"""
card_storage.py — S3 upload utility for variant card images.

Public API
----------
get_s3_client()
    Create and return a boto3 S3 client using ambient AWS credentials
    (environment variables or instance profile).

build_s3_key(cardset_id, player_id, variant, card_type)
    Construct the S3 object key for a variant card image.

build_s3_url(s3_key, render_date)
    Return the full HTTPS S3 URL with a cache-busting date query param.

upload_card_to_s3(s3_client, png_bytes, s3_key)
    Upload raw PNG bytes to S3 with correct ContentType and CacheControl headers.

backfill_variant_image_url(player_id, variant, card_type, cardset_id, png_path)
    End-to-end: read PNG from disk, upload to S3, update BattingCard or
    PitchingCard.image_url in the database. All exceptions are caught and
    logged; this function never raises (safe to call as a background task).

Design notes
------------
- S3 credentials are resolved from the environment by boto3 at call time;
  no credentials are hard-coded here.
- The cache-bust ?d= param matches the card-creation pipeline convention so
  that clients can compare URLs across pipelines.
"""

import logging
import os
from datetime import date

import boto3

from app.db_engine import BattingCard, PitchingCard

logger = logging.getLogger(__name__)

S3_BUCKET = os.environ.get("S3_BUCKET", "paper-dynasty")
S3_REGION = os.environ.get("S3_REGION", "us-east-1")


def get_s3_client():
    """Create and return a boto3 S3 client for the configured region.

    Credentials are resolved by boto3 from the standard chain:
    environment variables → ~/.aws/credentials → instance profile.

    Returns:
        A boto3 S3 client instance.
    """
    return boto3.client("s3", region_name=S3_REGION)


def build_s3_key(cardset_id: int, player_id: int, variant: int, card_type: str) -> str:
    """Construct the S3 object key for a variant card image.

    Key format:
        cards/cardset-{csid:03d}/player-{pid}/v{variant}/{card_type}card.png

    Args:
        cardset_id: Numeric cardset ID (zero-padded to 3 digits).
        player_id:  Player ID.
        variant:    Variant number (0 = base, 1-4 = refractor tiers).
        card_type:  Either "batting" or "pitching".

    Returns:
        The S3 object key string.
    """
    return (
        f"cards/cardset-{cardset_id:03d}/player-{player_id}"
        f"/v{variant}/{card_type}card.png"
    )


def build_s3_url(s3_key: str, render_date: date) -> str:
    """Return the full HTTPS S3 URL for a card image with a cache-bust param.

    URL format:
        https://{bucket}.s3.{region}.amazonaws.com/{key}?d={date}

    The ?d= query param matches the card-creation pipeline convention so that
    clients invalidate their cache after each re-render.

    Args:
        s3_key:      S3 object key (from build_s3_key).
        render_date: The date the card was rendered, used for cache-busting.

    Returns:
        Full HTTPS URL string.
    """
    base_url = f"https://{S3_BUCKET}.s3.{S3_REGION}.amazonaws.com"
    date_str = render_date.strftime("%Y-%m-%d")
    return f"{base_url}/{s3_key}?d={date_str}"


def upload_card_to_s3(s3_client, png_bytes: bytes, s3_key: str) -> None:
    """Upload raw PNG bytes to S3 with the standard card image headers.

    Sets ContentType=image/png and CacheControl=public, max-age=300 (5 min)
    so that CDN and browser caches are refreshed within a short window after
    a re-render.

    Args:
        s3_client: A boto3 S3 client (from get_s3_client).
        png_bytes: Raw PNG image bytes.
        s3_key:    S3 object key (from build_s3_key).

    Returns:
        None
    """
    s3_client.put_object(
        Bucket=S3_BUCKET,
        Key=s3_key,
        Body=png_bytes,
        ContentType="image/png",
        CacheControl="public, max-age=300",
    )


def backfill_variant_image_url(
    player_id: int,
    variant: int,
    card_type: str,
    cardset_id: int,
    png_path: str,
) -> None:
    """Read a rendered PNG from disk, upload it to S3, and update the DB row.

    Determines the correct card model (BattingCard or PitchingCard) from
    card_type, then:
      1. Reads PNG bytes from png_path.
      2. Uploads to S3 via upload_card_to_s3.
      3. Fetches the card row by (player_id, variant).
      4. Sets image_url to the new S3 URL and calls save().

    All exceptions are caught and logged — this function is intended to be
    called as a background task and must never propagate exceptions.

    Args:
        player_id:  Player ID used to locate the card row.
        variant:    Variant number (matches the card row's variant field).
        card_type:  "batting" or "pitching" — selects the model.
        cardset_id: Cardset ID used for the S3 key.
        png_path:   Absolute path to the rendered PNG file on disk.

    Returns:
        None
    """
    try:
        # 1. Read PNG from disk
        with open(png_path, "rb") as f:
            png_bytes = f.read()

        # 2. Build key and upload
        s3_key = build_s3_key(
            cardset_id=cardset_id,
            player_id=player_id,
            variant=variant,
            card_type=card_type,
        )
        s3_client = get_s3_client()
        upload_card_to_s3(s3_client, png_bytes, s3_key)

        # 3. Build URL with today's date for cache-busting
        image_url = build_s3_url(s3_key, render_date=date.today())

        # 4. Locate the card row and update image_url
        if card_type == "batting":
            card = BattingCard.get(
                BattingCard.player_id == player_id, BattingCard.variant == variant
            )
        else:
            card = PitchingCard.get(
                PitchingCard.player_id == player_id, PitchingCard.variant == variant
            )

        card.image_url = image_url
        card.save()

        logger.info(
            "backfill_variant_image_url: updated %s card player=%s variant=%s url=%s",
            card_type,
            player_id,
            variant,
            image_url,
        )

    except Exception:
        logger.exception(
            "backfill_variant_image_url: failed for player=%s variant=%s card_type=%s",
            player_id,
            variant,
            card_type,
        )