"""Dividir, cortar faixas e apagar clipes.

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

import copy
import xml.etree.ElementTree as ET
from typing import List, Tuple

from ..models import (
    TimeValue,
)


class CutMixin:
    """Dividir, cortar faixas e apagar clipes."""

    # SPLIT & DELETE OPERATIONS
    # ========================================================================

    @staticmethod
    def _filter_children_for_segment(
        clip: ET.Element,
        seg_start: 'TimeValue',
        seg_duration: 'TimeValue',
    ) -> None:
        """Remove markers/keywords/titles from *clip* that fall outside the segment range.

        After ``split_clip`` deepcopy's the original clip into each segment, every
        segment inherits all child elements.  Markers whose ``start`` falls outside
        ``[seg_start, seg_start + seg_duration)`` are phantom duplicates and must be
        removed.  Keywords that partially overlap get their ``start``/``duration``
        clamped to the segment boundaries.

        A lane-nested ``<title>`` (a "text" voice action's on-screen callout,
        or a caption from an earlier `generate_dynamic_subtitles` pass) is
        the same kind of phantom duplicate, just keyed on ``offset`` instead
        of ``start`` — its offset lives in the same source-media coordinate
        space as a marker's ``start`` (see ``add_text_title``/``add_marker``,
        both anchored at ``parent.start``). Left unfiltered, every further
        cut (silence removal, filler removal) duplicates it into every
        resulting piece, so the same word shows up several times across the
        edited timeline instead of once where it was placed.
        """
        seg_end = seg_start + seg_duration
        to_remove = []
        for child in clip:
            tag = child.tag
            if tag in ('marker', 'chapter-marker'):
                child_start = TimeValue.from_timecode(child.get('start', '0s'))
                if child_start < seg_start or child_start >= seg_end:
                    to_remove.append(child)
            elif tag == 'title':
                title_offset = TimeValue.from_timecode(child.get('offset', '0s'))
                if title_offset < seg_start or title_offset >= seg_end:
                    to_remove.append(child)
            elif tag == 'keyword':
                kw_start = TimeValue.from_timecode(child.get('start', '0s'))
                kw_dur = TimeValue.from_timecode(child.get('duration', '0s'))
                kw_end = kw_start + kw_dur
                # Completely outside segment → remove
                if kw_end <= seg_start or kw_start >= seg_end:
                    to_remove.append(child)
                else:
                    # Clamp keyword range to segment boundaries
                    clamped_start = max(kw_start, seg_start)
                    clamped_end = min(kw_end, seg_end)
                    child.set('start', clamped_start.to_fcpxml())
                    child.set('duration', (clamped_end - clamped_start).to_fcpxml())
        for child in to_remove:
            clip.remove(child)

    def split_clip(
        self,
        clip_id: str,
        split_points: List[str]
    ) -> List[ET.Element]:
        """
        Split a clip at specified timecodes.

        Args:
            clip_id: Clip to split
            split_points: Timecodes within the clip to split at

        Returns:
            List of resulting clip elements
        """
        spine, clip, clip_index = self._require_spine_clip(clip_id)

        # Get clip properties
        clip_start, clip_duration, clip_offset = self._get_clip_times(clip)
        clip_name = clip.get('name', 'Clip')

        # Sort split points
        split_times = sorted([self._parse_time(sp) for sp in split_points])

        # Remove original clip
        spine.remove(clip)

        # Create new clips
        new_clips = []
        current_offset = clip_offset
        current_start = clip_start

        all_points = split_times + [clip_duration]

        for i, split_time in enumerate(all_points):
            if i == 0:
                segment_duration = split_time
            else:
                segment_duration = split_time - split_times[i - 1]

            if segment_duration <= TimeValue.zero():
                continue

            # Create new clip
            new_clip = copy.deepcopy(clip)
            new_clip.set('name', clip_name)
            new_clip.set('offset', current_offset.to_fcpxml())
            new_clip.set('start', current_start.to_fcpxml())
            new_clip.set('duration', segment_duration.to_fcpxml())

