/**
 * API service for castle extension expense operations
 */

import { BaseService } from '@/core/base/BaseService'
import type {
  Account,
  ExpenseEntryRequest,
  ExpenseEntry,
  AccountNode
} from '../types'
import { appConfig } from '@/app.config'

export class ExpensesAPI extends BaseService {
  protected readonly metadata = {
    name: 'ExpensesAPI',
    version: '1.0.0',
    dependencies: [] // No dependencies - wallet key is passed as parameter
  }

  private get config() {
    return appConfig.modules.expenses.config
  }

  private get baseUrl() {
    return this.config?.apiConfig?.baseUrl || ''
  }

  protected async onInitialize(): Promise<void> {
    console.log('[ExpensesAPI] Initialized with config:', {
      baseUrl: this.baseUrl,
      timeout: this.config?.apiConfig?.timeout
    })
  }

  /**
   * Get authentication headers with provided wallet key
   */
  private getHeaders(walletKey: string): HeadersInit {
    return {
      'Content-Type': 'application/json',
      'X-Api-Key': walletKey
    }
  }

  /**
   * Get all accounts from castle
   *
   * @param walletKey - Wallet key for authentication
   * @param filterByUser - If true, only return accounts the user has permissions for
   */
  async getAccounts(walletKey: string, filterByUser: boolean = false): Promise<Account[]> {
    try {
      const url = new URL(`${this.baseUrl}/castle/api/v1/accounts`)
      if (filterByUser) {
        url.searchParams.set('filter_by_user', 'true')
      }

      const response = await fetch(url.toString(), {
        method: 'GET',
        headers: this.getHeaders(walletKey),
        signal: AbortSignal.timeout(this.config?.apiConfig?.timeout || 30000)
      })

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

      const accounts = await response.json()
      return accounts as Account[]
    } catch (error) {
      console.error('[ExpensesAPI] Error fetching accounts:', error)
      throw error
    }
  }

  /**
   * Get accounts in hierarchical tree structure
   *
   * Converts flat account list to nested tree based on colon-separated names
   * e.g., "Expenses:Groceries:Organic" becomes nested structure
   *
   * @param walletKey - Wallet key for authentication
   * @param rootAccount - Optional root account to filter by (e.g., "Expenses")
   * @param filterByUser - If true, only return accounts the user has permissions for
   */
  async getAccountHierarchy(
    walletKey: string,
    rootAccount?: string,
    filterByUser: boolean = false
  ): Promise<AccountNode[]> {
    const accounts = await this.getAccounts(walletKey, filterByUser)

    // Filter by root account if specified
    let filteredAccounts = accounts
    if (rootAccount) {
      filteredAccounts = accounts.filter(
        (acc) =>
          acc.name === rootAccount || acc.name.startsWith(`${rootAccount}:`)
      )
    }

    // Build hierarchy
    const accountMap = new Map<string, AccountNode>()

    // First pass: Create nodes for all accounts
    for (const account of filteredAccounts) {
      const parts = account.name.split(':')
      const level = parts.length - 1
      const parentName = parts.slice(0, -1).join(':')

      accountMap.set(account.name, {
        account: {
          ...account,
          level,
          parent_account: parentName || undefined,
          has_children: false
        },
        children: []
      })
    }

    // Second pass: Build parent-child relationships
    const rootNodes: AccountNode[] = []

    for (const [_name, node] of accountMap.entries()) {
      const parentName = node.account.parent_account

      if (parentName && accountMap.has(parentName)) {
        // Add to parent's children
        const parent = accountMap.get(parentName)!
        parent.children.push(node)
        parent.account.has_children = true
      } else {
        // Root level node
        rootNodes.push(node)
      }
    }

    // Sort children by name at each level
    const sortNodes = (nodes: AccountNode[]) => {
      nodes.sort((a, b) => a.account.name.localeCompare(b.account.name))
      nodes.forEach((node) => sortNodes(node.children))
    }
    sortNodes(rootNodes)

    return rootNodes
  }

  /**
   * Submit expense entry to castle
   */
  async submitExpense(walletKey: string, request: ExpenseEntryRequest): Promise<ExpenseEntry> {
    try {
      const response = await fetch(`${this.baseUrl}/castle/api/v1/entries/expense`, {
        method: 'POST',
        headers: this.getHeaders(walletKey),
        body: JSON.stringify(request),
        signal: AbortSignal.timeout(this.config?.apiConfig?.timeout || 30000)
      })

      if (!response.ok) {
        const errorData = await response.json().catch(() => ({}))
        const errorMessage =
          errorData.detail || `Failed to submit expense: ${response.statusText}`
        throw new Error(errorMessage)
      }

      const entry = await response.json()
      return entry as ExpenseEntry
    } catch (error) {
      console.error('[ExpensesAPI] Error submitting expense:', error)
      throw error
    }
  }

  /**
   * Get user's expense entries
   */
  async getUserExpenses(walletKey: string): Promise<ExpenseEntry[]> {
    try {
      const response = await fetch(`${this.baseUrl}/castle/api/v1/entries/user`, {
        method: 'GET',
        headers: this.getHeaders(walletKey),
        signal: AbortSignal.timeout(this.config?.apiConfig?.timeout || 30000)
      })

      if (!response.ok) {
        throw new Error(
          `Failed to fetch user expenses: ${response.statusText}`
        )
      }

      const entries = await response.json()
      return entries as ExpenseEntry[]
    } catch (error) {
      console.error('[ExpensesAPI] Error fetching user expenses:', error)
      throw error
    }
  }

  /**
   * Get user's balance with castle
   */
  async getUserBalance(walletKey: string): Promise<{ balance: number; currency: string }> {
    try {
      const response = await fetch(`${this.baseUrl}/castle/api/v1/balance`, {
        method: 'GET',
        headers: this.getHeaders(walletKey),
        signal: AbortSignal.timeout(this.config?.apiConfig?.timeout || 30000)
      })

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

      return await response.json()
    } catch (error) {
      console.error('[ExpensesAPI] Error fetching balance:', error)
      throw error
    }
  }

  /**
   * Get available currencies from LNbits instance
   */
  async getCurrencies(): Promise<string[]> {
    try {
      const response = await fetch(`${this.baseUrl}/api/v1/currencies`, {
        method: 'GET',
        signal: AbortSignal.timeout(this.config?.apiConfig?.timeout || 30000)
      })

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

      return await response.json()
    } catch (error) {
      console.error('[ExpensesAPI] Error fetching currencies:', error)
      throw error
    }
  }

  /**
   * Get default currency from LNbits instance
   */
  async getDefaultCurrency(): Promise<string | null> {
    try {
      const response = await fetch(`${this.baseUrl}/api/v1/default-currency`, {
        method: 'GET',
        signal: AbortSignal.timeout(this.config?.apiConfig?.timeout || 30000)
      })

      if (!response.ok) {
        throw new Error(`Failed to fetch default currency: ${response.statusText}`)
      }

      const data = await response.json()
      return data.default_currency
    } catch (error) {
      console.error('[ExpensesAPI] Error fetching default currency:', error)
      throw error
    }
  }
}