"use client";

import React, { useState, useEffect, useCallback, useRef } from "react";
import {
  Dialog, DialogContent, DialogDescription, DialogFooter, DialogHeader, DialogTitle,
} from "@/components/ui/dialog";
import { Button } from "@/components/ui/button";
import { Input } from "@/components/ui/input";
import { Label } from "@/components/ui/label";
import { Textarea } from "@/components/ui/textarea";
import { Badge } from "@/components/ui/badge";
import {
  Select, SelectContent, SelectItem, SelectTrigger, SelectValue,
} from "@/components/ui/select";
import { Plus, X, Loader2, Search, GripVertical, Users, ArrowDown, Layers, FileText } from "lucide-react";
import { toast } from "sonner";
import {
  createApprovalRequest,
  getApprovalTemplates,
  getTemplateSteps,
  type ApprovalLineTemplate,
} from "@/lib/api/approval";
import { getUserList } from "@/lib/api/user";

// 결재 방식
type ApprovalMode = "sequential" | "parallel";

// 결재 유형
type ApprovalType = "self" | "escalation" | "consensus" | "post";

// step_type 라벨 매핑
const STEP_TYPE_LABEL: Record<string, { label: string; variant: "default" | "secondary" | "outline" }> = {
  approval: { label: "결재", variant: "default" },
  consensus: { label: "합의", variant: "secondary" },
  notification: { label: "통보", variant: "outline" },
};

interface ApproverRow {
  id: string;
  user_id: string;
  user_name: string;
  position_name: string;
  dept_name: string;
  step_type?: "approval" | "consensus" | "notification";
  step_order?: number;
}

export interface ApprovalModalEventDetail {
  targetTable: string;
  targetRecordId: string;
  targetRecordData?: Record<string, any>;
  definitionId?: number;
  screenId?: number;
  buttonComponentId?: string;
}

interface ApprovalRequestModalProps {
  open: boolean;
  onOpenChange: (open: boolean) => void;
  eventDetail?: ApprovalModalEventDetail | null;
}

interface UserSearchResult {
  userId: string;
  userName: string;
  positionName?: string;
  deptName?: string;
  deptCode?: string;
  email?: string;
  user_id?: string;
  user_name?: string;
  position_name?: string;
  dept_name?: string;
}

function genId(): string {
  return `a_${Date.now()}_${Math.random().toString(36).slice(2, 7)}`;
}

export const ApprovalRequestModal: React.FC<ApprovalRequestModalProps> = ({
  open,
  onOpenChange,
  eventDetail,
}) => {
  const [title, setTitle] = useState("");
  const [description, setDescription] = useState("");
  const [approvalMode, setApprovalMode] = useState<ApprovalMode>("sequential");
  const [approvers, setApprovers] = useState<ApproverRow[]>([]);
  const [isSubmitting, setIsSubmitting] = useState(false);
  const [error, setError] = useState<string | null>(null);

  // 결재 유형 상태
  const [approvalType, setApprovalType] = useState<ApprovalType>("escalation");

  // 템플릿 상태
  const [templates, setTemplates] = useState<ApprovalLineTemplate[]>([]);
  const [selectedTemplateId, setSelectedTemplateId] = useState<number | null>(null);
  const [showTemplatePopover, setShowTemplatePopover] = useState(false);
  const [isLoadingTemplates, setIsLoadingTemplates] = useState(false);

  // 사용자 검색 상태
  const [searchOpen, setSearchOpen] = useState(false);
  const [searchQuery, setSearchQuery] = useState("");
  const [searchResults, setSearchResults] = useState<UserSearchResult[]>([]);
  const [isSearching, setIsSearching] = useState(false);
  const searchInputRef = useRef<HTMLInputElement>(null);
  const searchTimerRef = useRef<NodeJS.Timeout | null>(null);

  // 모달 닫힐 때 초기화
  useEffect(() => {
    if (!open) {
      setTitle("");
      setDescription("");
      setApprovalMode("sequential");
      setApprovalType("escalation");
      setApprovers([]);
      setError(null);
      setSearchOpen(false);
      setSearchQuery("");
      setSearchResults([]);
      setSelectedTemplateId(null);
      setShowTemplatePopover(false);
    }
  }, [open]);

