'use client'

/**
 * BatchModeSelector - 批次處理模式選擇器
 * =======================================
 * Phase 11: #50 批次處理功能
 *
 * Features:
 * - 全部接受: 批次核准所有低/中風險
 * - 逐一審核: 依序審核
 * - 僅顯示 CRITICAL: 過濾高風險
 *
 * 安全限制:
 * - CRITICAL + DESTRUCTIVE 禁止批次核准
 *
 * i18n: 100% next-intl
 */

import { useState, useMemo, useCallback } from 'react'
import { useTranslations } from 'next-intl'
import { cn } from '@/lib/utils'
import { CURRENT_USER } from '@/lib/constants'
import {
  useApprovalStore,
  usePendingApprovals,
  toFrontendApproval,
} from '@/stores/approval.store'
import { StatusOrb } from '@/components/ui/status-orb'
import {
  CheckCircle2,
  ListFilter,
  AlertTriangle,
  Loader2,
  Shield,
} from 'lucide-react'
// ApprovalRequest type used implicitly via toFrontendApproval

// =============================================================================
// Types
// =============================================================================

export type BatchMode = 'sequential' | 'filter_critical' | 'bulk_approve'

interface BatchModeSelectorProps {
  className?: string
  /** 批次核准完成後的回調 */
  onBulkComplete?: (succeeded: number, failed: number, skipped: number) => void
  /** 簽核者資訊 */
  signerId?: string
  signerName?: string
}

interface BulkApproveResult {
  approval_id: string
  success: boolean
  message: string
  execution_triggered: boolean
}

interface BulkApproveResponse {
  total: number
  succeeded: number
  failed: number
  skipped: number
  results: BulkApproveResult[]
}

// =============================================================================
// Component
// =============================================================================

export function BatchModeSelector({
  className,
  onBulkComplete,
  signerId = CURRENT_USER.id,
  signerName = CURRENT_USER.name,
}: BatchModeSelectorProps) {
  const t = useTranslations('approval')
  const tBatch = useTranslations('approval.batch')

  const pendingApprovals = usePendingApprovals()
  const { fetchPending } = useApprovalStore()

  const [mode, setMode] = useState<BatchMode>('sequential')
  const [isProcessing, setIsProcessing] = useState(false)

  // 轉換為前端格式
  const approvals = useMemo(() => {
    return pendingApprovals.map((a) => toFrontendApproval(a))
  }, [pendingApprovals])

  // 統計各風險等級數量
  const stats = useMemo(() => {
    const result = {
      total: approvals.length,
      low: 0,
      medium: 0,
      high: 0,
      critical: 0,
      canBulkApprove: 0,
    }

    approvals.forEach((a) => {
      switch (a.riskLevel) {
        case 'low':
          result.low++
          result.canBulkApprove++
          break
        case 'medium':
          result.medium++
          result.canBulkApprove++
          break
        case 'high':
          result.high++
          // HIGH 風險允許批次，但 DESTRUCTIVE 不允許
          if (a.blastRadius.dataImpact !== 'DESTRUCTIVE') {
            result.canBulkApprove++
          }
          break
        case 'critical':
          result.critical++
          // CRITICAL 禁止批次
          break
      }
    })

    return result
  }, [approvals])

  // 批次核准處理
  const handleBulkApprove = useCallback(async () => {
    if (stats.canBulkApprove === 0) return

    setIsProcessing(true)

    try {
      // 取得可批次核准的 ID 列表
      const bulkApproveIds = approvals
        .filter((a) => {
          // 排除 CRITICAL
          if (a.riskLevel === 'critical') return false
          // 排除 DESTRUCTIVE
          if (a.blastRadius.dataImpact === 'DESTRUCTIVE') return false
          return true
        })
        .map((a) => a.id)

      const response = await fetch('/api/v1/approvals/bulk-approve', {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
        },
        body: JSON.stringify({
          approval_ids: bulkApproveIds,
          signer_id: signerId,
          signer_name: signerName,
          comment: 'Bulk approved via ConversationalView',
        }),
      })

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

      const result: BulkApproveResponse = await response.json()

      // 刷新列表
      await fetchPending()

      // 回調通知
      onBulkComplete?.(result.succeeded, result.failed, result.skipped)

    } catch (error) {
      console.error('Bulk approve failed:', error)
    } finally {
      setIsProcessing(false)
    }
  }, [approvals, stats.canBulkApprove, signerId, signerName, fetchPending, onBulkComplete])

  return (
    <div className={cn('p-4 bg-white rounded-xl border border-nothing-gray-200', className)}>
      {/* 統計概覽 */}
      <div className="flex items-center justify-between mb-4">
        <h3 className="font-heading text-sm font-bold text-nothing-gray-900">
          {tBatch('title')}
        </h3>
        <div className="flex items-center gap-2 text-xs font-body">
          <span className="text-nothing-gray-400">{stats.total} {t('pendingApprovals')}</span>
        </div>
      </div>

