#!/usr/bin/env python3
# vim:fileencoding=utf-8
# License: GPL v3 Copyright: 2018, Kovid Goyal <kovid at kovidgoyal.net>

import codecs
import os
import sys
from base64 import standard_b64encode
from collections import defaultdict, deque
from contextlib import suppress
from enum import IntEnum
from itertools import count
from typing import (
    Any, Callable, ClassVar, DefaultDict, Deque, Dict, Generic, Iterator, List,
    Optional, Sequence, Tuple, Type, TypeVar, Union, cast
)

from kitty.conf.utils import positive_float, positive_int
from kitty.fast_data_types import create_canvas
from kitty.typing import (
    GRT_C, CompletedProcess, GRT_a, GRT_d, GRT_f, GRT_m, GRT_o, GRT_t,
    HandlerType
)
from kitty.utils import ScreenSize, find_exe, fit_image

from .operations import cursor

try:
    fsenc = sys.getfilesystemencoding() or 'utf-8'
    codecs.lookup(fsenc)
except Exception:
    fsenc = 'utf-8'


class Dispose(IntEnum):
    undefined = 0
    none = 1
    background = 2
    previous = 3


class Frame:
    gap: int  # milliseconds
    canvas_width: int
    canvas_height: int
    width: int
    height: int
    index: int
    xdpi: float
    ydpi: float
    canvas_x: int
    canvas_y: int
    mode: str
    needs_blend: bool
    dispose: Dispose
    path: str = ''

    def __init__(self, identify_data: Union['Frame', Dict[str, str]]):
        if isinstance(identify_data, Frame):
            for k in Frame.__annotations__:
                setattr(self, k, getattr(identify_data, k))
        else:
            self.gap = max(0, int(identify_data['gap']) * 10)
            sz, pos = identify_data['canvas'].split('+', 1)
            self.canvas_width, self.canvas_height = map(positive_int, sz.split('x', 1))
            self.canvas_x, self.canvas_y = map(int, pos.split('+', 1))
            self.width, self.height = map(positive_int, identify_data['size'].split('x', 1))
            self.xdpi, self.ydpi = map(positive_float, identify_data['dpi'].split('x', 1))
            self.index = positive_int(identify_data['index'])
            q = identify_data['transparency'].lower()
            self.mode = 'rgba' if q in ('blend', 'true') else 'rgb'
            self.needs_blend = q == 'blend'
            self.dispose = getattr(Dispose, identify_data['dispose'].lower())

    def __repr__(self) -> str:
        canvas = f'{self.canvas_width}x{self.canvas_height}:{self.canvas_x}+{self.canvas_y}'
        geom = f'{self.width}x{self.height}'
        return f'Frame(index={self.index}, gap={self.gap}, geom={geom}, canvas={canvas}, dispose={self.dispose.name})'


class ImageData:

    def __init__(self, fmt: str, width: int, height: int, mode: str, frames: List[Frame]):
        self.width, self.height, self.fmt, self.mode = width, height, fmt, mode
        self.transmit_fmt: GRT_f = (24 if self.mode == 'rgb' else 32)
        self.frames = frames

    def __len__(self) -> int:
        return len(self.frames)

    def __iter__(self) -> Iterator[Frame]:
        yield from self.frames

    def __repr__(self) -> str:
        frames = '\n  '.join(map(repr, self.frames))
        return f'Image(fmt={self.fmt}, mode={self.mode},\n  {frames}\n)'


class OpenFailed(ValueError):

    def __init__(self, path: str, message: str):
        ValueError.__init__(
            self, 'Failed to open image: {} with error: {}'.format(path, message)
        )
        self.path = path


class ConvertFailed(ValueError):

    def __init__(self, path: str, message: str):
        ValueError.__init__(
            self, 'Failed to convert image: {} with error: {}'.format(path, message)
        )
        self.path = path


class NoImageMagick(Exception):
    pass


class OutdatedImageMagick(ValueError):

    def __init__(self, detailed_error: str):
        super().__init__('ImageMagick on this system is too old ImageMagick 7+ required which was first released in 2016')
        self.detailed_error = detailed_error


last_imagemagick_cmd: Sequence[str] = ()


