wrolpi/app/public/epub/epub.html

<!DOCTYPE html>
<!--Copyright (c) 2013, FuturePress

All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this
   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.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

The views and conclusions contained in the software and documentation are those
of the authors and should not be interpreted as representing official policies,
either expressed or implied, of the FreeBSD Project. -->
<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;
    // Where the reader left off (an EPUB CFI).  A search result's `loc` wins over it.
    let startCfi = (params && params.get("cfi")) ? params.get("cfi") : null;

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

    rendition.display(currentSectionIndex !== undefined ? currentSectionIndex : (startCfi || undefined));

    // How far through the book `location` is, from its chapter and its page within that chapter.  Cheaper
    // than `book.locations.generate()`, which stalls a Raspberry Pi on a large book.
    function readingProgress(location) {
        if (location.atEnd) {
            return 1;
        }
        const start = location.start;
        const sections = book.spine.length || 1;
        const displayed = start.displayed || {page: 1, total: 1};
        const withinSection = (displayed.page - 1) / Math.max(displayed.total, 1);
        return Math.min((start.index + withinSection) / sections, 1);
    }

    // Tell the WROLPi page that embeds this viewer where the reader is, so it can save their place.  Nothing is
    // posted at the start of the book: that is where a finished book opens, and saving it would un-finish it.
    function postLocation(location) {
        if (window.parent === window || !location || !location.start || location.atStart) {
            return;
        }
        window.parent.postMessage({
            type: "wrolpi:epub-location",
            cfi: location.start.cfi,
            progress: readingProgress(location),
        }, window.location.origin);
    }

    // --- 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";
        }

        postLocation(location);
    });

    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>