'use client'

import { useRef, useEffect, useState, useCallback } from 'react'
import { motion } from 'motion/react'
import { cn } from '@/lib/utils'
import { Badge } from '@/components/ui/badge'

type StageNode = {
  id: string
  name: string
  stageType: string
  sortOrder: number
  _count?: { projectStageStates: number }
}

type FlowchartTrack = {
  id: string
  name: string
  kind: string
  sortOrder: number
  stages: StageNode[]
}

type PipelineFlowchartProps = {
  tracks: FlowchartTrack[]
  selectedStageId?: string | null
  onStageSelect?: (stageId: string) => void
  className?: string
  compact?: boolean
}

const stageTypeColors: Record<string, { bg: string; border: string; text: string; glow: string }> = {
  INTAKE: { bg: '#eff6ff', border: '#93c5fd', text: '#1d4ed8', glow: '#3b82f6' },
  FILTER: { bg: '#fffbeb', border: '#fcd34d', text: '#b45309', glow: '#f59e0b' },
  EVALUATION: { bg: '#faf5ff', border: '#c084fc', text: '#7e22ce', glow: '#a855f7' },
  SELECTION: { bg: '#fff1f2', border: '#fda4af', text: '#be123c', glow: '#f43f5e' },
  LIVE_FINAL: { bg: '#ecfdf5', border: '#6ee7b7', text: '#047857', glow: '#10b981' },
  RESULTS: { bg: '#ecfeff', border: '#67e8f9', text: '#0e7490', glow: '#06b6d4' },
}

const NODE_WIDTH = 140
const NODE_HEIGHT = 70
const NODE_GAP = 32
const ARROW_SIZE = 6
const TRACK_LABEL_HEIGHT = 28
const TRACK_GAP = 20

export function PipelineFlowchart({
  tracks,
  selectedStageId,
  onStageSelect,
  className,
  compact = false,
}: PipelineFlowchartProps) {
  const containerRef = useRef<HTMLDivElement>(null)
  const [hoveredStageId, setHoveredStageId] = useState<string | null>(null)

  const sortedTracks = [...tracks].sort((a, b) => a.sortOrder - b.sortOrder)

  // Calculate dimensions
  const nodeW = compact ? 100 : NODE_WIDTH
  const nodeH = compact ? 50 : NODE_HEIGHT
  const gap = compact ? 20 : NODE_GAP

  const maxStages = Math.max(...sortedTracks.map((t) => t.stages.length), 1)
  const totalWidth = maxStages * nodeW + (maxStages - 1) * gap + 40
  const totalHeight =
    sortedTracks.length * (nodeH + TRACK_LABEL_HEIGHT + TRACK_GAP) - TRACK_GAP + 20

  const getNodePosition = useCallback(
    (trackIndex: number, stageIndex: number) => {
      const x = 20 + stageIndex * (nodeW + gap)
      const y = 10 + trackIndex * (nodeH + TRACK_LABEL_HEIGHT + TRACK_GAP) + TRACK_LABEL_HEIGHT
      return { x, y }
    },
    [nodeW, nodeH, gap]
  )

  return (
    <div
      ref={containerRef}
      className={cn('relative rounded-lg border bg-card', className)}
    >
      <div className="overflow-x-auto">
      <svg
        width={totalWidth}
        height={totalHeight}
        viewBox={`0 0 ${totalWidth} ${totalHeight}`}
        className="min-w-full"
      >
        <defs>
          <marker
            id="arrowhead"
            markerWidth={ARROW_SIZE}
            markerHeight={ARROW_SIZE}
            refX={ARROW_SIZE}
            refY={ARROW_SIZE / 2}
            orient="auto"
          >
            <path
              d={`M 0 0 L ${ARROW_SIZE} ${ARROW_SIZE / 2} L 0 ${ARROW_SIZE} Z`}
              fill="#94a3b8"
            />
          </marker>
          {/* Glow filter for selected node */}
          <filter id="selectedGlow" x="-20%" y="-20%" width="140%" height="140%">
            <feGaussianBlur stdDeviation="3" result="blur" />
            <feFlood floodColor="#3b82f6" floodOpacity="0.3" result="color" />
            <feComposite in="color" in2="blur" operator="in" result="glow" />
            <feMerge>
              <feMergeNode in="glow" />
              <feMergeNode in="SourceGraphic" />
            </feMerge>
          </filter>
        </defs>

        {sortedTracks.map((track, trackIndex) => {
          const sortedStages = [...track.stages].sort(
            (a, b) => a.sortOrder - b.sortOrder
          )
          const trackY = 10 + trackIndex * (nodeH + TRACK_LABEL_HEIGHT + TRACK_GAP)

          return (
            <g key={track.id}>
              {/* Track label */}
              <text
                x={20}
                y={trackY + 14}
                className="fill-muted-foreground text-[11px] font-medium"
                style={{ fontFamily: 'inherit' }}
              >
                {track.name}
                {track.kind !== 'MAIN' && ` (${track.kind})`}
              </text>

