// ==UserScript==
// @name         获取哔哩哔哩视频音频
// @description  下载音频(支持分P)
// @license      The Unlicense
// @version      1.1.0
// @author       girl-dream
// @namespace    https://github.com/girl-dream/
// @match        https://www.bilibili.com/video/*
// @icon         https://www.bilibili.com/favicon.ico
// @run-at       document-end
// ==/UserScript==

(async () => {
    'use strict'

    const dashCache = new Map()

    let data = __playinfo__?.data?.dash
    let dataCid = null
    if (!data) {
        throw new Error("未获取音频信息")
    }

    // ==================== 拦截切换分P/合集时返回的数据 ====================
    const xhrOpen = XMLHttpRequest.prototype.open
    XMLHttpRequest.prototype.open = function () {
        const xhr = this
        const url = arguments[1]

        // 此处拦截切换合集返回的数据
        if (typeof url === 'string' && url.includes('wbi/playurl')) {
            // playurl 的参数放在 query 上,顺手记下这次请求的是哪个分P
            let cid = null
            try {
                cid = Number(new URL(url, location.origin).searchParams.get('cid')) || null
            } catch { /* 解析失败就不缓存 */ }

            const responseTextGetter = Object.getOwnPropertyDescriptor(
                XMLHttpRequest.prototype,
                'responseText'
            )

            // 拦截responseText
            Object.defineProperty(xhr, 'responseText', {
                get: function () {
                    const result = JSON.parse(responseTextGetter.get.call(this))
                    const dash = result?.data?.dash
                    if (dash) {
                        data = dash
                        dataCid = cid
                        if (cid) dashCache.set(cid, dash)
                    }
                    return JSON.stringify(result)
                }
            })
        }
        return xhrOpen.apply(this, arguments)
    }

    const apiGet = async (url) => {
        const res = await fetch(url, { credentials: 'include' })
        if (!res.ok) throw new Error('请求失败 HTTP ' + res.status)
        const json = await res.json()
        if (json.code !== 0) throw new Error(json.message || ('接口返回 code ' + json.code))
        return json.data
    }

    const getBvid = () => location.pathname.match(/\/video\/(BV[\w]+)/)?.[1]

    // 视频信息(含分P列表),pages: [{ cid, page, part, duration }]
    const getVideoInfo = async () => {
        const bvid = getBvid()
        if (!bvid) throw new Error('未找到 bvid')
        const d = await apiGet('https://api.bilibili.com/x/web-interface/view?bvid=' + bvid)
        return { aid: d.aid, title: d.title, pages: d.pages ?? [] }
    }

    // 当前是第几个分P
    const getCurrentPage = () => Number(new URLSearchParams(location.search).get('p')) || 1

    // 某个分P的 dash,优先复用已有数据,避免重复请求
    const getDash = async (aid, cid) => {
        if (dashCache.has(cid)) return dashCache.get(cid)
        if (dataCid !== null && cid === dataCid) return data
        const query = new URLSearchParams({
            avid: aid,
            cid: cid,
            qn: 127,
            fnver: 0,
            fnval: 4048,
            fourk: 1
        })
        const d = await apiGet('https://api.bilibili.com/x/player/playurl?' + query)
        dashCache.set(cid, d.dash)
        return d.dash
    }

    // ==================== 音频流 ====================
    const AUDIO_NAMES = {
        30216: '64K',
        30232: '132K',
        30280: '192K'
    }

    // 优先取备用地址里不带端口的,带端口的镜像在部分网络环境下不可用
    const pickUrl = (item) => {
        if (!item) return null
        const list = (item.backupUrl ?? []).concat(item.baseUrl ?? [])
        return list.find(u => {
            try { return new URL(u).port === '' } catch { return false }
        }) ?? item.baseUrl ?? null
    }

    // dash -> [{ key, name, url }]
    const listAudios = (dash) => {
        if (!dash) return []
        const audios = (dash.audio ?? []).map(a => ({
            key: String(a.id),
            name: AUDIO_NAMES[a.id] ?? String(a.id),
            url: pickUrl(a)
        }))
        if (dash.dolby?.audio?.length) {
            audios.push({ key: 'dolby', name: '杜比音效', url: pickUrl(dash.dolby.audio[0]) })
        }
        if (dash.flac?.audio) {
            audios.push({ key: 'flac', name: 'Hi-Res', url: pickUrl(dash.flac.audio) })
        }
        return audios.filter(a => a.url)
    }