def run_imagemagick(path: str, cmd: Sequence[str], keep_stdout: bool = True) -> CompletedProcess:
    global last_imagemagick_cmd
    import subprocess
    last_imagemagick_cmd = cmd
    try:
        p = subprocess.run(cmd, stdout=subprocess.PIPE if keep_stdout else subprocess.DEVNULL, stderr=subprocess.PIPE)
    except FileNotFoundError:
        raise NoImageMagick('ImageMagick is required to process images')
    if p.returncode != 0:
        raise OpenFailed(path, p.stderr.decode('utf-8'))
    return p


def identify(path: str) -> ImageData:
    import json
    q = '{"fmt":"%m","canvas":"%g","transparency":"%A","gap":"%T","index":"%p","size":"%wx%h","dpi":"%xx%y","dispose":"%D"},'
    exe = find_exe('magick')
    if exe:
        cmd = [exe, 'identify']
    else:
        cmd = ['identify']
    p = run_imagemagick(path, cmd + ['-format', q, '--', path])
    data = json.loads(b'[' + p.stdout.rstrip(b',') + b']')
    first = data[0]
    frames = list(map(Frame, data))
    image_fmt = first['fmt'].lower()
    if image_fmt == 'gif' and not any(f.gap > 0 for f in frames):
        # Some broken GIF images have all zero gaps, browsers with their usual
        # idiot ideas render these with a default 100ms gap https://bugzilla.mozilla.org/show_bug.cgi?id=125137
        # Browsers actually force a 100ms gap at any zero gap frame, but that
        # just means it is impossible to deliberately use zero gap frames for
        # sophisticated blending, so we dont do that.
        for f in frames:
            f.gap = 100
    mode = 'rgb'
    for f in frames:
        if f.mode == 'rgba':
            mode = 'rgba'
            break
    return ImageData(image_fmt, frames[0].canvas_width, frames[0].canvas_height, mode, frames)


class RenderedImage(ImageData):

    def __init__(self, fmt: str, width: int, height: int, mode: str):
        super().__init__(fmt, width, height, mode, [])


def render_image(
    path: str, output_prefix: str,
    m: ImageData,
    available_width: int, available_height: int,
    scale_up: bool,
    only_first_frame: bool = False
) -> RenderedImage:
    import tempfile
    has_multiple_frames = len(m) > 1
    get_multiple_frames = has_multiple_frames and not only_first_frame
    exe = find_exe('magick')
    if exe:
        cmd = [exe, 'convert']
    else:
        exe = find_exe('convert')
        if exe is None:
            raise OSError('Failed to find the ImageMagick convert executable, make sure it is present in PATH')
        cmd = [exe]
    cmd += ['-background', 'none', '--', path]
    if only_first_frame and has_multiple_frames:
        cmd[-1] += '[0]'
    scaled = False
    width, height = m.width, m.height
    if scale_up:
        if width < available_width:
            r = available_width / width
            width, height = available_width, int(height * r)
            scaled = True
    if scaled or width > available_width or height > available_height:
        width, height = fit_image(width, height, available_width, available_height)
        resize_cmd = ['-resize', '{}x{}!'.format(width, height)]
        if get_multiple_frames:
            # we have to coalesce, resize and de-coalesce all frames
            resize_cmd = ['-coalesce'] + resize_cmd + ['-deconstruct']
        cmd += resize_cmd
    cmd += ['-depth', '8', '-auto-orient', '-set', 'filename:f', '%w-%h-%g-%p']
    ans = RenderedImage(m.fmt, width, height, m.mode)
    if only_first_frame:
        ans.frames = [Frame(m.frames[0])]
    else:
        ans.frames = list(map(Frame, m.frames))
    bytes_per_pixel = 3 if m.mode == 'rgb' else 4

    def check_resize(frame: Frame) -> None:
        # ImageMagick sometimes generates RGBA images smaller than the specified
        # size. See https://github.com/kovidgoyal/kitty/issues/276 for examples
        sz = os.path.getsize(frame.path)
        expected_size = bytes_per_pixel * frame.width * frame.height
        if sz < expected_size:
            missing = expected_size - sz
            if missing % (bytes_per_pixel * width) != 0:
                raise ConvertFailed(
                    path, 'ImageMagick failed to convert {} correctly,'
                    ' it generated {} < {} of data (w={}, h={}, bpp={})'.format(
                        path, sz, expected_size, frame.width, frame.height, bytes_per_pixel))
            frame.height -= missing // (bytes_per_pixel * frame.width)
            if frame.index == 0:
                ans.height = frame.height
                ans.width = frame.width

