IMDb Tomatoes

Add Rotten Tomatoes ratings to IMDb movie and TV show pages
目前為 2021-07-11 提交的版本，檢視最新版本。
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// ==UserScript==
// @name          IMDb Tomatoes
// @description   Add Rotten Tomatoes ratings to IMDb movie and TV show pages
// @author        chocolateboy
// @copyright     chocolateboy
// @version       4.0.0
// @namespace     https://github.com/chocolateboy/userscripts
// @license       GPL
// @include       /^https://www\.imdb\.com/title/tt[0-9]+/([#?].*)?$/
// @require       https://code.jquery.com/jquery-3.6.0.min.js
// @require       https://cdn.jsdelivr.net/gh/urin/jquery.balloon.js@8b79aab63b9ae34770bfa81c9bfe30019d9a13b0/jquery.balloon.js
// @require       https://unpkg.com/[email protected]/dayjs.min.js
// @require       https://unpkg.com/[email protected]/plugin/relativeTime.js
// @require       https://unpkg.com/@chocolateboy/[email protected]/dist/polyfill.iife.min.js
// @require       https://unpkg.com/[email protected]/dist/index.umd.min.js
// @require       https://unpkg.com/[email protected]/dice.js
// @resource      api https://pastebin.com/raw/hcN4ysZD
// @resource      fallback https://pastebin.com/raw/RpaikqH0
// @grant         GM_addStyle
// @grant         GM_deleteValue
// @grant         GM_getResourceText
// @grant         GM_getValue
// @grant         GM_listValues
// @grant         GM_registerMenuCommand
// @grant         GM_setValue
// @grant         GM_xmlhttpRequest
// @connect       www.rottentomatoes.com
// @run-at        document-start
// @noframes
// ==/UserScript==

/// <reference types="greasemonkey" />
/// <reference types="jquery" />
/// <reference types="tampermonkey" />

/**
 * @typedef {Object} AsyncGetOptions
 *
 * @prop {Record<string, string | number | boolean>} [params]
 * @prop {string} [title]
 * @prop {Partial<Tampermonkey.Request>} [request]
 */

'use strict';

/* begin */ {

const INACTIVE_MONTHS = 3
const NO_CONSENSUS    = 'No consensus yet.'
const NO_MATCH        = 'no matching results'
const ONE_DAY         = 1000 * 60 * 60 * 24
const ONE_WEEK        = ONE_DAY * 7
const RT_BASE         = 'https://www.rottentomatoes.com'
const SCRIPT_NAME     = GM_info.script.name
const SCRIPT_VERSION  = GM_info.script.version

// the version of each cached record is a combination of the schema version and
// the major part of the script's (SemVer) version, and an additional number
// (the cache-generation) which can be incremented to force the cache to be
// cleared. the generation is reset when the schema or major versions change
//
// e.g. 4 (schema) + 3 (major) + 0 (generation) gives a version of "4/3.0"
//
// this means cached records are invalidated either a) when the schema changes,
// b) when the major version of the script changes, or c) when the generation is
// bumped
const SCHEMA_VERSION = 4
const SCRIPT_MAJOR = SCRIPT_VERSION.split('.')[0]
const CACHE_GENERATION = 0
const DATA_VERSION = `${SCHEMA_VERSION}/${SCRIPT_MAJOR}.${CACHE_GENERATION}`

const BALLOON_OPTIONS = {
    classname: 'rt-consensus-balloon',
    css: {
        fontFamily: 'Roboto, Helvetica, Arial, sans-serif',
        fontSize: '0.9rem',
        lineHeight: '1.26rem',
        maxWidth: '31rem',
        padding: '0.75rem',
    },
    html: true,
    position: 'bottom',
}

const COLOR = {
    tbd: '#d9d9d9',
    fresh: '#66cc33',
    rotten: '#ff0000',
}

const RT_TYPE = {
    movie: 'movie',
    tvMovie: 'movie',
    tvSeries: 'tvSeries',
    tvMiniSeries: 'tvSeries',
}

const UNSHARED = Object.freeze({
    got: -1,
    want: 1,
    max: 0,
})