    // 取指定音质,该分P没有这个音质时退化成它自己的最高音质
    const pickAudio = (dash, key) => {
        const audios = listAudios(dash)
        if (!audios.length) return null
        return audios.find(a => a.key === key) ?? audios[0]
    }

    const safeName = (name) => (name ?? '')
        .trim()
        .replaceAll(/[\\/:*?"<>|]/g, '_')
        .replaceAll(/\s+/g, ' ')
        .slice(0, 60)

    const formatProgress = (progress) => progress.total
        ? (progress.loaded / progress.total * 100).toFixed(2) + '%'
        : (progress.loaded / 1048576).toFixed(2) + 'MB'

    const download = (url, filename, onProgress) => new Promise((resolve, reject) => {
        const xhr = new XMLHttpRequest()
        xhr.open('GET', url, true)
        xhr.responseType = 'blob'

        xhr.onload = function () {
            if (xhr.status !== 200) {
                reject(new Error('下载失败,状态码:' + xhr.status))
                return
            }
            const blob = new Blob([xhr.response])
            const objectUrl = URL.createObjectURL(blob)
            const a = document.createElement('a')
            a.href = objectUrl
            a.download = filename
            a.click()
            URL.revokeObjectURL(objectUrl)
            resolve()
        }
        xhr.onerror = function () {
            reject(new Error('请求失败'))
        }
        xhr.onprogress = onProgress
        xhr.send()
    })

    const isElementLoaded = async (selector, root = document) => {
        const getElement = () => root.querySelector(selector)
        return new Promise((resolve) => {
            const element = getElement()
            if (element) return resolve(element)
            const observer = new MutationObserver(() => {
                const element2 = getElement()
                if (!element2) return
                resolve(element2)
                observer.disconnect()
            });
            observer.observe(root === document ? root.documentElement : root, {
                childList: true,
                subtree: true
            })
        })
    }

    // ==================== 弹窗 ====================
    const pop = document.createElement('div')
    pop.style.cssText = `
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        background: rgba(0,0,0,0.5);
        display: flex;
        justify-content: center;
        align-items: center;
        z-index: 999999;`

    const content = document.createElement('div')
    content.style.cssText = `
            background: var(--bg1_float);
            padding: 20px;
            border-radius: 8px;
            width: 340px;
            max-width: 90%;
            max-height: 80vh;
            overflow-y: auto;
            color:var(--text1);`
    content.innerHTML = `
    <div style="font-size: 1.5rem;margin-bottom: 10px;">下载音频</div>
        <div id="parts-box" style="display: none;">
            <div style="display: flex; justify-content: space-between; align-items: center; font-size: 12px; color: var(--text3,#9499a0); margin-bottom: 6px;">
                <span id="parts-tip"></span>
                <a id="parts-toggle" style="cursor: pointer; color: var(--brand_blue);">全选/反选</a>
            </div>
            <div id="parts-list" style="max-height: 180px; overflow-y: auto; border: 1px solid var(--Ga1); border-radius: 4px; margin-bottom: 12px;"></div>
        </div>
        <div style="font-size: 12px; color: var(--text3,#9499a0); margin-bottom: 6px;">选择音频类型</div>
        <select id="quality" style="background: var(--bg3); color: var(--text1); padding: 4px; width: 100%; margin-bottom: 15px;"></select>
        <div style="display: flex; justify-content: flex-end; gap: 10px;">
        <button id="cancel-btn" style="padding: 8px 16px; border: none; background: var(--bpx-dmsend-disable-button-bg,var(--graph_bg_thin));color: var(--text1);border-radius: 4px; cursor: pointer;">
            取消
        </button>
        <button id="confirm-btn" style="padding: 8px 16px; border: none; background: var(--brand_blue); color: var(--text1); border-radius: 4px; cursor: pointer;">
            下载
        </button>
    </div>`

    const select = content.querySelector('#quality')
    const partsBox = content.querySelector('#parts-box')
    const partsList = content.querySelector('#parts-list')
    const partsTip = content.querySelector('#parts-tip')

    // 当前视频信息,取不到分P列表时为 null,退化成只下载当前分P
    let videoInfo = null
    // videoInfo 对应的 bvid,同个视频重复打开弹窗时不重复请求
    let videoBvid = null

    const renderAudios = (dash) => {
        select.replaceChildren()
        listAudios(dash).forEach(audio => {
            const op = document.createElement('option')
            op.value = audio.key
            op.textContent = audio.name
            select.append(op)
        })
    }

    const renderParts = () => {
        const current = getCurrentPage()
        partsList.replaceChildren()
        videoInfo.pages.forEach(page => {
            const row = document.createElement('label')
            row.style.cssText = `
                display: flex;
                align-items: center;
                gap: 6px;
                padding: 4px 8px;
                cursor: pointer;
                font-size: 13px;
                color: var(--text1);`
            const box = document.createElement('input')
            box.type = 'checkbox'
            box.value = page.cid
            box.checked = page.page === current
            box.style.cssText = 'flex: none; margin: 0;'
            const text = document.createElement('span')
            text.textContent = `P${page.page} ${page.part}`
            text.title = page.part
            text.style.cssText = 'overflow: hidden; text-overflow: ellipsis; white-space: nowrap;'
            row.append(box, text)
            partsList.append(row)
        })
        partsTip.textContent = `共 ${videoInfo.pages.length} 个分P(可多选,默认当前P)`
        partsBox.style.display = ''
    }

    const openPop = async () => {
        pop.remove()
        pop.append(content)
        document.body.append(pop)

        renderAudios(data)
        partsBox.style.display = 'none'
        partsList.replaceChildren()
        partsTip.textContent = '正在获取分P列表...'

