import { createBtcAmount, SATS_PER_BTC } from "../../btc/index.js";
import {
  appendLegendListItem,
  createLegendItem,
  createLegendList,
} from "../../legend/index.js";
import { createPoolLogo } from "../../pools/index.js";
import { createUsdAmount, renderUsdAmount } from "../../usd/index.js";
import { brk } from "../../utils/client.js";
import { createFeeChart } from "./fee-chart.js";

/** @typedef {Awaited<ReturnType<typeof brk.getBlocksV1>>[number]} Block */

const MAX_BLOCK_WEIGHT = 4_000_000;

/** @param {number} bytes */
function formatBytes(bytes) {
  return bytes >= 1_000_000
    ? `${(bytes / 1_000_000).toFixed(2)} MB`
    : `${bytes.toLocaleString()} B`;
}

/** @param {number} rate */
function formatFeeRate(rate) {
  if (rate >= 1_000_000) return `${(rate / 1_000_000).toFixed(1)}M`;
  if (rate >= 100_000) return `${Math.round(rate / 1_000)}k`;
  if (rate >= 1_000) return `${(rate / 1_000).toFixed(1)}k`;
  if (rate >= 100) return Math.round(rate).toLocaleString();
  if (rate >= 10) return rate.toFixed(1);
  return rate.toFixed(2);
}

/** @param {number} unixSeconds */
function formatDateTime(unixSeconds) {
  return new Date(unixSeconds * 1_000).toLocaleString(undefined, {
    dateStyle: "medium",
    timeStyle: "medium",
  });
}

/** @param {number} height */
function createHeightElement(height) {
  const element = document.createElement("span");
  const prefix = document.createElement("span");
  const value = document.createElement("span");

  prefix.classList.add("dim");
  prefix.textContent = `#${"0".repeat(Math.max(0, 7 - String(height).length))}`;
  value.textContent = String(height);
  element.append(prefix, value);

  return element;
}

/** @param {string} hash */
function createHashElement(hash) {
  const element = document.createElement("span");
  const prefix = document.createElement("span");
  const value = document.createElement("span");
  const firstNonZero = hash.search(/[^0]/);
  const visibleStart = firstNonZero === -1 ? hash.length : firstNonZero;

  element.dataset.blockHash = "";
  prefix.classList.add("dim");
  prefix.textContent = hash.slice(0, visibleStart);
  value.textContent = hash.slice(visibleStart);
  element.append(prefix, value);

  return element;
}

/** @param {number} height */
function createTitle(height) {
  const label = document.createElement("span");
  const value = document.createElement("span");

  label.classList.add("title-label");
  value.classList.add("title-height");
  label.textContent = "Block";
  value.append(createHeightElement(height));

  return [label, value];
}

/**
 * @param {string} term
 * @param {string | Node | null | undefined} value
 */
function createRow(term, value) {
  if (value == null || value === "") return null;

  const row = document.createElement("div");
  const dt = document.createElement("dt");
  const dd = document.createElement("dd");

  dt.textContent = term;
  dd.append(value);
  row.append(dt, dd);

  return row;
}

/**
 * @param {string} label
 * @param {string | Node} value
 */
function createStat(label, value) {
  const stat = document.createElement("div");
  const name = document.createElement("span");
  const amount = document.createElement("strong");

  stat.dataset.stat = "";
  name.textContent = label;
  amount.append(value);
  stat.append(name, amount);

  return stat;
}

/** @param {[string, string | Node][]} items */
function createStats(items) {
  const stats = document.createElement("div");

  stats.dataset.stats = "";
  stats.append(...items.map(([label, value]) => createStat(label, value)));

  return stats;
}

/** @param {string} title */
function groupName(title) {
  return title.toLowerCase().replace(/[^a-z0-9]+/g, "-");
}

/**
 * @param {string} title
 * @param {[string, string | Node][]} stats
 * @param {Node[]} [children]
 */
function createStatBox(title, stats, children = []) {
  const box = document.createElement("div");
  const heading = document.createElement("h3");

  box.dataset.statBox = groupName(title);
  heading.textContent = title;
  box.append(heading, createStats(stats), ...children);

  return box;
}

/**
 * @param {string} label
 * @param {(string | Node)[]} values
 */
function createInlineRow(label, values) {
  const row = document.createElement("div");
  const name = document.createElement("span");
  const data = document.createElement("strong");

  row.dataset.inlineRow = "";
  name.textContent = label;
  data.append(...values);
  row.append(name, data);

  return row;
}

/**
 * @param {string} label
 * @param {string | Node} value
 */
function createInlineBox(label, value) {
  const box = document.createElement("div");

  box.dataset.blockBox = "inline";
  box.append(createInlineRow(label, [value]));

  return box;
}

/** @param {Block} block */
function formatBlockFill(block) {
  return `${((block.weight / MAX_BLOCK_WEIGHT) * 100).toFixed(1)}%`;
}