/*
 * the minimum number of elements shared between two arrays for them to be
 * deemed similar
 *
 * @type {<T>(smallest: Set<T>, largest: Set<T>) => number}
 */
const MINIMUM_SHARED = smallest => Math.round(smallest.size / 2)

// log a message to the console
const { debug, info, log } = console

// a custom version of get-wild's `get` function which uses a simpler/faster
// path parser since we don't use the extended syntax
const get = exports.getter({ split: '.' })

// register a jQuery plugin which extracts and returns JSON-LD data for the
// current page.
//
// used to extract metadata on Rotten Tomatoes
$.fn.jsonLd = function jsonLd (id) {
    const $script = this.find('script[type="application/ld+json"]')

    let data

    if ($script.length) {
        try {
            data = JSON.parse($script.first().text().trim())
        } catch (e) {
            throw new Error(`Can't parse JSON-LD data for ${id}: ${e}`)
        }
    } else {
        throw new Error(`Can't find JSON-LD data for ${id}`)
    }

    return data
}

/**
 * a helper class which keeps a running total of scores for two values (a and
 * b). used to rank values in a sort function
 *
 * @param {number} order
 * @return {void}
 */
class Score {
    constructor () {
        this.a = 0
        this.b = 0
    }

    /**
     * add a score to the total
     *
     * @param {number} order
     * @param {number=} points
     * @return {void}
     */
    add (order, points = 1) {
        if (order < 0) {
            this.a += points
        } else if (order > 0) {
            this.b += points
        }
    }
}

/**
 * raise a non-error exception indicating no matching result has been found
 *
 * @param {string} message
 * @throws {Error}
 */
function abort (message) {
    throw Object.assign(new Error(message), { abort: true })
}

/**
 * add a Rotten Tomatoes widget to the ratings bar
 *
 * @param {JQuery} $ratings
 * @param {JQuery} $imdbRating
 * @param {Object} data
 * @param {string} data.url
 * @param {string} data.consensus
 * @param {number} data.rating
 */
function addWidget ($ratings, $imdbRating, { consensus, rating, url }) {
    let style

    if (rating === -1) {
        style = 'tbd'
    } else if (rating < 60) {
        style = 'rotten'
    } else {
        style = 'fresh'
    }

    // clone the IMDb rating widget
    const $rtRating = $imdbRating.clone()

    // 1) assign a unique ID
    $rtRating.attr('id', 'rt-rating')

    // 2) add a custom stylesheet which:
    //
    // - sets the star (SVG) to the right color
    // - restores support for italics in the consensus text
    // - reorders the appended widget (see attachWidget)
    GM_addStyle(`
        #rt-rating svg { color: ${COLOR[style]}; }
        #rt-rating { order: -1; }
        .rt-consensus-balloon em { font-style: italic; }
    `)

    // 3) remove the review count and its preceding spacer element
    $rtRating
        .find('[class^="AggregateRatingButton__TotalRatingAmount-"]')
        .prev()
        .addBack()
        .remove()

    // 4) replace "IMDb Rating" with "RT Rating"
    $rtRating.find('[class^="RatingBarButtonBase__Header-"]')
        .text('RT RATING')

    // 5) replace the IMDb rating with the RT score and remove the "/ 10" suffix
    const score = rating === -1 ? 'N/A' : `${rating}%`
    $rtRating
        .find('[class^="AggregateRatingButton__RatingScore-"]')
        .text(score)
        .next()
        .remove()

    // 6) rename the testids, e.g.:
    // hero-rating-bar__aggregate-rating -> hero-rating-bar__rt-rating
    $rtRating.find('[data-testid]').addBack().each(function () {
        $(this).attr('data-testid', (_, id) => id.replace('aggregate', 'rt'))
    })

