/**
 * DSR API Client
 *
 * API client for Data Subject Request management.
 * Connects to the native compliance backend (Python/FastAPI).
 */

import {
  DSRRequest,
  DSRCreateRequest,
  DSRStatistics,
} from './types'

// =============================================================================
// SDK API FUNCTIONS (via Next.js proxy to compliance backend)
// =============================================================================

interface BackendDSR {
  id: string
  tenant_id: string
  request_number: string
  request_type: string
  status: string
  priority: string
  requester_name: string
  requester_email: string
  requester_phone?: string
  requester_address?: string
  requester_customer_id?: string
  source: string
  source_details?: string
  request_text?: string
  notes?: string
  internal_notes?: string
  received_at: string
  deadline_at: string
  extended_deadline_at?: string
  extension_reason?: string
  extension_approved_by?: string
  extension_approved_at?: string
  identity_verified: boolean
  verification_method?: string
  verified_at?: string
  verified_by?: string
  verification_notes?: string
  verification_document_ref?: string
  assigned_to?: string
  assigned_at?: string
  assigned_by?: string
  completed_at?: string
  completion_notes?: string
  rejection_reason?: string
  rejection_legal_basis?: string
  erasure_checklist?: any[]
  data_export?: any
  rectification_details?: any
  objection_details?: any
  affected_systems?: string[]
  created_at: string
  updated_at: string
  created_by?: string
  updated_by?: string
}

/**
 * Transform flat backend DSR to nested SDK DSRRequest format.
 * New compliance backend already uses the same status names as frontend types.
 */
export function transformBackendDSR(b: BackendDSR): DSRRequest {
  return {
    id: b.id,
    referenceNumber: b.request_number,
    type: b.request_type as DSRRequest['type'],
    status: (b.status as DSRRequest['status']) || 'intake',
    priority: (b.priority as DSRRequest['priority']) || 'normal',
    requester: {
      name: b.requester_name,
      email: b.requester_email,
      phone: b.requester_phone,
      address: b.requester_address,
      customerId: b.requester_customer_id,
    },
    source: (b.source as DSRRequest['source']) || 'email',
    sourceDetails: b.source_details,
    requestText: b.request_text,
    receivedAt: b.received_at,
    deadline: {
      originalDeadline: b.deadline_at,
      currentDeadline: b.extended_deadline_at || b.deadline_at,
      extended: !!b.extended_deadline_at,
      extensionReason: b.extension_reason,
      extensionApprovedBy: b.extension_approved_by,
      extensionApprovedAt: b.extension_approved_at,
    },
    completedAt: b.completed_at,
    identityVerification: {
      verified: b.identity_verified,
      method: b.verification_method as any,
      verifiedAt: b.verified_at,
      verifiedBy: b.verified_by,
      notes: b.verification_notes,
      documentRef: b.verification_document_ref,
    },
    assignment: {
      assignedTo: b.assigned_to || null,
      assignedAt: b.assigned_at,
      assignedBy: b.assigned_by,
    },
    notes: b.notes,
    internalNotes: b.internal_notes,
    erasureChecklist: b.erasure_checklist ? { items: b.erasure_checklist, canProceedWithErasure: true } : undefined,
    dataExport: b.data_export && Object.keys(b.data_export).length > 0 ? b.data_export : undefined,
    rectificationDetails: b.rectification_details && Object.keys(b.rectification_details).length > 0 ? b.rectification_details : undefined,
    objectionDetails: b.objection_details && Object.keys(b.objection_details).length > 0 ? b.objection_details : undefined,
    createdAt: b.created_at,
    createdBy: b.created_by || 'system',
    updatedAt: b.updated_at,
    updatedBy: b.updated_by,
    tenantId: b.tenant_id,
  }
}

function getSdkHeaders(): HeadersInit {
  if (typeof window === 'undefined') return {}
  return {
    'Content-Type': 'application/json',
    'X-Tenant-ID': localStorage.getItem('bp_tenant_id') || '',
    'X-User-ID': localStorage.getItem('bp_user_id') || '',
  }
}

