"use client";

import React, { useState, useEffect, useCallback } 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 { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from "@/components/ui/select";
import { Textarea } from "@/components/ui/textarea";
import { Plus, X, Loader2 } from "lucide-react";
import {
  getApprovalDefinitions,
  getApprovalTemplates,
  createApprovalRequest,
  type ApprovalDefinition,
  type ApprovalLineTemplate,
} from "@/lib/api/approval";

// 결재자 행 타입
interface ApproverRow {
  id: string; // 로컬 임시 ID
  approver_id: string;
  approver_name: string;
  approver_position: string;
  approver_dept: string;
  approver_label: string;
}

// 모달 열기 이벤트로 전달되는 데이터
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;
}

function generateLocalId(): string {
  return `row_${Date.now()}_${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 [selectedDefinitionId, setSelectedDefinitionId] = useState<string>("");
  const [selectedTemplateId, setSelectedTemplateId] = useState<string>("");
  const [approvers, setApprovers] = useState<ApproverRow[]>([]);
  const [definitions, setDefinitions] = useState<ApprovalDefinition[]>([]);
  const [templates, setTemplates] = useState<ApprovalLineTemplate[]>([]);
  const [isSubmitting, setIsSubmitting] = useState(false);
  const [isLoadingDefs, setIsLoadingDefs] = useState(false);
  const [isLoadingTemplates, setIsLoadingTemplates] = useState(false);
  const [error, setError] = useState<string | null>(null);

  // 결재 유형 목록 로딩
  useEffect(() => {
    if (!open) return;
    const load = async () => {
      setIsLoadingDefs(true);
      const res = await getApprovalDefinitions({ is_active: "Y" });
      if (res.success && res.data) setDefinitions(res.data);
      setIsLoadingDefs(false);
    };
    load();
  }, [open]);

  // 결재 유형 변경 시 템플릿 목록 로딩
  useEffect(() => {
    if (!selectedDefinitionId) {
      setTemplates([]);
      setSelectedTemplateId("");
      return;
    }
    const load = async () => {
      setIsLoadingTemplates(true);
      const res = await getApprovalTemplates({
        definition_id: Number(selectedDefinitionId),
        is_active: "Y",
      });
      if (res.success && res.data) setTemplates(res.data);
      setIsLoadingTemplates(false);
    };
    load();
  }, [selectedDefinitionId]);

  // 템플릿 선택 시 결재선 자동 세팅
  useEffect(() => {
    if (!selectedTemplateId) return;
    const template = templates.find((t) => String(t.template_id) === selectedTemplateId);
    if (!template?.steps) return;

    const rows: ApproverRow[] = template.steps
      .sort((a, b) => a.step_order - b.step_order)
      .map((step) => ({
        id: generateLocalId(),
        approver_id: step.approver_user_id || "",
        approver_name: step.approver_label || "",
        approver_position: step.approver_position || "",
        approver_dept: step.approver_dept_code || "",
        approver_label: step.approver_label || `${step.step_order}차 결재`,
      }));
    setApprovers(rows);
  }, [selectedTemplateId, templates]);

  // eventDetail에서 definitionId 자동 세팅
  useEffect(() => {
    if (open && eventDetail?.definitionId) {
      setSelectedDefinitionId(String(eventDetail.definitionId));
    }
  }, [open, eventDetail]);

  // 모달 닫힐 때 초기화
  useEffect(() => {
    if (!open) {
      setTitle("");
      setDescription("");
      setSelectedDefinitionId("");
      setSelectedTemplateId("");
      setApprovers([]);
      setError(null);
    }
  }, [open]);

  const handleAddApprover = () => {
    setApprovers((prev) => [
      ...prev,
      {
        id: generateLocalId(),
        approver_id: "",
        approver_name: "",
        approver_position: "",
        approver_dept: "",
        approver_label: `${prev.length + 1}차 결재`,
      },
    ]);
  };

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

  const handleApproverChange = (id: string, field: keyof ApproverRow, value: string) => {
    setApprovers((prev) =>
      prev.map((a) => (a.id === id ? { ...a, [field]: value } : a))
    );
  };

  const handleSubmit = async () => {
    if (!title.trim()) {
      setError("결재 제목을 입력해주세요.");
      return;
    }
    if (approvers.length === 0) {
      setError("결재자를 1명 이상 추가해주세요.");
      return;
    }
    const emptyApprover = approvers.find((a) => !a.approver_id.trim());
    if (emptyApprover) {
      setError("모든 결재자의 사번/ID를 입력해주세요.");
      return;
    }

    if (!eventDetail?.targetTable || !eventDetail?.targetRecordId) {
      setError("결재 대상 정보가 없습니다. 버튼 설정을 확인해주세요.");
      return;
    }

    setIsSubmitting(true);
    setError(null);

    const res = await createApprovalRequest({
      title: title.trim(),
      description: description.trim() || undefined,
      definition_id: selectedDefinitionId ? Number(selectedDefinitionId) : undefined,
      target_table: eventDetail.targetTable,
      target_record_id: eventDetail.targetRecordId,
      target_record_data: eventDetail.targetRecordData,
      screen_id: eventDetail.screenId,
      button_component_id: eventDetail.buttonComponentId,
      approvers: approvers.map((a) => ({
        approver_id: a.approver_id.trim(),
        approver_name: a.approver_name.trim() || undefined,
        approver_position: a.approver_position.trim() || undefined,
        approver_dept: a.approver_dept.trim() || undefined,
        approver_label: a.approver_label.trim() || undefined,
      })),
    });

    setIsSubmitting(false);

    if (res.success) {
      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 요청</DialogTitle>
          <DialogDescription className="text-xs sm:text-sm">
            결재자를 지정하고 결재를 요청합니다.
          </DialogDescription>
        </DialogHeader>