    // 7) add the tooltip class to the link and update its label and URL
    const balloonOptions = Object.assign({}, BALLOON_OPTIONS, { contents: consensus })
    $rtRating.find('a[role="button"]')
        .addClass('rt-consensus')
        .balloon(balloonOptions)
        .attr('aria-label', 'View RT Rating')
        .attr('href', url)

    // 8) prepend the element to the ratings bar
    attachWidget($ratings, $rtRating)
}

/**
 * promisified cross-origin HTTP requests
 *
 * @param {string} url
 * @param {AsyncGetOptions} [options]
 */
function asyncGet (url, options = {}) {
    if (options.params) {
        url = url + '?' + $.param(options.params)
    }

    const id = options.title || url
    const request = Object.assign({ method: 'GET', url }, options.request || {})

    return new Promise((resolve, reject) => {
        request.onload = res => {
            if (res.status >= 400) {
                reject(new Error(`error fetching ${id} (${res.status} ${res.statusText})`))
            } else {
                resolve(res)
            }
        }

        // XXX the +onerror+ response object doesn't contain any useful info
        request.onerror = _res => {
            reject(new Error(`error fetching ${id}`))
        }

        GM_xmlhttpRequest(request)
    })
}

/**
 * attach the RT ratings widget to the ratings bar
 *
 * although the widget appears to be prepended to the bar, we need to append it
 * (and reorder it via CSS) to work around React reconciliation (updating the
 * DOM to match the underlying model) after we've added the RT widget
 *
 * when this synchronisation occurs, React will try to restore nodes
 * (attributes, text, elements) within each widget to match the widget's props,
 * so the first widget will be updated in place to match the data for the IMDb
 * rating etc. this changes some, but not all nodes within an element, and most
 * attributes added to/changed in the RT widget remain in the updated IMDb
 * widget, including its ID attribute (rt-rating) which controls the color of
 * the rating star. as a result, we end up with a restored IMDb widget but with
 * an RT-colored star (and with the RT widget removed since it's not in the
 * ratings-bar model)
 *
 * if we *append* the RT widget, none of the other widgets will need to be
 * changed/updated if the DOM is re-synced so we won't end up with a mangled
 * IMDb widget; however, our RT widget will still be removed since it's not in
 * the model. to rectify this, we use a mutation observer to detect and revert
 * its removal
 *
 * @param {JQuery} $target
 * @param {JQuery} $rtRating
 */
function attachWidget ($target, $rtRating) {
    const init = { childList: true }
    const target = $target.get(0)
    const rtRating = $rtRating.get(0)
    const callback = () => {
        if (target.lastElementChild !== rtRating) {
            observer.disconnect()
            target.appendChild(rtRating)
            observer.observe(target, init)
        }
    }

    const observer = new MutationObserver(callback)
    target.appendChild(rtRating)
    observer.observe(target, init)
}

/**
 * check the fallback data in case of a failed match, but only use it as a last
 * resort, i.e. try the verifier first, if defined, in case the data has
 * been fixed/updated
 *
 * @param {any} matched
 * @param {string} imdbId
 */
function checkFallback (matched, imdbId) {
    const fallback = JSON.parse(GM_getResourceText('fallback'))
    const url = fallback[imdbId]

    if (url) {
        const $url = JSON.stringify(url)
        const { verify } = matched

        if (!matched.match) { // missing result
            debug('fallback:', $url)
            matched.match = { url }
        } else if (matched.match.url !== url) { // wrong result
            const $overridden = JSON.stringify(matched.match.url)
            debug(`override: ${$overridden} -> ${$url}`)
            matched.match.url = url
        }

        if (verify) {
            matched.verify = $rt => {
                if (!verify($rt)) { // missing/incompatible RT data
                    debug('force:', true)
                }

                return true
            }
        }
    }

    return matched
}

/**
 * extract IMDb metadata from the GraphQL data embedded in the page
 *
 * @param {string} imdbId
 * @returns {any}
 */
function getIMDbMetadata (imdbId) {
    const data = JSON.parse($('#__NEXT_DATA__').text())
    const pageType = get(data, 'props.requestContext.pageType')

    const decorate = data => {
        return { data, size: Object.keys(data).length }
    }