/** @param {number | string} bits */
function formatBits(bits) {
  return typeof bits === "number" ? `0x${bits.toString(16)}` : bits;
}

/**
 * @param {string} label
 * @param {string} value
 */
function createMinerStat(label, value) {
  const stat = document.createElement("div");
  const name = document.createElement("span");
  const amount = document.createElement("strong");

  stat.dataset.minerStat = "";
  name.textContent = label;
  amount.textContent = value;
  stat.append(name, amount);

  return stat;
}

/** @param {Block} block */
function createMinerSummary(block) {
  const { pool } = block.extras;
  const pane = document.createElement("div");
  const head = document.createElement("div");
  const identity = document.createElement("div");
  const name = document.createElement("strong");
  const slug = document.createElement("span");
  const stats = document.createElement("div");
  const logo = createPoolLogo(pool);

  pane.dataset.minerPane = "";
  head.dataset.minerHead = "";
  identity.dataset.minerIdentity = "";
  slug.dataset.minerSlug = "";
  stats.dataset.minerStats = "";
  logo.dataset.minerLogo = "";

  name.textContent = pool.name;
  slug.textContent = `#${pool.slug}`;
  identity.append(name, slug);
  head.append(identity, logo);
  stats.append(
    createMinerStat("Difficulty", block.difficulty.toLocaleString()),
    createMinerStat("Bits", formatBits(block.bits)),
    createMinerStat("Nonce", block.nonce.toLocaleString()),
  );
  pane.append(head, stats);

  return pane;
}

/**
 * @param {number} sats
 * @param {number} total
 */
function formatShare(sats, total) {
  return `${((sats / total) * 100).toFixed(2)}%`;
}

/**
 * @param {number} sats
 * @param {number} price
 */
function getSatsUsd(sats, price) {
  return (sats / SATS_PER_BTC) * price;
}

/**
 * @param {number} sats
 * @param {number} price
 */
function createSatsUsdAmount(sats, price) {
  return createUsdAmount("span", getSatsUsd(sats, price));
}

/**
 * @param {number} sats
 * @param {number} total
 * @param {number} price
 */
function createRewardDetail(sats, total, price) {
  const detail = document.createDocumentFragment();

  detail.append(createSatsUsdAmount(sats, price), " · ", formatShare(sats, total));

  return detail;
}

const REWARD_COLORS = /** @type {const} */ ({
  subsidy: "var(--orange)",
  fees: "var(--green)",
});

/** @typedef {keyof typeof REWARD_COLORS} RewardType */

/**
 * @param {RewardType} type
 * @param {number} sats
 * @param {number} total
 */
function createRewardSegment(type, sats, total) {
  const segment = document.createElement("span");

  segment.dataset.rewardSegment = type;
  segment.dataset.rewardKey = type;
  segment.style.setProperty("--share", `${(sats / total) * 100}%`);

  return segment;
}

/**
 * @param {RewardType} type
 * @param {string} label
 * @param {number} sats
 * @param {number} total
 * @param {number} price
 */
function createRewardPart(type, label, sats, total, price) {
  const { button: part, value } = createLegendItem({
    label,
    color: REWARD_COLORS[type],
    ariaLabel: `Highlight ${label}`,
    detail: createRewardDetail(sats, total, price),
  });
  const amount = createBtcAmount("span", sats);

  part.dataset.rewardPart = type;
  part.dataset.rewardKey = type;
  value.replaceChildren(amount);

  return part;
}

/**
 * @param {number} sats
 * @param {number} price
 */
function createRewardTotal(sats, price) {
  const total = document.createElement("div");
  const amount = createBtcAmount("strong", sats);
  const usd = createSatsUsdAmount(sats, price);

  total.dataset.rewardTotal = "";
  total.append(amount, usd);

  return total;
}

/** @param {EventTarget | null} target */
function getRewardKey(target) {
  if (!(target instanceof HTMLElement)) return null;

  return target.closest("[data-reward-key]")?.getAttribute("data-reward-key") ?? null;
}

/**
 * @param {HTMLElement} rewards
 * @param {string | null} activeKey
 */
function setRewardPreview(rewards, activeKey) {
  for (const element of rewards.querySelectorAll("[data-reward-key]")) {
    if (!(element instanceof HTMLElement)) continue;

    if (element.dataset.rewardKey === activeKey) {
      element.dataset.preview = "";
      delete element.dataset.muted;
    } else if (activeKey) {
      element.dataset.muted = "";
      delete element.dataset.preview;
    } else {
      delete element.dataset.muted;
      delete element.dataset.preview;
    }
  }
}

