#!/usr/bin/env python
"""Finalize a generated social image with exact brand formatting.

This script keeps the AI-generated image and the company logo separate:
generate the base image first, then overlay the real logo here so the brand mark
does not get distorted by the image model.
"""

from __future__ import annotations

import argparse
from pathlib import Path

try:
    from PIL import Image, ImageDraw, ImageOps
except ModuleNotFoundError as exc:  # pragma: no cover - friendly CLI error
    raise SystemExit(
        "Pillow is required. Install it with: "
        "python -m pip install Pillow"
    ) from exc


def _open_rgba(path: Path) -> Image.Image:
    return Image.open(path).convert("RGBA")


def _fit_cover(img: Image.Image, size: tuple[int, int]) -> Image.Image:
    target_w, target_h = size
    src_w, src_h = img.size
    scale = max(target_w / src_w, target_h / src_h)
    resized = img.resize(
        (round(src_w * scale), round(src_h * scale)),
        Image.Resampling.LANCZOS,
    )
    left = (resized.width - target_w) // 2
    top = (resized.height - target_h) // 2
    return resized.crop((left, top, left + target_w, top + target_h))


def _fit_contain(img: Image.Image, size: tuple[int, int]) -> Image.Image:
    target_w, target_h = size
    src_w, src_h = img.size
    scale = min(target_w / src_w, target_h / src_h)
    resized = img.resize(
        (round(src_w * scale), round(src_h * scale)),
        Image.Resampling.LANCZOS,
    )
    canvas = Image.new("RGBA", size, (255, 255, 255, 255))
    x = (target_w - resized.width) // 2
    y = (target_h - resized.height) // 2
    canvas.alpha_composite(resized, (x, y))
    return canvas


def _parse_size(value: str) -> tuple[int, int]:
    try:
        w_text, h_text = value.lower().split("x", 1)
        width = int(w_text.strip())
        height = int(h_text.strip())
    except Exception as exc:
        raise argparse.ArgumentTypeError(
            "Size must be formatted like 1200x628"
        ) from exc
    if width < 300 or height < 300:
        raise argparse.ArgumentTypeError("Size must be at least 300x300")
    return width, height


def finalize_image(
    source: Path,
    logo: Path,
    output: Path,
    size: tuple[int, int],
    fit: str,
    logo_width_pct: float,
    margin_pct: float,
    plate: bool,
) -> None:
    base = _open_rgba(source)
    canvas = _fit_cover(base, size) if fit == "cover" else _fit_contain(base, size)

    logo_img = _open_rgba(logo)
    max_logo_w = round(size[0] * logo_width_pct / 100)
    max_logo_h = round(size[1] * 0.12)
    logo_img.thumbnail((max_logo_w, max_logo_h), Image.Resampling.LANCZOS)

    margin = round(size[0] * margin_pct / 100)
    plate_pad_x = max(12, round(logo_img.width * 0.24))
    plate_pad_y = max(8, round(logo_img.height * 0.22))

    logo_x = size[0] - margin - logo_img.width
    logo_y = size[1] - margin - logo_img.height

    if plate:
        draw = ImageDraw.Draw(canvas)
        rect = (
            logo_x - plate_pad_x,
            logo_y - plate_pad_y,
            logo_x + logo_img.width + plate_pad_x,
            logo_y + logo_img.height + plate_pad_y,
        )
        radius = max(10, round(min(logo_img.size) * 0.22))
        draw.rounded_rectangle(
            rect,
            radius=radius,
            fill=(255, 255, 255, 225),
            outline=(229, 231, 235, 160),
            width=1,
        )

    canvas.alpha_composite(logo_img, (logo_x, logo_y))

    output.parent.mkdir(parents=True, exist_ok=True)
    rgb = ImageOps.exif_transpose(canvas).convert("RGB")
    rgb.save(output, quality=95, optimize=True)


def main() -> None:
    parser = argparse.ArgumentParser(
        description="Resize a generated image and overlay the company logo.",
    )
    parser.add_argument("--source", required=True, type=Path)
    parser.add_argument("--logo", required=True, type=Path)
    parser.add_argument("--out", required=True, type=Path)
    parser.add_argument("--size", type=_parse_size, default=(1200, 628))
    parser.add_argument("--fit", choices=("cover", "contain"), default="cover")
    parser.add_argument("--logo-width-pct", type=float, default=12.0)
    parser.add_argument("--margin-pct", type=float, default=3.0)
    parser.add_argument(
        "--no-plate",
        action="store_true",
        help="Do not draw a subtle white plate behind the logo.",
    )
    args = parser.parse_args()

    finalize_image(
        source=args.source,
        logo=args.logo,
        output=args.out,
        size=args.size,
        fit=args.fit,
        logo_width_pct=args.logo_width_pct,
        margin_pct=args.margin_pct,
        plate=not args.no_plate,
    )
    print(f"Saved branded image: {args.out}")


if __name__ == "__main__":
    main()