            # Remove markers/keywords that belong to other segments
            self._filter_children_for_segment(
                new_clip, current_start, segment_duration
            )
            self._reassign_text_style_ids(new_clip)
            self._reassign_tracking_shape_ids(new_clip)

            spine.insert(clip_index + len(new_clips), new_clip)
            new_clips.append(new_clip)

            # Update for next iteration
            current_offset = current_offset + segment_duration
            current_start = current_start + segment_duration

        # Update clip index: remove stale original entry, add split entries
        self.clips.pop(clip_id, None)
        for i, new_clip in enumerate(new_clips):
            new_id = f"{clip_id}_split_{i}"
            self.clips[new_id] = new_clip

        return new_clips

    def cut_clip_ranges(
        self,
        clip: ET.Element,
        cut_ranges: List[Tuple['TimeValue', 'TimeValue']],
    ) -> 'TimeValue':
        """Remove clip-relative time ranges from a spine clip, rippling after.

        Element-based on purpose: callers that walk the spine (e.g. media
        silence removal) pass the exact element, so duplicate-named clips are
        never ambiguous the way name-keyed operations are.

        Args:
            clip: The spine clip element to cut (must be a direct spine child).
            cut_ranges: (start, end) TimeValue pairs measured from the clip's
                own head. Overlapping/unsorted ranges are merged; portions
                outside [0, clip duration] are clamped. A cut covering the
                whole clip removes it entirely.

        Returns:
            Total removed duration (zero if no effective ranges).
        """
        spine = self._get_spine()
        clip_start, clip_duration, clip_offset = self._get_clip_times(clip)
        clip_index = list(spine).index(clip)
        zero = TimeValue.zero()

        # Clamp, sort, merge.
        clamped = []
        for start, end in cut_ranges:
            start = start if start > zero else zero
            end = end if end < clip_duration else clip_duration
            if end > start:
                clamped.append((start, end))
        clamped.sort(key=lambda r: r[0])
        merged: List[Tuple[TimeValue, TimeValue]] = []
        for start, end in clamped:
            if merged and start <= merged[-1][1]:
                if end > merged[-1][1]:
                    merged[-1] = (merged[-1][0], end)
            else:
                merged.append((start, end))
        if not merged:
            return zero

        # Keep ranges = complement of the merged cuts.
        keeps: List[Tuple[TimeValue, TimeValue]] = []
        cursor = zero
        for start, end in merged:
            if start > cursor:
                keeps.append((cursor, start))
            cursor = end
        if cursor < clip_duration:
            keeps.append((cursor, clip_duration))

        # A keep segment shorter than MIN_KEEP_SECONDS is leftover between
        # two cuts, not a real clip — at the very start/end of the clip it's
        # cut padding with no kept audio on the outer side; in the interior
        # it's the pause BETWEEN two things that were both cut (e.g. two
        # consecutive deactivated phrases in the voice-editing flow), which
        # belongs to neither side by construction. At the edges we fold it
        # into the one neighboring KEEP segment there is, which simply starts
        # earlier / ends later to absorb it. In the interior both neighbors
        # are CUT, not keep, so there is nothing to fold into — it is just
        # dropped, extending the surrounding cut across it instead of
        # surviving as a third near-invisible micro-clip.
        #
        # The threshold is bigger than one frame on purpose: measured on a
        # real voice-edit (0.07-0.23s residues), a single frame did not catch
        # them — this is pause/padding leftover, not intentional short
        # content, so treating anything under a third of a second this way
        # is safe for this cut path.
        min_keep_seconds = max(6 * float(self.frame_duration_fraction()), 0.3)
        i = 0
        while len(keeps) > 1 and i < len(keeps):
            start, end = keeps[i]
            if (end - start).to_seconds() >= min_keep_seconds:
                i += 1
                continue
            if i == 0:
                keeps[1] = (start, keeps[1][1])
                keeps.pop(0)
            elif i == len(keeps) - 1:
                keeps[i - 1] = (keeps[i - 1][0], end)
                keeps.pop(i)
            else:
                keeps.pop(i)
            # Re-check the same index: the segment now there might itself be
            # short enough to absorb again (two short keeps in a row).

