import {
    type DragEventHandler,
    type RefObject,
    useEffect,
    useState,
} from 'react';
import { Alert, Pagination, styled } from '@mui/material';
import useFeatureStrategyApi from 'hooks/api/actions/useFeatureStrategyApi/useFeatureStrategyApi';
import { formatUnknownError } from 'utils/formatUnknownError';
import useToast from 'hooks/useToast';
import type { IFeatureEnvironment } from 'interfaces/featureToggle';
import { useRequiredPathParam } from 'hooks/useRequiredPathParam';
import { useFeature } from 'hooks/api/getters/useFeature/useFeature';
import { useChangeRequestApi } from 'hooks/api/actions/useChangeRequestApi/useChangeRequestApi';
import { useChangeRequestsEnabled } from 'hooks/useChangeRequestsEnabled';
import { usePendingChangeRequests } from 'hooks/api/getters/usePendingChangeRequests/usePendingChangeRequests';
import usePagination from 'hooks/usePagination';
import type { IFeatureStrategy } from 'interfaces/strategy';
import { usePlausibleTracker } from 'hooks/usePlausibleTracker';
import { useUiFlag } from 'hooks/useUiFlag';
import isEqual from 'lodash/isEqual';
import { useReleasePlans } from 'hooks/api/getters/useReleasePlans/useReleasePlans';
import { ReleasePlan } from '../ReleasePlan/ReleasePlan';
import { SectionSeparator } from '../FeatureOverviewEnvironments/FeatureOverviewEnvironment/SectionSeparator/SectionSeparator';
import { Badge } from 'component/common/Badge/Badge';
import { ProjectEnvironmentStrategyDraggableItem } from '../FeatureOverviewEnvironments/FeatureOverviewEnvironment/EnvironmentAccordionBody/StrategyDraggableItem/ProjectEnvironmentStrategyDraggableItem';

interface IEnvironmentAccordionBodyProps {
    isDisabled: boolean;
    featureEnvironment?: IFeatureEnvironment;
    otherEnvironments?: IFeatureEnvironment['name'][];
}

const StyledAccordionBody = styled('div')(({ theme }) => ({
    width: '100%',
    position: 'relative',
    paddingBottom: theme.spacing(2),
}));

const StyledAccordionBodyInnerContainer = styled('div')(({ theme }) => ({
    [theme.breakpoints.down(400)]: {
        padding: theme.spacing(1),
    },
}));

const StyledBadge = styled(Badge)(({ theme }) => ({
    backgroundColor: theme.palette.primary.light,
    border: 'none',
    padding: theme.spacing(0.75, 1.5),
    borderRadius: theme.shape.borderRadiusLarge,
    color: theme.palette.common.white,
}));

/**
 * @deprecated initial version, clean up after done with `flagOverviewRedesign`
 */
export const FeatureOverviewEnvironmentBody = ({
    featureEnvironment,
    isDisabled,
    otherEnvironments,
}: IEnvironmentAccordionBodyProps) => {
    const projectId = useRequiredPathParam('projectId');
    const featureId = useRequiredPathParam('featureId');
    const { setStrategiesSortOrder } = useFeatureStrategyApi();
    const { addChange } = useChangeRequestApi();
    const { isChangeRequestConfigured } = useChangeRequestsEnabled(projectId);
    const { refetch: refetchChangeRequests } =
        usePendingChangeRequests(projectId);
    const { setToastData, setToastApiError } = useToast();
    const { refetchFeature } = useFeature(projectId, featureId);
    const manyStrategiesPagination = useUiFlag('manyStrategiesPagination');
    const [strategies, setStrategies] = useState(
        featureEnvironment?.strategies || [],
    );
    const { releasePlans } = useReleasePlans(
        projectId,
        featureId,
        featureEnvironment?.name,
    );
    const { trackEvent } = usePlausibleTracker();

    const [dragItem, setDragItem] = useState<{
        id: string;
        index: number;
        height: number;
    } | null>(null);

    const [isReordering, setIsReordering] = useState(false);

    useEffect(() => {
        if (isReordering) {
            if (isEqual(featureEnvironment?.strategies, strategies)) {
                setIsReordering(false);
            }
        } else {
            setStrategies(featureEnvironment?.strategies || []);
        }
    }, [featureEnvironment?.strategies]);

    useEffect(() => {
        if (strategies.length > 50) {
            trackEvent('many-strategies');
        }
    }, []);

    if (!featureEnvironment) {
        return null;
    }

    const pageSize = 20;
    const { page, pages, setPageIndex, pageIndex } =
        usePagination<IFeatureStrategy>(strategies, pageSize);

    const onReorder = async (payload: { id: string; sortOrder: number }[]) => {
        try {
            await setStrategiesSortOrder(
                projectId,
                featureId,
                featureEnvironment.name,
                payload,
            );
            refetchFeature();
            setToastData({
                text: 'Order of strategies updated',
                type: 'success',
            });
        } catch (error: unknown) {
            setToastApiError(formatUnknownError(error));
        }
    };

    const onChangeRequestReorder = async (
        payload: { id: string; sortOrder: number }[],
    ) => {
        await addChange(projectId, featureEnvironment.name, {
            action: 'reorderStrategy',
            feature: featureId,
            payload,
        });

