import {
    t,
    setLanguage,
    getLanguage,
    initI18n,
    onLanguageChange,
    faqMarkdown,
} from "./js/i18n.js";
import { state, clearUserState } from "./js/state.js";
import { toast } from "./js/dom.js";
import {
    handleAuthError,
    renderWelcome,
    renderPhasePill,
    renderCounts,
    renderMySuggestions,
    renderAllSuggestions,
    renderVotes,
    syncVoteScores,
    renderResults,
    renderPhaseTitles,
    updatePhaseNav,
    configureUiRuntime,
} from "./js/ui.js";
import { api } from "./js/api.js";
import { loadSuggestData, loadVoteData, refreshPhaseData } from "./js/data.js";
import { setupAuthHandlers } from "./js/app-auth-handlers.js";
import { setupAdminHandlers } from "./js/app-admin-handlers.js";
import { setupVoteNavigationHandlers } from "./js/app-vote-nav-handlers.js";

const REFRESH_MIN_MS = 3000;
const REFRESH_MAX_MS = 20000;
const EVENTS_RECONNECT_MIN_MS = 1000;
const EVENTS_RECONNECT_MAX_MS = 15000;
let refreshInFlight = null;
let refreshTimerId = null;
let refreshSchedulerStarted = false;
let unchangedRefreshCycles = 0;
let nextRefreshDelayMs = REFRESH_MIN_MS;
let stateEventSource = null;
let eventsReconnectTimerId = null;
let eventsReconnectDelayMs = EVENTS_RECONNECT_MIN_MS;

async function runSerializedRefresh() {
    if (refreshInFlight) return refreshInFlight;
    refreshInFlight = refreshPhaseData().finally(() => {
        refreshInFlight = null;
    });
    return refreshInFlight;
}

async function refreshWithUiErrorHandling() {
    try {
        const changed = await runSerializedRefresh();
        updateRefreshCadence(changed === true);
        if (state.isAuthenticated) {
            ensureStateEventStream();
        } else {
            closeStateEventStream();
        }
    } catch (err) {
        // Back off after transient failures to avoid hammering server/dependencies.
        nextRefreshDelayMs = Math.min(nextRefreshDelayMs * 2, REFRESH_MAX_MS);
        if (handleAuthError(err, clearUserState)) {
            closeStateEventStream();
            return;
        }

        toast(err.message, true);
    }
}

function closeStateEventStream() {
    if (eventsReconnectTimerId !== null) {
        window.clearTimeout(eventsReconnectTimerId);
        eventsReconnectTimerId = null;
    }

    if (stateEventSource) {
        stateEventSource.close();
        stateEventSource = null;
    }
}

function scheduleStateEventReconnect() {
    if (eventsReconnectTimerId !== null || !state.isAuthenticated) return;

    eventsReconnectTimerId = window.setTimeout(() => {
        eventsReconnectTimerId = null;
        ensureStateEventStream();
    }, eventsReconnectDelayMs);

    eventsReconnectDelayMs = Math.min(
        Math.round(eventsReconnectDelayMs * 1.8),
        EVENTS_RECONNECT_MAX_MS,
    );
}

function ensureStateEventStream() {
    if (!state.isAuthenticated || typeof window.EventSource === "undefined") {
        closeStateEventStream();
        return;
    }

    if (stateEventSource) return;

    stateEventSource = new EventSource(api.stateEventsUrl(), {
        withCredentials: true,
    });

    stateEventSource.onopen = () => {
        eventsReconnectDelayMs = EVENTS_RECONNECT_MIN_MS;
    };

    stateEventSource.onerror = () => {
        if (!stateEventSource) return;
        stateEventSource.close();
        stateEventSource = null;
        scheduleStateEventReconnect();
    };

    stateEventSource.addEventListener("state", () => {
        unchangedRefreshCycles = 0;
        nextRefreshDelayMs = baseRefreshDelayForPhase();
        if (!document.hidden && !state.adminStatusSelectActive) {
            refreshWithUiErrorHandling();
        }
    });
}

function scheduleNextRefresh() {
    refreshTimerId = window.setTimeout(async () => {
        if (!document.hidden && !state.adminStatusSelectActive) {
            await refreshWithUiErrorHandling();
        }
        scheduleNextRefresh();
    }, nextRefreshDelayMs);
}

function startRefreshScheduler() {
    if (refreshSchedulerStarted) return;
    refreshSchedulerStarted = true;

    document.addEventListener("visibilitychange", () => {
        if (!document.hidden && !state.adminStatusSelectActive) {
            unchangedRefreshCycles = 0;
            nextRefreshDelayMs = baseRefreshDelayForPhase();
            refreshWithUiErrorHandling();
        }
    });

    if (refreshTimerId !== null) {
        window.clearTimeout(refreshTimerId);
    }
    scheduleNextRefresh();
}

function updateRefreshCadence(changed) {
    const base = baseRefreshDelayForPhase();
    if (changed) {
        unchangedRefreshCycles = 0;
        nextRefreshDelayMs = base;
        return;
    }

    unchangedRefreshCycles = Math.min(unchangedRefreshCycles + 1, 8);
    const growth = Math.pow(1.35, unchangedRefreshCycles);
    nextRefreshDelayMs = Math.min(Math.round(base * growth), REFRESH_MAX_MS);
}

function baseRefreshDelayForPhase() {
    switch (state.phase) {
        case "Vote":
            return REFRESH_MIN_MS;
        case "Suggest":
            return 5000;
        case "Results":
            return 7000;
        default:
            return 5000;
    }
}