  // 모달 열릴 때 템플릿 목록 로드
  useEffect(() => {
    if (open) {
      loadTemplates();
    }
  }, [open]);

  const loadTemplates = async () => {
    setIsLoadingTemplates(true);
    try {
      const res = await getApprovalTemplates({ is_active: "Y" });
      if (res.success && res.data) {
        setTemplates(res.data);
      }
    } catch {
      // 템플릿 로드 실패는 무시 (선택사항이므로)
    } finally {
      setIsLoadingTemplates(false);
    }
  };

  // 템플릿 선택 시 결재자 리스트에 반영
  const applyTemplate = async (templateId: number) => {
    try {
      const res = await getTemplateSteps(templateId);
      if (!res.success || !res.data || res.data.length === 0) {
        toast.error("템플릿에 설정된 결재 단계가 없습니다.");
        return;
      }

      const steps = res.data;
      const hasMultipleTypes = new Set(steps.map((s) => s.step_type || "approval")).size > 1;

      // step_type이 혼합이면 escalation으로 설정
      if (hasMultipleTypes) {
        setApprovalType("escalation");
      }

      const newApprovers: ApproverRow[] = steps.map((step) => ({
        id: genId(),
        user_id: step.approver_user_id || "",
        user_name: step.approver_label || step.approver_user_id || "",
        position_name: step.approver_position || "",
        dept_name: step.approver_dept_code || "",
        step_type: step.step_type || "approval",
        step_order: step.step_order,
      }));

      setApprovers(newApprovers);
      setSelectedTemplateId(templateId);
      setShowTemplatePopover(false);
      toast.success("템플릿이 적용되었습니다.");
    } catch {
      toast.error("템플릿 적용 중 오류가 발생했습니다.");
    }
  };

  // 사용자 검색 (디바운스)
  const searchUsers = useCallback(async (query: string) => {
    if (!query.trim() || query.trim().length < 1) {
      setSearchResults([]);
      return;
    }

    setIsSearching(true);
    try {
      const res = await getUserList({ search: query.trim(), limit: 20 });
      const data = res?.data || res || [];
      const rawUsers: any[] = Array.isArray(data) ? data : [];
      const users: UserSearchResult[] = rawUsers.map((u: any) => ({
        userId: u.userId || u.user_id || "",
        userName: u.userName || u.user_name || "",
        positionName: u.positionName || u.position_name || "",
        deptName: u.deptName || u.dept_name || "",
        deptCode: u.deptCode || u.dept_code || "",
        email: u.email || "",
      }));
      const existingIds = new Set(approvers.map((a) => a.user_id));
      setSearchResults(users.filter((u) => u.userId && !existingIds.has(u.userId)));
    } catch {
      setSearchResults([]);
    } finally {
      setIsSearching(false);
    }
  }, [approvers]);

  useEffect(() => {
    if (searchTimerRef.current) clearTimeout(searchTimerRef.current);
    if (!searchQuery.trim()) {
      setSearchResults([]);
      return;
    }
    searchTimerRef.current = setTimeout(() => {
      searchUsers(searchQuery);
    }, 300);
    return () => {
      if (searchTimerRef.current) clearTimeout(searchTimerRef.current);
    };
  }, [searchQuery, searchUsers]);

  const addApprover = (user: UserSearchResult) => {
    setApprovers((prev) => [
      ...prev,
      {
        id: genId(),
        user_id: user.userId,
        user_name: user.userName,
        position_name: user.positionName || "",
        dept_name: user.deptName || "",
      },
    ]);
    setSearchQuery("");
    setSearchResults([]);
    setSearchOpen(false);
  };

  const removeApprover = (id: string) => {
    setApprovers((prev) => prev.filter((a) => a.id !== id));
  };

  const moveApprover = (idx: number, direction: "up" | "down") => {
    setApprovers((prev) => {
      const next = [...prev];
      const targetIdx = direction === "up" ? idx - 1 : idx + 1;
      if (targetIdx < 0 || targetIdx >= next.length) return prev;
      [next[idx], next[targetIdx]] = [next[targetIdx], next[idx]];
      return next;
    });
  };

