#!/usr/bin/env python3

############################################################################
#
# MODULE:       d.frame
# AUTHOR(S):    Martin Landa <landa.martin gmail.com>
#               Based on d.frame from GRASS 6
# PURPOSE:      Manages display frames on the user's graphics monitor
# COPYRIGHT:    (C) 2014-2015 by Martin Landa, and the GRASS Development Team
#
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 2 of the License, or
#  (at your option) any later version.
#
#  This program 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 General Public License for more details.
#
############################################################################
# %module
# % description: Manages display frames on the user's graphics monitor.
# % keyword: display
# % keyword: graphics
# % keyword: monitors
# % keyword: frame
# % overwrite: yes
# %end
# %flag
# % key: c
# % description: Create a new frame if doesn't exist and select
# %end
# %flag
# % key: e
# % description: Remove all frames, erase the screen and exit
# % suppress_required: yes
# %end
# %flag
# % key: p
# % description: Print name of current frame and exit
# % suppress_required: yes
# %end
# %flag
# % key: a
# % description: Print names of all frames including 'at' position and exit
# % suppress_required: yes
# %end
# %option
# % key: frame
# % type: string
# % required: yes
# % multiple: no
# % key_desc: name
# % description: Frame to be selected or created (if -c flag is given)
# %end
# %option
# % key: at
# % type: double
# % required: no
# % multiple: no
# % key_desc: bottom,top,left,right
# % label: Screen coordinates in percent where to place the frame (0,0 is lower-left)
# % options: 0-100
# % description: Implies only when -c or --overwrite flag is given
# %end

import os
import sys
from pathlib import Path

from grass.script.core import (
    fatal,
    parse_command,
    parser,
    read_command,
    run_command,
    warning,
)

# check if monitor is running


def check_monitor():
    return read_command("d.mon", flags="p", quiet=True).strip()


# read monitor file and return list of lines
# TODO: replace by d.info (see #2577)


def read_monitor_file(monitor, ftype="env"):
    mfile = check_monitor_file(monitor, ftype)
    try:
        fd = open(mfile)
    except OSError as e:
        fatal(_("Unable to get monitor info. %s"), e)

    lines = []
    for line in fd:
        lines.append(line)

    fd.close()

    return lines


# check if monitor file exists


def check_monitor_file(monitor, ftype="env"):
    mfile = parse_command("d.mon", flags="g").get(ftype, None)
    if mfile is None or not Path(mfile).is_file():
        fatal(_("Unable to get monitor info"))

    return mfile


# write new monitor file


def write_monitor_file(monitor, lines, ftype="env"):
    mfile = check_monitor_file(monitor, ftype)

    try:
        fd = open(mfile, "w")
    except OSError as e:
        fatal(_("Unable to get monitor info. %s"), e)

    fd.writelines(lines)
    fd.close()


# remove all frames and erase screen


def erase(monitor):
    # remove frames
    lines = []
    for line in read_monitor_file(monitor):
        if "FRAME" not in line:
            lines.append(line)

    write_monitor_file(monitor, lines)

    # erase screen
    run_command("d.erase")


# find frame for given monitor


def find_frame(monitor, frame):
    for line in read_monitor_file(monitor):
        if "FRAME" in line:
            if get_frame_name(line) == frame:
                return True

    return False


# print frames name(s) to stdout


def print_frames(monitor, current_only=False, full=False):
    for line in read_monitor_file(monitor):
        if "FRAME" not in line:
            continue
        if current_only and line.startswith("#"):
            continue
        sys.stdout.write(get_frame_name(line))
        if full:
            sys.stdout.write(":" + line.split("=", 1)[1].rsplit("#", 1)[0])
        sys.stdout.write("\n")


# get frame name from line


def get_frame_name(line):
    return line.rstrip("\n").rsplit("#", 1)[1].strip(" ")


def calculate_frame(frame, at, width, height):
    """Calculate absolute position of the frame from percentages

    at is from bottom left in percents (bottom,top,left,right)
    output is in pixels from top left (top,bottom,left,right)

    This function does also the necessary formatting.