configureUiRuntime({
    refreshPhaseData: runSerializedRefresh,
    loadSuggestData,
    loadVoteData,
    handleAuthError: (err) => handleAuthError(err, clearUserState),
});

function setupHandlers() {
    setupAuthHandlers({ runSerializedRefresh });
    setupAdminHandlers({ runSerializedRefresh });
    setupVoteNavigationHandlers({ runSerializedRefresh });
    setupLanguageSwitchers();
    document.getElementById("logout")?.addEventListener("click", () => {
        closeStateEventStream();
    });

    onLanguageChange(() => {
        updateLanguageButtons();
        renderWelcome();
        renderPhasePill();
        renderCounts();
        renderPhaseTitles();
        renderMySuggestions();
        renderAllSuggestions();
        if (state.phase === "Vote") {
            renderVotes();
            state.votesRendered = true;
            syncVoteScores();
        }
        if (state.phase === "Results") {
            renderResults();
        }
        updatePhaseNav();
    });

    document.querySelectorAll(".help-chip").forEach((chip) => {
        chip.addEventListener("click", () => openFaqModal());
    });
}

async function main() {
    await initI18n();
    setupHandlers();
    await refreshWithUiErrorHandling();
    startRefreshScheduler();
}

main();

function updateLanguageButtons() {
    document.querySelectorAll(".lang-button").forEach((btn) => {
        btn.textContent = "🌐";
        btn.title = t("lang.label");
        btn.setAttribute("aria-label", t("lang.label"));
    });
}

function setupLanguageSwitchers() {
    const switches = document.querySelectorAll(".lang-switch");
    const closeAll = () =>
        switches.forEach((wrap) =>
            wrap.querySelector(".lang-menu")?.classList.add("hidden"),
        );

    switches.forEach((wrap) => {
        const btn = wrap.querySelector(".lang-button");
        const menu = wrap.querySelector(".lang-menu");
        if (!btn || !menu) return;
        btn.addEventListener("click", (e) => {
            e.preventDefault();
            const isHidden = menu.classList.contains("hidden");
            closeAll();
            if (isHidden) menu.classList.remove("hidden");
        });
        menu.querySelectorAll("[data-lang]").forEach((item) =>
            item.addEventListener("click", () => {
                const lang = item.dataset.lang;
                if (lang) setLanguage(lang);
                closeAll();
            }),
        );
    });

    document.addEventListener("click", (e) => {
        if (!e.target.closest(".lang-switch")) closeAll();
    });

    updateLanguageButtons();
}

function markdownToHtml(md) {
    const lines = md.trim().split(/\r?\n/);
    const html = [];
    let inList = false;
    let inParagraph = false;

    const escapeHtml = (text) =>
        text.replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;");

    const formatInline = (text) =>
        escapeHtml(text)
            .replace(/\*\*(.+?)\*\*/g, "<strong>$1</strong>")
            .replace(/`([^`]+)`/g, "<code>$1</code>");

    const closeParagraph = () => {
        if (inParagraph) {
            html.push("</p>");
            inParagraph = false;
        }
    };

    const closeList = () => {
        if (inList) {
            html.push("</ul>");
            inList = false;
        }
    };

    lines.forEach((rawLine) => {
        const line = rawLine.trimEnd();
        const trimmed = line.trim();
        if (!trimmed) {
            closeParagraph();
            closeList();
            return;
        }

        if (/^-{5,}$/.test(trimmed)) {
            closeParagraph();
            closeList();
            html.push('<hr class="faq-divider" />');
            return;
        }

        const heading = trimmed.match(/^(#{1,3})\s+(.*)$/);
        if (heading) {
            closeParagraph();
            closeList();
            const level = heading[1].length;
            const tag = level === 1 ? "h2" : level === 2 ? "h3" : "h4";
            html.push(`<${tag}>${formatInline(heading[2].trim())}</${tag}>`);
            return;
        }

        if (/^[*-]\s+/.test(trimmed)) {
            closeParagraph();
            if (!inList) {
                html.push("<ul>");
                inList = true;
            }
            const text = trimmed.replace(/^[*-]\s+/, "");
            html.push(`<li>${formatInline(text)}</li>`);
            return;
        }

        if (!inParagraph) {
            html.push("<p>");
            inParagraph = true;
        }
        html.push(formatInline(trimmed));
    });

    closeParagraph();
    closeList();
    return html.join("\n");
}

function openFaqModal() {
    const overlay = document.createElement("div");
    overlay.className = "edit-modal";
    const panel = document.createElement("div");
    panel.className = "edit-panel faq-panel";
    panel.innerHTML = `
    <div class="edit-header">
      <h3>${t("help.title")}</h3>
      <button class="lightbox-close" aria-label="${t("modal.close")}">x</button>
    </div>
    <div class="edit-body">
      <div class="faq-list faq-content"></div>
    </div>
  `;

    const list = panel.querySelector(".faq-list");
    const lang = getLanguage();
    const md = faqMarkdown[lang] ?? faqMarkdown.en;
    list.innerHTML = markdownToHtml(md);

    const close = () => overlay.remove();
    overlay.addEventListener("click", (e) => {
        if (
            e.target.classList.contains("edit-modal") ||
            e.target.classList.contains("lightbox-close")
        )
            close();
    });

    overlay.appendChild(panel);
    document.body.appendChild(overlay);
}