"""Reordenar clipes e recalcular offsets/duração.

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

import xml.etree.ElementTree as ET
from typing import List

from ..models import (
    TimeValue,
)
from .helpers import SPINE_ELEMENT_TAGS


class ReorderMixin:
    """Reordenar clipes e recalcular offsets/duração."""

    # REORDER OPERATIONS
    # ========================================================================

    def reorder_clips(
        self,
        clip_ids: List[str],
        target_position: str,
        ripple: bool = True
    ) -> None:
        """
        Move clips to a new position in the timeline.

        Args:
            clip_ids: Clips to move (maintains relative order)
            target_position: 'start', 'end', timecode, or 'after:clip_id'/'before:clip_id'
            ripple: Whether to shift other clips
        """
        spine = self._get_spine()

        # Collect clips to move
        clips_to_move = []
        for clip_id in clip_ids:
            clip = self.clips.get(clip_id)
            if clip is not None and clip in list(spine):
                clips_to_move.append(clip)

        if not clips_to_move:
            raise ValueError(f"No clips found matching: {clip_ids}")

        # Calculate total duration of moving clips
        total_duration = TimeValue.zero()
        for clip in clips_to_move:
            dur = self._parse_time(clip.get('duration', '0s'))
            total_duration = total_duration + dur

        # Remove clips from current positions
        for clip in clips_to_move:
            spine.remove(clip)

        # Determine target offset and insert index
        spine_children = list(spine)
        target_offset, insert_index = self._resolve_insert_position(
            target_position, spine_children
        )

        # Insert clips at new position
        current_offset = target_offset
        for clip in clips_to_move:
            clip.set('offset', current_offset.to_fcpxml())
            spine.insert(insert_index, clip)
            insert_index += 1
            dur = self._parse_time(clip.get('duration', '0s'))
            current_offset = current_offset + dur

        # Recalculate all offsets if ripple
        if ripple:
            self._recalculate_offsets(spine)

    def _recalculate_offsets(self, spine: ET.Element) -> None:
        """Recalculate all clip offsets sequentially."""
        current_offset = TimeValue.zero()

        for child in spine:
            if child.tag in SPINE_ELEMENT_TAGS:
                child.set('offset', current_offset.to_fcpxml())
                duration_str = child.get('duration', '0s')
                duration = self._parse_time(duration_str)
                current_offset = current_offset + duration

    def _timeline_duration(self) -> 'TimeValue':
        """Return the total timeline duration as a TimeValue.

        Reads from the ``<sequence>`` element when available, falling back
        to summing all spine element durations.  Extracted from
        ``add_music_bed`` and ``batch_add_markers`` which both computed
        this independently.
        """
        sequence = self.root.find('.//sequence')
        if sequence is not None:
            dur_str = sequence.get('duration')
            if dur_str:
                return self._parse_time(dur_str)
        spine = self._get_spine()
        total = TimeValue.zero()
        for child in spine:
            if child.tag in SPINE_ELEMENT_TAGS:
                total = total + self._parse_time(child.get('duration', '0s'))
        return total

    def _update_sequence_duration(self) -> None:
        """Recompute the ``<sequence>`` duration from the spine content.

        Ripple edits (``cut_clip_ranges``, ``delete_clip``, ``split_clip``)
        change the total timeline length without rewriting the sequence
        element, so an exported file kept advertising the pre-edit duration —
        a 326.78s sequence still claimed 326.78s after 71s of silence was
        removed. This helper re-syncs the attribute to the actual spine sum.
        """
        sequence = self.root.find('.//sequence')
        if sequence is None:
            return
        spine = self._get_spine()
        total = TimeValue.zero()
        for child in spine:
            if child.tag in SPINE_ELEMENT_TAGS:
                total = total + self._parse_time(child.get('duration', '0s'))
        sequence.set('duration', total.to_fcpxml())

    # ========================================================================