    with tempfile.TemporaryDirectory(dir=os.path.dirname(output_prefix)) as tdir:
        output_template = os.path.join(tdir, f'im-%[filename:f].{m.mode}')
        if get_multiple_frames:
            cmd.append('+adjoin')
        run_imagemagick(path, cmd + [output_template])
        unseen = {x.index for x in m}
        for x in os.listdir(tdir):
            try:
                parts = x.split('.', 1)[0].split('-')
                index = int(parts[-1])
                unseen.discard(index)
                f = ans.frames[index]
                f.width, f.height = map(positive_int, parts[1:3])
                sz, pos = parts[3].split('+', 1)
                f.canvas_width, f.canvas_height = map(positive_int, sz.split('x', 1))
                f.canvas_x, f.canvas_y = map(int, pos.split('+', 1))
            except Exception:
                raise OutdatedImageMagick(f'Unexpected output filename: {x!r} produced by ImageMagick command: {last_imagemagick_cmd}')
            f.path = output_prefix + f'-{index}.{m.mode}'
            os.rename(os.path.join(tdir, x), f.path)
            check_resize(f)
    f = ans.frames[0]
    if f.width != ans.width or f.height != ans.height:
        with open(f.path, 'r+b') as ff:
            data = ff.read()
            ff.seek(0)
            ff.truncate()
            cd = create_canvas(data, f.width, f.canvas_x, f.canvas_y, ans.width, ans.height, 3 if ans.mode == 'rgb' else 4)
            ff.write(cd)
    if get_multiple_frames:
        if unseen:
            raise ConvertFailed(path, f'Failed to render {len(unseen)} out of {len(m)} frames of animation')
    elif not ans.frames[0].path:
        raise ConvertFailed(path, 'Failed to render image')

    return ans


def render_as_single_image(
    path: str, m: ImageData,
    available_width: int, available_height: int,
    scale_up: bool,
    tdir: Optional[str] = None
) -> Tuple[str, int, int]:
    import tempfile
    fd, output = tempfile.mkstemp(prefix='icat-', suffix=f'.{m.mode}', dir=tdir)
    os.close(fd)
    result = render_image(path, output, m, available_width, available_height, scale_up, only_first_frame=True)
    os.rename(result.frames[0].path, output)
    return output, result.width, result.height


def can_display_images() -> bool:
    import shutil
    ans: Optional[bool] = getattr(can_display_images, 'ans', None)
    if ans is None:
        ans = shutil.which('convert') is not None
        setattr(can_display_images, 'ans', ans)
    return ans


ImageKey = Tuple[str, int, int]
SentImageKey = Tuple[int, int, int]
T = TypeVar('T')


class Alias(Generic[T]):

    currently_processing: ClassVar[str] = ''

    def __init__(self, defval: T) -> None:
        self.name = ''
        self.defval = defval

    def __get__(self, instance: Optional['GraphicsCommand'], cls: Optional[Type['GraphicsCommand']] = None) -> T:
        if instance is None:
            return self.defval
        return cast(T, instance._actual_values.get(self.name, self.defval))

    def __set__(self, instance: 'GraphicsCommand', val: T) -> None:
        if val == self.defval:
            instance._actual_values.pop(self.name, None)
        else:
            instance._actual_values[self.name] = val

    def __set_name__(self, owner: Type['GraphicsCommand'], name: str) -> None:
        if len(name) == 1:
            Alias.currently_processing = name
        self.name = Alias.currently_processing


class GraphicsCommand:
    a = action = Alias(cast(GRT_a, 't'))
    q = quiet = Alias(0)
    f = format = Alias(32)
    t = transmission_type = Alias(cast(GRT_t, 'd'))
    s = data_width = animation_state = Alias(0)
    v = data_height = loop_count = Alias(0)
    S = data_size = Alias(0)
    O = data_offset = Alias(0)  # noqa
    i = image_id = Alias(0)
    I = image_number = Alias(0)  # noqa
    p = placement_id = Alias(0)
    o = compression = Alias(cast(Optional[GRT_o], None))
    m = more = Alias(cast(GRT_m, 0))
    x = left_edge = Alias(0)
    y = top_edge = Alias(0)
    w = width = Alias(0)
    h = height = Alias(0)
    X = cell_x_offset = blend_mode = Alias(0)
    Y = cell_y_offset = bgcolor = Alias(0)
    c = columns = other_frame_number = dest_frame = Alias(0)
    r = rows = frame_number = source_frame = Alias(0)
    z = z_index = gap = Alias(0)
    C = cursor_movement = compose_mode = Alias(cast(GRT_C, 0))
    d = delete_action = Alias(cast(GRT_d, 'a'))

