wrolpi/app/public/epub/epub.html

<!DOCTYPE html>
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   list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.

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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
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ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1"/>
    <script src="/epub/jszip.min.js"></script>
    <script src="/epub/epub.js"></script>
</head>
<body>

<style>
    body {
        margin: 0;
        background: #fafafa;
        font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
        color: #333;

        position: absolute;
        height: 100%;
        width: 100%;
    }

    #title {
        width: 900px;
        min-height: 18px;
        margin: 10px auto;
        text-align: center;
        font-size: 16px;
        color: #E2E2E2;
        font-weight: 400;
    }

    #title:hover {
        color: #777;
    }

    #viewer {
        width: 80%;
        height: 90%;
        box-shadow: 0 0 4px #ccc;
        padding: 10px 10px 0px 10px;
        margin: 5px auto;
        background: white;
    }

    #prev {
        left: 0;
    }

    #next {
        right: 0;
    }

    #toc {
        display: block;
        margin: 10px auto;
    }

    .arrow {
        position: fixed;
        top: 50%;
        margin-top: -32px;
        font-size: 64px;
        color: #E2E2E2;
        font-family: arial, sans-serif;
        font-weight: bold;
        cursor: pointer;
        -webkit-user-select: none;
        -moz-user-select: none;
        user-select: none;
        text-decoration: none;
    }

    .arrow:hover {
        color: #777;
    }

    .arrow:active {
        color: #000;
    }

    #book-viewer iframe {
        padding: 40px 40px;
    }

    #controls > input[type=range] {
        width: 400px;
    }

    #navigation h1 {
        width: 200px;
        font-size: 16px;
        font-weight: normal;
        color: #fff;
        margin-bottom: 10px;
    }

    #navigation h2 {
        font-size: 14px;
        font-weight: normal;
        color: #B0B0B0;
        margin-bottom: 20px;
    }

    #navigation ul {
        padding-left: 36px;
        margin-left: 0;
        margin-top: 12px;
        margin-bottom: 12px;
        width: 340px;
    }

    #navigation ul li {
        list-style: decimal;
        margin-bottom: 10px;
        color: #cccddd;
        font-size: 12px;
        padding-left: 0;
        margin-left: 0;
    }

    #navigation ul li a {
        color: #ccc;
        text-decoration: none;
    }

    #navigation ul li a:hover {
        color: #fff;
        text-decoration: underline;
    }

    #navigation ul li {
        color: #fff;
    }

    svg {
        display: block;
    }

    #toolbar {
        display: flex;
        align-items: center;
        gap: 8px;
        margin: 8px auto;
        padding: 0 12px;
        flex-wrap: wrap;
        font-size: 13px;
        color: #444;
    }

    #toolbar #toc {
        margin: 0;
    }

    #toolbar form {
        display: flex;
        gap: 4px;
        align-items: center;
        margin: 0;
    }

    #toolbar input[type="search"] {
        padding: 4px 6px;
        font-size: 13px;
        border: 1px solid #ccc;
        border-radius: 3px;
        min-width: 180px;
    }

    #toolbar button {
        padding: 3px 10px;
        font-size: 13px;
        border: 1px solid #ccc;
        background: #f6f6f6;
        border-radius: 3px;
        cursor: pointer;
        line-height: 1.4;
    }

    #toolbar button:disabled {
        opacity: 0.45;
        cursor: default;
    }

    #search-status {
        color: #666;
        min-width: 96px;
    }

    #search-status.error {
        color: #b00;
    }

</style>

<div id="toolbar">
    <select id="toc"></select>
    <form id="search-form" onsubmit="return false;">
        <input id="search-input" type="search" placeholder="Search in book…" aria-label="Search in book"/>
        <button id="search-submit" type="submit">Search</button>
        <button id="search-prev" type="button" title="Previous match" disabled>‹</button>
        <button id="search-next" type="button" title="Next match" disabled>›</button>
        <button id="search-clear" type="button" title="Clear search" disabled>×</button>
    </form>
    <span id="search-status"></span>
</div>
<div id="viewer"></div>
<a id="prev" href="#prev" class="arrow">‹</a>
<a id="next" href="#next" class="arrow">›</a>

<script>
    let params = URLSearchParams && new URLSearchParams(document.location.search.substring(1));
    let url = params && params.get("url") && decodeURIComponent(params.get("url"));
    let currentSectionIndex = (params && params.get("loc")) ? params.get("loc") : undefined;
    // Optional search term passed in from a search-result deep link. If present we'll
    // search the spine item at `loc` and jump to + highlight the first match.
    let searchQuery = (params && params.get("q")) ? params.get("q") : null;

    let book = ePub(url);
    let rendition = book.renderTo("viewer", {
        flow: "paginated",
        width: "100%",
        height: "100%"
    });

    rendition.display(currentSectionIndex);

