/**
 * @file Transcendence panel component for the second prestige layer.
 * @copyright nhcarrigan
 * @license Naomi's Public License
 * @author Naomi Carrigan
 */
/* eslint-disable max-lines-per-function -- Complex component with many render paths */
/* eslint-disable complexity -- Many conditional render paths */
/* eslint-disable max-statements -- Transcendence panel manages many local state variables */
/* eslint-disable max-lines -- Transcendence panel with CDN images exceeds line limit */
import { useState, type JSX } from "react";
import { useGame } from "../../context/gameContext.js";
import {
  TRANSCENDENCE_UPGRADES,
  TRANSCENDENCE_UPGRADE_CATEGORY_LABELS,
} from "../../data/transcendenceUpgrades.js";
import { cdnImage } from "../../utils/cdn.js";
import type { TranscendenceUpgradeCategory } from "@elysium/types";

const echoFormulaConstant = 853;
const finalBossId = "the_absolute_one";

/**
 * Calculates the echo preview for a transcendence.
 * @param prestigeCount - The current prestige count.
 * @param echoMetaMultiplier - The echo meta multiplier from upgrades.
 * @returns The predicted echo reward.
 */
const calculateEchoPreview = (
  prestigeCount: number,
  echoMetaMultiplier: number,
): number => {
  const safeCount = Math.max(prestigeCount, 1);
  return Math.floor(
    // eslint-disable-next-line stylistic/no-extra-parens -- Required by no-mixed-operators rule
    (echoFormulaConstant / Math.sqrt(safeCount)) * echoMetaMultiplier,
  );
};

const categoryOrder: Array<TranscendenceUpgradeCategory> = [
  "income",
  "combat",
  "prestige_threshold",
  "prestige_runestones",
  "echo_meta",
];

/**
 * Renders the transcendence panel with transcendence and echo shop tabs.
 * @returns The JSX element.
 */
const TranscendencePanel = (): JSX.Element => {
  const { state, formatInteger, transcend, buyEchoUpgrade } = useGame();
  const [ isPending, setIsPending ] = useState(false);
  const [ result, setResult ] = useState<{
    echoes: number;
    count:  number;
  } | null>(null);
  const [ error, setError ] = useState<string | null>(null);
  const [ buyingId, setBuyingId ] = useState<string | null>(null);
  type TranscendTab = "transcend" | "shop";
  const [ activeTab, setActiveTab ] = useState<TranscendTab>("transcend");

  if (state === null) {
    return (
      <section className="panel">
        <p>{"Loading..."}</p>
      </section>
    );
  }

  const { bosses, prestige: prestigeData, transcendence } = state;
  const hasDefeatedFinalBoss = bosses.some((boss) => {
    return boss.id === finalBossId && boss.status === "defeated";
  });
  const echoMetaMultiplier = transcendence?.echoMetaMultiplier ?? 1;
  const echoPreview = calculateEchoPreview(
    prestigeData.count,
    echoMetaMultiplier,
  );
  const currentEchoes = transcendence?.echoes ?? 0;
  const transcendenceCount = transcendence?.count ?? 0;

  async function handleTranscend(): Promise<void> {
    setIsPending(true);
    setError(null);
    try {
      const data = await transcend();
      setResult({ count: data.newTranscendenceCount, echoes: data.echoes });
    } catch (error_: unknown) {
      setError(
        error_ instanceof Error
          ? error_.message
          : "Transcendence failed",
      );
    } finally {
      setIsPending(false);
    }
  }

  async function handleBuyUpgrade(upgradeId: string): Promise<void> {
    setBuyingId(upgradeId);
    try {
      await buyEchoUpgrade(upgradeId);
    } finally {
      setBuyingId(null);
    }
  }

  const upgradesByCategory = categoryOrder.map((catId) => {
    const categoryLabels = TRANSCENDENCE_UPGRADE_CATEGORY_LABELS;
    const label = categoryLabels[catId] ?? catId;
    const upgrades = TRANSCENDENCE_UPGRADES.filter((upgrade) => {
      return upgrade.category === catId;
    });
    return { catId, label, upgrades };
  });

  function handleTranscendClick(): void {
    void handleTranscend();
  }

  function handleTranscendTabClick(): void {
    setActiveTab("transcend");
  }

  function handleShopTabClick(): void {
    setActiveTab("shop");
  }

  return (
    <section className="panel transcendence-panel">
      <h2>{"🌌 Transcendence"}</h2>

      <div className="prestige-tabs">
        <button
          className={`prestige-tab ${
            activeTab === "transcend"
              ? "active"
              : ""
          }`}
          onClick={handleTranscendTabClick}
          type="button"
        >
          {"Transcend"}
        </button>
        <button
          className={`prestige-tab ${activeTab === "shop"
            ? "active"
            : ""}`}
          onClick={handleShopTabClick}
          type="button"
        >
          {"✨ Echo Shop ("}
          {formatInteger(currentEchoes)}
          {" echoes)"}
        </button>
      </div>

