import { useCallback, useEffect, useState } from 'react'
import { Database, Loader2, Play, Zap } from 'lucide-react'
import type { SourceEngine } from '../../lib/dataSourceCatalog'
import { cn } from '../../lib/utils'
import { subTabActive, subTabIdle } from '../../lib/tabActive'

type Sample = { id: string; label: string; sql: string }
type SqlResult = {
  ok: boolean
  columns?: string[]
  rows?: unknown[][]
  row_count?: number
  elapsed_ms?: number
  error?: string
  sql?: string
}

type Engine = SourceEngine | 'trino'

type Props = {
  engine: Engine
  compact?: boolean
}

const ENGINE_META: Record<Engine, { title: string; sub: string; accent: string; queryLabel: string }> = {
  postgres: {
    title: 'PostgreSQL SQL Console',
    sub: 'DB Vault · 10.0.21.51:5432 · user mo',
    accent: 'text-sky-400',
    queryLabel: 'SQL',
  },
  mysql: {
    title: 'MySQL SQL Console',
    sub: 'DB Vault · 10.0.21.51:3306 · database hr · user mo',
    accent: 'text-amber-400',
    queryLabel: 'SQL',
  },
  mongodb: {
    title: 'MongoDB Query Console',
    sub: 'DB Vault · 10.0.21.51:27017 · supplychain',
    accent: 'text-emerald-400',
    queryLabel: 'Command',
  },
  cassandra: {
    title: 'Cassandra CQL Console',
    sub: 'DB Vault · 10.0.21.51:9042 · keyspace telemetry',
    accent: 'text-cyan-400',
    queryLabel: 'CQL',
  },
  neo4j: {
    title: 'Neo4j Cypher Console',
    sub: 'DB Vault · 10.0.21.51:7687 · graph database',
    accent: 'text-pink-400',
    queryLabel: 'Cypher',
  },
  trino: {
    title: 'Trino SQL Console',
    sub: 'Lakehouse · 10.0.21.50:8089 · federated queries',
    accent: 'text-violet-400',
    queryLabel: 'SQL',
  },
}

export function SqlWorkbench({ engine, compact }: Props) {
  const meta = ENGINE_META[engine]
  const [samples, setSamples] = useState<Sample[]>([])
  const [sql, setSql] = useState('')
  const [result, setResult] = useState<SqlResult | null>(null)
  const [benchmark, setBenchmark] = useState<{
    comparison?: { postgres_ms?: number; trino_ms?: number; faster?: string; speedup_factor?: number }
  } | null>(null)
  const [loading, setLoading] = useState(false)
  const [benchLoading, setBenchLoading] = useState(false)
  const [error, setError] = useState<string | null>(null)

  const loadSamples = useCallback(async () => {
    const r = await fetch(`/api/sql/samples/${engine}`)
    if (r.ok) {
      const j = await r.json()
      setSamples(j.samples || [])
      if (j.samples?.[0]) setSql(j.samples[0].sql)
    }
  }, [engine])

  useEffect(() => {
    loadSamples()
    setResult(null)
    setBenchmark(null)
    setError(null)
  }, [engine, loadSamples])

  const run = async (query?: string) => {
    const q = (query ?? sql).trim()
    if (!q) return
    setLoading(true)
    setError(null)
    try {
      const r = await fetch('/api/sql/execute', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ engine, sql: q }),
      })
      const j = await r.json()
      if (!r.ok || !j.ok) {
        setError(j.error || 'Query failed')
        setResult(null)
        return
      }
      setSql(q)
      setResult(j)
    } catch {
      setError('SQL API unavailable')
    } finally {
      setLoading(false)
    }
  }

  const runBenchmark = async () => {
    setBenchLoading(true)
    setError(null)
    try {
      const r = await fetch('/api/sql/benchmark', { method: 'POST' })
      const j = await r.json()
      if (!r.ok) {
        setError(j.error || 'Benchmark failed')
        return
      }
      setBenchmark(j)
    } catch {
      setError('Benchmark failed')
    } finally {
      setBenchLoading(false)
    }
  }

