# This file is part of CairoSVG
# Copyright © 2010-2015 Kozea
#
# This library is free software: you can redistribute it and/or modify it under
# the terms of the GNU Lesser General Public License as published by the Free
# Software Foundation, either version 3 of the License, or (at your option) any
# later version.
#
# This library is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with CairoSVG.  If not, see <http://www.gnu.org/licenses/>.

"""
Cairo surface creators.

"""

import io

import cairocffi as cairo

from .colors import color
from .defs import (
    apply_filter_after_painting, apply_filter_before_painting, clip_path,
    filter_, gradient_or_pattern, linear_gradient, marker, mask, paint_mask,
    parse_all_defs, pattern, prepare_filter, radial_gradient, use)
from .helpers import (
    UNITS, PointError, apply_matrix_transform, clip_rect, node_format,
    normalize, paint, preserved_ratio, size, transform)
from .image import image
from .parser import Tree
from .path import draw_markers, path
from .shapes import circle, ellipse, line, polygon, polyline, rect
from .svg import svg
from .text import text
from .url import parse_url

SHAPE_ANTIALIAS = {
    'optimizeSpeed': cairo.ANTIALIAS_FAST,
    'crispEdges': cairo.ANTIALIAS_NONE,
    'geometricPrecision': cairo.ANTIALIAS_BEST,
}

TEXT_ANTIALIAS = {
    'optimizeSpeed': cairo.ANTIALIAS_FAST,
    'optimizeLegibility': cairo.ANTIALIAS_GOOD,
    'geometricPrecision': cairo.ANTIALIAS_BEST,
}

TEXT_HINT_STYLE = {
    'geometricPrecision': cairo.HINT_STYLE_NONE,
    'optimizeLegibility': cairo.HINT_STYLE_FULL,
}

TEXT_HINT_METRICS = {
    'geometricPrecision': cairo.HINT_METRICS_OFF,
    'optimizeLegibility': cairo.HINT_METRICS_ON,
}

TAGS = {
    'a': text,
    'circle': circle,
    'clipPath': clip_path,
    'ellipse': ellipse,
    'filter': filter_,
    'image': image,
    'line': line,
    'linearGradient': linear_gradient,
    'marker': marker,
    'mask': mask,
    'path': path,
    'pattern': pattern,
    'polyline': polyline,
    'polygon': polygon,
    'radialGradient': radial_gradient,
    'rect': rect,
    'svg': svg,
    'text': text,
    'textPath': text,
    'tspan': text,
    'use': use,
}

PATH_TAGS = frozenset((
    'circle', 'ellipse', 'line', 'path', 'polygon', 'polyline', 'rect'))

INVISIBLE_TAGS = frozenset((
    'clipPath', 'filter', 'linearGradient', 'marker', 'mask', 'pattern',
    'radialGradient', 'symbol'))


class Surface(object):
    """Abstract base class for CairoSVG surfaces.

    The ``width`` and ``height`` attributes are in device units (pixels for
    PNG, else points).

    The ``context_width`` and ``context_height`` attributes are in user units
    (i.e. in pixels), they represent the size of the active viewport.

    """

    # Subclasses must either define this or override _create_surface()
    surface_class = None

    @classmethod
    def convert(cls, bytestring=None, **kwargs):
        """Convert a SVG document to the format for this class.

        Specify the input by passing one of these:

        :param bytestring: The SVG source as a byte-string.
        :param file_obj: A file-like object.
        :param url: A filename.

        And the output with:

        :param write_to: The filename of file-like object where to write the
                         output. If None or not provided, return a byte string.

        Only ``bytestring`` can be passed as a positional argument, other
        parameters are keyword-only.

