"""Platform modules.

Each module exposes two coroutines with a fixed shape:

    async def post(cdp_client, text, media_path, options) -> dict
        -> {"status": "ok" | "error", "detail": "..."}   (+ "screenshot" on error)

    async def check_login(cdp_client) -> bool

`post` owns its own tab: it opens one, drives the flow, closes it. The queue
guarantees only one of these runs at a time, so there is one browser and one
tab in play (proposal: "sequential per-platform").
"""

import os
import time
import traceback

from ..cdp import CDPError

SCREENSHOT_DIR = "/tmp/socialmag"


def screenshot_path(platform):
    os.makedirs(SCREENSHOT_DIR, exist_ok=True)
    return os.path.join(
        SCREENSHOT_DIR, f"{platform}-{time.strftime('%Y%m%d-%H%M%S')}.png"
    )


async def guard(platform, tab, coro):
    """Run one platform flow, turning any failure into a labelled result plus a
    screenshot of the page as it actually looked. Never masks the failure."""
    try:
        await coro
        return {"status": "ok", "detail": f"{platform}: posted"}
    except CDPError as exc:
        shot = None
        try:
            shot = await tab.screenshot(screenshot_path(platform))
        except Exception:  # the page may be gone; the original error still wins
            pass
        result = {"status": "error", "detail": f"{platform}: {exc}"}
        if shot:
            result["screenshot"] = shot
        return result
    except Exception as exc:  # noqa: BLE001 — surface it, never swallow it
        return {
            "status": "error",
            "detail": f"{platform}: unexpected {type(exc).__name__}: {exc}",
            "traceback": traceback.format_exc(),
        }


def require_media(platform, media_path):
    """ig/tiktok cannot post without media; nobody gets a silent no-op."""
    if not media_path:
        raise CDPError(f"{platform} requires a media file; none was given")
    validate_media(media_path)


def validate_media(media_path):
    if not media_path:
        return
    if not os.path.isabs(media_path):
        raise CDPError(f"media path must be absolute, got {media_path!r}")
    if not os.path.exists(media_path):
        raise CDPError(f"media file does not exist: {media_path}")


def require_text(platform, text):
    if not text or not text.strip():
        raise CDPError(f"{platform} requires non-empty text")