  return (
    <div className="flex h-full min-h-0 flex-col text-foreground">
      <header className={cn('flex shrink-0 flex-wrap items-center justify-between gap-2 border-b border-border/60', compact ? 'px-2 py-1' : 'px-3 py-2')}>
        <div>
          <h3 className={cn('flex items-center gap-1.5 font-semibold', meta.accent, compact ? 'text-xs' : 'text-sm')}>
            <Database className={compact ? 'h-3 w-3' : 'h-4 w-4'} />
            {meta.title}
          </h3>
          <p className="text-[9px] text-foreground-muted">{meta.sub}</p>
        </div>
        <div className="flex gap-1.5">
          <button type="button" onClick={() => run()} disabled={loading} className={cn('inline-flex items-center gap-1 rounded px-2 py-1 text-[10px]', subTabActive)}>
            {loading ? <Loader2 className="h-3 w-3 animate-spin" /> : <Play className="h-3 w-3" />}
            Run
          </button>
          {(engine === 'postgres' || engine === 'trino') && (
            <button type="button" onClick={runBenchmark} disabled={benchLoading} className={cn('inline-flex items-center gap-1 rounded px-2 py-1 text-[10px]', subTabIdle)}>
              {benchLoading ? <Loader2 className="h-3 w-3 animate-spin" /> : <Zap className="h-3 w-3 text-amber-400" />}
              PG vs Trino
            </button>
          )}
        </div>
      </header>

      <div className="flex min-h-0 flex-1 overflow-hidden">
        <aside className={cn('flex min-h-0 shrink-0 flex-col border-r border-border/60 p-1.5', compact ? 'w-44' : 'w-52')}>
          <p className="mb-0.5 text-[8px] font-semibold uppercase tracking-wider text-foreground-faint">Demo queries</p>
          <div className="scrollbar-thin min-h-0 flex-1 space-y-0.5 overflow-y-auto">
            {samples.map((s) => (
              <button
                key={s.id}
                type="button"
                onClick={() => { setSql(s.sql); run(s.sql) }}
                className="block w-full rounded border border-transparent px-1.5 py-0.5 text-left text-[9px] hover:border-docker/30 hover:bg-docker/5"
              >
                <span className="font-medium text-foreground">{s.label}</span>
              </button>
            ))}
          </div>
        </aside>

        <div className="flex min-h-0 min-w-0 flex-1 flex-col">
          <textarea
            value={sql}
            onChange={(e) => setSql(e.target.value)}
            className={cn(
              'shrink-0 resize-y border-b border-border/60 bg-[#0d1117] p-1.5 font-mono text-[10px] text-emerald-100 outline-none focus:ring-1 focus:ring-docker/40',
              compact ? 'min-h-[48px] max-h-[96px]' : 'min-h-[72px] max-h-[140px]',
            )}
            spellCheck={false}
            placeholder={`${meta.queryLabel}…`}
          />

          {error && <p className="shrink-0 px-2 py-0.5 text-[10px] text-danger">{error}</p>}

          {benchmark?.comparison && (
            <div className="shrink-0 border-b border-amber-500/30 bg-amber-500/10 px-2 py-1 text-[10px]">
              <span className="font-semibold text-amber-300">Benchmark: </span>
              PG <span className="font-mono">{benchmark.comparison.postgres_ms}ms</span>
              {' · '}Trino <span className="font-mono">{benchmark.comparison.trino_ms}ms</span>
              {' — '}
              <span className="font-semibold text-success">
                {benchmark.comparison.faster} {benchmark.comparison.speedup_factor ? `${benchmark.comparison.speedup_factor}×` : ''}
              </span>
            </div>
          )}

          <div className="scrollbar-thin min-h-0 flex-1 overflow-auto p-1.5">
            {result?.ok && result.columns && (
              <>
                <p className="mb-0.5 font-mono text-[8px] text-foreground-faint">
                  {result.row_count} rows · {result.elapsed_ms}ms
                </p>
                <table className="w-full text-left font-mono text-[9px]">
                  <thead>
                    <tr className="border-b border-border text-docker">
                      {result.columns.map((c) => <th key={c} className="px-1 py-0.5">{c}</th>)}
                    </tr>
                  </thead>
                  <tbody>
                    {result.rows?.map((row, i) => (
                      <tr key={i} className="border-b border-border/30 hover:bg-white/5">
                        {row.map((cell, j) => (
                          <td key={j} className="max-w-[160px] truncate px-1 py-0.5 text-foreground-muted">
                            {cell === null ? 'NULL' : String(cell)}
                          </td>
                        ))}
                      </tr>
                    ))}
                  </tbody>
                </table>
              </>
            )}
            {!result && !loading && (
              <p className="py-3 text-center text-[10px] text-foreground-faint">Pick a command or write {meta.queryLabel}</p>
            )}
          </div>
        </div>
      </div>
    </div>
  )
}