        """
        dpi = kwargs.pop('dpi', 96)
        parent_width = kwargs.pop('parent_width', None)
        parent_height = kwargs.pop('parent_height', None)
        scale = kwargs.pop('scale', 1)
        write_to = kwargs.pop('write_to', None)
        kwargs['bytestring'] = bytestring
        tree = Tree(**kwargs)
        output = write_to or io.BytesIO()
        instance = cls(
            tree, output, dpi, None, parent_width, parent_height, scale)
        instance.finish()
        if write_to is None:
            return output.getvalue()

    def __init__(self, tree, output, dpi, parent_surface=None,
                 parent_width=None, parent_height=None, scale=1):
        """Create the surface from a filename or a file-like object.

        The rendered content is written to ``output`` which can be a filename,
        a file-like object, ``None`` (render in memory but do not write
        anything) or the built-in ``bytes`` as a marker.

        Call the ``.finish()`` method to make sure that the output is
        actually written.

        """
        self.cairo = None
        self.context_width, self.context_height = parent_width, parent_height
        self.cursor_position = [0, 0]
        self.cursor_d_position = [0, 0]
        self.text_path_width = 0
        self.tree_cache = {(tree.url, tree.get('id')): tree}
        if parent_surface:
            self.markers = parent_surface.markers
            self.gradients = parent_surface.gradients
            self.patterns = parent_surface.patterns
            self.masks = parent_surface.masks
            self.paths = parent_surface.paths
            self.filters = parent_surface.filters
        else:
            self.markers = {}
            self.gradients = {}
            self.patterns = {}
            self.masks = {}
            self.paths = {}
            self.filters = {}
        self._old_parent_node = self.parent_node = None
        self.output = output
        self.dpi = dpi
        self.font_size = size(self, '12pt')
        self.stroke_and_fill = True
        width, height, viewbox = node_format(self, tree)
        width *= scale
        height *= scale
        # Actual surface dimensions: may be rounded on raster surfaces types
        self.cairo, self.width, self.height = self._create_surface(
            width * self.device_units_per_user_units,
            height * self.device_units_per_user_units)
        self.context = cairo.Context(self.cairo)
        # We must scale the context as the surface size is using physical units
        self.context.scale(
            self.device_units_per_user_units, self.device_units_per_user_units)
        # Initial, non-rounded dimensions
        self.set_context_size(
            width, height, viewbox, scale, preserved_ratio(tree))
        self.context.move_to(0, 0)
        self.draw(tree)

    @property
    def points_per_pixel(self):
        """Surface resolution."""
        return 1 / (self.dpi * UNITS['pt'])

    @property
    def device_units_per_user_units(self):
        """Ratio between Cairo device units and user units.

        Device units are points for everything but PNG, and pixels for
        PNG. User units are pixels.

        """
        return self.points_per_pixel

    def _create_surface(self, width, height):
        """Create and return ``(cairo_surface, width, height)``."""
        cairo_surface = self.surface_class(self.output, width, height)
        return cairo_surface, width, height

    def set_context_size(self, width, height, viewbox, scale, preserved_ratio):
        """Set the Cairo context size, set the SVG viewport size."""
        if viewbox:
            x, y, x_size, y_size = viewbox
            self.context_width, self.context_height = x_size, y_size
            x_ratio, y_ratio = width / x_size, height / y_size
            matrix = cairo.Matrix()
            if preserved_ratio and x_ratio > y_ratio:
                matrix.translate((width - x_size * y_ratio) / 2, 0)
                matrix.scale(y_ratio, y_ratio)
                matrix.translate(-x / x_ratio * y_ratio, -y)
            elif preserved_ratio and x_ratio < y_ratio:
                matrix.translate(0, (height - y_size * x_ratio) / 2)
                matrix.scale(x_ratio, x_ratio)
                matrix.translate(-x, -y / y_ratio * x_ratio)
            else:
                matrix.scale(x_ratio, y_ratio)
                matrix.translate(-x, -y)
            apply_matrix_transform(self, matrix)
        else:
            self.context_width, self.context_height = width, height
            if scale != 1:
                matrix = cairo.Matrix()
                matrix.scale(scale, scale)
                apply_matrix_transform(self, matrix)

    def finish(self):
        """Read the surface content."""
        self.cairo.finish()

    def draw(self, node):
        """Draw ``node`` and its children."""

