# SPDX-License-Identifier: GPL-3.0-or-later
# Copyright (C) 2016-2020 by Nathan Lovato, Daniel Oakey, Razvan Radulescu, and contributors
from operator import attrgetter

import bpy

from .utils.doc import doc_brief, doc_description, doc_idname, doc_name
from .utils.functions import find_strips_in_range, move_selection, trim_strips


class POWER_SEQUENCER_OT_channel_offset(bpy.types.Operator):
    """
    Move selected strip to the nearest open channel above/down
    """

    doc = {
        "name": doc_name(__qualname__),
        "demo": "",
        "description": doc_description(__doc__),
        "shortcuts": [
            (
                {"type": "UP_ARROW", "value": "PRESS", "alt": True},
                {"direction": "up", "trim_target_channel": False},
                "Move to Open Channel Above",
            ),
            (
                {"type": "UP_ARROW", "value": "PRESS", "ctrl": True, "alt": True},
                {"direction": "up", "trim_target_channel": True},
                "Move to Channel Above and Trim",
            ),
            (
                {"type": "DOWN_ARROW", "value": "PRESS", "alt": True},
                {"direction": "down", "trim_target_channel": False},
                "Move to Open Channel Below",
            ),
            (
                {"type": "DOWN_ARROW", "value": "PRESS", "ctrl": True, "alt": True},
                {"direction": "down", "trim_target_channel": True},
                "Move to Channel Below and Trim",
            ),
        ],
        "keymap": "Sequencer",
    }
    bl_idname = doc_idname(__qualname__)
    bl_label = doc["name"]
    bl_description = doc_brief(doc["description"])
    bl_options = {"REGISTER", "UNDO"}

    direction: bpy.props.EnumProperty(
        items=[
            ("up", "up", "Move the selection 1 channel up"),
            ("down", "down", "Move the selection 1 channel down"),
        ],
        name="Direction",
        description="Move the sequences up or down",
        default="up",
    )
    trim_target_channel: bpy.props.BoolProperty(
        name="Trim strips",
        description="Trim strips to make space in the target channel",
        default=False,
    )
    keep_selection_offset: bpy.props.BoolProperty(
        name="Keep selection offset",
        description="The selected strips preserve their relative positions",
        default=True,
    )

    @classmethod
    def poll(cls, context):
        return context.selected_sequences

    def execute(self, context):

        max_channel = 32
        min_channel = 1

        if self.direction == "up":
            channel_offset = +1
            limit_channel = max_channel
            comparison_function = min

        if self.direction == "down":
            channel_offset = -1
            limit_channel = min_channel
            comparison_function = max

        selection = [s for s in context.selected_sequences if not s.lock]

        if not selection:
            return {"FINISHED"}

        sequences = sorted(selection, key=attrgetter("channel", "frame_final_start"))
        if self.direction == "up":
            sequences = [s for s in reversed(sequences)]

        head = sequences[0]
        if not self.keep_selection_offset or (
            head.channel != limit_channel and self.keep_selection_offset
        ):
            for s in sequences:
                if self.trim_target_channel:
                    channel_trim = s.channel + channel_offset
                    strips_in_trim_channel = [
                        sequence
                        for sequence in context.sequences
                        if (sequence.channel == channel_trim)
                    ]
                    if strips_in_trim_channel:
                        to_delete, to_trim = find_strips_in_range(
                            s.frame_final_start, s.frame_final_end, strips_in_trim_channel
                        )
                        trim_strips(
                            context, s.frame_final_start, s.frame_final_end, to_trim, to_delete
                        )

                s.channel = comparison_function(limit_channel, s.channel + channel_offset)
                if s.channel == limit_channel:
                    move_selection(context, [s], 0, 0)

            if self.keep_selection_offset and not self.trim_target_channel:
                start_frame = head.frame_final_start
                x_difference = 0
                while not head.channel == limit_channel:
                    move_selection(context, sequences, -x_difference, channel_offset)
                    x_difference = head.frame_final_start - start_frame
                    if x_difference == 0:
                        break
        return {"FINISHED"}