// composables/useStreams.js
import { nextTick } from 'vue'

export function useStreams({ instanceList, videoElement, wslist, openStr, VideoConverter }) {
    // 用 Map 做延迟队列，避免固定 8 个的限制
    const feedState = new Map()

    function ensureState(index) {
        if (!feedState.has(index)) {
            feedState.set(index, { processing: false, pending: null })
        }
        return feedState.get(index)
    }

    function pushFrame(index, buf) {
        const st = ensureState(index)
        if (st.processing) {
            // 覆盖旧的等待帧，保留最新
            st.pending = buf
            return
        }
        st.processing = true
        try {
            instanceList[index].converter.appendRawData(new Uint8Array(buf))
        } finally {
            st.processing = false
            if (st.pending) {
                const next = st.pending
                st.pending = null
                queueMicrotask(() => pushFrame(index, next))
            }
        }
    }

    function resetFeedState(index) {
        const st = feedState.get(index)
        if (!st) return
        st.processing = false
        st.pending = null
    }

    async function waitForVideoEl(udid, tries = 20, delay = 16) {
        for (let i = 0; i < tries; i++) {
            const el = videoElement.value?.[udid]
            if (el) return el
            await nextTick()
            await new Promise(r => setTimeout(r, delay))
        }
        return null
    }

    function refreshStream(index, hard = true) {
        const devices = Object.keys(videoElement.value || {})
        const udid = devices[index]
        const video = videoElement.value?.[udid]
        if (!video || !instanceList[index]) return

        resetFeedState(index)
        try { instanceList[index].converter?.destroy?.() } catch { }
        instanceList[index].converter = null

        if (hard) {
            try { video.pause?.() } catch { }
            try { video.removeAttribute?.('src') } catch { }
            try { video.load?.() } catch { }
        }

        // 重新挂新的 converter
        instanceList[index].converter = new VideoConverter(video, 60, 1)

        // 让后端尽快推关键帧
        try { wslist[index]?.send?.(openStr) } catch { }
    }

    return {
        feedState,
        pushFrame,
        resetFeedState,
        waitForVideoEl,
        refreshStream,
    }
}