"""Text-Einblendungen und Overlays via ffmpeg drawtext."""

from __future__ import annotations

import subprocess
from pathlib import Path


def _run(cmd: list[str]) -> subprocess.CompletedProcess:
    return subprocess.run(cmd, capture_output=True, text=True, check=False)


_POSITION_MAP = {
    "center": ("(w-text_w)/2", "(h-text_h)/2"),
    "top": ("(w-text_w)/2", "50"),
    "bottom": ("(w-text_w)/2", "h-text_h-50"),
}


def create_text_clip(
    output_path: Path,
    content: str,
    duration: float = 3.0,
    font_size: int = 72,
    font_color: str = "white",
    background_color: str = "black",
    position: str = "center",
    width: int = 1920,
    height: int = 1080,
) -> Path:
    """Text-Standbild-Clip erzeugen (schwarzer/farbiger Hintergrund)."""
    output_path.parent.mkdir(parents=True, exist_ok=True)

    x_expr, y_expr = _POSITION_MAP.get(position, _POSITION_MAP["center"])

    # Hintergrund-Farbe: "transparent" → schwarzer Hintergrund mit alpha
    bg = "black" if background_color == "transparent" else background_color

    drawtext = (
        f"drawtext=text='{_escape_text(content)}':"
        f"fontsize={font_size}:"
        f"fontcolor={font_color}:"
        f"x={x_expr}:y={y_expr}"
    )

    cmd = [
        "ffmpeg", "-y",
        "-f", "lavfi",
        "-i", f"color=c={bg}:size={width}x{height}:rate=25:duration={duration}",
        "-vf", drawtext,
        "-c:v", "libx264",
        "-pix_fmt", "yuv420p",
        str(output_path),
    ]
    result = _run(cmd)
    if result.returncode != 0:
        raise RuntimeError(f"ffmpeg drawtext Fehler: {result.stderr}")

    return output_path


def add_text_overlay(
    input_path: Path,
    output_path: Path,
    text: str,
    position: str = "bottom",
    duration: float | None = None,
    font_size: int = 48,
    font_color: str = "white",
) -> Path:
    """Text-Overlay auf ein laufendes Video legen."""
    output_path.parent.mkdir(parents=True, exist_ok=True)

    x_expr, y_expr = _POSITION_MAP.get(position, _POSITION_MAP["bottom"])

    if duration is not None:
        enable = f"enable='between(t,0,{duration})'"
    else:
        enable = "enable=1"

    drawtext = (
        f"drawtext=text='{_escape_text(text)}':"
        f"fontsize={font_size}:"
        f"fontcolor={font_color}:"
        f"x={x_expr}:y={y_expr}:"
        f"{enable}"
    )

    cmd = [
        "ffmpeg", "-y",
        "-i", str(input_path),
        "-vf", drawtext,
        "-c:a", "copy",
        str(output_path),
    ]
    result = _run(cmd)
    if result.returncode != 0:
        raise RuntimeError(f"ffmpeg overlay Fehler: {result.stderr}")

    return output_path


def _escape_text(text: str) -> str:
    """Sonderzeichen für ffmpeg drawtext escapen."""
    return text.replace("'", "\\'").replace(":", "\\:").replace("\\", "\\\\")