/**
 * Fetch DSR list from compliance backend via proxy
 */
export async function fetchSDKDSRList(): Promise<{ requests: DSRRequest[]; statistics: DSRStatistics }> {
  // Fetch list and stats in parallel
  const [listRes, statsRes] = await Promise.all([
    fetch('/api/sdk/v1/compliance/dsr?limit=100', { headers: getSdkHeaders() }),
    fetch('/api/sdk/v1/compliance/dsr/stats', { headers: getSdkHeaders() }),
  ])

  if (!listRes.ok) {
    throw new Error(`HTTP ${listRes.status}`)
  }

  const listData = await listRes.json()
  const backendDSRs: BackendDSR[] = listData.requests || []
  const requests = backendDSRs.map(transformBackendDSR)

  let statistics: DSRStatistics
  if (statsRes.ok) {
    const statsData = await statsRes.json()
    statistics = {
      total: statsData.total || 0,
      byStatus: statsData.by_status || { intake: 0, identity_verification: 0, processing: 0, completed: 0, rejected: 0, cancelled: 0 },
      byType: statsData.by_type || { access: 0, rectification: 0, erasure: 0, restriction: 0, portability: 0, objection: 0 },
      overdue: statsData.overdue || 0,
      dueThisWeek: statsData.due_this_week || 0,
      averageProcessingDays: statsData.average_processing_days || 0,
      completedThisMonth: statsData.completed_this_month || 0,
    }
  } else {
    // Fallback: calculate locally
    const now = new Date()
    statistics = {
      total: requests.length,
      byStatus: {
        intake: requests.filter(r => r.status === 'intake').length,
        identity_verification: requests.filter(r => r.status === 'identity_verification').length,
        processing: requests.filter(r => r.status === 'processing').length,
        completed: requests.filter(r => r.status === 'completed').length,
        rejected: requests.filter(r => r.status === 'rejected').length,
        cancelled: requests.filter(r => r.status === 'cancelled').length,
      },
      byType: {
        access: requests.filter(r => r.type === 'access').length,
        rectification: requests.filter(r => r.type === 'rectification').length,
        erasure: requests.filter(r => r.type === 'erasure').length,
        restriction: requests.filter(r => r.type === 'restriction').length,
        portability: requests.filter(r => r.type === 'portability').length,
        objection: requests.filter(r => r.type === 'objection').length,
      },
      overdue: 0,
      dueThisWeek: 0,
      averageProcessingDays: 0,
      completedThisMonth: 0,
    }
  }

  return { requests, statistics }
}

/**
 * Create a new DSR via compliance backend
 */
export async function createSDKDSR(request: DSRCreateRequest): Promise<void> {
  const body = {
    request_type: request.type,
    requester_name: request.requester.name,
    requester_email: request.requester.email,
    requester_phone: request.requester.phone || null,
    requester_address: request.requester.address || null,
    requester_customer_id: request.requester.customerId || null,
    source: request.source,
    source_details: request.sourceDetails || null,
    request_text: request.requestText || '',
    priority: request.priority || 'normal',
  }
  const res = await fetch('/api/sdk/v1/compliance/dsr', {
    method: 'POST',
    headers: getSdkHeaders(),
    body: JSON.stringify(body),
  })
  if (!res.ok) {
    throw new Error(`HTTP ${res.status}`)
  }
}

/**
 * Fetch a single DSR by ID from compliance backend
 */
export async function fetchSDKDSR(id: string): Promise<DSRRequest | null> {
  const res = await fetch(`/api/sdk/v1/compliance/dsr/${id}`, {
    headers: getSdkHeaders(),
  })
  if (!res.ok) {
    return null
  }
  const data = await res.json()
  if (!data || !data.id) return null
  return transformBackendDSR(data)
}

/**
 * Update DSR status via compliance backend
 */
export async function updateSDKDSRStatus(id: string, status: string): Promise<void> {
  const res = await fetch(`/api/sdk/v1/compliance/dsr/${id}/status`, {
    method: 'POST',
    headers: getSdkHeaders(),
    body: JSON.stringify({ status }),
  })
  if (!res.ok) {
    throw new Error(`HTTP ${res.status}`)
  }
}

