# Authors: see git history
#
# Copyright (c) 2021 Authors
# Licensed under the GNU GPL version 3.0 or later.  See the file LICENSE for details.

import json
from math import atan2, degrees

from inkex import Transform, errormsg
from inkex.units import convert_unit

from ..elements import Stroke
from ..i18n import _
from ..lettering import get_font_by_id
from ..svg import get_correction_transform
from ..svg.tags import EMBROIDERABLE_TAGS, INKSTITCH_LETTERING, SVG_GROUP_TAG
from ..utils import DotDict
from ..utils import Point as InkstitchPoint
from .base import InkstitchExtension


class LetteringAlongPath(InkstitchExtension):
    '''
    This extension aligns an Ink/Stitch Lettering group along a path
    '''
    def __init__(self, *args, **kwargs):
        InkstitchExtension.__init__(self, *args, **kwargs)
        self.arg_parser.add_argument("--notebook")
        self.arg_parser.add_argument("-p", "--text-position", type=str, default='left', dest="text_position")

    def effect(self):
        # we ignore everything but the first path/text
        text, path = self.get_selection()
        if text is None or path is None:
            errormsg(_("Please select one path and one Ink/Stitch lettering group."))
            return

        TextAlongPath(self.svg, text, path, self.options.text_position)

    def get_selection(self):
        groups = list()
        paths = list()

        for node in self.svg.selection:
            lettering = False
            if node.tag == SVG_GROUP_TAG and INKSTITCH_LETTERING in node.attrib:
                groups.append(node)
                lettering = True
                continue

            for group in node.iterancestors(SVG_GROUP_TAG):
                if INKSTITCH_LETTERING in group.attrib:
                    groups.append(group)
                    lettering = True
                    break

            if not lettering and node.tag in EMBROIDERABLE_TAGS:
                paths.append(node)

        if not groups or not paths:
            return [None, None]

        return [groups[0], paths[0]]


class TextAlongPath:
    '''
    Aligns an Ink/Stitch Lettering group along a path
    '''
    def __init__(self, svg, text, path, text_position):
        self.svg = svg
        self.text = text
        self.path = Stroke(path).as_multi_line_string().geoms[0]
        self.text_position = text_position

        self.glyphs = [glyph for glyph in self.text.iterdescendants(SVG_GROUP_TAG) if glyph.label and len(glyph.label) == 1]
        if not self.glyphs:
            errormsg(_("The text doesn't contain any glyphs."))
            return

        self.load_settings()

        if self.glyphs[0].get('transform', None) is not None:
            self._reset_glyph_transforms()

        hidden_commands = self.hide_commands()
        space_indices, stretch_space, text_baseline = self.get_position_and_stretch_values()
        start_position = self.get_start_position()
        self.transform_glyphs(start_position, stretch_space, space_indices, text_baseline)
        self.restore_commands(hidden_commands)

    def _reset_glyph_transforms(self):
        font = get_font_by_id(self.settings.font)
        if font is not None:
            try:
                text_group = list(self.text.iterchildren(SVG_GROUP_TAG))[0]
            except IndexError:
                pass
            for glyph in text_group.iterchildren():
                glyph.delete()
            rendered_text = font.render_text(
                self.settings.text,
                text_group,
                None,  # we don't know the font variant (?)
                self.settings.back_and_forth,
                self.settings.trim_option,
                self.settings.use_trim_symbols
            )
            self.glyphs = [glyph for glyph in rendered_text.iterdescendants(SVG_GROUP_TAG) if glyph.label and len(glyph.label) == 1]

    def get_start_position(self):
        start_position = 0
        text_length = self.text_length()
        path_length = self.path.length
        if self.text_position == 'center':
            start_position = (path_length - text_length) / 2
        if self.text_position == 'right':
            start_position = path_length - text_length
        return start_position

    def get_position_and_stretch_values(self):
        text_bbox = self.glyphs[0].getparent().bounding_box()
        text_baseline = text_bbox.bottom

        if self.text_position == 'stretch':
            text_content = self.settings.text
            space_indices = [i for i, t in enumerate(text_content) if t == " "]
            text_bbox = self.text.bounding_box()
            text_width = convert_unit(text_bbox.width, 'px', self.svg.unit)

            if len(text_content) - 1 != 0:
                path_length = self.path.length
                stretch_space = (path_length - text_width) / (len(text_content) - 1)
            else:
                stretch_space = 0
        else:
            stretch_space = 0
            space_indices = []

        return space_indices, stretch_space, text_baseline

    def text_length(self):
        return convert_unit(self.text.bounding_box().width, 'px', self.svg.unit)

    def hide_commands(self):
        # hide commmands for bounding box calculation
        hidden_commands = []
        for glyph in self.glyphs:
            for group in glyph.iterdescendants(SVG_GROUP_TAG):
                if group.get_id().startswith("command_group") and group.style('display', 'inline') != 'none':
                    hidden_commands.append(group)
                    group.style['display'] = 'none'
        return hidden_commands

    def restore_commands(self, hidden_commands):
        for command in hidden_commands:
            command.style['display'] = "inline"

    def transform_glyphs(self, start_position, stretch_space, space_indices, text_baseline):
        text_scale = Transform(f'scale({self.settings.scale / 100})')
        distance = start_position
        old_bbox = None
        i = 0

        for glyph in self.glyphs:
            # dimensions
            bbox = glyph.bounding_box()
            transformed_bbox = glyph.bounding_box(glyph.getparent().composed_transform())
            left = bbox.left
            transformed_left = transformed_bbox.left
            width = convert_unit(transformed_bbox.width, 'px', self.svg.unit)

            # adjust position
            if old_bbox:
                distance += convert_unit(transformed_left - old_bbox.right, 'px', self.svg.unit) + stretch_space

            if self.text_position == 'stretch' and i in space_indices:
                distance += stretch_space
                i += 1

            new_distance = distance + width

            # calculate and apply transform
            first = self.path.interpolate(distance)
            last = self.path.interpolate(new_distance)

            angle = degrees(atan2(last.y - first.y, last.x - first.x)) % 360
            translate = InkstitchPoint(first.x, first.y) - InkstitchPoint(left, text_baseline)

            transform = Transform(f"rotate({angle}, {first.x}, {first.y}) translate({translate.x} {translate.y})")
            correction_transform = Transform(get_correction_transform(glyph))
            glyph.transform = correction_transform @ transform @ glyph.transform @ text_scale

            # set values for next iteration
            distance = new_distance
            old_bbox = transformed_bbox
            i += 1

    def load_settings(self):
        """Load the settings saved into the text element"""

        self.settings = DotDict({
            "text": "",
            "back_and_forth": False,
            "font": None,
            "scale": 100,
            "trim_option": 0,
            "use_trim_symbols": False
        })

        if INKSTITCH_LETTERING in self.text.attrib:
            try:
                self.settings.update(json.loads(self.text.get(INKSTITCH_LETTERING)))
            except (TypeError, ValueError):
                pass