"""Escrita do documento FCPXML: assets de vídeo, timebases e serialização.

Extraído de writer.py — ver fcpxml/writer/__init__.py para o conjunto.
"""

import logging
import subprocess
import xml.etree.ElementTree as ET
from pathlib import Path
from typing import Optional

from ..models import (
    TimeValue,
)
from .validation import validate_fcpxml

_log = logging.getLogger(__name__)

# ============================================================================
# STILL IMAGE AUTO-CONVERSION (v0.6.0)
# ============================================================================

_STILL_IMAGE_EXTENSIONS = {'.png', '.jpg', '.jpeg', '.tiff', '.tif', '.bmp'}


def _ensure_video_asset(
    src_path: str,
    duration: float = 10.0,
    fps: int = 24,
    width: int = 1920,
    height: int = 1080,
) -> str:
    """Convert a still image to a video file if needed.

    Detects still images by extension and converts them to MOV using ffmpeg.
    Video files are returned as-is.

    Args:
        src_path: Path to the source media file.
        duration: Duration in seconds for the still-to-video conversion.
        fps: Frame rate for the output video.
        width: Output width (even number).
        height: Output height (even number).

    Returns:
        Path to the video file (original path if already video, new .mov path
        if converted from still).

    Raises:
        FileNotFoundError: If ffmpeg is not installed.
    """
    # Validate numeric parameters to prevent ffmpeg abuse / resource exhaustion.
    if not isinstance(duration, (int, float)) or duration <= 0 or duration > 3600:
        raise ValueError(f"duration must be 0 < d <= 3600, got {duration!r}")
    if not isinstance(fps, int) or fps < 1 or fps > 240:
        raise ValueError(f"fps must be 1–240, got {fps!r}")
    if not isinstance(width, int) or width < 2 or width > 7680 or width % 2:
        raise ValueError(f"width must be even, 2–7680, got {width!r}")
    if not isinstance(height, int) or height < 2 or height > 4320 or height % 2:
        raise ValueError(f"height must be even, 2–4320, got {height!r}")

    path = Path(src_path)
    if path.suffix.lower() not in _STILL_IMAGE_EXTENSIONS:
        return src_path

    output_path = path.with_suffix('.mov')
    if output_path.exists():
        return str(output_path)

    # Build ffmpeg command: still image → video with specified duration
    cmd = [
        'ffmpeg', '-y',
        '-loop', '1',
        '-i', str(path),
        '-c:v', 'prores_ks',
        '-profile:v', '0',
        '-t', str(duration),
        '-r', str(fps),
        '-vf', f'scale={width}:{height}:force_original_aspect_ratio=decrease,'
               f'pad={width}:{height}:(ow-iw)/2:(oh-ih)/2',
        '-pix_fmt', 'yuva444p10le',
        str(output_path),
    ]
    try:
        subprocess.run(cmd, check=True, capture_output=True, timeout=120)
    except FileNotFoundError:
        raise FileNotFoundError(
            "ffmpeg not found. Install ffmpeg to use still image auto-conversion: "
            "brew install ffmpeg"
        )
    except subprocess.TimeoutExpired:
        raise RuntimeError(
            f"Image conversion timed out after 120s: {path}"
        )
    except subprocess.CalledProcessError as e:
        stderr_msg = e.stderr.decode(errors='replace') if e.stderr else str(e)
        raise RuntimeError(f"ffmpeg conversion failed: {stderr_msg}")
    return str(output_path)


def _enforce_standard_timebases(root: ET.Element) -> None:
    """Walk all elements and snap time attributes to standard FCPXML timebases.

    Targets offset, start, duration, and tcStart attributes. Values that
    already use a standard denominator are left untouched.
    """
    time_attrs = ('offset', 'start', 'duration', 'tcStart')
    for elem in root.iter():
        for attr in time_attrs:
            val = elem.get(attr)
            if val and val.endswith('s') and '/' in val:
                try:
                    tv = TimeValue.from_timecode(val)
                    if not tv.is_standard_timebase():
                        # Snap to nearest frame at 2400 ticks/sec
                        snapped = tv.snap_to_frame(24)
                        elem.set(attr, snapped.to_fcpxml())
                except (ValueError, ZeroDivisionError):
                    pass  # Skip unparseable values


def write_fcpxml(
    root: ET.Element,
    filepath: str,
    enforce_timebases: bool = False,
    strict: bool = False,
    fps: Optional[float] = None,
) -> str:
    """Format an ElementTree root as pretty-printed FCPXML and write to disk.

    Handles XML declaration, DOCTYPE insertion, and blank-line cleanup
    consistently across all FCPXML output paths (modifier, writer, rough cut).

    Args:
        root: The <fcpxml> root Element to serialize.
        filepath: Destination file path.
        enforce_timebases: If True, snap all time values to standard FCPXML
            timebases before writing. Default False for backward compat.
        strict: If True, raise ValueError on validation errors.
            If False (default), log warnings.
        fps: Frame rate for the frame-alignment validation check. Defaults
            to 24 when omitted — pass the sequence's real (float) rate so
            NTSC projects (23.976/29.97/59.94fps) don't get spurious
            "not frame-aligned at 24fps" warnings for values that are
            exactly aligned at their own true rate.

    Returns:
        The filepath written to.
    """
    if enforce_timebases:
        _enforce_standard_timebases(root)

    # Auto-validate before writing
    issues = validate_fcpxml(root, fps=fps if fps is not None else 24.0)
    if issues:
        errors = [i for i in issues if i.severity == "error"]
        warnings = [i for i in issues if i.severity == "warning"]
        for w in warnings:
            _log.warning("FCPXML validation: %s", w.message)
        if errors and strict:
            msg = "; ".join(e.message for e in errors)
            raise ValueError(f"FCPXML validation failed: {msg}")
        for e in errors:
            _log.error("FCPXML validation: %s", e.message)

    from ..safe_xml import serialize_xml

    return serialize_xml(root, filepath, doctype='<!DOCTYPE fcpxml>')