import { Link } from 'react-router-dom'
import { Plus, MapPin } from 'lucide-react'
import { cn } from '@/lib/utils'
import type { CoverageResponse } from '@/types/flowpilot-analytics'

interface CoverageHeatmapProps {
  data: CoverageResponse
}

function getCellStyle(value: number, thresholds: { green: number; amber: number }, inverse?: boolean) {
  if (inverse) {
    if (value <= thresholds.green) return 'bg-emerald-400/10 text-emerald-400'
    if (value <= thresholds.amber) return 'bg-amber-400/10 text-amber-400'
    return 'bg-rose-500/10 text-rose-500'
  }
  if (value >= thresholds.green) return 'bg-emerald-400/10 text-emerald-400'
  if (value >= thresholds.amber) return 'bg-amber-400/10 text-amber-400'
  return 'bg-rose-500/10 text-rose-500'
}

function getCellTitle(value: number, label: string, thresholds: { green: number; amber: number }, inverse?: boolean): string {
  const pct = (value * 100).toFixed(1)
  if (inverse) {
    if (value <= thresholds.green) return `${label}: ${pct}% (Good — below ${(thresholds.green * 100).toFixed(0)}%)`
    if (value <= thresholds.amber) return `${label}: ${pct}% (Needs Improvement — below ${(thresholds.amber * 100).toFixed(0)}%)`
    return `${label}: ${pct}% (Critical — above ${(thresholds.amber * 100).toFixed(0)}%)`
  }
  if (value >= thresholds.green) return `${label}: ${pct}% (Good — above ${(thresholds.green * 100).toFixed(0)}%)`
  if (value >= thresholds.amber) return `${label}: ${pct}% (Needs Improvement — above ${(thresholds.amber * 100).toFixed(0)}%)`
  return `${label}: ${pct}% (Critical — below ${(thresholds.amber * 100).toFixed(0)}%)`
}

function getFlowCountStyle(count: number) {
  if (count >= 5) return 'bg-emerald-400/10 text-emerald-400'
  if (count >= 1) return 'bg-amber-400/10 text-amber-400'
  return 'bg-rose-500/10 text-rose-500'
}

export default function CoverageHeatmap({ data }: CoverageHeatmapProps) {
  if (data.domains.length === 0) {
    return (
      <div className="card-flat p-6">
        <div className="flex items-center gap-2 mb-2">
          <MapPin size={16} className="text-foreground" />
          <h3 className="font-heading text-sm font-semibold text-foreground">Domain Coverage</h3>
        </div>
        <p className="text-sm text-muted-foreground">
          No session data for this period. Start using FlowPilot to see coverage metrics.
        </p>
      </div>
    )
  }

  return (
    <div className="card-flat p-3 sm:p-5">
      <div className="mb-4">
        <div className="flex items-center gap-2 mb-1">
          <MapPin size={16} className="text-foreground" />
          <h3 className="font-heading text-sm font-semibold text-foreground">Domain Coverage</h3>
        </div>
        <p className="text-xs text-muted-foreground">
          Resolution coverage and knowledge gaps by problem domain
        </p>
      </div>