// =============================================================================
// WORKFLOW ACTIONS
// =============================================================================

/**
 * Verify identity of DSR requester
 */
export async function verifyDSRIdentity(id: string, data: { method: string; notes?: string; document_ref?: string }): Promise<DSRRequest> {
  const res = await fetch(`/api/sdk/v1/compliance/dsr/${id}/verify-identity`, {
    method: 'POST',
    headers: getSdkHeaders(),
    body: JSON.stringify(data),
  })
  if (!res.ok) throw new Error(`HTTP ${res.status}`)
  return transformBackendDSR(await res.json())
}

/**
 * Assign DSR to a user
 */
export async function assignDSR(id: string, assigneeId: string): Promise<DSRRequest> {
  const res = await fetch(`/api/sdk/v1/compliance/dsr/${id}/assign`, {
    method: 'POST',
    headers: getSdkHeaders(),
    body: JSON.stringify({ assignee_id: assigneeId }),
  })
  if (!res.ok) throw new Error(`HTTP ${res.status}`)
  return transformBackendDSR(await res.json())
}

/**
 * Extend DSR deadline (Art. 12 Abs. 3 DSGVO)
 */
export async function extendDSRDeadline(id: string, reason: string, days: number = 60): Promise<DSRRequest> {
  const res = await fetch(`/api/sdk/v1/compliance/dsr/${id}/extend`, {
    method: 'POST',
    headers: getSdkHeaders(),
    body: JSON.stringify({ reason, days }),
  })
  if (!res.ok) throw new Error(`HTTP ${res.status}`)
  return transformBackendDSR(await res.json())
}

/**
 * Complete a DSR
 */
export async function completeDSR(id: string, summary?: string): Promise<DSRRequest> {
  const res = await fetch(`/api/sdk/v1/compliance/dsr/${id}/complete`, {
    method: 'POST',
    headers: getSdkHeaders(),
    body: JSON.stringify({ summary }),
  })
  if (!res.ok) throw new Error(`HTTP ${res.status}`)
  return transformBackendDSR(await res.json())
}

/**
 * Reject a DSR with legal basis
 */
export async function rejectDSR(id: string, reason: string, legalBasis?: string): Promise<DSRRequest> {
  const res = await fetch(`/api/sdk/v1/compliance/dsr/${id}/reject`, {
    method: 'POST',
    headers: getSdkHeaders(),
    body: JSON.stringify({ reason, legal_basis: legalBasis }),
  })
  if (!res.ok) throw new Error(`HTTP ${res.status}`)
  return transformBackendDSR(await res.json())
}

// =============================================================================
// COMMUNICATIONS
// =============================================================================

/**
 * Fetch communications for a DSR
 */
export async function fetchDSRCommunications(id: string): Promise<any[]> {
  const res = await fetch(`/api/sdk/v1/compliance/dsr/${id}/communications`, {
    headers: getSdkHeaders(),
  })
  if (!res.ok) throw new Error(`HTTP ${res.status}`)
  return res.json()
}

/**
 * Send a communication for a DSR
 */
export async function sendDSRCommunication(id: string, data: { communication_type?: string; channel?: string; subject?: string; content: string }): Promise<any> {
  const res = await fetch(`/api/sdk/v1/compliance/dsr/${id}/communicate`, {
    method: 'POST',
    headers: getSdkHeaders(),
    body: JSON.stringify({ communication_type: 'outgoing', channel: 'email', ...data }),
  })
  if (!res.ok) throw new Error(`HTTP ${res.status}`)
  return res.json()
}

// =============================================================================
// EXCEPTION CHECKS (Art. 17)
// =============================================================================

/**
 * Fetch exception checks for an erasure DSR
 */
export async function fetchDSRExceptionChecks(id: string): Promise<any[]> {
  const res = await fetch(`/api/sdk/v1/compliance/dsr/${id}/exception-checks`, {
    headers: getSdkHeaders(),
  })
  if (!res.ok) throw new Error(`HTTP ${res.status}`)
  return res.json()
}