    // there are multiple matching subtrees (with different but partially
    // overlapping keys). order them in descending order of size (number of keys)
    const titles = get(data, 'props.urqlState.*.data.title', [])
        .filter(title => title.id === imdbId)
        .map(decorate)
        .sort((a, b) => b.size - a.size)
        .map(it => it.data)

    const [main, extra] = titles
    const mainCast = get(main, 'principalCast.*.credits.*.name.nameText.text', [])
    const extraCast = get(main, 'cast.edges.*.node.name.nameText.text', [])
    const fullCast = Array.from(new Set([...mainCast, ...extraCast]))
    const title = get(main, 'titleText.text', '')
    const originalTitle = get(main, 'originalTitleText.text', '')
    const type = get(main, 'titleType.id', '')
    const year = get(main, 'releaseYear.year') || 0
    const meta = {
        id: imdbId,
        cast: mainCast,
        fullCast,
        title,
        originalTitle,
        type,
    }

    if (RT_TYPE[type] === 'tvSeries') {
        meta.startYear = year
        meta.endYear = get(extra, 'releaseYear.endYear') || 0
        meta.seasons = get(main, 'episodes.seasons.length') || 0
    } else if (RT_TYPE[type] === 'movie') {
        meta.directors = get(main, 'directors.*.credits.*.name.nameText.text', [])
        meta.year = year
    }

    return { meta, pageType }
}

// parse the API's response and extract the RT rating and consensus.
//
// if there's no consensus, default to "No consensus yet."
// if there's no rating, default to -1
async function getRTData (imdb) {
    /**
     * @throws {Error}
     */
    function fail (message) {
        throw new Error(message)
    }

    const rtType = RT_TYPE[imdb.type]

    log(`querying API for ${JSON.stringify(imdb.title)}`)

    /** @type {AsyncGetOptions} */
    const request = {
        params: { t: rtType, q: imdb.title, limit: 100 },
        request: { responseType: 'json' },
        title: 'API',
    }

    const api = GM_getResourceText('api')
    const response = await asyncGet(api, request)
    log(`response: ${response.status} ${response.statusText}`)

    let results

    try {
        results = JSON.parse(response.responseText)
    } catch (e) {
        fail(`can't parse response: ${e}`)
    }

    if (!results) {
        fail('invalid JSON type')
    }

    debug('results:', results)

    const matcher = rtType === 'movie' ? matchMovie : matchTV
    const matched = matcher(results, imdb) || {}
    const { match, verify } = checkFallback(matched, imdb.id)

    if (!match) {
        abort(NO_MATCH)
    }

    debug('match:', match)
    // @ts-ignore
    const url = RT_BASE + match.url
    log(`loading RT URL: ${url}`)
    const res = await asyncGet(url)
    log(`response: ${res.status} ${res.statusText}`)

    const parser = new DOMParser()
    const dom = parser.parseFromString(res.responseText, 'text/html')
    const $rt = $(dom)
    const $consensus = $rt.find('[data-qa="score-panel-critics-consensus"], [data-qa="critics-consensus"]')

    let consensus

    if ($consensus.length && (consensus = $consensus.html().trim())) {
        consensus = consensus.replace(/--/g, '&#8212;')
    } else {
        consensus = NO_CONSENSUS
    }

    const meta = $rt.jsonLd(url)

    if (verify) {
        Object.assign($rt, { meta })

        if (!verify($rt)) {
            abort(NO_MATCH)
        }
    }

    const updated = getUpdated(meta, rtType)
    const $rating = meta.aggregateRating
    const rating = Number(($rating.name === 'Tomatometer' ? $rating.ratingValue : null) ?? -1)

