#
# The Python Imaging Library.
# $Id$
#
# PIL raster font management
#
# History:
# 1996-08-07 fl   created (experimental)
# 1997-08-25 fl   minor adjustments to handle fonts from pilfont 0.3
# 1999-02-06 fl   rewrote most font management stuff in C
# 1999-03-17 fl   take pth files into account in load_path (from Richard Jones)
# 2001-02-17 fl   added freetype support
# 2001-05-09 fl   added TransposedFont wrapper class
# 2002-03-04 fl   make sure we have a "L" or "1" font
# 2002-12-04 fl   skip non-directory entries in the system path
# 2003-04-29 fl   add embedded default font
# 2003-09-27 fl   added support for truetype charmap encodings
#
# Todo:
# Adapt to PILFONT2 format (16-bit fonts, compressed, single file)
#
# Copyright (c) 1997-2003 by Secret Labs AB
# Copyright (c) 1996-2003 by Fredrik Lundh
#
# See the README file for information on usage and redistribution.
#

from . import Image
from ._util import isDirectory, isPath, py3
import os
import sys

LAYOUT_BASIC = 0
LAYOUT_RAQM = 1


class _imagingft_not_installed(object):
    # module placeholder
    def __getattr__(self, id):
        raise ImportError("The _imagingft C module is not installed")


try:
    from . import _imagingft as core
except ImportError:
    core = _imagingft_not_installed()


# FIXME: add support for pilfont2 format (see FontFile.py)

# --------------------------------------------------------------------
# Font metrics format:
#       "PILfont" LF
#       fontdescriptor LF
#       (optional) key=value... LF
#       "DATA" LF
#       binary data: 256*10*2 bytes (dx, dy, dstbox, srcbox)
#
# To place a character, cut out srcbox and paste at dstbox,
# relative to the character position.  Then move the character
# position according to dx, dy.
# --------------------------------------------------------------------


class ImageFont(object):
    "PIL font wrapper"

    def _load_pilfont(self, filename):

        with open(filename, "rb") as fp:
            for ext in (".png", ".gif", ".pbm"):
                try:
                    fullname = os.path.splitext(filename)[0] + ext
                    image = Image.open(fullname)
                except:
                    pass
                else:
                    if image and image.mode in ("1", "L"):
                        break
            else:
                raise IOError("cannot find glyph data file")

            self.file = fullname

            return self._load_pilfont_data(fp, image)

    def _load_pilfont_data(self, file, image):

        # read PILfont header
        if file.readline() != b"PILfont\n":
            raise SyntaxError("Not a PILfont file")
        file.readline().split(b";")
        self.info = []  # FIXME: should be a dictionary
        while True:
            s = file.readline()
            if not s or s == b"DATA\n":
                break
            self.info.append(s)

        # read PILfont metrics
        data = file.read(256*20)

        # check image
        if image.mode not in ("1", "L"):
            raise TypeError("invalid font image mode")

        image.load()

        self.font = Image.core.font(image.im, data)

    def getsize(self, text, *args, **kwargs):
        return self.font.getsize(text)

    def getmask(self, text, mode="", *args, **kwargs):
        return self.font.getmask(text, mode)


##
# Wrapper for FreeType fonts.  Application code should use the
# <b>truetype</b> factory function to create font objects.

class FreeTypeFont(object):
    "FreeType font wrapper (requires _imagingft service)"

    def __init__(self, font=None, size=10, index=0, encoding="",
                 layout_engine=None):
        # FIXME: use service provider instead

        self.path = font
        self.size = size
        self.index = index
        self.encoding = encoding

        if layout_engine not in (LAYOUT_BASIC, LAYOUT_RAQM):
            layout_engine = LAYOUT_BASIC
            if core.HAVE_RAQM:
                layout_engine = LAYOUT_RAQM
        if layout_engine == LAYOUT_RAQM and not core.HAVE_RAQM:
            layout_engine = LAYOUT_BASIC

        self.layout_engine = layout_engine

        if isPath(font):
            self.font = core.getfont(font, size, index, encoding, layout_engine=layout_engine)
        else:
            self.font_bytes = font.read()
            self.font = core.getfont(
                "", size, index, encoding, self.font_bytes, layout_engine)

    def _multiline_split(self, text):
        split_character = "\n" if isinstance(text, str) else b"\n"
        return text.split(split_character)

    def getname(self):
        return self.font.family, self.font.style

    def getmetrics(self):
        return self.font.ascent, self.font.descent

    def getsize(self, text, direction=None, features=None):
        size, offset = self.font.getsize(text, direction, features)
        return (size[0] + offset[0], size[1] + offset[1])

    def getsize_multiline(self, text, direction=None, spacing=4, features=None):
        max_width = 0
        lines = self._multiline_split(text)
        line_spacing = self.getsize('A')[1] + spacing
        for line in lines:
            line_width, line_height = self.getsize(line, direction, features)
            max_width = max(max_width, line_width)

        return max_width, len(lines)*line_spacing - spacing

    def getoffset(self, text):
        return self.font.getsize(text)[1]

    def getmask(self, text, mode="", direction=None, features=None):
        return self.getmask2(text, mode, direction=direction, features=features)[0]

    def getmask2(self, text, mode="", fill=Image.core.fill, direction=None, features=None, *args, **kwargs):
        size, offset = self.font.getsize(text, direction, features)
        im = fill("L", size, 0)
        self.font.render(text, im.id, mode == "1", direction, features)
        return im, offset

    def font_variant(self, font=None, size=None, index=None, encoding=None,
                     layout_engine=None):
        """
        Create a copy of this FreeTypeFont object,
        using any specified arguments to override the settings.

