/**
 * Who won the blocks, and what became of the rewards.
 *
 * **This table reports flows and does not judge them.** Every figure is
 * something the chain recorded — direction comes from each transfer event's own
 * `from` and `to` — but what the figures *mean* is a question the data cannot
 * settle. An operator may hold several addresses, may settle off-chain, or may
 * simply be a solo miner keeping what it earned, which is the ordinary case and
 * unremarkable.
 *
 * So there is no badge, no flag, and no word like "delinquent" anywhere here.
 * What earns the table its place is **comparison**: one miner's recipient count
 * says almost nothing, and beside its neighbours' it says a great deal. The
 * reader draws the conclusion; the site lays out the evidence and names its
 * limits.
 *
 * The name column is the weakest thing on the page and is marked as such. There
 * is no such thing as a "pool" on this chain — the word appears only inside a
 * name an operator reports over telemetry, and a site that flagged entities as
 * delinquent on the strength of a name they chose themselves would be one bad
 * match away from libelling someone.
 */

import { useEffect, useState } from 'react'
import { Link } from 'react-router-dom'

import type { Distribution } from '../api/generated/Distribution'
import { RequestFailed, fetchDistribution } from '../api/rest'
import { height as fmtHeight, share as fmtShare, shortAddress, tokens } from '../lib/format'
import { href } from '../lib/routes'
import type { Window as WindowName } from '../api/generated/Window'

export function DistributionPanel({
  chain,
  window: windowName,
  decimals,
  symbol,
}: {
  chain: string
  window: WindowName
  decimals: number
  /** The unit, shown once in the header rather than on every cell: six columns
   *  of amounts each repeating "QTC" is noise, and they are all the same unit. */
  symbol: string
}) {
  const [data, setData] = useState<Distribution | null>(null)
  const [error, setError] = useState<string | null>(null)

  useEffect(() => {
    const controller = new AbortController()
    setData(null)
    setError(null)
    fetchDistribution(chain, windowName, controller.signal)
      .then(setData)
      .catch((e: unknown) => {
        if (controller.signal.aborted) return
        setError(e instanceof RequestFailed ? e.message : 'Could not reach the observer.')
      })
    return () => controller.abort()
  }, [chain, windowName])

  if (error) return <p className="empty">{error}</p>
  if (!data) return <p className="empty">Following the rewards…</p>

  const amount = (raw: string | null | undefined) =>
    raw === null || raw === undefined ? '—' : tokens(raw, decimals, 1)

  return (
    <section className="panel" style={{ marginBottom: 26 }}>
      <div className="panel-head">
        <h2 className="panel-title">Where the rewards went</h2>
        <span className="eyebrow">
          {fmtHeight(data.window_blocks)}-block window · amounts in {symbol} ·{' '}
          {data.indexed_from !== null && data.indexed_to !== null
            ? `blocks ${fmtHeight(data.indexed_from)}–${fmtHeight(data.indexed_to)}`
            : 'nothing indexed yet'}
        </span>
      </div>

      <div className="scroll-x">
        <table className="board">
          <caption className="visually-hidden">
            Each miner&apos;s share of blocks, what it was paid, and what it has sent on
          </caption>
          <thead>
            <tr>
              <th scope="col" className="left">
                Miner
              </th>
              <th scope="col">Share</th>
              <th scope="col">Mined</th>
              <th
                scope="col"
                title="Everything ever credited to this address. A mining address is keyless, so nothing can transfer out of it and this number can only rise — it is a receipt total, not a holding."
              >
                Received
              </th>
              <th
                scope="col"
                title="Transfers whose sender the chain recorded. Wormhole sends record none, so a zero here is not evidence that nothing left."
              >
                Sent visibly
              </th>
              <th scope="col">Recipients</th>
            </tr>
          </thead>
          <tbody>
            {data.miners.map((m) => {
              const recipients = m.flows?.recipients ?? null
              return (
                <tr key={m.miner}>
                  <td className="left">
                    <div className="call-cell">
                      <Link to={href({ chain, miner: m.miner, window: windowName })}>
                        {m.display}
                      </Link>
                      {/* Only where the name is not already the address: an
                          unattributed miner renders as its payout address, and
                          repeating it underneath is one string printed twice. */}
                      {m.address && m.attribution !== 'preimage' && (
                        <span className="runtime-type">{shortAddress(m.address)}</span>
                      )}
                    </div>
                  </td>
                  <td className="numeral">{fmtShare(m.share)}</td>
                  <td className="numeral">{amount(m.mined)}</td>
                  <td className="numeral">{amount(m.received)}</td>
                  <td className="numeral">{amount(m.flows?.sent)}</td>
                  <td className="numeral">{recipients === null ? '—' : fmtHeight(recipients)}</td>
                </tr>
              )
            })}
          </tbody>
        </table>
      </div>

      <p className="panel-note">
        <strong>This chain hides who sends.</strong> A wormhole transfer records its recipient and
        its amount but not its origin — on mainnet, 9,894 such transfers reached 654 recipients with
        no sender recorded at all. So <em>sent visibly</em> and <em>recipients</em> count only the
        transfers that named a sender, and{' '}
        <strong>a zero in those columns is not evidence that nothing left</strong>. It is evidence
        that nothing left by a route the chain writes down. Payouts here are very plausibly wormhole
        transactions, and the privacy is a feature of the chain rather than a gap in this table.
      </p>
      <p className="panel-note">
        <strong>
          There is no column here that can tell you whether a miner is paying out, and there cannot
          be.
        </strong>{' '}
        The chain pays a mining reward to an address derived from the miner&apos;s own reward
        preimage — a Poseidon hash that no key signs for. Nothing can transfer out of it. The only
        way to move the value is a wormhole exit, which credits its destination{' '}
        <em>without debiting the source</em>. So <em>received</em> is a running total of everything
        ever credited, it rises and never falls, and it does that identically for an operator who
        pays out in full and one who pays out nothing. Measured over all of mainnet&apos;s history,
        the largest miner&apos;s balance rose at every sample and fell at none.
      </p>
      <p className="panel-note">
        That is also why this table no longer carries a “retained” percentage. It read close to 100%
        for every miner on the chain, because it had to, and a number that is the same for everyone
        reads as an accusation aimed at whoever happens to be at the top — which here is simply
        whoever mined the most. The place any of this is observable is the{' '}
        <Link to={href({ chain, index: 'wormhole' })}>wormhole page</Link>, which counts what has
        gone in and come out without claiming to know who moved it.
      </p>
      <p className="panel-note">
        The names are the weakest column and come from telemetry, not the chain — an operator
        chooses what its node calls itself, so a name containing “pool” is a claim rather than a
        fact. <em>Received</em> is chain state and is true now, while <em>mined</em>,{' '}
        <em>sent visibly</em> and <em>recipients</em> are counted over the indexed range above; on a
        chain read from genesis those agree, on one still being indexed backwards they do not.
      </p>
    </section>
  )
}