        # Do not draw defs
        if node.tag == 'defs':
            parse_all_defs(self, node)
            return

        # Do not draw elements with width or height of 0
        if (('width' in node and size(self, node['width']) == 0) or
           ('height' in node and size(self, node['height']) == 0)):
            return

        # Save context and related attributes
        old_parent_node = self.parent_node
        old_font_size = self.font_size
        old_context_size = self.context_width, self.context_height
        self.parent_node = node
        self.font_size = size(self, node.get('font-size', '12pt'))
        self.context.save()

        # Apply transformations
        transform(self, node.get('transform'))

        # Find and prepare opacity, masks and filters
        mask = parse_url(node.get('mask')).fragment
        filter_ = parse_url(node.get('filter')).fragment
        opacity = float(node.get('opacity', 1))

        if filter_:
            prepare_filter(self, node, filter_)

        if filter_ or mask or (opacity < 1 and node.children):
            self.context.push_group()

        # Move to (node.x, node.y)
        self.context.move_to(
            size(self, node.get('x'), 'x'),
            size(self, node.get('y'), 'y'))

        # Set node's drawing informations if the ``node.tag`` method exists
        line_cap = node.get('stroke-linecap')
        if line_cap == 'square':
            self.context.set_line_cap(cairo.LINE_CAP_SQUARE)
        if line_cap == 'round':
            self.context.set_line_cap(cairo.LINE_CAP_ROUND)

        join_cap = node.get('stroke-linejoin')
        if join_cap == 'round':
            self.context.set_line_join(cairo.LINE_JOIN_ROUND)
        if join_cap == 'bevel':
            self.context.set_line_join(cairo.LINE_JOIN_BEVEL)

        dash_array = normalize(node.get('stroke-dasharray', '')).split()
        if dash_array:
            dashes = [size(self, dash) for dash in dash_array]
            if sum(dashes):
                offset = size(self, node.get('stroke-dashoffset'))
                self.context.set_dash(dashes, offset)

        miter_limit = float(node.get('stroke-miterlimit', 4))
        self.context.set_miter_limit(miter_limit)

        # Clip
        rect_values = clip_rect(node.get('clip'))
        if len(rect_values) == 4:
            top = size(self, rect_values[0], 'y')
            right = size(self, rect_values[1], 'x')
            bottom = size(self, rect_values[2], 'y')
            left = size(self, rect_values[3], 'x')
            x = size(self, node.get('x'), 'x')
            y = size(self, node.get('y'), 'y')
            width = size(self, node.get('width'), 'x')
            height = size(self, node.get('height'), 'y')
            self.context.save()
            self.context.translate(x, y)
            self.context.rectangle(
                left, top, width - left - right, height - top - bottom)
            self.context.restore()
            self.context.clip()
        clip_path = parse_url(node.get('clip-path')).fragment
        if clip_path:
            path = self.paths.get(clip_path)
            if path:
                self.context.save()
                if path.get('clipPathUnits') == 'objectBoundingBox':
                    x = size(self, node.get('x'), 'x')
                    y = size(self, node.get('y'), 'y')
                    width = size(self, node.get('width'), 'x')
                    height = size(self, node.get('height'), 'y')
                    self.context.translate(x, y)
                    self.context.scale(width, height)
                path.tag = 'g'
                self.stroke_and_fill = False
                self.draw(path)
                self.stroke_and_fill = True
                self.context.restore()
                # TODO: fill rules are not handled by cairo for clips
                # if node.get('clip-rule') == 'evenodd':
                #     self.context.set_fill_rule(cairo.FILL_RULE_EVEN_ODD)
                self.context.clip()
                self.context.set_fill_rule(cairo.FILL_RULE_WINDING)

        # Only draw known tags
        if node.tag in TAGS:
            try:
                TAGS[node.tag](self, node)
            except PointError:
                # Error in point parsing, do nothing
                pass