        // 同一个视频直接复用已经取到的分P列表,不再重复请求
        if (videoInfo && videoBvid === getBvid()) {
            renderParts()
            return
        }

        try {
            videoInfo = await getVideoInfo()
            videoBvid = getBvid()
            // 页面内联的播放数据对应的就是 url 上的当前分P,首次进来时确定它的归属
            if (dataCid === null) dataCid = videoInfo.pages[getCurrentPage() - 1]?.cid ?? null
            renderParts()
        } catch (e) {
            // 拿不到分P列表就退化成只下载当前分P,不影响原有使用
            console.error('获取分P列表失败:', e)
            videoInfo = null
            videoBvid = null
        }
    }

    content.querySelector('#cancel-btn').onclick = () => {
        pop.remove()
    }

    content.querySelector('#parts-toggle').onclick = () => {
        const boxes = [...partsList.querySelectorAll('input[type=checkbox]')]
        const allChecked = boxes.every(b => b.checked)
        boxes.forEach(b => { b.checked = !allChecked })
    }

    content.querySelector('#confirm-btn').onclick = async () => {
        const qualityKey = select.value

        // 选中的分P,拿不到分P列表时退化成当前分P
        const targets = videoInfo?.pages?.length
            ? videoInfo.pages.filter(p => [...partsList.querySelectorAll('input[type=checkbox]:checked')]
                .some(b => Number(b.value) === p.cid))
            : [null]
        if (!targets.length) {
            alert('请至少选择一个分P')
            return
        }

        const title = videoInfo?.title || document.querySelector('.video-title')?.textContent.trim() || 'audio'
        const multi = (videoInfo?.pages?.length ?? 0) > 1
        const total = targets.length
        let failed = 0

        pop.remove()

        for (let i = 0; i < total; i++) {
            const page = targets[i]
            const name = `P${page?.page ?? getCurrentPage()}`
            const prefix = total > 1 ? `(${i + 1}/${total}) ` : ''
            progressDiv.textContent = `${prefix}正在获取 ${name} 的音频信息...`

            let dash
            try {
                dash = page ? await getDash(videoInfo.aid, page.cid) : data
            } catch (e) {
                console.error(`${name} 获取音频信息失败:`, e)
                progressDiv.textContent = `${prefix}${name} 获取音频信息失败`
                failed++
                continue
            }

            const audio = pickAudio(dash, qualityKey)
            if (!audio) {
                console.error(`${name} 没有可用的音频流`)
                progressDiv.textContent = `${prefix}${name} 没有可用的音频流`
                failed++
                continue
            }

            const filename = multi
                ? `${safeName(title)}_P${page.page}_${safeName(page.part)}.m4s`
                : `${safeName(title)}.m4s`
            // 该分P没有所选音质时会自动降级,在进度里标出来
            const degrade = audio.key === qualityKey ? '' : `(${audio.name})`

            try {
                await download(audio.url, filename, (progress) => {
                    progressDiv.textContent = `${prefix}${name} ${degrade}${formatProgress(progress)}`
                })
            } catch (e) {
                console.error(`${name} 下载失败:`, e)
                progressDiv.textContent = `${prefix}${name} 下载失败`
                failed++
                continue
            }

            // 多个文件连续下载时留点间隔,避免被浏览器拦截
            if (i < total - 1) await new Promise(r => setTimeout(r, 300))
        }

        progressDiv.textContent = failed
            ? `完成 ${total - failed}/${total} 个音频,${failed} 个失败(详见控制台)`
            : (total > 1 ? `已下载 ${total} 个音频` : null)
    }

    // ==================== 工具栏按钮 ====================
    const toolbarLeft = document.querySelector('.video-toolbar-left-main')
    const progressDiv = document.createElement('div')
    progressDiv.style.color = 'var(--text2)'
    progressDiv.style.fontSize = '12px'

    const div = document.createElement('div')
    div.className = 'video-toolbar-right-item'
    div.title = '下载音频'
    div.innerHTML = '<svg viewBox="0 0 1024 1024" version="1.1" xmlns="http://www.w3.org/2000/svg"><path d="M544.256 605.184l244.224-244.224a31.744 31.744 0 0 1 45.056 45.056l-295.424 295.424a36.864 36.864 0 0 1-51.2 0L190.464 406.528a31.744 31.744 0 1 1 45.056-45.056l244.224 244.224V111.104a32.256 32.256 0 1 1 64 0zM153.6 902.656a32.256 32.256 0 0 1 0-64h716.8a32.256 32.256 0 0 1 0 64z" fill="#5A5A68" p-id="1650"></path></svg>'
    div.style.cssText = `
        width: 35px;
        height: 35px;
        margin-right: 18px;`
    div.addEventListener('click', () => {
        openPop()
    })
    await Promise.all([isElementLoaded('.nav-search-input[maxlength]'), isElementLoaded('.view-icon[width]')])
    toolbarLeft.append(div, progressDiv)
})();