/**
 * Initialize Art. 17(3) exception checks for an erasure DSR
 */
export async function initDSRExceptionChecks(id: string): Promise<any[]> {
  const res = await fetch(`/api/sdk/v1/compliance/dsr/${id}/exception-checks/init`, {
    method: 'POST',
    headers: getSdkHeaders(),
  })
  if (!res.ok) throw new Error(`HTTP ${res.status}`)
  return res.json()
}

/**
 * Update a single exception check
 */
export async function updateDSRExceptionCheck(dsrId: string, checkId: string, data: { applies: boolean; notes?: string }): Promise<any> {
  const res = await fetch(`/api/sdk/v1/compliance/dsr/${dsrId}/exception-checks/${checkId}`, {
    method: 'PUT',
    headers: getSdkHeaders(),
    body: JSON.stringify(data),
  })
  if (!res.ok) throw new Error(`HTTP ${res.status}`)
  return res.json()
}

// =============================================================================
// HISTORY
// =============================================================================

/**
 * Fetch status change history for a DSR
 */
export async function fetchDSRHistory(id: string): Promise<any[]> {
  const res = await fetch(`/api/sdk/v1/compliance/dsr/${id}/history`, {
    headers: getSdkHeaders(),
  })
  if (!res.ok) throw new Error(`HTTP ${res.status}`)
  return res.json()
}

/**
 * Update DSR fields (priority, notes, etc.)
 */
export async function updateDSR(id: string, data: Record<string, any>): Promise<DSRRequest> {
  const res = await fetch(`/api/sdk/v1/compliance/dsr/${id}`, {
    method: 'PUT',
    headers: getSdkHeaders(),
    body: JSON.stringify(data),
  })
  if (!res.ok) throw new Error(`HTTP ${res.status}`)
  return transformBackendDSR(await res.json())
}

// =============================================================================
// MOCK DATA FUNCTIONS (kept as fallback)
// =============================================================================

export function createMockDSRList(): DSRRequest[] {
  const now = new Date()