        <div className="space-y-3 sm:space-y-4">
          {/* 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-description" className="text-xs sm:text-sm">
              결재 사유
            </Label>
            <Textarea
              id="approval-description"
              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 선택 */}
          <div>
            <Label className="text-xs sm:text-sm">결재 유형</Label>
            <Select
              value={selectedDefinitionId}
              onValueChange={(v) => {
                setSelectedDefinitionId(v);
                setSelectedTemplateId("");
                setApprovers([]);
              }}
            >
              <SelectTrigger className="h-8 text-xs sm:h-10 sm:text-sm">
                <SelectValue placeholder={isLoadingDefs ? "로딩 중..." : "결재 유형 선택 (선택사항)"} />
              </SelectTrigger>
              <SelectContent>
                <SelectItem value="">유형 없음</SelectItem>
                {definitions.map((def) => (
                  <SelectItem key={def.definition_id} value={String(def.definition_id)}>
                    {def.definition_name}
                  </SelectItem>
                ))}
              </SelectContent>
            </Select>
          </div>

          {/* 결재선 템플릿 선택 */}
          {selectedDefinitionId && (
            <div>
              <Label className="text-xs sm:text-sm">결재선 템플릿</Label>
              <Select
                value={selectedTemplateId}
                onValueChange={setSelectedTemplateId}
              >
                <SelectTrigger className="h-8 text-xs sm:h-10 sm:text-sm">
                  <SelectValue placeholder={isLoadingTemplates ? "로딩 중..." : "템플릿 선택 (선택사항)"} />
                </SelectTrigger>
                <SelectContent>
                  <SelectItem value="">직접 입력</SelectItem>
                  {templates.map((tmpl) => (
                    <SelectItem key={tmpl.template_id} value={String(tmpl.template_id)}>
                      {tmpl.template_name}
                    </SelectItem>
                  ))}
                </SelectContent>
              </Select>
              <p className="text-muted-foreground mt-1 text-[10px] sm:text-xs">
                템플릿 선택 시 결재선이 자동으로 채워집니다
              </p>
            </div>
          )}

          {/* 결재선 */}
          <div>
            <div className="mb-2 flex items-center justify-between">
              <Label className="text-xs sm:text-sm">
                결재선 <span className="text-destructive">*</span>
              </Label>
              <Button
                type="button"
                variant="outline"
                size="sm"
                className="h-7 text-xs"
                onClick={handleAddApprover}
              >
                <Plus className="mr-1 h-3 w-3" />
                결재자 추가
              </Button>
            </div>

            {approvers.length === 0 && (
              <p className="text-muted-foreground rounded-md border border-dashed p-4 text-center text-xs">
                결재자를 추가하거나 템플릿을 선택하세요
              </p>
            )}

            <div className="space-y-2">
              {approvers.map((approver, idx) => (
                <div key={approver.id} className="rounded-md border p-2 sm:p-3">
                  <div className="mb-2 flex items-center justify-between">
                    <span className="text-muted-foreground text-[10px] sm:text-xs">
                      {idx + 1}차 결재
                    </span>
                    <Button
                      type="button"
                      variant="ghost"
                      size="sm"
                      className="h-6 w-6 p-0"
                      onClick={() => handleRemoveApprover(approver.id)}
                    >
                      <X className="h-3 w-3" />
                    </Button>
                  </div>
                  <div className="grid grid-cols-2 gap-2">
                    <div>
                      <Label className="text-[10px] sm:text-xs">
                        사번/ID <span className="text-destructive">*</span>
                      </Label>
                      <Input
                        value={approver.approver_id}
                        onChange={(e) => handleApproverChange(approver.id, "approver_id", e.target.value)}
                        placeholder="사번 또는 ID"
                        className="h-7 text-[10px] sm:h-8 sm:text-xs"
                      />
                    </div>
                    <div>
                      <Label className="text-[10px] sm:text-xs">이름</Label>
                      <Input
                        value={approver.approver_name}
                        onChange={(e) => handleApproverChange(approver.id, "approver_name", e.target.value)}
                        placeholder="결재자 이름"
                        className="h-7 text-[10px] sm:h-8 sm:text-xs"
                      />
                    </div>
                    <div>
                      <Label className="text-[10px] sm:text-xs">직급</Label>
                      <Input
                        value={approver.approver_position}
                        onChange={(e) => handleApproverChange(approver.id, "approver_position", e.target.value)}
                        placeholder="직급"
                        className="h-7 text-[10px] sm:h-8 sm:text-xs"
                      />
                    </div>
                    <div>
                      <Label className="text-[10px] sm:text-xs">라벨</Label>
                      <Input
                        value={approver.approver_label}
                        onChange={(e) => handleApproverChange(approver.id, "approver_label", e.target.value)}
                        placeholder="예: 팀장, 최종 결재"
                        className="h-7 text-[10px] sm:h-8 sm:text-xs"
                      />
                    </div>
                  </div>
                </div>
              ))}
            </div>
          </div>

          {/* 에러 메시지 */}
          {error && (
            <p className="text-destructive text-xs">{error}</p>
          )}
        </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}
            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...
              </>
            ) : (
              "결재 요청"
            )}
          </Button>
        </DialogFooter>
      </DialogContent>
    </Dialog>
  );
};

export default ApprovalRequestModal;