"""Image rendering abstraction — kitty graphics, sixel, or ASCII art."""

from __future__ import annotations

import base64
import shutil
import subprocess
import sys
from pathlib import Path


def render_image_kitty(path: str) -> str:
    """Return kitty graphics protocol escape sequence for the image."""
    data = Path(path).read_bytes()
    b64 = base64.standard_b64encode(data).decode()
    chunks = [b64[i:i + 4096] for i in range(0, len(b64), 4096)]
    escape = ""
    for i, chunk in enumerate(chunks):
        m = 1 if i < len(chunks) - 1 else 0
        if i == 0:
            escape += f"\033_Ga=T,f=100,m={m};{chunk}\033\\"
        else:
            escape += f"\033_Gm={m};{chunk}\033\\"
    return escape


def render_image_sixel(path: str) -> str:
    """Convert image to sixel using chafa or img2sixel."""
    if shutil.which("chafa"):
        result = subprocess.run(
            ["chafa", "--format=sixel", "--size=80x40", str(path)],
            capture_output=True, text=True,
        )
        if result.returncode == 0:
            return result.stdout
    if shutil.which("img2sixel"):
        result = subprocess.run(
            ["img2sixel", "-w", "640", str(path)],
            capture_output=True, text=True,
        )
        if result.returncode == 0:
            return result.stdout
    return f"[Sixel unavailable — install chafa or libsixel. Image: {path}]"


def render_image_ascii(path: str) -> str:
    """Convert image to ASCII/Unicode block art using chafa."""
    if shutil.which("chafa"):
        result = subprocess.run(
            ["chafa", "--size=60x30", str(path)],
            capture_output=True, text=True,
        )
        if result.returncode == 0:
            return result.stdout
    return f"[Image: {path}]"


def render_image(path: str, protocol: str) -> str:
    """Render an image using the specified protocol. Returns terminal-ready string."""
    p = Path(path)

    if p.suffix.lower() == ".svg":
        try:
            import cairosvg
            png_path = p.with_suffix(".png")
            cairosvg.svg2png(url=str(p), write_to=str(png_path))
            path = str(png_path)
        except ImportError:
            return f"[SVG display requires cairosvg: pip install cairosvg. File: {path}]"

    if protocol == "kitty":
        return render_image_kitty(path)
    elif protocol == "sixel":
        return render_image_sixel(path)
    else:
        return render_image_ascii(path)