    return { data: { consensus, rating, url }, updated }
}

/**
 * get the timestamp (ISO-8601 string) of the last time the RT page was updated,
 * e.g. the date of the most-recently published review
 *
 * @param {any} rtMeta
 * @param {'movie' | 'tvSeries'} rtType
 */
function getUpdated (rtMeta, rtType) {
    const [reviewProp, rootProp] = rtType === 'movie'
        ? ['dateCreated', 'dateModified']
        : ['datePublished', 'datePublished']

    let updated

    if (rtMeta.review?.length) {
        debug('reviews:', rtMeta.review.length)

        const [latest] = rtMeta.review
            .flatMap(review => {
                return review[reviewProp]
                    ? [{ review, mtime: dayjs(review[reviewProp]).unix() }]
                    : []
            })
            .sort((a, b) => b.mtime - a.mtime)

        if (latest) {
            updated = latest.review[reviewProp]
            debug('updated (most recent review):', updated)
        }
    }

    if (!updated && (updated = rtMeta[rootProp])) {
        debug('updated (page modified):', updated)
    }

    return updated
}

/**
 * return a movie record ({ url: string }) from the API results which
 * matches the supplied IMDb data
 *
 * @param {any} rtResults
 * @param {any} imdb
 * @return {{ match: { url: string }, verify?: (meta: any, $rt: JQuery) => boolean } | void}
 */
function matchMovie (rtResults, imdb) {
    const sorted = rtResults.movies
        .flatMap((rt, index) => {
            if (!(rt.name && rt.url && rt.castItems)) {
                return []
            }

            const { name: title } = rt
            const rtCast = pluck(rt.castItems, 'name').map(stripRtName)

            let castMatch

            if (rtCast.length) {
                const { got, want } = shared(rtCast, imdb.fullCast)

                if (got < want) {
                    return []
                } else {
                    castMatch = got
                }
            } else {
                castMatch = -1
            }

            const yearDiff = (imdb.year && rt.year)
                ? { value: Math.abs(imdb.year - rt.year) }
                : null

            if (yearDiff && yearDiff.value > 3) {
                return []
            }

            const titleMatch = titleSimilarity({ imdb, rt: { title } })

            const result = {
                title,
                url: rt.url,
                rating: rt.meterScore,
                popularity: (rt.meterScore == null ? 0 : 1),
                cast: rtCast,
                year: rt.year,
                index,
                titleMatch,
                castMatch,
                yearDiff
            }

            return [result]
        })
        .sort((a, b) => {
            // combine the title and the year
            //
            // being a year or two out shouldn't be a dealbreaker, and it's not
            // uncommon for an RT title to differ from the IMDb title (e.g. an
            // AKA), so we don't want one of these to pre-empt the other (just yet)
            const score = new Score()

            score.add(b.titleMatch - a.titleMatch)

            if (a.yearDiff && b.yearDiff) {
                score.add(a.yearDiff.value - b.yearDiff.value)
            }

            return (b.castMatch - a.castMatch)
                || (score.b - score.a)
                || (b.titleMatch - a.titleMatch) // prioritise the title if we're still deadlocked
                || (b.popularity - a.popularity) // last resort
        })

    debug('matches:', sorted)

    if (sorted.length) {
        const [match] = sorted

        if (match.cast.length) { // already verified
            return { match }
        } else {
            // in theory, we can verify the cast when the page is loaded. in
            // practice, it doesn't work: if the cast is missing from the API
            // results, it's also missing from the page's metadata
            //
            // when the cast is missing from the metadata, the directors are
            // often missing from the metadata as well, so we try to scrape them
            // instead

            const verify = $rt => {
                const rtDirectors = $rt.meta.director?.length
                    ? pluck($rt.meta.director, 'name').map(stripRtName)
                    : $rt.find('[data-qa="movie-info-director"]').get().map(it => it.textContent)
                return verifyShared({ imdb: imdb.directors, rt: rtDirectors, name: 'directors' })
            }

