'use client';

import { useParams } from 'next/navigation';
import { useMemo } from 'react';
import { useQuery, useQueryClient } from '@tanstack/react-query';
import { DndContext, closestCenter, type DragEndEvent } from '@dnd-kit/core';

import { PipelineColumn } from '@/components/interests/pipeline-column';
import { apiFetch } from '@/lib/api/client';
import { usePipelineStore } from '@/stores/pipeline-store';
import { PIPELINE_STAGES } from '@/lib/constants';

const STAGE_LABELS: Record<string, string> = {
  open: 'Open',
  details_sent: 'Details Sent',
  in_communication: 'In Communication',
  visited: 'Visited',
  signed_eoi_nda: 'Signed EOI/NDA',
  deposit_10pct: 'Deposit 10%',
  contract: 'Contract',
  completed: 'Completed',
};

interface InterestRow {
  id: string;
  clientName: string | null;
  berthMooringNumber: string | null;
  leadCategory: string | null;
  pipelineStage: string;
  updatedAt: string;
}

export function PipelineBoard() {
  const params = useParams<{ portSlug: string }>();
  const portSlug = params?.portSlug ?? '';
  const queryClient = useQueryClient();
  const { boardFilters } = usePipelineStore();

  const { data: allData, isLoading } = useQuery<{ data: InterestRow[] }>({
    queryKey: ['interests-board', portSlug],
    queryFn: () => apiFetch('/api/v1/interests?limit=500'),
  });

  const interests = useMemo(() => {
    if (!allData?.data) return [];
    return allData.data.filter((i) => {
      if (boardFilters.leadCategory && i.leadCategory !== boardFilters.leadCategory) return false;
      if (boardFilters.search) {
        const q = boardFilters.search.toLowerCase();
        if (!i.clientName?.toLowerCase().includes(q)) return false;
      }
      return true;
    });
  }, [allData, boardFilters]);

  const grouped = useMemo(() => {
    const map: Record<string, InterestRow[]> = {};
    for (const stage of PIPELINE_STAGES) {
      map[stage] = [];
    }
    for (const interest of interests) {
      if (map[interest.pipelineStage]) {
        map[interest.pipelineStage]!.push(interest);
      }
    }
    return map;
  }, [interests]);

  async function handleDragEnd(event: DragEndEvent) {
    const { active, over } = event;
    if (!over || active.id === over.id) return;

    // over.id is a stage when dropped on a column, or an item id when dropped on a card
    let newStage = over.id as string;

    // If dropped on a card (not a stage), find which stage that card belongs to
    if (!PIPELINE_STAGES.includes(newStage as (typeof PIPELINE_STAGES)[number])) {
      const targetInterest = interests.find((i) => i.id === newStage);
      if (!targetInterest) return;
      newStage = targetInterest.pipelineStage;
    }

    const interestId = active.id as string;
    const currentInterest = interests.find((i) => i.id === interestId);
    if (!currentInterest || currentInterest.pipelineStage === newStage) return;

    // Optimistic update
    queryClient.setQueryData<{ data: InterestRow[] }>(['interests-board', portSlug], (old) => {
      if (!old) return old;
      return {
        ...old,
        data: old.data.map((i) => (i.id === interestId ? { ...i, pipelineStage: newStage } : i)),
      };
    });

    try {
      await apiFetch(`/api/v1/interests/${interestId}/stage`, {
        method: 'PATCH',
        body: { pipelineStage: newStage },
      });
      queryClient.invalidateQueries({ queryKey: ['interests'] });
    } catch {
      // Revert optimistic update
      queryClient.invalidateQueries({ queryKey: ['interests-board', portSlug] });
    }
  }

  if (isLoading) {
    return <div className="flex gap-3 overflow-x-auto pb-4 animate-pulse h-64" />;
  }

  return (
    <DndContext collisionDetection={closestCenter} onDragEnd={handleDragEnd}>
      <div className="flex gap-3 overflow-x-auto pb-4">
        {PIPELINE_STAGES.map((stage) => (
          <PipelineColumn
            key={stage}
            stage={stage}
            label={STAGE_LABELS[stage] ?? stage}
            items={grouped[stage] ?? []}
          />
        ))}
      </div>
    </DndContext>
  );
}