              {/* Arrows between stages */}
              {sortedStages.map((stage, stageIndex) => {
                if (stageIndex === 0) return null
                const from = getNodePosition(trackIndex, stageIndex - 1)
                const to = getNodePosition(trackIndex, stageIndex)
                const arrowY = from.y + nodeH / 2
                return (
                  <line
                    key={`arrow-${stage.id}`}
                    x1={from.x + nodeW}
                    y1={arrowY}
                    x2={to.x - 2}
                    y2={arrowY}
                    stroke="#94a3b8"
                    strokeWidth={1.5}
                    markerEnd="url(#arrowhead)"
                  />
                )
              })}

              {/* Stage nodes */}
              {sortedStages.map((stage, stageIndex) => {
                const pos = getNodePosition(trackIndex, stageIndex)
                const isSelected = selectedStageId === stage.id
                const isHovered = hoveredStageId === stage.id
                const colors = stageTypeColors[stage.stageType] ?? {
                  bg: '#f8fafc',
                  border: '#cbd5e1',
                  text: '#475569',
                  glow: '#64748b',
                }
                const projectCount = stage._count?.projectStageStates ?? 0

                return (
                  <g
                    key={stage.id}
                    onClick={() => onStageSelect?.(stage.id)}
                    onMouseEnter={() => setHoveredStageId(stage.id)}
                    onMouseLeave={() => setHoveredStageId(null)}
                    className={cn(onStageSelect && 'cursor-pointer')}
                    filter={isSelected ? 'url(#selectedGlow)' : undefined}
                  >
                    {/* Selection ring */}
                    {isSelected && (
                      <motion.rect
                        initial={{ opacity: 0 }}
                        animate={{ opacity: 1 }}
                        x={pos.x - 3}
                        y={pos.y - 3}
                        width={nodeW + 6}
                        height={nodeH + 6}
                        rx={10}
                        fill="none"
                        stroke={colors.glow}
                        strokeWidth={2}
                        strokeDasharray="none"
                      />
                    )}

                    {/* Node background */}
                    <rect
                      x={pos.x}
                      y={pos.y}
                      width={nodeW}
                      height={nodeH}
                      rx={8}
                      fill={colors.bg}
                      stroke={isSelected ? colors.glow : colors.border}
                      strokeWidth={isSelected ? 2 : 1}
                      style={{
                        transition: 'stroke 0.15s, stroke-width 0.15s',
                        transform: isHovered && !isSelected ? 'scale(1.02)' : undefined,
                        transformOrigin: `${pos.x + nodeW / 2}px ${pos.y + nodeH / 2}px`,
                      }}
                    />

                    {/* Stage name */}
                    <text
                      x={pos.x + nodeW / 2}
                      y={pos.y + (compact ? 20 : 24)}
                      textAnchor="middle"
                      fill={colors.text}
                      className={cn(compact ? 'text-[10px]' : 'text-xs', 'font-medium')}
                      style={{ fontFamily: 'inherit' }}
                    >
                      {stage.name.length > (compact ? 12 : 16)
                        ? stage.name.slice(0, compact ? 10 : 14) + '...'
                        : stage.name}
                    </text>

                    {/* Type badge */}
                    <text
                      x={pos.x + nodeW / 2}
                      y={pos.y + (compact ? 34 : 40)}
                      textAnchor="middle"
                      fill={colors.text}
                      className="text-[9px]"
                      style={{ fontFamily: 'inherit', opacity: 0.7 }}
                    >
                      {stage.stageType.replace('_', ' ')}
                    </text>

                    {/* Project count */}
                    {!compact && projectCount > 0 && (
                      <>
                        <rect
                          x={pos.x + nodeW / 2 - 14}
                          y={pos.y + nodeH - 18}
                          width={28}
                          height={14}
                          rx={7}
                          fill={colors.border}
                          opacity={0.3}
                        />
                        <text
                          x={pos.x + nodeW / 2}
                          y={pos.y + nodeH - 8}
                          textAnchor="middle"
                          fill={colors.text}
                          className="text-[9px] font-medium"
                          style={{ fontFamily: 'inherit' }}
                        >
                          {projectCount}
                        </text>
                      </>
                    )}
                  </g>
                )
              })}
            </g>
          )
        })}
      </svg>
      </div>
      {/* Scroll hint gradient for mobile */}
      {totalWidth > 400 && (
        <div className="absolute right-0 top-0 bottom-0 w-8 bg-gradient-to-l from-card to-transparent pointer-events-none sm:hidden" />
      )}
    </div>
  )
}