            return { match, verify }
        }
    }
}

/**
 * return a TV show record ({ url: string }) from the API results
 * which matches the supplied IMDb data
 *
 * returns an additional validation function to run against the RT page's
 * metadata to confirm the match
 *
 * @param {any} rtResults
 * @param {any} imdb
 * @return {{ match: { url: string }, verify?: (meta: any, $rt: JQuery) => boolean } | void}
 */
function matchTV (rtResults, imdb) {
    const verify = ({ meta }) => {
        const rtCast = pluck(meta.actor, 'name').map(stripRtName)
        const diff1 = Math.abs(rtCast.length - imdb.fullCast.length)
        const diff2 = Math.abs(rtCast.length - imdb.cast.length)
        const imdbCast = diff1 > diff2 ? imdb.fullCast : imdb.cast
        return verifyShared({ imdb: imdbCast, rt: rtCast })
    }

    const sorted = rtResults.tvSeries
        .flatMap((rt, index) => {
            const { title, startYear, endYear, url } = rt

            if (!(title && (startYear || endYear) && url)) {
                return []
            }

            const titleMatch = titleSimilarity({ imdb, rt })

            if (titleMatch < 0.6) {
                return []
            }

            const dateDiffs = {}

            for (const dateProp of ['startYear', 'endYear']) {
                if (imdb[dateProp] && rt[dateProp]) {
                    const diff = Math.abs(imdb[dateProp] - rt[dateProp])

                    if (diff > 3) {
                        return []
                    } else {
                        dateDiffs[dateProp] = { value: diff }
                    }
                }
            }

            const seasonsDiff = (url.endsWith('/s01') && imdb.seasons)
                ? { value: imdb.seasons - 1 }
                : null

            const score = {
                title,
                url,
                rating: rt.meterScore,
                popularity: (rt.meterScore == null ? 0 : 1),
                startYear,
                endYear,
                index,
                titleMatch,
                startYearDiff: dateDiffs.startYear,
                endYearDiff: dateDiffs.endYear,
                seasonsDiff,
            }

            return [score]
        })
        .sort((a, b) => {
            const score = new Score()

            score.add(b.titleMatch - a.titleMatch)

            if (a.startYearDiff && b.startYearDiff) {
                score.add(a.startYearDiff.value - b.startYearDiff.value)
            }

            if (a.endYearDiff && b.endYearDiff) {
                score.add(a.endYearDiff.value - b.endYearDiff.value)
            }

            if (a.seasonsDiff && b.seasonsDiff) {
                score.add(a.seasonsDiff.value - b.seasonsDiff.value)
            }

            return (score.b - score.a)
                || (b.titleMatch - a.titleMatch) // prioritise the title if we're still deadlocked
                || (b.popularity - a.popularity) // last resort
        })

    debug('matches:', sorted)

    const [match] = sorted

    if (match) {
        if (match.url.match(/^\/tv\/[^/]+$/)) {
            match.url += '/s01'
        }

        return { match, verify }
    }
}

/**
 * normalize names so matches don't fail due to minor differences in casing or
 * punctuation
 *
 * @param {string} name
 * @returns {string}
 */
function normalize (name) {
    return name
        .normalize('NFKD')
        .replace(/[\u0300-\u036F]/g, '')
        .toLowerCase()
        .replace(/[^a-z0-9]/g, ' ')
        .replace(/\s+/g, ' ')
        .trim()
}

/**
 * extract the value of a property (+name+ by default) from each member of an
 * array
 *
 * @param {any[] | undefined} array
 * @param {string} path
 * @returns {any[]}
 */
function pluck (array, path) {
    return (array || []).map(it => get(it, path))
}