  const handleSubmit = async () => {
    if (!title.trim()) {
      setError("결재 제목을 입력해주세요.");
      return;
    }
    // 자기결재가 아닌 경우 결재자 필수
    if (approvalType !== "self" && approvers.length === 0) {
      setError("결재자를 1명 이상 추가해주세요.");
      return;
    }
    if (!eventDetail?.targetTable) {
      setError("결재 대상 테이블 정보가 없습니다. 버튼 설정을 확인해주세요.");
      return;
    }

    setIsSubmitting(true);
    setError(null);

    // 혼합형 여부: approvers에 step_type이 설정된 경우
    const hasMixedStepTypes = approvers.some((a) => a.step_type);

    const res = await createApprovalRequest({
      title: title.trim(),
      description: description.trim() || undefined,
      target_table: eventDetail.targetTable,
      target_record_id: eventDetail.targetRecordId || undefined,
      target_record_data: eventDetail.targetRecordData,
      approval_mode: approvalType === "consensus" ? "parallel" : approvalMode,
      approval_type: approvalType,
      screen_id: eventDetail.screenId,
      button_component_id: eventDetail.buttonComponentId,
      approvers: approvalType === "self"
        ? []
        : approvers.map((a, idx) => ({
            approver_id: a.user_id,
            approver_name: a.user_name,
            approver_position: a.position_name || undefined,
            approver_dept: a.dept_name || undefined,
            step_type: hasMixedStepTypes ? (a.step_type || "approval") : undefined,
            step_order: hasMixedStepTypes ? (a.step_order ?? idx + 1) : undefined,
            approver_label: hasMixedStepTypes
              ? STEP_TYPE_LABEL[a.step_type || "approval"]?.label
              : approvalMode === "sequential"
                ? `${idx + 1}차 결재`
                : "동시 결재",
          })),
    });

    setIsSubmitting(false);

    if (res.success) {
      toast.success("결재 요청이 완료되었습니다.");
      onOpenChange(false);
    } else {
      setError(res.error || res.message || "결재 요청에 실패했습니다.");
    }
  };

  return (
    <Dialog open={open} onOpenChange={onOpenChange}>
      <DialogContent className="max-w-[95vw] sm:max-w-[560px]">
        <DialogHeader>
          <DialogTitle className="text-base sm:text-lg">결재 상신</DialogTitle>
          <DialogDescription className="text-xs sm:text-sm">
            결재 방식을 선택하고 결재자를 검색하여 추가합니다.
          </DialogDescription>
        </DialogHeader>

        <div className="max-h-[65vh] space-y-4 overflow-y-auto pr-1">
          {/* 결재 제목 */}
          <div>
            <Label htmlFor="approval-title" className="text-xs sm:text-sm">
              결재 제목 <span className="text-destructive">*</span>
            </Label>
            <Input
              id="approval-title"
              value={title}
              onChange={(e) => setTitle(e.target.value)}
              placeholder="결재 제목을 입력하세요"
              className="h-8 text-xs sm:h-10 sm:text-sm"
            />
          </div>

          {/* 결재 사유 */}
          <div>
            <Label htmlFor="approval-desc" className="text-xs sm:text-sm">
              결재 사유
            </Label>
            <Textarea
              id="approval-desc"
              value={description}
              onChange={(e) => setDescription(e.target.value)}
              placeholder="결재 사유를 입력하세요 (선택사항)"
              className="min-h-[60px] text-xs sm:text-sm"
            />
          </div>