  return [
    {
      id: 'dsr-001',
      referenceNumber: 'DSR-2025-000001',
      type: 'access',
      status: 'intake',
      priority: 'high',
      requester: {
        name: 'Max Mustermann',
        email: 'max.mustermann@example.de'
      },
      source: 'web_form',
      sourceDetails: 'Kontaktformular auf breakpilot.de',
      receivedAt: new Date(now.getTime() - 2 * 24 * 60 * 60 * 1000).toISOString(),
      deadline: {
        originalDeadline: new Date(now.getTime() + 28 * 24 * 60 * 60 * 1000).toISOString(),
        currentDeadline: new Date(now.getTime() + 28 * 24 * 60 * 60 * 1000).toISOString(),
        extended: false
      },
      identityVerification: {
        verified: false
      },
      assignment: {
        assignedTo: null
      },
      createdAt: new Date(now.getTime() - 2 * 24 * 60 * 60 * 1000).toISOString(),
      createdBy: 'system',
      updatedAt: new Date(now.getTime() - 2 * 24 * 60 * 60 * 1000).toISOString(),
      tenantId: 'default-tenant'
    },
    {
      id: 'dsr-002',
      referenceNumber: 'DSR-2025-000002',
      type: 'erasure',
      status: 'identity_verification',
      priority: 'high',
      requester: {
        name: 'Anna Schmidt',
        email: 'anna.schmidt@example.de',
        phone: '+49 170 1234567'
      },
      source: 'email',
      requestText: 'Ich moechte, dass alle meine Daten geloescht werden.',
      receivedAt: new Date(now.getTime() - 5 * 24 * 60 * 60 * 1000).toISOString(),
      deadline: {
        originalDeadline: new Date(now.getTime() + 9 * 24 * 60 * 60 * 1000).toISOString(),
        currentDeadline: new Date(now.getTime() + 9 * 24 * 60 * 60 * 1000).toISOString(),
        extended: false
      },
      identityVerification: {
        verified: false
      },
      assignment: {
        assignedTo: 'DSB Mueller',
        assignedAt: new Date(now.getTime() - 4 * 24 * 60 * 60 * 1000).toISOString()
      },
      createdAt: new Date(now.getTime() - 5 * 24 * 60 * 60 * 1000).toISOString(),
      createdBy: 'system',
      updatedAt: new Date(now.getTime() - 4 * 24 * 60 * 60 * 1000).toISOString(),
      tenantId: 'default-tenant'
    },
    {
      id: 'dsr-003',
      referenceNumber: 'DSR-2025-000003',
      type: 'rectification',
      status: 'processing',
      priority: 'normal',
      requester: {
        name: 'Peter Meier',
        email: 'peter.meier@example.de'
      },
      source: 'email',
      requestText: 'Meine Adresse ist falsch gespeichert.',
      receivedAt: new Date(now.getTime() - 7 * 24 * 60 * 60 * 1000).toISOString(),
      deadline: {
        originalDeadline: new Date(now.getTime() + 7 * 24 * 60 * 60 * 1000).toISOString(),
        currentDeadline: new Date(now.getTime() + 7 * 24 * 60 * 60 * 1000).toISOString(),
        extended: false
      },
      identityVerification: {
        verified: true,
        method: 'existing_account',
        verifiedAt: new Date(now.getTime() - 6 * 24 * 60 * 60 * 1000).toISOString(),
        verifiedBy: 'DSB Mueller'
      },
      assignment: {
        assignedTo: 'DSB Mueller',
        assignedAt: new Date(now.getTime() - 6 * 24 * 60 * 60 * 1000).toISOString()
      },
      rectificationDetails: {
        fieldsToCorrect: [
          {
            field: 'Adresse',
            currentValue: 'Musterstr. 1, 12345 Berlin',
            requestedValue: 'Musterstr. 10, 12345 Berlin',
            corrected: false
          }
        ]
      },
      createdAt: new Date(now.getTime() - 7 * 24 * 60 * 60 * 1000).toISOString(),
      createdBy: 'system',
      updatedAt: new Date(now.getTime() - 1 * 24 * 60 * 60 * 1000).toISOString(),
      tenantId: 'default-tenant'
    },
    {
      id: 'dsr-004',
      referenceNumber: 'DSR-2025-000004',
      type: 'portability',
      status: 'processing',
      priority: 'normal',
      requester: {
        name: 'Lisa Weber',
        email: 'lisa.weber@example.de'
      },
      source: 'web_form',
      receivedAt: new Date(now.getTime() - 10 * 24 * 60 * 60 * 1000).toISOString(),
      deadline: {
        originalDeadline: new Date(now.getTime() + 20 * 24 * 60 * 60 * 1000).toISOString(),
        currentDeadline: new Date(now.getTime() + 20 * 24 * 60 * 60 * 1000).toISOString(),
        extended: false
      },
      identityVerification: {
        verified: true,
        method: 'id_document',
        verifiedAt: new Date(now.getTime() - 8 * 24 * 60 * 60 * 1000).toISOString(),
