#!/usr/bin/env python3
"""Document picture-in-picture: the reel, in a window, scrolling.

Run against a locally running backend:

    backend/main.py &
    .venv/bin/python tests/smoke_docpip.py

A video picture-in-picture window renders one <video>'s frames and cannot
scroll. Document picture-in-picture opens a real document instead, so the feed
is *moved* into it -- the same elements, another window. That is what these
checks are about: the move must be a move (no rebuild, playback intact), the
window must scroll the reel for real, and closing it must put the feed back
where it came from.
"""
import sys
from playwright.sync_api import sync_playwright

BASE = "http://127.0.0.1:5000/"
SERVER = "https://hottubapp.io"
CHANNEL = "xvideos"

SEED = """([server, channel]) => {
    localStorage.setItem('config', JSON.stringify({ servers: [{ [server]: {} }] }));
    localStorage.setItem('preferences', JSON.stringify({ [server]: { channelId: channel } }));
    localStorage.removeItem('session');
}"""

# The feed can be read from either document. Only App.state lives in the page --
# the window's document has no scripts of its own; it holds the moved elements,
# whose handlers are still the page's closures. That is the whole design, so the
# probe takes the document to look in and always runs in the page.
PROBE = """(where) => {
    const doc = where === 'pip'
        ? (documentPictureInPicture.window && documentPictureInPicture.window.document)
        : document;
    if (!doc) return null;
    const root = doc.getElementById('feed-view');
    const active = doc.querySelector('.feed-slide.is-active');
    const scroller = doc.getElementById('feed-scroll');
    return {
        rooted_here: !!root,
        slides: doc.querySelectorAll('.feed-slide').length,
        step: App.state.feedActiveIndex,
        video: App.state.feedActiveVideoId,
        playing: active ? Array.from(active.querySelectorAll('.feed-video'))
            .map(v => !v.paused && v.readyState >= 2) : null,
        scrollable: scroller ? scroller.scrollHeight > scroller.clientHeight + 1 : false,
        unique: (() => {
            const ids = Array.from(doc.querySelectorAll('.feed-pane')).map(p => p.dataset.videoId);
            return ids.length === new Set(ids).size;
        })(),
    };
}"""


class Checks:
    def __init__(self):
        self.failed = 0

    def ok(self, label, condition, detail=""):
        if not condition:
            self.failed += 1
        print(f"  [{'PASS' if condition else 'FAIL'}] {label}"
              + (f" -- {detail}" if detail and not condition else ""))


def open_reels(page):
    page.goto(BASE, wait_until="domcontentloaded")
    page.evaluate(SEED, [SERVER, CHANNEL])
    page.goto(BASE, wait_until="load")
    try:
        page.wait_for_selector(".video-card", timeout=90000)
    except Exception:
        page.goto(BASE, wait_until="load")
        page.wait_for_selector(".video-card", timeout=90000)
    page.wait_for_timeout(4000)
    page.evaluate("() => App.feed.toggle()")
    page.wait_for_selector(".feed-slide", timeout=20000)
    page.wait_for_timeout(3000)


def main():
    c = Checks()
    with sync_playwright() as p:
        browser = p.chromium.launch(args=[
            "--no-sandbox", "--disable-dev-shm-usage", "--disable-gpu",
            "--renderer-process-limit=1",
        ])
        context = browser.new_context(viewport={"width": 1400, "height": 1000})
        page = context.new_page()
        open_reels(page)

        c.ok("this browser offers document picture-in-picture",
             page.evaluate("() => App.feed.docPipSupported()"))

        before = page.evaluate(PROBE, 'page')
        c.ok("the feed starts in the page", before["rooted_here"])
        c.ok("and is scrollable there", before["scrollable"])

        print("\nthe picture-in-picture button opens a window")
        # A click, not an evaluate: requestWindow needs a user gesture, which is
        # exactly the reason the tab-switch path cannot use this API.
        with context.expect_page(timeout=15000) as caught:
            page.click(".feed-slide.is-active .feed-pane .feed-pip-btn")
        pip = caught.value
        pip.wait_for_timeout(3000)

        c.ok("the feed reports a window open", page.evaluate("() => App.feed.docPipOpen()"))
        c.ok("the feed left the page", not page.evaluate(
            "() => !!document.getElementById('feed-view')"))
        c.ok("the page underneath is usable again", page.evaluate(
            "() => document.body.style.overflow === 'auto'"))

        moved = page.evaluate(PROBE, 'pip')
        c.ok("the feed is in the window", moved["rooted_here"], str(moved))
        c.ok("its slides came with it", moved["slides"] > 0, str(moved["slides"]))
        # The point of moving rather than rebuilding: the <video> elements are
        # the same ones, so nothing reloads and nothing stops.
        c.ok("playback survived the move", moved["playing"] and all(moved["playing"]),
             str(moved["playing"]))
        c.ok("it landed on the same video", moved["video"] == before["video"],
             f"{before['video']} -> {moved['video']}")

        print("\nthe window scrolls the reel")
        c.ok("the window's feed is scrollable", moved["scrollable"], str(moved))
        pip.evaluate("() => { const s = document.getElementById('feed-scroll');"
                     "        s.scrollTop += s.clientHeight; }")
        pip.wait_for_timeout(3500)
        scrolled = page.evaluate(PROBE, 'pip')
        c.ok("scrolling moved to the next step", scrolled["step"] == moved["step"] + 1,
             f"{moved['step']} -> {scrolled['step']}")
        c.ok("and to another video", scrolled["video"] != moved["video"],
             f"{moved['video']} -> {scrolled['video']}")
        c.ok("the new step is playing", scrolled["playing"] and all(scrolled["playing"]),
             str(scrolled["playing"]))

        print("\nclosing the window brings the feed home")
        pip.close()
        page.wait_for_timeout(3500)
        back = page.evaluate(PROBE, 'page')
        c.ok("no window is open", not page.evaluate("() => App.feed.docPipOpen()"))
        c.ok("the feed is in the page again", back["rooted_here"], str(back))
        c.ok("reels is still open", page.evaluate("() => App.feed.isOpen()"))
        c.ok("the page is back in reels mode", page.evaluate(
            "() => document.body.classList.contains('feed-mode-open')"))
        # The window was scrolled while it was out; coming back must not undo it.
        c.ok("it kept where the window left off", back["video"] == scrolled["video"],
             f"{scrolled['video']} -> {back['video']}")
        c.ok("the feed still scrolls here", back["scrollable"], str(back))
        c.ok("no video was duplicated by the round trip", back["unique"])

        print("\nleaving reels while the window is open")
        with context.expect_page(timeout=15000) as caught2:
            page.click(".feed-slide.is-active .feed-pane .feed-pip-btn")
        pip2 = caught2.value
        pip2.wait_for_timeout(2500)
        page.evaluate("() => App.feed.close()")
        page.wait_for_timeout(2000)
        c.ok("closing reels closes the window", pip2.is_closed() or
             not page.evaluate("() => App.feed.docPipOpen()"))
        c.ok("the feed came back before it was torn down", page.evaluate(
            "() => !!document.getElementById('feed-view')"))
        c.ok("the page is scrollable again", page.evaluate(
            "() => document.body.style.overflow === 'auto'"))

        context.close()
        browser.close()

    print(f"\n{'FAILED' if c.failed else 'OK'}: {c.failed} check(s) failed")
    return 1 if c.failed else 0


if __name__ == "__main__":
    sys.exit(main())