import { useState, useEffect } from 'react';
import { useAuth } from '@/contexts/AuthContext';
import { getWorkflowDetails } from '@/services/workflowApi';
import { getAllConfigurations, AdminConfiguration } from '@/services/adminApi';

export interface RequestTemplate {
  id: string;
  name: string;
  description: string;
  category: string;
  icon: React.ComponentType<any>;
  estimatedTime: string;
  commonApprovers: string[];
  suggestedSLA: number;
  priority: 'high' | 'medium' | 'low';
  fields: {
    amount?: boolean;
    vendor?: boolean;
    timeline?: boolean;
    impact?: boolean;
  };
}

export interface FormData {
  template: string;
  title: string;
  description: string;
  category: string;
  priority: string;
  urgency: string;
  businessImpact: string;
  amount: string;
  currency: string;
  vendor: string;
  timeline: string;
  slaTemplate: string;
  slaHours: number;
  customSlaHours: number;
  slaEndDate: Date | undefined;
  expectedCompletionDate: Date | undefined;
  breachEscalation: boolean;
  reminderSchedule: '25' | '50' | '75';
  workflowType: 'sequential' | 'parallel';
  requiresAllApprovals: boolean;
  escalationEnabled: boolean;
  reminderEnabled: boolean;
  minimumLevel: number;
  maxLevel: number;
  approvers: any[];
  approverCount: number;
  spectators: any[];
  ccList: any[];
  invitedUsers: any[];
  allowComments: boolean;
  allowDocumentUpload: boolean;
  documents: File[];
  tags: string[];
  relatedRequests: string[];
  costCenter: string;
  project: string;
}

const initialFormData: FormData = {
  template: '',
  title: '',
  description: '',
  category: '',
  priority: '',
  urgency: '',
  businessImpact: '',
  amount: '',
  currency: 'USD',
  vendor: '',
  timeline: '',
  slaTemplate: '',
  slaHours: 0,
  customSlaHours: 0,
  slaEndDate: undefined,
  expectedCompletionDate: undefined,
  breachEscalation: true,
  reminderSchedule: '50',
  workflowType: 'sequential',
  requiresAllApprovals: true,
  escalationEnabled: true,
  reminderEnabled: true,
  minimumLevel: 1,
  maxLevel: 1,
  approvers: [],
  approverCount: 1,
  spectators: [],
  ccList: [],
  invitedUsers: [],
  allowComments: true,
  allowDocumentUpload: true,
  documents: [],
  tags: [],
  relatedRequests: [],
  costCenter: '',
  project: ''
};

export interface SystemPolicy {
  maxApprovalLevels: number;
  maxParticipants: number;
  allowSpectators: boolean;
  maxSpectators: number;
}

export interface DocumentPolicy {
  maxFileSizeMB: number;
  allowedFileTypes: string[];
}

/**
 * Custom Hook: useCreateRequestForm
 * 
 * Purpose: Manages form state, policies, and draft loading for CreateRequest
 * 
 * Responsibilities:
 * - Manages form data state
 * - Loads system and document policies
 * - Handles draft loading in edit mode
 * - Provides form data update functions
 */
export function useCreateRequestForm(
  isEditing: boolean,
  editRequestId: string,
  templates: RequestTemplate[]
) {
  const { user } = useAuth();
  const [formData, setFormData] = useState<FormData>(initialFormData);
  const [selectedTemplate, setSelectedTemplate] = useState<RequestTemplate | null>(null);
  const [loadingDraft, setLoadingDraft] = useState(isEditing);
  const [systemPolicy, setSystemPolicy] = useState<SystemPolicy>({
    maxApprovalLevels: 10,
    maxParticipants: 50,
    allowSpectators: true,
    maxSpectators: 20
  });
  const [documentPolicy, setDocumentPolicy] = useState<DocumentPolicy>({
    maxFileSizeMB: 10,
    allowedFileTypes: ['pdf', 'doc', 'docx', 'xls', 'xlsx', 'ppt', 'pptx', 'jpg', 'jpeg', 'png', 'gif']
  });
  const [existingDocuments, setExistingDocuments] = useState<any[]>([]);

  // Load policies on mount
  useEffect(() => {
    const loadPolicies = async () => {
      try {
        // Load document policy
        const docConfigs = await getAllConfigurations('DOCUMENT_POLICY');
        const docConfigMap: Record<string, string> = {};
        docConfigs.forEach((c: AdminConfiguration) => {
          docConfigMap[c.configKey] = c.configValue;
        });

        const maxFileSizeMB = parseInt(docConfigMap['MAX_FILE_SIZE_MB'] || '10');
        const allowedFileTypesStr = docConfigMap['ALLOWED_FILE_TYPES'] || 'pdf,doc,docx,xls,xlsx,ppt,pptx,jpg,jpeg,png,gif';
        const allowedFileTypes = allowedFileTypesStr.split(',').map(ext => ext.trim().toLowerCase());

        setDocumentPolicy({
          maxFileSizeMB,
          allowedFileTypes
        });

