"use client";

import React, { useCallback, useMemo, useRef } from "react";
import {
  ChevronLeft,
  ChevronRight,
  Calendar,
  Plus,
  Loader2,
  ZoomIn,
  ZoomOut,
} from "lucide-react";
import { Button } from "@/components/ui/button";
import { toast } from "sonner";
import {
  TimelineSchedulerComponentProps,
  ScheduleItem,
  ZoomLevel,
} from "./types";
import { useTimelineData } from "./hooks/useTimelineData";
import { TimelineHeader, ResourceRow, TimelineLegend } from "./components";
import { zoomLevelOptions, defaultTimelineSchedulerConfig } from "./config";
import { detectConflicts, addDaysToDateString } from "./utils/conflictDetection";

/**
 * v2-timeline-scheduler 메인 컴포넌트
 *
 * 간트차트 형태의 일정/계획 시각화 및 편집 컴포넌트
 */
export function TimelineSchedulerComponent({
  config,
  isDesignMode = false,
  formData,
  externalSchedules,
  externalResources,
  isLoading: externalLoading,
  error: externalError,
  componentId,
  onDragEnd,
  onResizeEnd,
  onScheduleClick,
  onCellClick,
  onAddSchedule,
}: TimelineSchedulerComponentProps) {
  const containerRef = useRef<HTMLDivElement>(null);

  // 타임라인 데이터 훅
  const {
    schedules,
    resources,
    isLoading: hookLoading,
    error: hookError,
    zoomLevel,
    setZoomLevel,
    viewStartDate,
    viewEndDate,
    goToPrevious,
    goToNext,
    goToToday,
    updateSchedule,
  } = useTimelineData(config, externalSchedules, externalResources);

  const isLoading = externalLoading ?? hookLoading;
  const error = externalError ?? hookError;

  // 설정값
  const rowHeight =
    config.rowHeight || defaultTimelineSchedulerConfig.rowHeight!;
  const headerHeight =
    config.headerHeight || defaultTimelineSchedulerConfig.headerHeight!;
  const resourceColumnWidth =
    config.resourceColumnWidth ||
    defaultTimelineSchedulerConfig.resourceColumnWidth!;
  const cellWidthConfig =
    config.cellWidth || defaultTimelineSchedulerConfig.cellWidth!;
  const cellWidth = cellWidthConfig[zoomLevel] || 60;

  // 리소스 자동 생성 (리소스 테이블 미설정 시 스케줄 데이터에서 추출)
  const effectiveResources = useMemo(() => {
    if (resources.length > 0) return resources;

    const uniqueResourceIds = new Set<string>();
    schedules.forEach((s) => {
      if (s.resourceId) uniqueResourceIds.add(s.resourceId);
    });

    return Array.from(uniqueResourceIds).map((id) => ({ id, name: id }));
  }, [resources, schedules]);

  // 리소스별 스케줄 그룹화
  const schedulesByResource = useMemo(() => {
    const grouped = new Map<string, ScheduleItem[]>();

    effectiveResources.forEach((r) => grouped.set(r.id, []));

    schedules.forEach((schedule) => {
      const list = grouped.get(schedule.resourceId);
      if (list) {
        list.push(schedule);
      } else {
        const firstResource = effectiveResources[0];
        if (firstResource) {
          grouped.get(firstResource.id)?.push(schedule);
        }
      }
    });

    return grouped;
  }, [schedules, effectiveResources]);

  // ────────── 충돌 감지 ──────────
  const conflictIds = useMemo(() => {
    if (config.showConflicts === false) return new Set<string>();
    return detectConflicts(schedules);
  }, [schedules, config.showConflicts]);

  // ────────── 줌 레벨 변경 ──────────
  const handleZoomIn = useCallback(() => {
    const levels: ZoomLevel[] = ["month", "week", "day"];
    const idx = levels.indexOf(zoomLevel);
    if (idx < levels.length - 1) setZoomLevel(levels[idx + 1]);
  }, [zoomLevel, setZoomLevel]);

  const handleZoomOut = useCallback(() => {
    const levels: ZoomLevel[] = ["month", "week", "day"];
    const idx = levels.indexOf(zoomLevel);
    if (idx > 0) setZoomLevel(levels[idx - 1]);
  }, [zoomLevel, setZoomLevel]);