        # Get stroke and fill opacity
        stroke_opacity = float(node.get('stroke-opacity', 1))
        fill_opacity = float(node.get('fill-opacity', 1))
        if opacity < 1 and not node.children:
            stroke_opacity *= opacity
            fill_opacity *= opacity

        # Manage display and visibility
        display = node.get('display', 'inline') != 'none'
        visible = display and (node.get('visibility', 'visible') != 'hidden')

        # Set font rendering properties
        self.context.set_antialias(SHAPE_ANTIALIAS.get(
            node.get('shape-rendering'), cairo.ANTIALIAS_DEFAULT))

        font_options = self.context.get_font_options()
        font_options.set_antialias(TEXT_ANTIALIAS.get(
            node.get('text-rendering'), cairo.ANTIALIAS_DEFAULT))
        font_options.set_hint_style(TEXT_HINT_STYLE.get(
            node.get('text-rendering'), cairo.HINT_STYLE_DEFAULT))
        font_options.set_hint_metrics(TEXT_HINT_METRICS.get(
            node.get('text-rendering'), cairo.HINT_METRICS_DEFAULT))
        self.context.set_font_options(font_options)

        # Fill and stroke
        if self.stroke_and_fill and visible and node.tag in TAGS:
            # Fill
            self.context.save()
            paint_source, paint_color = paint(node.get('fill', 'black'))
            if not gradient_or_pattern(self, node, paint_source):
                if node.get('fill-rule') == 'evenodd':
                    self.context.set_fill_rule(cairo.FILL_RULE_EVEN_ODD)
                self.context.set_source_rgba(*color(paint_color, fill_opacity))
            self.context.fill_preserve()
            self.context.restore()

            # Stroke
            self.context.save()
            self.context.set_line_width(
                size(self, node.get('stroke-width', '1')))
            paint_source, paint_color = paint(node.get('stroke'))
            if not gradient_or_pattern(self, node, paint_source):
                self.context.set_source_rgba(
                    *color(paint_color, stroke_opacity))
            self.context.stroke()
            self.context.restore()
        elif not visible:
            self.context.new_path()

        # Draw path markers
        draw_markers(self, node)

        # Draw children
        if display and node.tag not in INVISIBLE_TAGS:
            for child in node.children:
                self.draw(child)

        # Apply filter, mask and opacity
        if filter_ or mask or (opacity < 1 and node.children):
            self.context.pop_group_to_source()
            if filter_:
                apply_filter_before_painting(self, node, filter_)
            if mask in self.masks:
                paint_mask(self, node, mask, opacity)
            else:
                self.context.paint_with_alpha(opacity)
            if filter_:
                apply_filter_after_painting(self, node, filter_)

        # Clean cursor's position after 'text' tags
        if node.tag == 'text':
            self.cursor_position = [0, 0]
            self.cursor_d_position = [0, 0]
            self.text_path_width = 0

        self.context.restore()
        self.parent_node = old_parent_node
        self.font_size = old_font_size
        self.context_width, self.context_height = old_context_size


class PDFSurface(Surface):
    """A surface that writes in PDF format."""
    surface_class = cairo.PDFSurface


class PSSurface(Surface):
    """A surface that writes in PostScript format."""
    surface_class = cairo.PSSurface


class PNGSurface(Surface):
    """A surface that writes in PNG format."""
    device_units_per_user_units = 1

    def _create_surface(self, width, height):
        """Create and return ``(cairo_surface, width, height)``."""
        width = int(width)
        height = int(height)
        cairo_surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, width, height)
        return cairo_surface, width, height

    def finish(self):
        """Read the PNG surface content."""
        if self.output is not None:
            self.cairo.write_to_png(self.output)
        return super().finish()


class SVGSurface(Surface):
    """A surface that writes in SVG format.

    It may seem pointless to render SVG to SVG, but this can be used
    with ``output=None`` to get a vector-based single page cairo surface.

    """
    surface_class = cairo.SVGSurface