    def __init__(self) -> None:
        self._actual_values: Dict[str, Any] = {}

    def __repr__(self) -> str:
        return self.serialize().decode('ascii').replace('\033', '^]')

    def clone(self) -> 'GraphicsCommand':
        ans = GraphicsCommand()
        ans._actual_values = self._actual_values.copy()
        return ans

    def serialize(self, payload: Union[bytes, str] = b'') -> bytes:
        items = []
        for k, val in self._actual_values.items():
            items.append('{}={}'.format(k, val))

        ans: List[bytes] = []
        w = ans.append
        w(b'\033_G')
        w(','.join(items).encode('ascii'))
        if payload:
            w(b';')
            if isinstance(payload, str):
                payload = standard_b64encode(payload.encode('utf-8'))
            w(payload)
        w(b'\033\\')
        return b''.join(ans)

    def clear(self) -> None:
        self._actual_values = {}

    def iter_transmission_chunks(self, data: Optional[bytes] = None, level: int = -1, compression_threshold: int = 1024) -> Iterator[bytes]:
        if data is None:
            yield self.serialize()
            return
        gc = self.clone()
        gc.S = len(data)
        if level and len(data) >= compression_threshold:
            import zlib
            compressed = zlib.compress(data, level)
            if len(compressed) < len(data):
                gc.o = 'z'
                data = compressed
                gc.S = len(data)
        data = standard_b64encode(data)
        while data:
            chunk, data = data[:4096], data[4096:]
            gc.m = 1 if data else 0
            yield gc.serialize(chunk)
            gc.clear()


class Placement:
    cmd: GraphicsCommand
    x: int = 0
    y: int = 0

    def __init__(self, cmd: GraphicsCommand, x: int = 0, y: int = 0):
        self.cmd = cmd
        self.x = x
        self.y = y


class ImageManager:

    def __init__(self, handler: HandlerType):
        self.image_id_counter = count()
        self.handler = handler
        self.filesystem_ok: Optional[bool] = None
        self.image_data: Dict[str, ImageData] = {}
        self.failed_images: Dict[str, Exception] = {}
        self.converted_images: Dict[ImageKey, ImageKey] = {}
        self.sent_images: Dict[ImageKey, int] = {}
        self.image_id_to_image_data: Dict[int, ImageData] = {}
        self.image_id_to_converted_data: Dict[int, ImageKey] = {}
        self.transmission_status: Dict[int, Union[str, int]] = {}
        self.placements_in_flight: DefaultDict[int, Deque[Placement]] = defaultdict(deque)
        self.update_image_placement_for_resend: Optional[Callable[[int, Placement], bool]]

    @property
    def next_image_id(self) -> int:
        return next(self.image_id_counter) + 2

    @property
    def screen_size(self) -> ScreenSize:
        return self.handler.screen_size

    def __enter__(self) -> None:
        import tempfile
        self.tdir = tempfile.mkdtemp(prefix='kitten-images-')
        with tempfile.NamedTemporaryFile(dir=self.tdir, delete=False) as f:
            f.write(b'abcd')
        gc = GraphicsCommand()
        gc.a = 'q'
        gc.s = gc.v = gc.i = 1
        gc.t = 'f'
        self.handler.cmd.gr_command(gc, standard_b64encode(f.name.encode(fsenc)))

    def __exit__(self, *a: Any) -> None:
        import shutil
        shutil.rmtree(self.tdir, ignore_errors=True)
        self.handler.cmd.clear_images_on_screen(delete_data=True)
        self.delete_all_sent_images()
        del self.handler

    def delete_all_sent_images(self) -> None:
        gc = GraphicsCommand()
        gc.a = 'd'
        for img_id in self.transmission_status:
            gc.i = img_id
            self.handler.cmd.gr_command(gc)
        self.transmission_status.clear()