  // ────────── 스케줄 클릭 ──────────
  const handleScheduleClick = useCallback(
    (schedule: ScheduleItem) => {
      const resource = effectiveResources.find(
        (r) => r.id === schedule.resourceId
      );
      if (resource && onScheduleClick) {
        onScheduleClick({ schedule, resource });
      }
    },
    [effectiveResources, onScheduleClick]
  );

  // ────────── 빈 셀 클릭 ──────────
  const handleCellClick = useCallback(
    (resourceId: string, date: Date) => {
      if (onCellClick) {
        onCellClick({
          resourceId,
          date: date.toISOString().split("T")[0],
        });
      }
    },
    [onCellClick]
  );

  // ────────── 드래그 완료 (핵심 로직) ──────────
  const handleDragComplete = useCallback(
    async (schedule: ScheduleItem, deltaX: number) => {
      // 줌 레벨에 따라 1셀당 일수가 달라짐
      let daysPerCell = 1;
      if (zoomLevel === "week") daysPerCell = 7;
      if (zoomLevel === "month") daysPerCell = 30;

      const deltaDays = Math.round((deltaX / cellWidth) * daysPerCell);
      if (deltaDays === 0) return;

      const newStartDate = addDaysToDateString(schedule.startDate, deltaDays);
      const newEndDate = addDaysToDateString(schedule.endDate, deltaDays);

      try {
        await updateSchedule(schedule.id, {
          startDate: newStartDate,
          endDate: newEndDate,
        });

        // 외부 이벤트 핸들러 호출
        onDragEnd?.({
          scheduleId: schedule.id,
          newStartDate,
          newEndDate,
        });

        toast.success("스케줄 이동 완료", {
          description: `${schedule.title}: ${newStartDate} ~ ${newEndDate}`,
        });
      } catch (err: any) {
        toast.error("스케줄 이동 실패", {
          description: err.message || "잠시 후 다시 시도해주세요",
        });
      }
    },
    [cellWidth, zoomLevel, updateSchedule, onDragEnd]
  );

  // ────────── 리사이즈 완료 (핵심 로직) ──────────
  const handleResizeComplete = useCallback(
    async (
      schedule: ScheduleItem,
      direction: "start" | "end",
      deltaX: number
    ) => {
      let daysPerCell = 1;
      if (zoomLevel === "week") daysPerCell = 7;
      if (zoomLevel === "month") daysPerCell = 30;

      const deltaDays = Math.round((deltaX / cellWidth) * daysPerCell);
      if (deltaDays === 0) return;

      let newStartDate = schedule.startDate;
      let newEndDate = schedule.endDate;

      if (direction === "start") {
        newStartDate = addDaysToDateString(schedule.startDate, deltaDays);
        // 시작일이 종료일을 넘지 않도록
        if (new Date(newStartDate) >= new Date(newEndDate)) {
          toast.warning("시작일은 종료일보다 이전이어야 합니다");
          return;
        }
      } else {
        newEndDate = addDaysToDateString(schedule.endDate, deltaDays);
        // 종료일이 시작일보다 앞서지 않도록
        if (new Date(newEndDate) <= new Date(newStartDate)) {
          toast.warning("종료일은 시작일보다 이후여야 합니다");
          return;
        }
      }

      try {
        await updateSchedule(schedule.id, {
          startDate: newStartDate,
          endDate: newEndDate,
        });

        onResizeEnd?.({
          scheduleId: schedule.id,
          newStartDate,
          newEndDate,
          direction,
        });

        const days =
          Math.round(
            (new Date(newEndDate).getTime() -
              new Date(newStartDate).getTime()) /
              (1000 * 60 * 60 * 24)
          ) + 1;

        toast.success("기간 변경 완료", {
          description: `${schedule.title}: ${days}일 (${newStartDate} ~ ${newEndDate})`,
        });
      } catch (err: any) {
        toast.error("기간 변경 실패", {
          description: err.message || "잠시 후 다시 시도해주세요",
        });
      }
    },
    [cellWidth, zoomLevel, updateSchedule, onResizeEnd]
  );

