export interface Transaction {
  id: number
  family_id: number
  description: string | null
  type: string
  datetime: string
  category: string
  amount: number
  created_at: string
  created_by: number
  receipt_id: number | null
}

interface TransactionsResponse {
  items: Transaction[]
}

interface GetTransactionsOptions {
  familyId?: number
  limit?: number
  offset?: number
}

export async function getTransactions(options: GetTransactionsOptions = {}): Promise<Transaction[]> {
  const params = new URLSearchParams()

  if (typeof options.familyId === 'number' && Number.isFinite(options.familyId) && options.familyId > 0) {
    params.set('family_id', String(options.familyId))
  }

  params.set('limit', String(options.limit ?? 100))
  params.set('offset', String(options.offset ?? 0))

  const query = params.toString()
  const response = await fetch(`/api/v1/transactions${query ? `?${query}` : ''}`)

  if (!response.ok) {
    throw new Error(`Failed to fetch transactions: ${response.status}`)
  }

  const payload = await response.json() as TransactionsResponse
  return Array.isArray(payload.items) ? payload.items : []
}

export interface CreateTransactionData {
  family_id: number
  type?: string
  category?: string
  amount?: number
  datetime?: string
  description?: string
  receipt_number?: string
  receipt_date?: string
}

// TODO: Replace with the authenticated user id when frontend auth is implemented.
const TRANSACTION_CREATOR_ID = 1

export async function createTransaction(data: CreateTransactionData): Promise<Transaction> {
  const response = await fetch('/api/v1/transactions', {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
    },
    body: JSON.stringify({
      ...data,
      created_by: TRANSACTION_CREATOR_ID,
    }),
  })

  if (!response.ok) {
    const error = await response.json().catch(() => ({ message: response.statusText }))
    throw new Error(error.message || `Failed to create transaction: ${response.status}`)
  }

  return response.json() as Promise<Transaction>
}

export interface CreateTransactionPhotoData {
  photo: File
  family_id: number
  type?: string
  category?: string
  description?: string
}

export async function createTransactionFromPhoto(data: CreateTransactionPhotoData): Promise<Transaction> {
  const formData = new FormData()
  formData.append('photo', data.photo)
  formData.append('family_id', String(data.family_id))
  formData.append('created_by', String(TRANSACTION_CREATOR_ID))
  if (data.type) formData.append('type', data.type)
  if (data.category) formData.append('category', data.category)
  if (data.description) formData.append('description', data.description)

  const response = await fetch('/api/v1/transactions', {
    method: 'POST',
    body: formData,
  })

  if (!response.ok) {
    const error = await response.json().catch(() => ({ message: response.statusText }))
    throw new Error(error.message || `Failed to create transaction from photo: ${response.status}`)
  }

  return response.json() as Promise<Transaction>
}