          {/* 결재 유형 + 템플릿 불러오기 */}
          <div>
            <div className="flex items-end gap-2">
              <div className="flex-1">
                <Label className="text-xs sm:text-sm">결재 유형</Label>
                <Select
                  value={approvalType}
                  onValueChange={(v) => setApprovalType(v as ApprovalType)}
                >
                  <SelectTrigger size="default" className="mt-1 h-8 text-xs sm:h-10 sm:text-sm">
                    <SelectValue />
                  </SelectTrigger>
                  <SelectContent>
                    <SelectItem value="escalation">상신결재</SelectItem>
                    <SelectItem value="self">자기결재 (전결)</SelectItem>
                    <SelectItem value="consensus">합의결재</SelectItem>
                    <SelectItem value="post">후결</SelectItem>
                  </SelectContent>
                </Select>
              </div>
              {templates.length > 0 && (
                <Button
                  type="button"
                  variant="outline"
                  size="sm"
                  className="h-8 shrink-0 text-xs sm:h-10 sm:text-sm"
                  onClick={() => setShowTemplatePopover(!showTemplatePopover)}
                >
                  <FileText className="mr-1 h-3.5 w-3.5" />
                  템플릿
                </Button>
              )}
            </div>

            {/* 템플릿 선택 드롭다운 */}
            {showTemplatePopover && (
              <>
                <div
                  className="fixed inset-0 z-40"
                  onClick={() => setShowTemplatePopover(false)}
                />
                <div className="relative z-50 mt-2 rounded-md border bg-popover p-2 shadow-lg">
                  <p className="text-muted-foreground mb-2 text-[10px] font-medium">결재선 템플릿 선택</p>
                  {isLoadingTemplates ? (
                    <div className="flex items-center justify-center p-3">
                      <Loader2 className="text-muted-foreground h-4 w-4 animate-spin" />
                    </div>
                  ) : templates.length === 0 ? (
                    <p className="text-muted-foreground p-3 text-center text-xs">등록된 템플릿이 없습니다.</p>
                  ) : (
                    <div className="max-h-40 space-y-1 overflow-y-auto">
                      {templates.map((tpl) => (
                        <button
                          key={tpl.template_id}
                          type="button"
                          onClick={() => applyTemplate(tpl.template_id)}
                          className={`flex w-full items-center gap-2 rounded-md px-3 py-2 text-left text-xs transition-colors hover:bg-accent ${
                            selectedTemplateId === tpl.template_id ? "bg-accent" : ""
                          }`}
                        >
                          <FileText className="text-muted-foreground h-3.5 w-3.5 shrink-0" />
                          <div className="min-w-0 flex-1">
                            <p className="truncate font-medium">{tpl.template_name}</p>
                            {tpl.description && (
                              <p className="text-muted-foreground truncate text-[10px]">{tpl.description}</p>
                            )}
                          </div>
                        </button>
                      ))}
                    </div>
                  )}
                </div>
              </>
            )}
          </div>

          {/* 후결 안내 배너 */}
          {approvalType === "post" && (
            <div className="rounded-md border border-amber-200 bg-amber-50 p-3 text-sm text-amber-800 dark:border-amber-800 dark:bg-amber-950 dark:text-amber-200">
              먼저 처리 후 나중에 결재받습니다. 결재 반려 시 별도 조치가 필요할 수 있습니다.
            </div>
          )}

          {/* 자기결재: 결재자 섹션 대신 안내 메시지 */}
          {approvalType === "self" ? (
            <div className="bg-muted text-muted-foreground rounded-md p-4 text-sm">
              본인이 직접 승인합니다.
            </div>
          ) : (
            <>
              {/* 결재 방식 (escalation, post에서만 표시. consensus는 순서 무관) */}
              {approvalType !== "consensus" && (
                <div>
                  <Label className="text-xs sm:text-sm">결재 방식</Label>
                  <div className="mt-1.5 grid grid-cols-2 gap-2">
                    <button
                      type="button"
                      onClick={() => setApprovalMode("sequential")}
                      className={`flex items-center gap-2 rounded-md border p-3 text-left transition-colors ${
                        approvalMode === "sequential"
                          ? "border-primary bg-primary/5 ring-1 ring-primary"
                          : "hover:bg-muted/50"
                      }`}
                    >
                      <ArrowDown className="h-4 w-4 shrink-0" />
                      <div>
                        <p className="text-xs font-medium sm:text-sm">다단 결재</p>
                        <p className="text-muted-foreground text-[10px]">순차적으로 결재</p>
                      </div>
                    </button>
                    <button
                      type="button"
                      onClick={() => setApprovalMode("parallel")}
                      className={`flex items-center gap-2 rounded-md border p-3 text-left transition-colors ${
                        approvalMode === "parallel"
                          ? "border-primary bg-primary/5 ring-1 ring-primary"
                          : "hover:bg-muted/50"
                      }`}
                    >
                      <Layers className="h-4 w-4 shrink-0" />
                      <div>
                        <p className="text-xs font-medium sm:text-sm">동시 결재</p>
                        <p className="text-muted-foreground text-[10px]">모든 결재자 동시 진행</p>
                      </div>
                    </button>
                  </div>
                </div>
              )}