      {activeTab === "transcend"
        && <>
          <p className="transcendence-intro">
            {"Transcendence is the ultimate reset. It wipes "}
            <strong>{"everything"}</strong>
            {" — resources, prestige, runestones, upgrades, and equipment"
              + " — but grants "}
            <strong>{"Echoes"}</strong>
            {", a permanent currency that survives all future resets."}
            {" Echoes power upgrades that permanently amplify every run."}
          </p>
          <p className="transcendence-intro">
            <em>
              {"Fewer prestiges = more Echoes."}
              {" Optimise your run for maximum yield!"}
            </em>
          </p>

          <div className="transcendence-status">
            {transcendenceCount > 0
              && <p>
                {"Transcendence count: "}
                <strong>{transcendenceCount}</strong>
              </p>
            }
            <p>
              {"Current Echoes: "}
              <strong>{formatInteger(currentEchoes)}</strong>
            </p>
            <p>
              {"Current prestige count: "}
              <strong>{prestigeData.count}</strong>
            </p>
            {hasDefeatedFinalBoss
              ? <p className="echo-preview">
                {"Echoes on transcendence: "}
                <strong>
                  {"+"}
                  {formatInteger(echoPreview)}
                </strong>
                {echoMetaMultiplier > 1
                  && <span className="echo-meta-bonus">
                    {" (×"}
                    {echoMetaMultiplier.toFixed(2)}
                    {" meta bonus applied)"}
                  </span>
                }
              </p>
              : null}
          </div>

          {hasDefeatedFinalBoss
            ? null
            : <div className="transcendence-locked">
              <p>
                {"🔒 "}
                <strong>{"Defeat The Absolute One"}</strong>
                {" to unlock transcendence."}
              </p>
              <p className="transcendence-hint">
                {"The Absolute One is the final boss of The Absolute zone,"
                  + " requiring Prestige 90 to challenge."}
              </p>
            </div>
          }

          {hasDefeatedFinalBoss
            ? <div className="prestige-form">
              <p>
                {"You are ready to transcend. This action is "}
                <strong>{"irreversible"}</strong>
                {"."}
              </p>
              <button
                className="transcendence-button"
                disabled={isPending}
                onClick={handleTranscendClick}
                type="button"
              >
                {isPending
                  ? "Transcending..."
                  : `🌌 Transcend (+${formatInteger(echoPreview)} Echoes)`}
              </button>
              {error === null
                ? null
                : <p className="error">{error}</p>}
              {result === null
                ? null
                : <p className="success">
                  {"Transcended! Earned "}
                  <strong>
                    {formatInteger(result.echoes)}
                    {" Echoes"}
                  </strong>
                  {". This is Transcendence "}
                  {result.count}
                  {". A new cycle begins."}
                </p>
              }
            </div>
            : null}
        </>
      }

      {activeTab === "shop"
        && <div className="echo-shop">
          <p className="shop-balance">
            {"Balance: "}
            <strong>
              {formatInteger(currentEchoes)}
              {" Echoes"}
            </strong>
          </p>
          <p className="echo-shop-description">
            {"Echo upgrades are "}
            <strong>{"permanent"}</strong>
            {" — they survive all future prestiges and transcendences."}
          </p>

          {upgradesByCategory.map(({ catId, label, upgrades }) => {
            return (
              <div className="shop-category" key={catId}>
                <h3>{label}</h3>
                <div className="shop-upgrades">
                  {upgrades.map((upgrade) => {
                    const purchased = (
                      transcendence?.purchasedUpgradeIds ?? []
                    ).includes(upgrade.id);
                    const canAfford = currentEchoes >= upgrade.cost;
                    const isLoading = buyingId === upgrade.id;

                    function handleBuyClick(): void {
                      void handleBuyUpgrade(upgrade.id);
                    }

                    return (
                      <div
                        className={`shop-upgrade-card echo-upgrade-card ${
                          purchased
                            ? "purchased"
                            : ""
                        } ${!canAfford && !purchased
                          ? "unaffordable"
                          : ""}`}
                        key={upgrade.id}
                      >
                        <img
                          alt={upgrade.name}
                          className="card-thumbnail"
                          src={cdnImage("transcendence-upgrades", upgrade.id)}
                        />
                        <div className="shop-upgrade-info">
                          <h4>{upgrade.name}</h4>
                          <p>{upgrade.description}</p>
                          <p className="upgrade-cost">
                            {purchased
                              ? "✅ Purchased"
                              : `✨ ${formatInteger(upgrade.cost)} Echoes`}
                          </p>
                        </div>
                        {purchased
                          ? null
                          : <button
                            className="buy-upgrade-button echo-buy-button"
                            disabled={
                              !canAfford || isLoading || buyingId !== null
                            }
                            onClick={handleBuyClick}
                            type="button"
                          >
                            {isLoading
                              ? "Buying..."
                              : "Buy"}
                          </button>
                        }
                      </div>
                    );
                  })}
                </div>
              </div>
            );
          })}
        </div>
      }
    </section>
  );
};

export { TranscendencePanel };