    def handle_response(self, apc: str) -> None:
        cdata, payload = apc[1:].partition(';')[::2]
        control = {}
        for x in cdata.split(','):
            k, v = x.partition('=')[::2]
            control[k] = v
        try:
            image_id = int(control.get('i', '0'))
        except Exception:
            image_id = 0
        if image_id == 1:
            self.filesystem_ok = payload == 'OK'
            return
        if not image_id:
            return
        if not self.transmission_status.get(image_id):
            self.transmission_status[image_id] = payload
        else:
            in_flight = self.placements_in_flight[image_id]
            if in_flight:
                pl = in_flight.popleft()
                if payload.startswith('ENOENT:'):
                    with suppress(Exception):
                        self.resend_image(image_id, pl)
                if not in_flight:
                    self.placements_in_flight.pop(image_id, None)

    def resend_image(self, image_id: int, pl: Placement) -> None:
        if self.update_image_placement_for_resend is not None and not self.update_image_placement_for_resend(image_id, pl):
            return
        image_data = self.image_id_to_image_data[image_id]
        skey = self.image_id_to_converted_data[image_id]
        self.transmit_image(image_data, image_id, *skey)
        with cursor(self.handler.write):
            self.handler.cmd.set_cursor_position(pl.x, pl.y)
            self.handler.cmd.gr_command(pl.cmd)

    def send_image(self, path: str, max_cols: Optional[int] = None, max_rows: Optional[int] = None, scale_up: bool = False) -> SentImageKey:
        path = os.path.abspath(path)
        if path in self.failed_images:
            raise self.failed_images[path]
        if path not in self.image_data:
            try:
                self.image_data[path] = identify(path)
            except Exception as e:
                self.failed_images[path] = e
                raise
        m = self.image_data[path]
        ss = self.screen_size
        if max_cols is None:
            max_cols = ss.cols
        if max_rows is None:
            max_rows = ss.rows
        available_width = max_cols * ss.cell_width
        available_height = max_rows * ss.cell_height
        key = path, available_width, available_height
        skey = self.converted_images.get(key)
        if skey is None:
            try:
                self.converted_images[key] = skey = self.convert_image(path, available_width, available_height, m, scale_up)
            except Exception as e:
                self.failed_images[path] = e
                raise
        final_width, final_height = skey[1:]
        if final_width == 0:
            return 0, 0, 0
        image_id = self.sent_images.get(skey)
        if image_id is None:
            image_id = self.next_image_id
            self.transmit_image(m, image_id, *skey)
            self.sent_images[skey] = image_id
        self.image_id_to_converted_data[image_id] = skey
        self.image_id_to_image_data[image_id] = m
        return image_id, skey[1], skey[2]

    def hide_image(self, image_id: int) -> None:
        gc = GraphicsCommand()
        gc.a = 'd'
        gc.i = image_id
        self.handler.cmd.gr_command(gc)

    def show_image(self, image_id: int, x: int, y: int, src_rect: Optional[Tuple[int, int, int, int]] = None) -> None:
        gc = GraphicsCommand()
        gc.a = 'p'
        gc.i = image_id
        if src_rect is not None:
            gc.x, gc.y, gc.w, gc.h = map(int, src_rect)
        self.placements_in_flight[image_id].append(Placement(gc, x, y))
        with cursor(self.handler.write):
            self.handler.cmd.set_cursor_position(x, y)
            self.handler.cmd.gr_command(gc)

    def convert_image(self, path: str, available_width: int, available_height: int, image_data: ImageData, scale_up: bool = False) -> ImageKey:
        rgba_path, width, height = render_as_single_image(path, image_data, available_width, available_height, scale_up, tdir=self.tdir)
        return rgba_path, width, height

    def transmit_image(self, image_data: ImageData, image_id: int, rgba_path: str, width: int, height: int) -> int:
        self.transmission_status[image_id] = 0
        gc = GraphicsCommand()
        gc.a = 't'
        gc.f = image_data.transmit_fmt
        gc.s = width
        gc.v = height
        gc.i = image_id
        if self.filesystem_ok:
            gc.t = 'f'
            self.handler.cmd.gr_command(
                gc, standard_b64encode(rgba_path.encode(fsenc)))
        else:
            import zlib
            with open(rgba_path, 'rb') as f:
                data = f.read()
            gc.S = len(data)
            data = zlib.compress(data)
            gc.o = 'z'
            data = standard_b64encode(data)
            while data:
                chunk, data = data[:4096], data[4096:]
                gc.m = 1 if data else 0
                self.handler.cmd.gr_command(gc, chunk)
                gc.clear()
        return image_id
