#!/usr/bin/env python3
"""The privacy veil: the page blurs whenever this window is not the one in front.

Run against a locally running backend:

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

Headless Chromium keeps every tab visible and focused -- opening a second tab
and bringing it to the front changes neither, and neither does freezing the
page over CDP -- so there is no way to genuinely send this window to the back.
The transitions are therefore dispatched by hand, which tests what this change
owns -- what the page does when the browser says it has gone away -- and not
what the browser does with a backgrounded tab.
"""
import sys
from playwright.sync_api import sync_playwright

BASE = "http://127.0.0.1:5000/"

VEILED = """() => {
    const veil = document.getElementById('privacy-veil');
    return !!veil && veil.classList.contains('is-on');
}"""

OPACITY = """() => getComputedStyle(document.getElementById('privacy-veil')).opacity"""

# What a tap in the middle of the window would land on.
UNDER_FINGER = """() => {
    const el = document.elementFromPoint(innerWidth / 2, innerHeight / 2);
    return el ? el.id || el.className || el.tagName : null;
}"""

# Neither a second tab nor CDP can put this window in the background, so the
# two halves of a tab switch are announced the way the browser would announce
# them.
HIDE = """() => {
    Object.defineProperty(document, 'visibilityState',
        { configurable: true, get: () => 'hidden' });
    document.dispatchEvent(new Event('visibilitychange'));
}"""

SHOW = """() => {
    Object.defineProperty(document, 'visibilityState',
        { configurable: true, get: () => 'visible' });
    document.dispatchEvent(new Event('visibilitychange'));
}"""

# The highest z-index anywhere in the app's own stylesheet, veil excluded: the
# veil has to beat the player and the reels feed, not just the page behind them.
HIGHEST_OTHER = """() => {
    let top = 0;
    for (const sheet of document.styleSheets) {
        let rules;
        try { rules = sheet.cssRules; } catch (err) { continue; }
        for (const rule of rules || []) {
            if (!rule.selectorText || rule.selectorText.includes('privacy-veil')) continue;
            const z = parseInt(rule.style && rule.style.zIndex, 10);
            if (!isNaN(z) && z > top) top = z;
        }
    }
    return top;
}"""


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

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


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",
            "--js-flags=--max-old-space-size=512",
        ])
        page = browser.new_page(viewport={"width": 430, "height": 930})
        crashes = []
        page.on("pageerror", lambda e: crashes.append(str(e)))

        page.goto(BASE, wait_until="load")
        page.wait_for_function("() => window.App && App.privacy && App.privacy.isVeiled", timeout=30000)
        page.wait_for_timeout(300)

        print("\nthe window in front")
        c.ok("nothing is veiled", page.evaluate(VEILED) is False)
        c.ok("and the veil is out of the way", page.evaluate(OPACITY) == "0")
        c.ok("so taps reach the page", page.evaluate(UNDER_FINGER) != "privacy-veil",
             str(page.evaluate(UNDER_FINGER)))

        print("\nthe tab going to the back")
        page.evaluate(HIDE)
        c.ok("the page goes behind the blur", page.evaluate(VEILED) is True)
        c.ok("fully, and at once", page.evaluate(OPACITY) == "1")
        c.ok("with nothing underneath reachable", page.evaluate(UNDER_FINGER) == "privacy-veil",
             str(page.evaluate(UNDER_FINGER)))
        c.ok("and it sits above everything the app can show",
             page.evaluate("() => parseInt(getComputedStyle(document.getElementById('privacy-veil')).zIndex, 10)")
             > page.evaluate(HIGHEST_OTHER),
             str(page.evaluate(HIGHEST_OTHER)))

        print("\ncoming back to it")
        page.evaluate(SHOW)
        page.wait_for_timeout(300)
        c.ok("the blur lifts", page.evaluate(VEILED) is False)

        print("\nlosing focus without leaving the tab -- another window, say")
        page.evaluate("() => window.dispatchEvent(new Event('blur'))")
        c.ok("the page goes behind the blur too", page.evaluate(VEILED) is True)
        page.evaluate("() => window.dispatchEvent(new Event('focus'))")
        c.ok("and comes back when focus does", page.evaluate(VEILED) is False)

        print("\na touch on the veil")
        page.evaluate("() => window.dispatchEvent(new Event('blur'))")
        c.ok("veiled to start with", page.evaluate(VEILED) is True)
        page.evaluate("""() => document.getElementById('privacy-veil')
            .dispatchEvent(new PointerEvent('pointerdown', { bubbles: true }))""")
        c.ok("lifts it rather than pressing what is underneath", page.evaluate(VEILED) is False)

        print("\nthe tab going away altogether")
        page.evaluate("() => window.dispatchEvent(new Event('pagehide'))")
        c.ok("leaves it blurred behind us", page.evaluate(VEILED) is True)

        c.ok("nothing threw along the way", not crashes, str(crashes[:2]))
        browser.close()

    print(f"\n{'OK' if not c.failed else 'FAILED'}: {c.failed} check(s) failed")
    return 1 if c.failed else 0


sys.exit(main())