              {/* 결재자 추가 (사용자 검색) */}
              <div>
                <div className="mb-2 flex items-center justify-between">
                  <Label className="text-xs sm:text-sm">
                    {approvalType === "consensus" ? "합의 결재자" : "결재자"}{" "}
                    <span className="text-destructive">*</span>
                  </Label>
                  <span className="text-muted-foreground text-[10px]">
                    {approvers.length}명 선택됨
                  </span>
                </div>

                {/* 검색 입력 */}
                <div className="relative">
                  <Search className="text-muted-foreground absolute left-3 top-1/2 h-4 w-4 -translate-y-1/2" />
                  <Input
                    ref={searchInputRef}
                    value={searchQuery}
                    onChange={(e) => {
                      setSearchQuery(e.target.value);
                      setSearchOpen(true);
                    }}
                    onFocus={() => setSearchOpen(true)}
                    placeholder="이름 또는 사번으로 검색..."
                    className="h-8 pl-9 text-xs sm:h-10 sm:text-sm"
                  />

                  {/* 검색 결과 드롭다운 */}
                  {searchOpen && searchQuery.trim() && (
                    <div className="absolute top-full left-0 z-50 mt-1 w-full rounded-md border bg-popover shadow-lg">
                      {isSearching ? (
                        <div className="flex items-center justify-center p-4">
                          <Loader2 className="text-muted-foreground h-4 w-4 animate-spin" />
                          <span className="text-muted-foreground ml-2 text-xs">검색 중...</span>
                        </div>
                      ) : searchResults.length === 0 ? (
                        <div className="p-4 text-center">
                          <p className="text-muted-foreground text-xs">검색 결과가 없습니다.</p>
                        </div>
                      ) : (
                        <div className="max-h-48 overflow-y-auto">
                          {searchResults.map((user) => (
                            <button
                              key={user.userId}
                              type="button"
                              onClick={() => addApprover(user)}
                              className="flex w-full items-center gap-3 px-3 py-2 text-left transition-colors hover:bg-accent"
                            >
                              <div className="bg-muted flex h-8 w-8 shrink-0 items-center justify-center rounded-full">
                                <Users className="h-4 w-4" />
                              </div>
                              <div className="min-w-0 flex-1">
                                <p className="truncate text-xs font-medium sm:text-sm">
                                  {user.userName}
                                  <span className="text-muted-foreground ml-1 text-[10px]">
                                    ({user.userId})
                                  </span>
                                </p>
                                <p className="text-muted-foreground truncate text-[10px]">
                                  {[user.deptName, user.positionName].filter(Boolean).join(" / ") || "-"}
                                </p>
                              </div>
                              <Plus className="text-muted-foreground h-4 w-4 shrink-0" />
                            </button>
                          ))}
                        </div>
                      )}
                    </div>
                  )}
                </div>

                {/* 클릭 외부 영역 닫기 */}
                {searchOpen && (
                  <div
                    className="fixed inset-0 z-40"
                    onClick={() => setSearchOpen(false)}
                  />
                )}