        Parameters are identical to the parameters used to initialize this
        object.

        :return: A FreeTypeFont object.
        """
        return FreeTypeFont(font=self.path if font is None else font,
                            size=self.size if size is None else size,
                            index=self.index if index is None else index,
                            encoding=self.encoding if encoding is None else encoding,
                            layout_engine=self.layout_engine if layout_engine is None else layout_engine
                            )


class TransposedFont(object):
    "Wrapper for writing rotated or mirrored text"

    def __init__(self, font, orientation=None):
        """
        Wrapper that creates a transposed font from any existing font
        object.

        :param font: A font object.
        :param orientation: An optional orientation.  If given, this should
            be one of Image.FLIP_LEFT_RIGHT, Image.FLIP_TOP_BOTTOM,
            Image.ROTATE_90, Image.ROTATE_180, or Image.ROTATE_270.
        """
        self.font = font
        self.orientation = orientation  # any 'transpose' argument, or None

    def getsize(self, text, *args, **kwargs):
        w, h = self.font.getsize(text)
        if self.orientation in (Image.ROTATE_90, Image.ROTATE_270):
            return h, w
        return w, h

    def getmask(self, text, mode="", *args, **kwargs):
        im = self.font.getmask(text, mode, *args, **kwargs)
        if self.orientation is not None:
            return im.transpose(self.orientation)
        return im


def load(filename):
    """
    Load a font file.  This function loads a font object from the given
    bitmap font file, and returns the corresponding font object.

    :param filename: Name of font file.
    :return: A font object.
    :exception IOError: If the file could not be read.
    """
    f = ImageFont()
    f._load_pilfont(filename)
    return f


def truetype(font=None, size=10, index=0, encoding="",
             layout_engine=None):
    """
    Load a TrueType or OpenType font from a file or file-like object,
    and create a font object.
    This function loads a font object from the given file or file-like
    object, and creates a font object for a font of the given size.

    This function requires the _imagingft service.

    :param font: A filename or file-like object containing a TrueType font.
                     Under Windows, if the file is not found in this filename,
                     the loader also looks in Windows :file:`fonts/` directory.
    :param size: The requested size, in points.
    :param index: Which font face to load (default is first available face).
    :param encoding: Which font encoding to use (default is Unicode). Common
                     encodings are "unic" (Unicode), "symb" (Microsoft
                     Symbol), "ADOB" (Adobe Standard), "ADBE" (Adobe Expert),
                     and "armn" (Apple Roman). See the FreeType documentation
                     for more information.
    :param layout_engine: Which layout engine to use, if available:
                     `ImageFont.LAYOUT_BASIC` or `ImageFont.LAYOUT_RAQM`.
    :return: A font object.
    :exception IOError: If the file could not be read.
    """

    try:
        return FreeTypeFont(font, size, index, encoding, layout_engine)
    except IOError:
        ttf_filename = os.path.basename(font)

        dirs = []
        if sys.platform == "win32":
            # check the windows font repository
            # NOTE: must use uppercase WINDIR, to work around bugs in
            # 1.5.2's os.environ.get()
            windir = os.environ.get("WINDIR")
            if windir:
                dirs.append(os.path.join(windir, "fonts"))
        elif sys.platform in ('linux', 'linux2'):
            lindirs = os.environ.get("XDG_DATA_DIRS", "")
            if not lindirs:
                # According to the freedesktop spec, XDG_DATA_DIRS should
                # default to /usr/share
                lindirs = '/usr/share'
            dirs += [os.path.join(lindir, "fonts")
                     for lindir in lindirs.split(":")]
        elif sys.platform == 'darwin':
            dirs += ['/Library/Fonts', '/System/Library/Fonts',
                     os.path.expanduser('~/Library/Fonts')]

        ext = os.path.splitext(ttf_filename)[1]
        first_font_with_a_different_extension = None
        for directory in dirs:
            for walkroot, walkdir, walkfilenames in os.walk(directory):
                for walkfilename in walkfilenames:
                    if ext and walkfilename == ttf_filename:
                        fontpath = os.path.join(walkroot, walkfilename)
                        return FreeTypeFont(fontpath, size, index, encoding, layout_engine)
                    elif not ext and os.path.splitext(walkfilename)[0] == ttf_filename:
                        fontpath = os.path.join(walkroot, walkfilename)
                        if os.path.splitext(fontpath)[1] == '.ttf':
                            return FreeTypeFont(fontpath, size, index, encoding, layout_engine)
                        if not ext and first_font_with_a_different_extension is None:
                            first_font_with_a_different_extension = fontpath
        if first_font_with_a_different_extension:
            return FreeTypeFont(first_font_with_a_different_extension, size,
                                index, encoding, layout_engine)
        raise


def load_path(filename):
    """
    Load font file. Same as :py:func:`~PIL.ImageFont.load`, but searches for a
    bitmap font along the Python path.

    :param filename: Name of font file.
    :return: A font object.
    :exception IOError: If the file could not be read.
    """
    for directory in sys.path:
        if isDirectory(directory):
            if not isinstance(filename, str):
                if py3:
                    filename = filename.decode("utf-8")
                else:
                    filename = filename.encode("utf-8")
            try:
                return load(os.path.join(directory, filename))
            except IOError:
                pass
    raise IOError("cannot find font file")


def load_default():
    """Load a "better than nothing" default font.

    .. versionadded:: 1.1.4