y/noNoninteractiveTabindex: <explanation>
        <pre style={{ overflowX: 'auto', overflowY: 'hidden' }} tabIndex={0}>
            <code>{changes.length === 0 ? '(no changes)' : changes}</code>
        </pre>
    );
};

export default EventDiff;