/**
 * purge expired entries from the cache
 *
 * @param {number} date
 */
function purgeCached (date) {
    for (const key of GM_listValues()) {
        const json = GM_getValue(key)
        const value = JSON.parse(json)

        if (value.version !== DATA_VERSION) {
            log(`purging invalid value (obsolete data version (${value.version})): ${key}`)
            GM_deleteValue(key)
        } else if (date === -1 || (typeof value.expires !== 'number') || (date > value.expires)) {
            log(`purging expired value: ${key}`)
            GM_deleteValue(key)
        }
    }
}

/**
 * given two arrays of strings, return an object containing:
 *
 *   - got: the number of strings common to both
 *   - want: the required number of shared strings (minimum: 1)
 *   - max: the maximum number of shared strings
 *
 * if either array is empty, the number of strings they have in commin is -1
 *
 * @param {Iterable<string>} a
 * @param {Iterable<string>} b
 * @param {Object} [options]
 * @param {(smallest: Set<string>, largest: Set<string>) => number} [options.min]
 * @param {(value: string) => string} [options.map]
 * @return {{ got: number, want: number, max: number }}
 */
function shared (a, b, { min = MINIMUM_SHARED, map: transform = normalize } = {}) {
    const $a = new Set(Array.from(a, transform))

    if ($a.size === 0) {
        return UNSHARED
    }

    const $b = new Set(Array.from(b, transform))

    if ($b.size === 0) {
        return UNSHARED
    }

    const [smallest, largest] = $a.size < $b.size ? [$a, $b] : [$b, $a]

    // we always want at least 1 even if the maximum is 0
    const want = Math.max(min(smallest, largest), 1)

    let count = 0

    for (const value of smallest) {
        if (largest.has(value)) {
            ++count
        }
    }

    return { got: count, want, max: smallest.size }
}

/**
 * return the similarity between two strings, ranging from 0 (no similarity) to
 * 2 (identical)
 *
 * @param {string} a
 * @param {string} b
 */
function similarity (a, b) {
    return a === b ? 2 : exports.dice(normalize(a), normalize(b))
}

/**
 * strip trailing sequence numbers in names in RT metadata (they're not present
 * in the search results), e.g.
 *
 *   - "Meng Li (IX)"       -> "Meng Li"
 *   - "Michael Dwyer (X) " -> "Michael Dwyer"
 *
 * @param {string} name
 * @return string
 */
function stripRtName (name) {
    return name.replace(/\s+\([IVXLCDM]+\)\s*$/, '')
}

/*
 * measure the similarity of an IMDb title and an RT title returned by the API
 *
 * the latter sometimes contain the original title at the end in brackets for
 * foreign-language films/shows, so we take that into account
 *
 * note, we only use this if the original IMDb title differs from the main IMDb
 * title
 *
 *   similarity("The Swarm", "The Swarm (La Nuée)")                    // 0.66
 *   titleSimilarity({ imdb: "The Swarm", rt: "The Swarm (La Nuée)" }) // 2
 *
 * @param {Object} options
 * @param {{ title: string }} options.imdb
 * @param {{ title: string }} options.rt
 * @return {number}
 */
function titleSimilarity ({ imdb, rt }) {
    const rtTitle = rt.title
        .trim()
        .replace(/\s+/, ' ') // remove extraneous spaces, e.g. tt2521668
        .replace(/\s+\((?:US|UK)\)$/, '')

    if (imdb.originalTitle && imdb.title !== imdb.originalTitle) {
        const match = rtTitle.match(/^(.+?)\s+\(([^)]+)\)$/)

        if (match) {
            const s1 = similarity(imdb.title, match[1])
            const s2 = similarity(imdb.title, match[2])
            const s3 = similarity(imdb.title, rtTitle)
            return Math.max(s1, s2, s3)
        } else {
            const s1 = similarity(imdb.title, rtTitle)
            const s2 = similarity(imdb.originalTitle, rtTitle)
            return Math.max(s1, s2)
        }
    }

    return similarity(imdb.title, rtTitle)
}

/**
 * return true if the supplied arrays are similar (sufficiently overlap), false
 * otherwise
 *
 * @param {Object} options
 * @param {string[]} options.imdb
 * @param {string=} options.name
 * @param {string[]} options.rt
 */
function verifyShared ({ imdb, rt, name = 'cast' }) {
    debug(`verifying ${name}`)
    debug(`imdb ${name}:`, imdb)
    debug(`rt ${name}:`, rt)
    const $shared = shared(rt, imdb)
    debug(`shared ${name}:`, $shared)
    const verified = $shared.got >= $shared.want
    debug('verified:', verified)
    return verified
}