        verifiedBy: 'DSB Mueller'
      },
      assignment: {
        assignedTo: 'IT Team',
        assignedAt: new Date(now.getTime() - 8 * 24 * 60 * 60 * 1000).toISOString()
      },
      notes: 'JSON-Export wird vorbereitet',
      createdAt: new Date(now.getTime() - 10 * 24 * 60 * 60 * 1000).toISOString(),
      createdBy: 'system',
      updatedAt: new Date(now.getTime() - 2 * 24 * 60 * 60 * 1000).toISOString(),
      tenantId: 'default-tenant'
    },
    {
      id: 'dsr-005',
      referenceNumber: 'DSR-2025-000005',
      type: 'objection',
      status: 'rejected',
      priority: 'low',
      requester: {
        name: 'Thomas Klein',
        email: 'thomas.klein@example.de'
      },
      source: 'letter',
      requestText: 'Ich widerspreche der Verarbeitung meiner Daten fuer Marketingzwecke.',
      receivedAt: new Date(now.getTime() - 35 * 24 * 60 * 60 * 1000).toISOString(),
      deadline: {
        originalDeadline: new Date(now.getTime() - 5 * 24 * 60 * 60 * 1000).toISOString(),
        currentDeadline: new Date(now.getTime() - 5 * 24 * 60 * 60 * 1000).toISOString(),
        extended: false
      },
      completedAt: new Date(now.getTime() - 7 * 24 * 60 * 60 * 1000).toISOString(),
      identityVerification: {
        verified: true,
        method: 'postal',
        verifiedAt: new Date(now.getTime() - 30 * 24 * 60 * 60 * 1000).toISOString(),
        verifiedBy: 'DSB Mueller'
      },
      assignment: {
        assignedTo: 'Rechtsabteilung',
        assignedAt: new Date(now.getTime() - 28 * 24 * 60 * 60 * 1000).toISOString()
      },
      objectionDetails: {
        processingPurpose: 'Marketing',
        legalBasis: 'Berechtigtes Interesse (Art. 6(1)(f))',
        objectionGrounds: 'Keine konkreten Gruende genannt',
        decision: 'rejected',
        decisionReason: 'Zwingende schutzwuerdige Gruende fuer die Verarbeitung ueberwiegen',
        decisionBy: 'Rechtsabteilung',
        decisionAt: new Date(now.getTime() - 7 * 24 * 60 * 60 * 1000).toISOString()
      },
      notes: 'Widerspruch unberechtigt - zwingende schutzwuerdige Gruende',
      createdAt: new Date(now.getTime() - 35 * 24 * 60 * 60 * 1000).toISOString(),
      createdBy: 'system',
      updatedAt: new Date(now.getTime() - 7 * 24 * 60 * 60 * 1000).toISOString(),
      tenantId: 'default-tenant'
    },
    {
      id: 'dsr-006',
      referenceNumber: 'DSR-2025-000006',
      type: 'access',
      status: 'completed',
      priority: 'normal',
      requester: {
        name: 'Sarah Braun',
        email: 'sarah.braun@example.de'
      },
      source: 'email',
      receivedAt: new Date(now.getTime() - 45 * 24 * 60 * 60 * 1000).toISOString(),
      deadline: {
        originalDeadline: new Date(now.getTime() - 15 * 24 * 60 * 60 * 1000).toISOString(),
        currentDeadline: new Date(now.getTime() - 15 * 24 * 60 * 60 * 1000).toISOString(),
        extended: false
      },
      completedAt: new Date(now.getTime() - 20 * 24 * 60 * 60 * 1000).toISOString(),
      identityVerification: {
        verified: true,
        method: 'id_document',
        verifiedAt: new Date(now.getTime() - 42 * 24 * 60 * 60 * 1000).toISOString(),
        verifiedBy: 'DSB Mueller'
      },
      assignment: {
        assignedTo: 'DSB Mueller',
        assignedAt: new Date(now.getTime() - 42 * 24 * 60 * 60 * 1000).toISOString()
      },
      dataExport: {
        format: 'pdf',
        generatedAt: new Date(now.getTime() - 20 * 24 * 60 * 60 * 1000).toISOString(),
        generatedBy: 'DSB Mueller',
        fileName: 'datenauskunft_sarah_braun.pdf',
        fileSize: 245000,
        includesThirdPartyData: false
      },
      createdAt: new Date(now.getTime() - 45 * 24 * 60 * 60 * 1000).toISOString(),
      createdBy: 'system',
      updatedAt: new Date(now.getTime() - 20 * 24 * 60 * 60 * 1000).toISOString(),
      tenantId: 'default-tenant'
    }
  ]
}

export function createMockStatistics(): DSRStatistics {
  return {
    total: 6,
    byStatus: {
      intake: 1,
      identity_verification: 1,
      processing: 2,
      completed: 1,
      rejected: 1,
      cancelled: 0
    },
    byType: {
      access: 2,
      rectification: 1,
      erasure: 1,
      restriction: 0,
      portability: 1,
      objection: 1
    },
    overdue: 0,
    dueThisWeek: 2,
    averageProcessingDays: 18,
    completedThisMonth: 1
  }
}