      <div className="overflow-x-auto">
        <table className="w-full">
          <thead>
            <tr className="border-b border-border">
              <th className="px-3 py-2 text-left font-sans text-xs text-[0.625rem] uppercase tracking-[0.1em] text-muted-foreground">
                Domain
              </th>
              <th className="px-3 py-2 text-right font-sans text-xs text-[0.625rem] uppercase tracking-[0.1em] text-muted-foreground">
                Flows
              </th>
              <th className="px-3 py-2 text-right font-sans text-xs text-[0.625rem] uppercase tracking-[0.1em] text-muted-foreground">
                Sessions
              </th>
              <th className="px-3 py-2 text-right font-sans text-xs text-[0.625rem] uppercase tracking-[0.1em] text-muted-foreground">
                Resolution %
              </th>
              <th className="px-3 py-2 text-right font-sans text-xs text-[0.625rem] uppercase tracking-[0.1em] text-muted-foreground">
                Escalation %
              </th>
              <th className="px-3 py-2 text-right font-sans text-xs text-[0.625rem] uppercase tracking-[0.1em] text-muted-foreground">
                Guided %
              </th>
              <th className="px-3 py-2 text-right font-sans text-xs text-[0.625rem] uppercase tracking-[0.1em] text-muted-foreground"
                title="Average time to resolve sessions in this domain. Green: &lt;10 min, Amber: 10–20 min, Red: &gt;20 min. Lower is better.">
                Avg Resolution
              </th>
            </tr>
          </thead>
          <tbody>
            {data.domains.map((row) => (
              <tr key={row.domain} className="border-b border-border">
                <td className="px-3 py-2 text-sm text-foreground font-medium">
                  {row.domain}
                </td>
                <td className="px-3 py-2 text-sm text-right">
                  {row.flow_count === 0 ? (
                    <Link
                      to="/trees/new"
                      className="inline-flex items-center gap-1 text-xs text-primary hover:underline"
                    >
                      <Plus size={10} />
                      Create Flow
                    </Link>
                  ) : (
                    <span
                      className={cn('inline-block rounded px-1.5 py-0.5 text-xs font-medium', getFlowCountStyle(row.flow_count))}
                      title={`${row.flow_count} flow${row.flow_count !== 1 ? 's' : ''} — ${row.flow_count >= 5 ? 'Good' : row.flow_count >= 1 ? 'Needs Improvement' : 'Critical'}`}
                    >
                      {row.flow_count}
                    </span>
                  )}
                </td>
                <td className="px-3 py-2 text-sm text-right text-muted-foreground">
                  {row.session_count}
                </td>
                <td className="px-3 py-2 text-sm text-right">
                  <span
                    className={cn('inline-block rounded px-1.5 py-0.5 text-xs font-medium', getCellStyle(row.resolution_rate, { green: 0.75, amber: 0.5 }))}
                    title={getCellTitle(row.resolution_rate, 'Resolution', { green: 0.75, amber: 0.5 })}
                  >
                    {(row.resolution_rate * 100).toFixed(1)}%
                  </span>
                </td>
                <td className="px-3 py-2 text-sm text-right">
                  <span
                    className={cn('inline-block rounded px-1.5 py-0.5 text-xs font-medium', getCellStyle(row.escalation_rate, { green: 0.10, amber: 0.25 }, true))}
                    title={getCellTitle(row.escalation_rate, 'Escalation', { green: 0.10, amber: 0.25 }, true)}
                  >
                    {(row.escalation_rate * 100).toFixed(1)}%
                  </span>
                </td>
                <td className="px-3 py-2 text-sm text-right">
                  <span
                    className={cn('inline-block rounded px-1.5 py-0.5 text-xs font-medium', getCellStyle(row.guided_rate, { green: 0.60, amber: 0.30 }))}
                    title={getCellTitle(row.guided_rate, 'Guided', { green: 0.60, amber: 0.30 })}
                  >
                    {(row.guided_rate * 100).toFixed(1)}%
                  </span>
                </td>
                <td className="px-3 py-2 text-sm text-right">
                  {row.avg_resolution_minutes == null ? (
                    <span className="text-muted-foreground">—</span>
                  ) : (
                    <span
                      className={cn(
                        'inline-block rounded px-1.5 py-0.5 text-xs font-medium',
                        row.avg_resolution_minutes < 10
                          ? 'bg-emerald-400/10 text-emerald-400'
                          : row.avg_resolution_minutes <= 20
                            ? 'bg-amber-400/10 text-amber-400'
                            : 'bg-rose-500/10 text-rose-500',
                      )}
                      title={`Avg resolution: ${row.avg_resolution_minutes.toFixed(1)} min — ${row.avg_resolution_minutes < 10 ? 'Good (<10 min)' : row.avg_resolution_minutes <= 20 ? 'Needs Improvement (10–20 min)' : 'Slow (>20 min)'}`}
                    >
                      {row.avg_resolution_minutes.toFixed(1)} min
                    </span>
                  )}
                </td>
              </tr>
            ))}
          </tbody>
          {data.unmapped_session_count > 0 && (
            <tfoot>
              <tr>
                <td colSpan={7} className="px-3 py-2 text-xs text-muted-foreground">
                  {data.unmapped_session_count} sessions had no domain classification
                </td>
              </tr>
            </tfoot>
          )}
        </table>
      </div>

      <div className="flex flex-wrap gap-4 mt-3 text-[0.625rem] font-sans text-xs text-muted-foreground">
        <span><span className="inline-block w-2 h-2 rounded-full bg-emerald-400 mr-1" />Good</span>
        <span><span className="inline-block w-2 h-2 rounded-full bg-amber-400 mr-1" />Needs Improvement</span>
        <span><span className="inline-block w-2 h-2 rounded-full bg-rose-500 mr-1" />Critical</span>
      </div>
    </div>
  )
}