import { defineStore } from 'pinia'
import { ref, computed } from 'vue'
import { accountApi } from '@/api/accounts'
import type {
  FinancialAccount, AccountFormData, BalanceUpdateData,
  AccountHistoryRecord, DebtInstallment, DebtInstallmentFormData
} from '@/api/types'

export const useAccountStore = defineStore('account', () => {
  const accounts = ref<FinancialAccount[]>([])
  const installments = ref<DebtInstallment[]>([])
  const loading = ref(false)

  const savingsAccounts = computed(() =>
    accounts.value.filter(a => a.account_type === 'savings' && a.is_active)
  )

  const debtAccounts = computed(() =>
    accounts.value.filter(a => a.account_type === 'debt' && a.is_active)
  )

  const totalSavings = computed(() =>
    savingsAccounts.value.reduce((sum, a) => sum + a.balance, 0)
  )

  const totalDebt = computed(() =>
    debtAccounts.value.reduce((sum, a) => sum + a.balance, 0)
  )

  const netAssets = computed(() => totalSavings.value - totalDebt.value)

  const activeInstallments = computed(() =>
    installments.value.filter(i => !i.is_completed && i.days_until_payment !== null)
  )

  const upcomingPayments = computed(() =>
    activeInstallments.value
      .filter(i => i.days_until_payment! >= 0)
      .sort((a, b) => a.days_until_payment! - b.days_until_payment!)
  )

  // ============ 账户操作 ============

  async function fetchAccounts() {
    loading.value = true
    try {
      accounts.value = await accountApi.getAccounts()
    } catch (error) {
      console.error('获取账户列表失败:', error)
    } finally {
      loading.value = false
    }
  }

  async function createAccount(data: AccountFormData): Promise<FinancialAccount | null> {
    try {
      const account = await accountApi.createAccount(data)
      accounts.value.push(account)
      return account
    } catch (error) {
      console.error('创建账户失败:', error)
      return null
    }
  }

  async function updateAccount(id: number, data: Partial<AccountFormData>): Promise<FinancialAccount | null> {
    try {
      const updated = await accountApi.updateAccount(id, data)
      const index = accounts.value.findIndex(a => a.id === id)
      if (index !== -1) {
        accounts.value[index] = updated
      }
      return updated
    } catch (error) {
      console.error('更新账户失败:', error)
      return null
    }
  }

  async function deleteAccount(id: number): Promise<boolean> {
    try {
      await accountApi.deleteAccount(id)
      accounts.value = accounts.value.filter(a => a.id !== id)
      return true
    } catch (error) {
      console.error('删除账户失败:', error)
      return false
    }
  }

  async function updateBalance(id: number, data: BalanceUpdateData): Promise<FinancialAccount | null> {
    try {
      const updated = await accountApi.updateBalance(id, data)
      const index = accounts.value.findIndex(a => a.id === id)
      if (index !== -1) {
        accounts.value[index] = updated
      }
      return updated
    } catch (error) {
      console.error('更新余额失败:', error)
      return null
    }
  }

  async function fetchHistory(id: number, page = 1, pageSize = 20): Promise<AccountHistoryResponse> {
    try {
      return await accountApi.getHistory(id, { page, page_size: pageSize })
    } catch (error) {
      console.error('获取变更历史失败:', error)
      return { total: 0, page: 1, page_size: pageSize, records: [] }
    }
  }

  // ============ 分期计划操作 ============

  async function fetchInstallments() {
    try {
      installments.value = await accountApi.getInstallments()
    } catch (error) {
      console.error('获取分期计划失败:', error)
    }
  }

  async function createInstallment(data: DebtInstallmentFormData): Promise<DebtInstallment | null> {
    try {
      const inst = await accountApi.createInstallment(data)
      installments.value.push(inst)
      installments.value.sort((a, b) => {
        const aActive = !a.is_completed && a.days_until_payment !== null ? 0 : 1
        const bActive = !b.is_completed && b.days_until_payment !== null ? 0 : 1
        if (aActive !== bActive) return aActive - bActive
        return (a.days_until_payment ?? 9999) - (b.days_until_payment ?? 9999)
      })
      return inst
    } catch (error) {
      console.error('创建分期计划失败:', error)
      return null
    }
  }

  async function updateInstallment(id: number, data: Partial<DebtInstallmentFormData>): Promise<DebtInstallment | null> {
    try {
      const updated = await accountApi.updateInstallment(id, data)
      const index = installments.value.findIndex(i => i.id === id)
      if (index !== -1) {
        installments.value[index] = updated
      }
      return updated
    } catch (error) {
      console.error('更新分期计划失败:', error)
      return null
    }
  }

  async function deleteInstallment(id: number): Promise<boolean> {
    try {
      await accountApi.deleteInstallment(id)
      installments.value = installments.value.filter(i => i.id !== id)
      return true
    } catch (error) {
      console.error('删除分期计划失败:', error)
      return false
    }
  }

  async function payInstallment(id: number): Promise<DebtInstallment | null> {
    try {
      const updated = await accountApi.payInstallment(id)
      const index = installments.value.findIndex(i => i.id === id)
      if (index !== -1) {
        installments.value[index] = updated
      }
      return updated
    } catch (error) {
      console.error('标记还款失败:', error)
      return null
    }
  }

  async function init() {
    await Promise.all([fetchAccounts(), fetchInstallments()])
  }

  return {
    accounts,
    installments,
    loading,
    savingsAccounts,
    debtAccounts,
    totalSavings,
    totalDebt,
    netAssets,
    activeInstallments,
    upcomingPayments,
    fetchAccounts,
    createAccount,
    updateAccount,
    deleteAccount,
    updateBalance,
    fetchHistory,
    fetchInstallments,
    createInstallment,
    updateInstallment,
    deleteInstallment,
    payInstallment,
    init,
  }
})