                {/* 선택된 결재자 목록 */}
                {approvers.length === 0 ? (
                  <p className="text-muted-foreground mt-3 rounded-md border border-dashed p-4 text-center text-xs">
                    위 검색창에서 결재자를 검색하여 추가하세요
                  </p>
                ) : (
                  <div className="mt-3 space-y-2">
                    {approvers.map((approver, idx) => (
                      <div
                        key={approver.id}
                        className="bg-muted/30 flex items-center gap-2 rounded-md border p-2"
                      >
                        {/* 순서 표시: consensus에서는 drag 숨김 */}
                        {approvalType === "consensus" ? (
                          <Badge variant="secondary" className="h-5 shrink-0 px-1.5 text-[10px]">
                            합의
                          </Badge>
                        ) : approvalMode === "sequential" ? (
                          <div className="flex shrink-0 flex-col items-center gap-0.5">
                            <button
                              type="button"
                              onClick={() => moveApprover(idx, "up")}
                              disabled={idx === 0}
                              className="text-muted-foreground hover:text-foreground disabled:opacity-30"
                            >
                              <GripVertical className="h-3 w-3 rotate-90" />
                            </button>
                            <Badge variant="outline" className="h-5 min-w-[24px] justify-center px-1 text-[10px]">
                              {idx + 1}
                            </Badge>
                            <button
                              type="button"
                              onClick={() => moveApprover(idx, "down")}
                              disabled={idx === approvers.length - 1}
                              className="text-muted-foreground hover:text-foreground disabled:opacity-30"
                            >
                              <GripVertical className="h-3 w-3 rotate-90" />
                            </button>
                          </div>
                        ) : (
                          <Badge variant="secondary" className="h-5 shrink-0 px-1.5 text-[10px]">
                            동시
                          </Badge>
                        )}

                        {/* step_type 뱃지 (템플릿에서 불러온 혼합형일 때) */}
                        {approver.step_type && (
                          <Badge
                            variant={STEP_TYPE_LABEL[approver.step_type]?.variant || "outline"}
                            className="h-5 shrink-0 px-1.5 text-[10px]"
                          >
                            {STEP_TYPE_LABEL[approver.step_type]?.label || approver.step_type}
                          </Badge>
                        )}

                        {/* 사용자 정보 */}
                        <div className="min-w-0 flex-1">
                          <p className="truncate text-xs font-medium">
                            {approver.user_name}
                            <span className="text-muted-foreground ml-1 text-[10px]">
                              ({approver.user_id})
                            </span>
                          </p>
                          <p className="text-muted-foreground truncate text-[10px]">
                            {[approver.dept_name, approver.position_name].filter(Boolean).join(" / ") || "-"}
                          </p>
                        </div>

                        {/* 제거 버튼 */}
                        <Button
                          type="button"
                          variant="ghost"
                          size="icon"
                          className="h-6 w-6 shrink-0"
                          onClick={() => removeApprover(approver.id)}
                        >
                          <X className="h-3 w-3" />
                        </Button>
                      </div>
                    ))}

                    {/* 결재 흐름 시각화 (consensus가 아니고 sequential일 때만) */}
                    {approvalType !== "consensus" && approvalMode === "sequential" && approvers.length > 1 && (
                      <p className="text-muted-foreground text-center text-[10px]">
                        {approvers.map((a) => a.user_name).join(" → ")}
                      </p>
                    )}
                  </div>
                )}
              </div>
            </>
          )}

          {/* 에러 메시지 */}
          {error && (
            <div className="bg-destructive/10 rounded-md p-2">
              <p className="text-destructive text-xs">{error}</p>
            </div>
          )}
        </div>

        <DialogFooter className="gap-2 sm:gap-0">
          <Button
            variant="outline"
            onClick={() => onOpenChange(false)}
            disabled={isSubmitting}
            className="h-8 flex-1 text-xs sm:h-10 sm:flex-none sm:text-sm"
          >
            취소
          </Button>
          <Button
            onClick={handleSubmit}
            disabled={isSubmitting || (approvalType !== "self" && approvers.length === 0)}
            className="h-8 flex-1 text-xs sm:h-10 sm:flex-none sm:text-sm"
          >
            {isSubmitting ? (
              <>
                <Loader2 className="mr-2 h-4 w-4 animate-spin" />
                요청 중...
              </>
            ) : approvalType === "self" ? (
              "전결 처리"
            ) : (
              `결재 상신 (${approvers.length}명)`
            )}
          </Button>
        </DialogFooter>
      </DialogContent>
    </Dialog>
  );
};

export default ApprovalRequestModal;