        setToastData({
            text: 'Strategy execution order added to draft',
            type: 'success',
        });
        refetchChangeRequests();
    };

    const onStrategyReorder = async (
        payload: { id: string; sortOrder: number }[],
    ) => {
        try {
            if (isChangeRequestConfigured(featureEnvironment.name)) {
                await onChangeRequestReorder(payload);
            } else {
                await onReorder(payload);
            }
        } catch (error: unknown) {
            setToastApiError(formatUnknownError(error));
        }
    };

    const onDragStartRef =
        (
            ref: RefObject<HTMLDivElement>,
            index: number,
        ): DragEventHandler<HTMLButtonElement> =>
        (event) => {
            setIsReordering(true);
            setDragItem({
                id: strategies[index].id,
                index,
                height: ref.current?.offsetHeight || 0,
            });

            if (ref?.current) {
                event.dataTransfer.effectAllowed = 'move';
                event.dataTransfer.setData('text/html', ref.current.outerHTML);
                event.dataTransfer.setDragImage(ref.current, 20, 20);
            }
        };

    const onDragOver =
        (targetId: string) =>
        (
            ref: RefObject<HTMLDivElement>,
            targetIndex: number,
        ): DragEventHandler<HTMLDivElement> =>
        (event) => {
            if (dragItem === null || ref.current === null) return;
            if (dragItem.index === targetIndex || targetId === dragItem.id)
                return;

            const { top, bottom } = ref.current.getBoundingClientRect();
            const overTargetTop = event.clientY - top < dragItem.height;
            const overTargetBottom = bottom - event.clientY < dragItem.height;
            const draggingUp = dragItem.index > targetIndex;

            // prevent oscillating by only reordering if there is sufficient space
            if (
                (overTargetTop && draggingUp) ||
                (overTargetBottom && !draggingUp)
            ) {
                const newStrategies = [...strategies];
                const movedStrategy = newStrategies.splice(
                    dragItem.index,
                    1,
                )[0];
                newStrategies.splice(targetIndex, 0, movedStrategy);
                setStrategies(newStrategies);
                setDragItem({
                    ...dragItem,
                    index: targetIndex,
                });
            }
        };

    const onDragEnd = () => {
        setDragItem(null);
        onStrategyReorder(
            strategies.map((strategy, sortOrder) => ({
                id: strategy.id,
                sortOrder,
            })),
        );
    };

    const strategiesToDisplay = isReordering
        ? strategies
        : featureEnvironment.strategies;

    return (
        <StyledAccordionBody>
            <StyledAccordionBodyInnerContainer>
                {(releasePlans.length > 0 || strategiesToDisplay.length > 0) &&
                isDisabled ? (
                    <Alert severity='warning' sx={{ mb: 2 }}>
                        This environment is disabled, which means that none of
                        your strategies are executing.
                    </Alert>
                ) : null}
                {releasePlans.length > 0 || strategiesToDisplay.length > 0 ? (
                    <>
                        {releasePlans.map((plan) => (
                            <ReleasePlan
                                key={plan.id}
                                plan={plan}
                                environmentIsDisabled={isDisabled}
                            />
                        ))}
                        {releasePlans.length > 0 && strategies.length > 0 ? (
                            <SectionSeparator>
                                <StyledBadge>OR</StyledBadge>
                            </SectionSeparator>
                        ) : null}
                        {strategiesToDisplay.length < 50 ||
                        !manyStrategiesPagination ? (
                            <>
                                {strategiesToDisplay.map((strategy, index) => (
                                    <ProjectEnvironmentStrategyDraggableItem
                                        key={strategy.id}
                                        strategy={strategy}
                                        index={index}
                                        environmentName={
                                            featureEnvironment.name
                                        }
                                        otherEnvironments={otherEnvironments}
                                        isDragging={
                                            dragItem?.id === strategy.id
                                        }
                                        onDragStartRef={onDragStartRef}
                                        onDragOver={onDragOver(strategy.id)}
                                        onDragEnd={onDragEnd}
                                    />
                                ))}
                            </>
                        ) : (
                            <>
                                <Alert severity='error'>
                                    We noticed you're using a high number of
                                    activation strategies. To ensure a more
                                    targeted approach, consider leveraging
                                    constraints or segments.
                                </Alert>
                                <br />
                                {page.map((strategy, index) => (
                                    <ProjectEnvironmentStrategyDraggableItem
                                        key={strategy.id}
                                        strategy={strategy}
                                        index={index + pageIndex * pageSize}
                                        environmentName={
                                            featureEnvironment.name
                                        }
                                        otherEnvironments={otherEnvironments}
                                        isDragging={false}
                                        onDragStartRef={(() => {}) as any}
                                        onDragOver={(() => {}) as any}
                                        onDragEnd={(() => {}) as any}
                                    />
                                ))}
                                <br />
                                <Pagination
                                    count={pages.length}
                                    shape='rounded'
                                    page={pageIndex + 1}
                                    onChange={(_, page) =>
                                        setPageIndex(page - 1)
                                    }
                                />
                            </>
                        )}
                    </>
                ) : null}
                {/* TODO: fit "copy from other environment" option somewhere */}
            </StyledAccordionBodyInnerContainer>
        </StyledAccordionBody>
    );
};