    // --- In-book search ---------------------------------------------------
    // State is module-level so the toolbar buttons can drive it. `hits` is the
    // most recent search's results in spine order; `currentHitIndex` tracks
    // which one is "selected" for prev/next navigation.
    let hits = [];
    let currentHitIndex = -1;
    let searchInProgress = false;
    const SEARCH_CONCURRENCY = 8;

    const $input = document.getElementById("search-input");
    const $submit = document.getElementById("search-submit");
    const $prev = document.getElementById("search-prev");
    const $next = document.getElementById("search-next");
    const $clear = document.getElementById("search-clear");
    const $status = document.getElementById("search-status");
    const $form = document.getElementById("search-form");

    function setStatus(text, isError) {
        $status.textContent = text || "";
        $status.classList.toggle("error", !!isError);
    }

    function updateButtons() {
        const hasHits = hits.length > 0;
        $prev.disabled = !hasHits || searchInProgress;
        $next.disabled = !hasHits || searchInProgress;
        $clear.disabled = (!hasHits && !$input.value) || searchInProgress;
        $submit.disabled = searchInProgress;
    }

    function clearHighlights() {
        for (const hit of hits) {
            try {
                rendition.annotations.remove(hit.cfi, "highlight");
            } catch (e) { /* already gone — ignore */ }
        }
    }

    function clearSearch() {
        clearHighlights();
        hits = [];
        currentHitIndex = -1;
        setStatus("");
        updateButtons();
    }

    function gotoHit(i) {
        if (!hits.length) return;
        // Wrap around both directions for easy cycling.
        if (i < 0) i = hits.length - 1;
        if (i >= hits.length) i = 0;
        currentHitIndex = i;
        try {
            rendition.display(hits[i].cfi);
        } catch (e) {
            console.warn("failed to display hit", e);
        }
        setStatus(`${i + 1} of ${hits.length}`);
    }

    // Run a search across every spine item, collecting CFIs and excerpts.
    // Uses small-chunk concurrency so a 600-item book doesn't serialize one
    // load at a time and doesn't stampede memory by loading all at once.
    // `preferredSpineIndex` biases the initial hit selection. When a search is
    // kicked off from a `?loc=…&q=…` deep-link, callers pass the loc so the
    // viewer lands on the match in that chapter rather than jumping to the
    // first match in the whole book.
    async function runBookSearch(query, preferredSpineIndex) {
        query = (query || "").trim();
        if (!query) {
            clearSearch();
            return;
        }
        // Always clear prior state before starting a new search.
        clearHighlights();
        hits = [];
        currentHitIndex = -1;
        searchInProgress = true;
        updateButtons();
        setStatus("Searching…");

        const spineItems = (book.spine && book.spine.spineItems) || [];
        const total = spineItems.length;
        let processed = 0;
        const newHits = [];

        async function searchOne(item) {
            try {
                await Promise.resolve(item.load(book.load.bind(book)));
                const results = item.find(query) || [];
                for (const r of results) {
                    newHits.push({
                        spineIndex: item.index,
                        cfi: r.cfi,
                        excerpt: r.excerpt,
                    });
                }
            } catch (e) {
                console.warn("search failed for item", item && item.href, e);
            } finally {
                try { item.unload(); } catch (e) { /* ignore */ }
                processed += 1;
                // Live progress — users with big books want to know something's happening.
                if (processed % SEARCH_CONCURRENCY === 0 || processed === total) {
                    setStatus(`Searching… ${processed} / ${total}`);
                }
            }
        }

        // Simple fixed-concurrency pool.
        let cursor = 0;
        async function worker() {
            while (cursor < spineItems.length) {
                const i = cursor++;
                await searchOne(spineItems[i]);
            }
        }
        const workers = [];
        for (let i = 0; i < Math.min(SEARCH_CONCURRENCY, spineItems.length); i++) {
            workers.push(worker());
        }
        await Promise.all(workers);

        // Sort hits by spine order then position within the section. `spineIndex`
        // handles the first; CFI string comparison is a reasonable tiebreaker.
        newHits.sort((a, b) => {
            if (a.spineIndex !== b.spineIndex) return a.spineIndex - b.spineIndex;
            return a.cfi < b.cfi ? -1 : a.cfi > b.cfi ? 1 : 0;
        });