        spine.remove(clip)
        new_clips: List[ET.Element] = []
        current_offset = clip_offset
        kept_total = zero
        for keep_start, keep_end in keeps:
            seg_duration = keep_end - keep_start
            seg_start = clip_start + keep_start
            new_clip = copy.deepcopy(clip)
            new_clip.set('offset', current_offset.to_fcpxml())
            new_clip.set('start', seg_start.to_fcpxml())
            new_clip.set('duration', seg_duration.to_fcpxml())
            self._filter_children_for_segment(new_clip, seg_start, seg_duration)
            self._reassign_text_style_ids(new_clip)
            self._reassign_tracking_shape_ids(new_clip)
            spine.insert(clip_index + len(new_clips), new_clip)
            new_clips.append(new_clip)
            current_offset = current_offset + seg_duration
            kept_total = kept_total + seg_duration

        removed = clip_duration - kept_total
        self._ripple_from_index(spine, clip_index + len(new_clips), zero - removed)
        self._update_sequence_duration()

        # Keep the name index coherent, mirroring delete_clip/split_clip.
        name = clip.get('id') or clip.get('name') or ''
        if name and self.clips.get(name) is clip:
            if new_clips:
                self.clips[name] = new_clips[0]
            else:
                remaining = [
                    sc for _, sc in self._iter_spine_clips()
                    if (sc.get('id') or sc.get('name') or '') == name
                ]
                if remaining:
                    self.clips[name] = remaining[0]
                else:
                    self.clips.pop(name, None)
        return removed

    def remove_trailing_gaps(self) -> None:
        """Remove empty ``<gap>`` elements at the end of the timeline.

        Silence removal (and FCP round-trips) can leave a trailing gap holding
        the timeline open past the last real clip. This removes only *trailing*
        gaps — a gap in the middle is left untouched — and re-syncs the sequence
        duration so the exported file ends where the content ends.
        """
        spine = self._get_spine()
        children = list(spine)
        if not children:
            return
        last = children[-1]
        if last.tag != 'gap':
            return
        spine.remove(last)
        self._update_sequence_duration()

    def delete_clip(
        self,
        clip_ids: List[str],
        ripple: bool = True
    ) -> None:
        """
        Delete clips from timeline.

        Uses spine iteration instead of the name-indexed dict so that
        duplicate-named clips (e.g. four ``Interview_A``) are resolved
        correctly — always targeting the *first* spine match rather than
        the last-indexed entry.

        Args:
            clip_ids: Clips to delete
            ripple: If True, shift subsequent clips. If False, leave gaps.
        """
        spine = self._get_spine()

        for clip_id in clip_ids:
            # Walk spine directly to find the first clip matching this name,
            # avoiding the last-one-wins problem in self.clips.
            target = None
            for _spine_idx, spine_clip in self._iter_spine_clips():
                name = spine_clip.get('id') or spine_clip.get('name') or ''
                if name == clip_id:
                    target = spine_clip
                    break

            if target is None:
                continue

            _, clip_duration, clip_offset = self._get_clip_times(target)
            clip_index = list(spine).index(target)

            if ripple:
                spine.remove(target)
                self._ripple_from_index(
                    spine, clip_index, TimeValue.zero() - clip_duration
                )
            else:
                # Replace with gap
                gap = ET.Element('gap')
                gap.set('name', 'Gap')
                gap.set('offset', clip_offset.to_fcpxml())
                gap.set('duration', clip_duration.to_fcpxml())

                spine.remove(target)
                spine.insert(clip_index, gap)

            # Re-index: if other spine clips share this name, point the
            # dict entry at the next one; otherwise remove entirely.
            remaining = [
                sc for _, sc in self._iter_spine_clips()
                if (sc.get('id') or sc.get('name') or '') == clip_id
            ]
            if remaining:
                self.clips[clip_id] = remaining[0]
            else:
                self.clips.pop(clip_id, None)

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