"""Facebook posting flow.

    1. navigate facebook.com
    2. JS-click the composer: find the "on your mind" span, walk up to the
       enclosing [role=button], .click() it
       ⚠️ A real mouse click on the span opens Messenger instead.
    3. wait for the "Create post" dialog
    4. type into the dialog textbox
    5. optional: Photo/video -> setFileInputFiles
    6. optional: change audience when visibility != the current one
    7. click [aria-label="Post"]
    8. dialog closes = success
"""

import asyncio

from ..cdp import CDPError, human_delay
from . import guard, require_text, validate_media
from ..selectors import FACEBOOK as S

PLATFORM = "fb"
VALID_VISIBILITY = ("public", "friends")


async def post(cdp_client, text, media_path=None, options=None):
    options = options or {}
    require_text(PLATFORM, text)
    validate_media(media_path)

    visibility = options.get("visibility")
    if visibility is not None and visibility not in VALID_VISIBILITY:
        raise CDPError(
            f"fb visibility must be one of {VALID_VISIBILITY}, got {visibility!r}"
        )

    tab, reused = await cdp_client.get_or_open_tab(S["url"], "facebook.com")
    if reused:
        # Dismiss any leftover dialog (e.g. unsaved Create Post from a failed run)
        await tab.eval("window.onbeforeunload = null")
        await tab.navigate(S["url"])
    return await guard(PLATFORM, tab, _flow(tab, text, media_path, visibility))


async def _flow(tab, text, media_path, visibility):
    await asyncio.sleep(5)
    await tab.click_js(S["composer_trigger_js"])

    await tab.wait_for(S["dialog_textbox"], timeout=30.0)
    await tab.type_text(S["dialog_textbox"], text)

    if media_path:
        # TODO: VALIDATE LIVE — whether the hidden file input is already in the
        # DOM before the Photo/video button is clicked.
        if not await tab.exists(S["file_input"]):
            await tab.click_js(S["photo_video_js"])
            await tab.wait_for(S["file_input"], visible=False)
        await tab.set_file_input(S["file_input"], media_path)
        # TODO: VALIDATE LIVE — upload/preview settle time.
        await human_delay(2.0, 3.5)

    if visibility:
        # TODO: VALIDATE LIVE — the whole audience sub-dialog. We only open the
        # picker here; the option list itself is unmapped, so we refuse rather
        # than click something we haven't seen.
        raise CDPError(
            "fb visibility switching is not implemented: the audience sub-dialog "
            "has not been mapped live yet. Post without `visibility` to use the "
            "account's current default."
        )

    # Try aria-label first, fall back to text-match JS click
    if await tab.exists(S["post_button"]):
        await tab.click(S["post_button"])
    else:
        await tab.click_js(S["post_button_js"])
    # FB keeps hidden [role="dialog"] elements in the DOM after the composer
    # closes. Instead of waiting for all dialogs to vanish, check that the
    # composer textbox is gone — that's the real "posted" signal.
    await tab.wait_for_gone(S["dialog_textbox"], timeout=60.0)


async def check_login(cdp_client):
    tab, reused = await cdp_client.get_or_open_tab(S["url"], "facebook.com", activate=False)
    if reused:
        # Dismiss any leftover dialog (e.g. unsaved Create Post from a failed run)
        await tab.eval("window.onbeforeunload = null")
        await tab.navigate(S["url"])
    if await tab.exists(S["login_marker"]):
        return False
    # JS state, not the composer's "on your mind" span: that string is
    # localised, A/B'd, and absent until the feed renders, so a signed-in
    # account reads as signed out. The c_user cookie is the session itself.
    state = await tab.eval(
        "(() => { const m = document.cookie.match(/(?:^|;\\s*)c_user=(\\d+)/);"
        " return m ? 'in:' + m[1] : (document.cookie ? 'out' : 'unavailable'); })()"
    )
    if state.startswith("in:"):
        return True
    if state == "out":
        return False
    raise CDPError("fb: no cookies readable on facebook.com — cannot tell signed-in from signed-out")