/** @param {Block["extras"]} extras */
function createRewardSummary(extras) {
  const subsidy = extras.reward - extras.totalFees;
  const bar = document.createElement("div");
  const split = createLegendList({ fill: true });
  const rewards = createStatBox(
    "Rewards",
    [],
    [
      createRewardTotal(extras.reward, extras.price),
      bar,
      split,
    ],
  );

  appendLegendListItem(
    split,
    createRewardPart("subsidy", "Subsidy", subsidy, extras.reward, extras.price),
  );
  appendLegendListItem(
    split,
    createRewardPart("fees", "Fees", extras.totalFees, extras.reward, extras.price),
  );
  bar.dataset.rewardBar = "";
  bar.append(
    createRewardSegment("subsidy", subsidy, extras.reward),
    createRewardSegment("fees", extras.totalFees, extras.reward),
  );

  rewards.addEventListener("pointerenter", (event) => {
    setRewardPreview(rewards, getRewardKey(event.target));
  }, true);
  rewards.addEventListener("pointerleave", () => setRewardPreview(rewards, null));
  rewards.addEventListener("pointerdown", (event) => {
    setRewardPreview(rewards, getRewardKey(event.target));
  });
  rewards.addEventListener("pointerup", () => setRewardPreview(rewards, null));
  rewards.addEventListener("pointercancel", () => setRewardPreview(rewards, null));

  return rewards;
}

/** @param {Block} block */
function createTransactionSummary(block) {
  const { extras } = block;
  const box = document.createElement("div");
  const transactions = document.createElement("div");
  const io = document.createElement("div");

  box.dataset.blockBox = "";
  transactions.dataset.blockBox = "tx";
  io.dataset.blockIo = "";
  io.append(
    createInlineBox("Input", extras.totalInputs.toLocaleString()),
    createInlineBox("Output", extras.totalOutputs.toLocaleString()),
  );
  transactions.append(
    createInlineRow("Tx", [block.txCount.toLocaleString()]),
    io,
  );
  box.append(
    createInlineRow("Block", [`${formatBytes(block.size)} · ${formatBlockFill(block)}`]),
    transactions,
  );

  return box;
}

/**
 * @param {HTMLElement} parent
 * @param {string} title
 * @param {[string, string | Node | null | undefined][]} rows
 * @param {Node[]} [children]
 * @param {boolean} [showHeading]
 */
function appendGroup(parent, title, rows, children = [], showHeading = true) {
  const visibleRows = rows.flatMap(([term, value]) => {
    const row = createRow(term, value);

    return row ? [row] : [];
  });

  if (!visibleRows.length && !children.length) return;

  const section = document.createElement("section");
  const heading = document.createElement("h2");

  section.dataset.group = groupName(title);
  heading.textContent = title;
  section.append(...(showHeading ? [heading] : []), ...children);
  if (visibleRows.length) {
    const list = document.createElement("dl");

    list.append(...visibleRows);
    section.append(list);
  }
  parent.append(section);
}

export function createBlockDetails() {
  const element = document.createElement("section");
  const header = document.createElement("header");
  const titleRow = document.createElement("div");
  const title = document.createElement("h1");
  const summary = document.createElement("p");
  const price = createUsdAmount("output", 0, {
    size: "title",
    tone: "positive",
  });
  const content = document.createElement("div");

  element.id = "block-details";
  element.hidden = true;
  titleRow.dataset.blockTitle = "";
  titleRow.append(title, price);
  header.append(titleRow, summary);
  element.append(header, content);

  /** @param {Block} block */
  function update(block) {
    const extras = block.extras;

    element.hidden = false;
    title.replaceChildren(...createTitle(block.height));
    summary.replaceChildren(
      createHashElement(block.id),
      document.createElement("br"),
      formatDateTime(block.timestamp),
    );
    renderUsdAmount(price, extras.price, {
      size: "title",
      tone: "positive",
    });

    for (const chart of content.querySelectorAll("[data-fee-chart]")) {
      chart.dispatchEvent(new Event("chart:destroy"));
    }
    content.textContent = "";

    appendGroup(content, "Mining", [], [createMinerSummary(block)], false);

    appendGroup(content, "Rewards", [], [createRewardSummary(extras)], false);

    appendGroup(content, "Block", [], [createTransactionSummary(block)], false);

    appendGroup(content, "Fees", [], [
      createFeeChart(extras.feeRange, extras.avgFeeRate, formatFeeRate),
    ]);
  }

  return /** @type {const} */ ({
    element,
    update,
  });
}