        // Highlight each match. The annotation only renders visibly when its
        // section is rendered, but calling this up-front means navigating to
        // any hit arrives with the term already marked.
        for (const hit of newHits) {
            try {
                rendition.annotations.highlight(hit.cfi);
            } catch (e) { /* dup or invalid CFI — ignore */ }
        }

        hits = newHits;
        searchInProgress = false;

        if (hits.length === 0) {
            setStatus("No matches");
        } else {
            // If the caller pinned a preferred spine item (e.g. a deep-link with
            // `?loc=`), prefer the first hit inside that exact section. Fall back
            // to the first hit globally only when there's no match in the pin.
            let startIdx = 0;
            const pin = (preferredSpineIndex === undefined || preferredSpineIndex === null)
                ? null
                : parseInt(preferredSpineIndex, 10);
            if (pin !== null && !isNaN(pin)) {
                const pinned = hits.findIndex(h => h.spineIndex === pin);
                if (pinned !== -1) startIdx = pinned;
            }
            gotoHit(startIdx);
        }
        updateButtons();
    }

    // Wire up the toolbar.
    $form.addEventListener("submit", function (e) {
        e.preventDefault();
        runBookSearch($input.value);
    });
    $next.addEventListener("click", function () { gotoHit(currentHitIndex + 1); });
    $prev.addEventListener("click", function () { gotoHit(currentHitIndex - 1); });
    $clear.addEventListener("click", function () {
        $input.value = "";
        clearSearch();
    });
    $input.addEventListener("input", function () {
        // Enable/disable the clear button as the user types, even with no hits yet.
        updateButtons();
    });
    updateButtons();

    // Deep-link `q=` — pre-fill the box and run the full search once the book
    // is ready. Pass `loc` (when present) as the preferred spine index so the
    // viewer lands on the match inside that chapter rather than the first match
    // in the book. Manual searches triggered from the toolbar don't pass a pin.
    if (searchQuery) {
        $input.value = searchQuery;
        book.ready.then(function () {
            runBookSearch(searchQuery, currentSectionIndex);
        });
    }

    book.ready.then(() => {

        let next = document.getElementById("next");

        next.addEventListener("click", function (e) {
            book.package.metadata.direction === "rtl" ? rendition.prev() : rendition.next();
            e.preventDefault();
        }, false);

        let prev = document.getElementById("prev");
        prev.addEventListener("click", function (e) {
            book.package.metadata.direction === "rtl" ? rendition.next() : rendition.prev();
            e.preventDefault();
        }, false);

        let keyListener = function (e) {

            // Left Key
            if ((e.keyCode || e.which) === 37) {
                book.package.metadata.direction === "rtl" ? rendition.next() : rendition.prev();
            }

            // Right Key
            if ((e.keyCode || e.which) === 39) {
                book.package.metadata.direction === "rtl" ? rendition.prev() : rendition.next();
            }

        };

        rendition.on("keyup", keyListener);
        document.addEventListener("keyup", keyListener, false);

    })

    let title = document.getElementById("title");

    rendition.on("rendered", function (section) {
        let current = book.navigation && book.navigation.get(section.href);

        if (current) {
            let $select = document.getElementById("toc");
            let $selected = $select.querySelector("option[selected]");
            if ($selected) {
                $selected.removeAttribute("selected");
            }

            let $options = $select.querySelectorAll("option");
            for (let i = 0; i < $options.length; ++i) {
                let selected = $options[i].getAttribute("ref") === current.href;
                if (selected) {
                    $options[i].setAttribute("selected", "");
                }
            }
        }

    });

    rendition.on("relocated", function (location) {
        console.log(location);

        let next = book.package.metadata.direction === "rtl" ? document.getElementById("prev") : document.getElementById("next");
        let prev = book.package.metadata.direction === "rtl" ? document.getElementById("next") : document.getElementById("prev");

        if (location.atEnd) {
            next.style.visibility = "hidden";
        } else {
            next.style.visibility = "visible";
        }

        if (location.atStart) {
            prev.style.visibility = "hidden";
        } else {
            prev.style.visibility = "visible";
        }

    });

    rendition.on("layout", function (layout) {
        let viewer = document.getElementById("viewer");

        if (layout.spread) {
            viewer.classList.remove('single');
        } else {
            viewer.classList.add('single');
        }
    });

    window.addEventListener("unload", function () {
        console.log("unloading");
        this.book.destroy();
    });

    book.loaded.navigation.then(function (toc) {
        let $select = document.getElementById("toc"),
            docfrag = document.createDocumentFragment();

        toc.forEach(function (chapter) {
            let option = document.createElement("option");
            option.textContent = chapter.label;
            option.setAttribute("ref", chapter.href);

            docfrag.appendChild(option);
        });

        $select.appendChild(docfrag);

        $select.onchange = function () {
            let index = $select.selectedIndex,
                url = $select.options[index].getAttribute("ref");
            rendition.display(url);
            return false;
        };

    });

</script>

</body>

</html>