"""
Truevision Targa Graphic (TGA) picture parser.

Author: Victor Stinner
Creation: 18 december 2006
"""

from hachoir_parser import Parser
from hachoir_core.field import FieldSet, UInt8, UInt16, Enum, RawBytes
from hachoir_core.endian import LITTLE_ENDIAN
from hachoir_parser.image.common import PaletteRGB

class Line(FieldSet):
    def __init__(self, *args):
        FieldSet.__init__(self, *args)
        self._size = self["/width"].value * self["/bpp"].value

    def createFields(self):
        for x in xrange(self["/width"].value):
            yield UInt8(self, "pixel[]")

class Pixels(FieldSet):
    def __init__(self, *args):
        FieldSet.__init__(self, *args)
        self._size = self["/width"].value * self["/height"].value * self["/bpp"].value

    def createFields(self):
        if self["/options"].value == 0:
            RANGE = xrange(self["/height"].value-1,-1,-1)
        else:
            RANGE = xrange(self["/height"].value)
        for y in RANGE:
            yield Line(self, "line[%u]" % y)

class TargaFile(Parser):
    PARSER_TAGS = {
        "id": "targa",
        "category": "image",
        "file_ext": ("tga",),
        "mime": (u"image/targa", u"image/tga", u"image/x-tga"),
        "min_size": 18*8,
        "description": u"Truevision Targa Graphic (TGA)"
    }
    CODEC_NAME = {
         1: u"8-bit uncompressed",
         2: u"24-bit uncompressed",
         9: u"8-bit RLE",
        10: u"24-bit RLE",
    }
    endian = LITTLE_ENDIAN

    def validate(self):
        if self["version"].value != 1:
            return "Unknown version"
        if self["codec"].value not in self.CODEC_NAME:
            return "Unknown codec"
        if self["x_min"].value != 0 or self["y_min"].value != 0:
            return "(x_min, y_min) is not (0,0)"
        if self["bpp"].value not in (8, 24):
            return "Unknown bits/pixel value"
        return True

    def createFields(self):
        yield UInt8(self, "hdr_size", "Header size in bytes")
        yield UInt8(self, "version", "Targa version (always one)")
        yield Enum(UInt8(self, "codec", "Pixels encoding"), self.CODEC_NAME)
        yield UInt16(self, "palette_ofs", "Palette absolute file offset")
        yield UInt16(self, "nb_color", "Number of color")
        yield UInt8(self, "color_map_size", "Color map entry size")
        yield UInt16(self, "x_min")
        yield UInt16(self, "y_min")
        yield UInt16(self, "width")
        yield UInt16(self, "height")
        yield UInt8(self, "bpp", "Bits per pixel")
        yield UInt8(self, "options", "Options (0: vertical mirror)")
        if self["bpp"].value == 8:
            yield PaletteRGB(self, "palette", 256)
        if self["codec"].value == 1:
            yield Pixels(self, "pixels")
        else:
            size = (self.size - self.current_size) // 8
            if size:
                yield RawBytes(self, "raw_pixels", size)