  // ────────── 추가 버튼 클릭 ──────────
  const handleAddClick = useCallback(() => {
    if (onAddSchedule && effectiveResources.length > 0) {
      onAddSchedule(
        effectiveResources[0].id,
        new Date().toISOString().split("T")[0]
      );
    }
  }, [onAddSchedule, effectiveResources]);

  // ────────── 하단 영역 높이 계산 (툴바 + 범례) ──────────
  const showToolbar = config.showToolbar !== false;
  const showLegend = config.showLegend !== false;
  const toolbarHeight = showToolbar ? 36 : 0;
  const legendHeight = showLegend ? 28 : 0;

  // ────────── 디자인 모드 플레이스홀더 ──────────
  if (isDesignMode) {
    return (
      <div className="flex h-full min-h-[200px] w-full items-center justify-center rounded-lg border-2 border-dashed border-muted-foreground/30 bg-muted/10">
        <div className="text-center text-muted-foreground">
          <Calendar className="mx-auto mb-2 h-6 w-6 sm:h-8 sm:w-8" />
          <p className="text-xs font-medium sm:text-sm">타임라인 스케줄러</p>
          <p className="mt-1 text-[10px] sm:text-xs">
            {config.selectedTable
              ? `테이블: ${config.selectedTable}`
              : "테이블을 선택하세요"}
          </p>
        </div>
      </div>
    );
  }

  // ────────── 로딩 상태 ──────────
  if (isLoading) {
    return (
      <div
        className="flex w-full items-center justify-center rounded-lg bg-muted/10"
        style={{ height: config.height || 500 }}
      >
        <div className="flex items-center gap-2 text-muted-foreground">
          <Loader2 className="h-4 w-4 animate-spin sm:h-5 sm:w-5" />
          <span className="text-xs sm:text-sm">로딩 중...</span>
        </div>
      </div>
    );
  }

  // ────────── 에러 상태 ──────────
  if (error) {
    return (
      <div
        className="flex w-full items-center justify-center rounded-lg bg-destructive/10"
        style={{ height: config.height || 500 }}
      >
        <div className="text-center text-destructive">
          <p className="text-xs font-medium sm:text-sm">오류 발생</p>
          <p className="mt-1 text-[10px] sm:text-xs">{error}</p>
        </div>
      </div>
    );
  }

  // ────────── 데이터 없음 ──────────
  if (schedules.length === 0) {
    return (
      <div
        className="flex w-full items-center justify-center rounded-lg border bg-muted/10"
        style={{ height: config.height || 500 }}
      >
        <div className="text-center text-muted-foreground">
          <Calendar className="mx-auto mb-2 h-8 w-8 opacity-50 sm:mb-3 sm:h-10 sm:w-10" />
          <p className="text-xs font-medium sm:text-sm">
            스케줄 데이터가 없습니다
          </p>
          <p className="mt-1.5 max-w-[200px] text-[10px] sm:mt-2 sm:text-xs">
            좌측 테이블에서 품목을 선택하거나,
            <br />
            스케줄 생성 버튼을 눌러 스케줄을 생성하세요
          </p>
        </div>
      </div>
    );
  }

  // ────────── 메인 렌더링 ──────────
  return (
    <div
      ref={containerRef}
      className="flex w-full flex-col overflow-hidden rounded-lg border bg-background"
      style={{
        height: config.height || 500,
        maxHeight: config.maxHeight,
      }}
    >
      {/* 툴바 */}
      {showToolbar && (
        <div className="flex shrink-0 items-center justify-between border-b bg-muted/30 px-2 py-1.5 sm:px-3 sm:py-2">
          {/* 네비게이션 */}
          <div className="flex items-center gap-0.5 sm:gap-1">
            {config.showNavigation !== false && (
              <>
                <Button
                  variant="ghost"
                  size="sm"
                  onClick={goToPrevious}
                  className="h-6 px-1.5 sm:h-7 sm:px-2"
                >
                  <ChevronLeft className="h-3.5 w-3.5 sm:h-4 sm:w-4" />
                </Button>
                <Button
                  variant="ghost"
                  size="sm"
                  onClick={goToToday}
                  className="h-6 px-1.5 text-xs sm:h-7 sm:px-2 sm:text-sm"
                >
                  오늘
                </Button>
                <Button
                  variant="ghost"
                  size="sm"
                  onClick={goToNext}
                  className="h-6 px-1.5 sm:h-7 sm:px-2"
                >
                  <ChevronRight className="h-3.5 w-3.5 sm:h-4 sm:w-4" />
                </Button>
              </>
            )}