    >>> calculate_frame("apple", "0,49.8,0,50.2", 500, 500)
    'GRASS_RENDER_FRAME=251,500,0,251 # apple\\n'
    >>> calculate_frame("orange", "50.2,0,49.8,100", 500, 500)
    'GRASS_RENDER_FRAME=500,249,249,500 # orange\\n'
    >>> calculate_frame("odd_number", "0,49.8,0,50.2", 367, 367)
    'GRASS_RENDER_FRAME=184,367,0,184 # odd_number\\n'

    The following would give 182,367,0,184 if we would be truncating
    to integers instead of rounding, but that would be wrong because
    height of the frame would be 367 minus 182 which is 185 while
    0.502 times 367 is 184.234 which fits with the (correct) width of
    the frame which is 184.

    >>> calculate_frame("test_truncating_bug", "0,50.2,0,50.2", 367, 367)
    'GRASS_RENDER_FRAME=183,367,0,184 # test_truncating_bug\\n'
    """
    try:
        b, t, l, r = list(map(float, at.split(",")))
    except ValueError:
        fatal(_("Invalid frame position: %s") % at)

    top = round(height - (t / 100.0 * height))
    bottom = round(height - (b / 100.0 * height))
    left = round(l / 100.0 * width)
    right = round(r / 100.0 * width)

    # %d for floats works like int() - truncates
    return "GRASS_RENDER_FRAME=%d,%d,%d,%d # %s%s" % (
        top,
        bottom,
        left,
        right,
        frame,
        "\n",
    )


# create new frame


def create_frame(monitor, frame, at, overwrite=False):
    lines = read_monitor_file(monitor)
    # get width and height of the monitor
    width = height = -1
    for line in lines:
        try:
            if "WIDTH" in line:
                width = int(line.split("=", 1)[1].rsplit(" ", 1)[0])
            elif "HEIGHT" in line:
                height = int(line.split("=", 1)[1].rsplit(" ", 1)[0])
        except (ValueError, IndexError):
            pass

    if width < 0 or height < 0:
        fatal(_("Invalid monitor size: %dx%d") % (width, height))

    if not overwrite:
        lines.append(calculate_frame(frame, at, width, height))
    else:
        for idx in range(len(lines)):
            line = lines[idx]
            if "FRAME" not in line:
                continue
            if get_frame_name(line) == frame:
                lines[idx] = calculate_frame(frame, at, width, height)

    write_monitor_file(monitor, lines)


# select existing frame


def select_frame(monitor, frame):
    lines = read_monitor_file(monitor)
    for idx in range(len(lines)):
        line = lines[idx]
        if "FRAME" not in line:
            continue
        if get_frame_name(line) == frame:
            if line.startswith("#"):
                lines[idx] = line.lstrip("# ")  # un-comment line
        elif not line.startswith("#"):
            lines[idx] = "# " + line  # comment-line

    write_monitor_file(monitor, lines)


def main():
    # get currently selected monitor
    monitor = check_monitor()
    if not monitor:
        fatal(_("No graphics device selected. Use d.mon to select graphics device."))

    if flags["e"]:
        # remove frames and erase monitor and exit
        erase(monitor)
        return

    if flags["p"]:
        # print current frame and exit
        print_frames(monitor, current_only=True)
        return

    if flags["a"]:
        # print all frames including their position and exit
        print_frames(monitor, current_only=False, full=True)
        return

    found = find_frame(monitor, options["frame"])
    if not found:
        if not flags["c"]:
            fatal(
                _(
                    "Frame <%s> doesn't exist, exiting. "
                    "To create a new frame use '-c' flag."
                )
                % options["frame"]
            )
        else:
            if not options["at"]:
                fatal(_("Required parameter <%s> not set") % "at")
            # create new frame if not exists
            create_frame(monitor, options["frame"], options["at"])
    elif os.getenv("GRASS_OVERWRITE", "0") == "1":
        warning(
            _("Frame <%s> already exists and will be overwritten") % options["frame"]
        )
        create_frame(monitor, options["frame"], options["at"], overwrite=True)
    elif options["at"]:
        warning(
            _(
                "Frame <%s> already found. An existing frame can be "
                "overwritten by '%s' flag."
            )
            % (options["frame"], "--overwrite")
        )

    # select givenframe
    select_frame(monitor, options["frame"])


if __name__ == "__main__":
    if len(sys.argv) == 2 and sys.argv[1] == "--doctest":
        import doctest

        sys.exit(doctest.testmod().failed)
    options, flags = parser()
    sys.exit(main())