/******************************************************************************/

async function run () {
    const now = Date.now()

    // purgeCached(-1) // disable the cache
    purgeCached(now)

    const imdbId = $(`meta[property="imdb:pageConst"]`).attr('content')

    if (!imdbId) {
        // XXX shouldn't get here
        console.error("can't find IMDb ID:", location.href)
        return
    }

    log('id:', imdbId)

    // we clone the IMDb widget, so make sure it exists before navigating up to
    // its container
    const $imdbRating = $('[data-testid="hero-rating-bar__aggregate-rating"]').first()

    if (!$imdbRating.length) {
        info(`can't find IMDb rating for ${imdbId}`)
        return
    }

    const $ratings = $imdbRating.parent()

    // get the cached result for this page
    const cached = JSON.parse(GM_getValue(imdbId, 'null'))

    if (cached) {
        const expires = new Date(cached.expires).toLocaleString()

        if (cached.error) {
            log(`cached error (expires: ${expires}):`, cached.error)
        } else {
            log(`cached result (expires: ${expires}):`, cached.data)
            addWidget($ratings, $imdbRating, cached.data)
        }

        return
    } else {
        log('not cached')
    }

    const { meta: imdb, pageType } = getIMDbMetadata(imdbId)

    if (!imdb) {
        console.error(`can't find metadata for ${imdbId}`)
        return
    }

    log('metadata:', imdb)

    if (pageType !== 'title') {
        info(`invalid page type for ${imdbId}: ${pageType}`)
        return
    }

    if (!RT_TYPE[imdb.type]) {
        info(`invalid type for ${imdbId}: ${imdb.type}`)
        return
    }

    // add a { version, expires, data|error } entry to the cache
    const store = (dataOrError, ttl) => {
        const expires = now + ttl
        const cached = { version: DATA_VERSION, expires, ...dataOrError }
        const json = JSON.stringify(cached)

        GM_setValue(imdbId, json)
    }

    try {
        const { data, updated: $updated } = await getRTData(imdb)

        log('RT data:', data)

        dayjs.extend(dayjs_plugin_relativeTime)

        const updated = dayjs($updated)
        const date = dayjs()
        const delta = date.diff(updated, 'month')
        const ago = date.to(updated)

        log(`last update: ${updated.format('YYYY-MM-DD')} (${ago})`)

        if (delta <= INACTIVE_MONTHS) {
            log('caching result for: one day')
            store({ data }, ONE_DAY)
        } else {
            log('caching result for: one week')
            store({ data }, ONE_WEEK)
        }

        addWidget($ratings, $imdbRating, data)
    } catch (error) {
        const message = error.message || String(error) // stringify

        log(`caching error for one day: ${message}`)
        store({ error: message }, ONE_DAY)

        if (!error.abort) {
            console.error(error)
        }
    }
}

// register this first so data can be cleared even if there's an error
GM_registerMenuCommand(`${SCRIPT_NAME}: clear cache`, () => {
    purgeCached(-1)
});

// DOMContentLoaded typically fires several seconds after the IMDb ratings
// widget is displayed, which leads to an unacceptable delay if the result is
// already cached, so we hook into the earliest event which fires after the
// widget is loaded.
//
// this occurs when document.readyState transitions from "loading" to
// "interactive", which should be the first readystatechange event a script
// sees. on my system, this can occur up to 4 seconds before DOMContentLoaded
$(document).one('readystatechange', run)

/* end */ }