      {/* 風險等級分佈 */}
      <div className="grid grid-cols-4 gap-2 mb-4">
        <div className="flex items-center gap-1.5 px-2 py-1 rounded-lg bg-nothing-gray-50">
          <StatusOrb status="healthy" size="sm" />
          <span className="text-xs font-body text-nothing-gray-600">
            LOW: {stats.low}
          </span>
        </div>
        <div className="flex items-center gap-1.5 px-2 py-1 rounded-lg bg-claw-blue/5">
          <StatusOrb status="healthy" size="sm" />
          <span className="text-xs font-body text-claw-blue">
            MED: {stats.medium}
          </span>
        </div>
        <div className="flex items-center gap-1.5 px-2 py-1 rounded-lg bg-status-warning/5">
          <StatusOrb status="warning" size="sm" />
          <span className="text-xs font-body text-status-warning">
            HIGH: {stats.high}
          </span>
        </div>
        <div className="flex items-center gap-1.5 px-2 py-1 rounded-lg bg-status-critical/5">
          <StatusOrb status="critical" size="sm" pulse />
          <span className="text-xs font-body text-status-critical">
            CRIT: {stats.critical}
          </span>
        </div>
      </div>

      {/* 模式選擇按鈕 */}
      <div className="space-y-2">
        {/* 全部接受 (批次) */}
        <button
          onClick={handleBulkApprove}
          disabled={stats.canBulkApprove === 0 || isProcessing}
          className={cn(
            'w-full flex items-center justify-between p-3 rounded-lg transition-all',
            'border border-nothing-gray-200',
            'hover:bg-status-healthy/5 hover:border-status-healthy/30',
            'focus:outline-none focus:ring-2 focus:ring-status-healthy/50',
            'disabled:opacity-50 disabled:cursor-not-allowed',
            mode === 'bulk_approve' && 'bg-status-healthy/10 border-status-healthy/50'
          )}
        >
          <div className="flex items-center gap-2">
            {isProcessing ? (
              <Loader2 className="w-4 h-4 text-status-healthy animate-spin" />
            ) : (
              <CheckCircle2 className="w-4 h-4 text-status-healthy" />
            )}
            <span className="text-sm font-medium text-nothing-gray-900">
              {tBatch('bulkApprove')}
            </span>
          </div>
          <span className="text-xs font-body text-nothing-gray-400">
            {stats.canBulkApprove} {tBatch('eligible')}
          </span>
        </button>

        {/* 逐一審核 */}
        <button
          onClick={() => setMode('sequential')}
          className={cn(
            'w-full flex items-center justify-between p-3 rounded-lg transition-all',
            'border border-nothing-gray-200',
            'hover:bg-nothing-gray-50',
            'focus:outline-none focus:ring-2 focus:ring-claw-blue/50',
            mode === 'sequential' && 'bg-claw-blue/5 border-claw-blue/30'
          )}
        >
          <div className="flex items-center gap-2">
            <ListFilter className="w-4 h-4 text-claw-blue" />
            <span className="text-sm font-medium text-nothing-gray-900">
              {tBatch('sequential')}
            </span>
          </div>
          <span className="text-xs font-body text-nothing-gray-400">
            {stats.total} {tBatch('items')}
          </span>
        </button>

        {/* 僅顯示 CRITICAL */}
        <button
          onClick={() => setMode('filter_critical')}
          disabled={stats.critical === 0}
          className={cn(
            'w-full flex items-center justify-between p-3 rounded-lg transition-all',
            'border border-nothing-gray-200',
            'hover:bg-status-critical/5 hover:border-status-critical/30',
            'focus:outline-none focus:ring-2 focus:ring-status-critical/50',
            'disabled:opacity-50 disabled:cursor-not-allowed',
            mode === 'filter_critical' && 'bg-status-critical/10 border-status-critical/50'
          )}
        >
          <div className="flex items-center gap-2">
            <AlertTriangle className="w-4 h-4 text-status-critical" />
            <span className="text-sm font-medium text-nothing-gray-900">
              {tBatch('criticalOnly')}
            </span>
          </div>
          <span className="text-xs font-body text-status-critical">
            {stats.critical} {tBatch('items')}
          </span>
        </button>
      </div>

      {/* 安全提示 */}
      <div className="mt-4 flex items-start gap-2 p-2 rounded-lg bg-status-warning/5 border border-status-warning/20">
        <Shield className="w-4 h-4 text-status-warning flex-shrink-0 mt-0.5" />
        <p className="text-xs text-status-warning">
          {tBatch('securityNote')}
        </p>
      </div>
    </div>
  )
}