        // Load system policy
        const workflowConfigs = await getAllConfigurations('WORKFLOW_SHARING');
        const tatConfigs = await getAllConfigurations('TAT_SETTINGS');
        const allConfigs = [...workflowConfigs, ...tatConfigs];
        const configMap: Record<string, string> = {};
        allConfigs.forEach((c: AdminConfiguration) => {
          configMap[c.configKey] = c.configValue;
        });

        setSystemPolicy({
          maxApprovalLevels: parseInt(configMap['MAX_APPROVAL_LEVELS'] || '10'),
          maxParticipants: parseInt(configMap['MAX_PARTICIPANTS_PER_REQUEST'] || '50'),
          allowSpectators: configMap['ALLOW_ADD_SPECTATOR']?.toLowerCase() === 'true',
          maxSpectators: parseInt(configMap['MAX_SPECTATORS_PER_REQUEST'] || '20')
        });
      } catch (error) {
        console.error('Failed to load policies:', error);
      }
    };

    loadPolicies();
  }, []);

  // Load draft data when in edit mode
  useEffect(() => {
    if (!isEditing || !editRequestId) return;

    let mounted = true;
    (async () => {
      try {
        setLoadingDraft(true);
        const details = await getWorkflowDetails(editRequestId);
        if (!mounted || !details) return;

        const wf = details.workflow || {};
        const approvals = Array.isArray(details.approvals) ? details.approvals : [];
        const participants = Array.isArray(details.participants) ? details.participants : [];
        const documents = Array.isArray(details.documents) ? details.documents.filter((d: any) => !d.isDeleted) : [];
        
        // Store existing documents for tracking
        setExistingDocuments(documents);

        // Map priority
        const priority = (wf.priority || '').toString().toLowerCase();
        const priorityMap: Record<string, string> = {
          'standard': 'standard',
          'express': 'express'
        };

        // Map template type
        const templateType = wf.templateType === 'TEMPLATE' ? 'existing-template' : 'custom';
        const template = templates.find(t => t.id === templateType) || templates[0] || null;
        setSelectedTemplate(template);

        // Map approvers
        const mappedApprovers = approvals
          .sort((a: any, b: any) => (a.levelNumber || 0) - (b.levelNumber || 0))
          .map((approval: any) => {
            const tatHours = Number(approval.tatHours || 24);
            const tatDays = Math.floor(tatHours / 24);
            const tatHoursRemainder = tatHours % 24;
            return {
              id: approval.approverId || `temp-${approval.levelNumber}`,
              name: approval.approverName || approval.approverEmail || '',
              email: approval.approverEmail || '',
              role: approval.levelName || `Level ${approval.levelNumber}`,
              department: '',
              avatar: (approval.approverName || approval.approverEmail || 'XX').substring(0, 2).toUpperCase(),
              level: approval.levelNumber || 1,
              canClose: false,
              tat: tatDays > 0 ? tatDays : tatHoursRemainder,
              tatType: tatDays > 0 ? 'days' as const : 'hours' as const,
              userId: approval.approverId
            };
          });

        // Map spectators
        const mappedSpectators = participants
          .filter((p: any) => {
            const pt = (p.participantType || p.participant_type || '').toString().toUpperCase().trim();
            const isSpectator = pt === 'SPECTATOR';
            if (!isSpectator) return false;
            const hasEmail = !!(p.userEmail || p.user_email || p.email);
            return hasEmail;
          })
          .map((p: any, index: number) => {
            const userId = p.userId || p.user_id || p.id;
            const userName = p.userName || p.user_name || p.name || '';
            const userEmail = p.userEmail || p.user_email || p.email || '';
            const avatarText = userName || userEmail || 'XX';
            const avatar = avatarText
              .split(' ')
              .map((s: string) => s[0])
              .filter(Boolean)
              .join('')
              .slice(0, 2)
              .toUpperCase();

            return {
              id: userId || `spectator-${editRequestId}-${index}-${Date.now()}`,
              userId: userId,
              name: userName || userEmail || 'Spectator',
              email: userEmail,
              role: 'Spectator',
              department: p.department || '',
              avatar: avatar,
              level: 1,
              canClose: false
            };
          });

        setFormData(prev => ({
          ...prev,
          template: templateType,
          title: wf.title || '',
          description: wf.description || '',
          priority: priorityMap[priority] || 'standard',
          approvers: mappedApprovers,
          approverCount: mappedApprovers.length || 1,
          spectators: mappedSpectators,
          maxLevel: Math.max(...mappedApprovers.map((a: any) => a.level || 1), 1)
        }));
      } catch (error) {
        console.error('Failed to load draft:', error);
      } finally {
        if (mounted) setLoadingDraft(false);
      }
    })();

    return () => { mounted = false; };
  }, [isEditing, editRequestId, templates]);

  const updateFormData = (field: keyof FormData, value: any) => {
    setFormData(prev => ({ ...prev, [field]: value }));
  };

  return {
    formData,
    setFormData,
    updateFormData,
    selectedTemplate,
    setSelectedTemplate,
    loadingDraft,
    systemPolicy,
    documentPolicy,
    existingDocuments,
    setExistingDocuments
  };
}