            {/* 날짜 범위 표시 */}
            <span className="ml-1 text-[10px] text-muted-foreground sm:ml-2 sm:text-sm">
              {viewStartDate.getFullYear()}년 {viewStartDate.getMonth() + 1}월{" "}
              {viewStartDate.getDate()}일 ~ {viewEndDate.getMonth() + 1}월{" "}
              {viewEndDate.getDate()}일
            </span>
          </div>

          {/* 오른쪽 컨트롤 */}
          <div className="flex items-center gap-1 sm:gap-2">
            {/* 충돌 카운트 표시 */}
            {config.showConflicts !== false && conflictIds.size > 0 && (
              <span className="rounded-full bg-destructive/10 px-1.5 py-0.5 text-[9px] font-medium text-destructive sm:px-2 sm:text-[10px]">
                충돌 {conflictIds.size}건
              </span>
            )}

            {/* 줌 컨트롤 */}
            {config.showZoomControls !== false && (
              <div className="flex items-center gap-0.5 sm:gap-1">
                <Button
                  variant="ghost"
                  size="sm"
                  onClick={handleZoomOut}
                  disabled={zoomLevel === "month"}
                  className="h-6 px-1.5 sm:h-7 sm:px-2"
                >
                  <ZoomOut className="h-3.5 w-3.5 sm:h-4 sm:w-4" />
                </Button>
                <span className="min-w-[20px] text-center text-[10px] text-muted-foreground sm:min-w-[24px] sm:text-xs">
                  {
                    zoomLevelOptions.find((o) => o.value === zoomLevel)
                      ?.label
                  }
                </span>
                <Button
                  variant="ghost"
                  size="sm"
                  onClick={handleZoomIn}
                  disabled={zoomLevel === "day"}
                  className="h-6 px-1.5 sm:h-7 sm:px-2"
                >
                  <ZoomIn className="h-3.5 w-3.5 sm:h-4 sm:w-4" />
                </Button>
              </div>
            )}

            {/* 추가 버튼 */}
            {config.showAddButton !== false && config.editable && (
              <Button
                variant="default"
                size="sm"
                onClick={handleAddClick}
                className="h-6 text-xs sm:h-7 sm:text-sm"
              >
                <Plus className="mr-0.5 h-3.5 w-3.5 sm:mr-1 sm:h-4 sm:w-4" />
                추가
              </Button>
            )}
          </div>
        </div>
      )}

      {/* 타임라인 본문 (스크롤 영역) */}
      <div className="min-h-0 flex-1 overflow-auto">
        <div className="min-w-max">
          {/* 헤더 */}
          <TimelineHeader
            startDate={viewStartDate}
            endDate={viewEndDate}
            zoomLevel={zoomLevel}
            cellWidth={cellWidth}
            headerHeight={headerHeight}
            resourceColumnWidth={resourceColumnWidth}
            showTodayLine={config.showTodayLine}
          />

          {/* 리소스 행들 */}
          <div>
            {effectiveResources.map((resource) => (
              <ResourceRow
                key={resource.id}
                resource={resource}
                schedules={schedulesByResource.get(resource.id) || []}
                startDate={viewStartDate}
                endDate={viewEndDate}
                zoomLevel={zoomLevel}
                rowHeight={rowHeight}
                cellWidth={cellWidth}
                resourceColumnWidth={resourceColumnWidth}
                config={config}
                conflictIds={conflictIds}
                onScheduleClick={handleScheduleClick}
                onCellClick={handleCellClick}
                onDragComplete={handleDragComplete}
                onResizeComplete={handleResizeComplete}
              />
            ))}
          </div>
        </div>
      </div>

      {/* 범례 */}
      {showLegend && (
        <div className="shrink-0">
          <TimelineLegend config={config} />
        </div>
      )}
    </div>
  );
}