'use client'

import { useState } from 'react'
import { useAgentRuns } from '@/hooks/use-agent-runs'
import { Button } from '@/components/ui/button'
import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/components/ui/card'
import { Badge } from '@/components/ui/badge'
import {
  Check,
  X,
  Loader2,
  FileCode,
  Plus,
  Pencil,
  Trash2,
  ChevronDown,
  ChevronUp,
  AlertCircle,
} from 'lucide-react'
import { cn } from '@/lib/utils'
import type { Database } from '@/types/database'

type AgentRun = Database['public']['Tables']['agent_runs']['Row']

interface ApprovalPanelProps {
  projectId: string
  className?: string
}

export function ApprovalPanel({ projectId, className }: ApprovalPanelProps) {
  const { pendingRuns, loading, approve, reject } = useAgentRuns(projectId)
  const [expandedRun, setExpandedRun] = useState<string | null>(null)
  const [processing, setProcessing] = useState<string | null>(null)

  const handleApprove = async (runId: string) => {
    setProcessing(runId)
    try {
      await approve(runId)
    } finally {
      setProcessing(null)
    }
  }

  const handleReject = async (runId: string) => {
    setProcessing(runId)
    try {
      await reject(runId)
    } finally {
      setProcessing(null)
    }
  }

  if (loading) {
    return (
      <div className="flex items-center justify-center py-8">
        <Loader2 className="w-5 h-5 animate-spin text-muted-foreground" />
      </div>
    )
  }

  if (pendingRuns.length === 0) {
    return (
      <div className={cn('text-center py-8', className)}>
        <div className="text-muted-foreground text-sm">
          No pending approvals
        </div>
        <p className="text-xs text-muted-foreground mt-1">
          AI-proposed changes will appear here for review
        </p>
      </div>
    )
  }

  return (
    <div className={cn('space-y-3', className)}>
      <div className="flex items-center justify-between">
        <Badge variant="secondary" className="gap-1">
          <AlertCircle className="w-3 h-3" />
          {pendingRuns.length} pending
        </Badge>
      </div>

      <div className="overflow-y-auto max-h-[calc(100vh-20rem)] space-y-3 pr-1">
        {pendingRuns.map((run) => (
          <ApprovalCard
            key={run.id}
            run={run}
            expanded={expandedRun === run.id}
            onToggle={() => setExpandedRun(expandedRun === run.id ? null : run.id)}
            onApprove={() => handleApprove(run.id)}
            onReject={() => handleReject(run.id)}
            processing={processing === run.id}
          />
        ))}
      </div>
    </div>
  )
}

interface ApprovalCardProps {
  run: AgentRun
  expanded: boolean
  onToggle: () => void
  onApprove: () => void
  onReject: () => void
  processing: boolean
}

function ApprovalCard({
  run,
  expanded,
  onToggle,
  onApprove,
  onReject,
  processing,
}: ApprovalCardProps) {
  const changes = run.proposed_changes

  if (!changes) return null

  const fileCount = changes.files?.length || 0
  const operations = changes.files?.reduce(
    (acc, file) => {
      acc[file.operation] = (acc[file.operation] || 0) + 1
      return acc
    },
    {} as Record<string, number>
  ) || {}

  return (
    <Card className="overflow-hidden">
      <CardHeader className="p-3 pb-2">
        <div className="flex items-start justify-between gap-2">
          <div className="flex-1 min-w-0">
            <CardTitle className="text-sm font-medium truncate">
              {run.command}
            </CardTitle>
            <CardDescription className="text-xs mt-0.5 line-clamp-2">
              {changes.description}
            </CardDescription>
          </div>
          <button
            onClick={onToggle}
            className="text-muted-foreground hover:text-foreground transition-colors"
          >
            {expanded ? (
              <ChevronUp className="w-4 h-4" />
            ) : (
              <ChevronDown className="w-4 h-4" />
            )}
          </button>
        </div>

        <div className="flex items-center gap-2 mt-2">
          <Badge variant="outline" className="text-xs gap-1">
            <FileCode className="w-3 h-3" />
            {fileCount} file{fileCount !== 1 ? 's' : ''}
          </Badge>
          {operations.create && (
            <Badge variant="outline" className="text-xs gap-1 text-emerald-600 border-emerald-200">
              <Plus className="w-3 h-3" />
              {operations.create}
            </Badge>
          )}
          {operations.update && (
            <Badge variant="outline" className="text-xs gap-1 text-blue-600 border-blue-200">
              <Pencil className="w-3 h-3" />
              {operations.update}
            </Badge>
          )}
          {operations.delete && (
            <Badge variant="outline" className="text-xs gap-1 text-red-600 border-red-200">
              <Trash2 className="w-3 h-3" />
              {operations.delete}
            </Badge>
          )}
        </div>
      </CardHeader>

      {expanded && changes.files && (
        <CardContent className="p-3 pt-0">
          <div className="border rounded-md overflow-hidden mt-2">
            {changes.files.map((file, index) => (
              <div
                key={index}
                className={cn(
                  'px-3 py-2 text-xs font-mono border-b last:border-b-0',
                  file.operation === 'create' && 'bg-emerald-50 dark:bg-emerald-950/20',
                  file.operation === 'update' && 'bg-blue-50 dark:bg-blue-950/20',
                  file.operation === 'delete' && 'bg-red-50 dark:bg-red-950/20'
                )}
              >
                <div className="flex items-center gap-2">
                  {file.operation === 'create' && <Plus className="w-3 h-3 text-emerald-600" />}
                  {file.operation === 'update' && <Pencil className="w-3 h-3 text-blue-600" />}
                  {file.operation === 'delete' && <Trash2 className="w-3 h-3 text-red-600" />}
                  <span className="truncate">{file.path}</span>
                </div>
              </div>
            ))}
          </div>

          {changes.estimated_impact && (
            <p className="text-xs text-muted-foreground mt-2">
              Impact: {changes.estimated_impact}
            </p>
          )}
        </CardContent>
      )}

      <div className="flex items-center gap-2 p-3 pt-0">
        <Button
          size="sm"
          variant="outline"
          className="flex-1 h-8 text-xs"
          onClick={onReject}
          disabled={processing}
        >
          {processing ? (
            <Loader2 className="w-3 h-3 animate-spin" />
          ) : (
            <>
              <X className="w-3 h-3 mr-1" />
              Reject
            </>
          )}
        </Button>
        <Button
          size="sm"
          variant="brand"
          className="flex-1 h-8 text-xs"
          onClick={onApprove}
          disabled={processing}
        >
          {processing ? (
            <Loader2 className="w-3 h-3 animate-spin" />
          ) : (
            <>
              <Check className="w-3 h-3 mr-1" />
              Approve
            </>
          )}
        </Button>
      </div>
    </Card>
  )
}