#!/usr/bin/python3
#
# sspreview
# Copyright (C) 2024 Juan J. Martinez <jjm@usebox.net>
#
# 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 3 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.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#

from argparse import ArgumentParser
from tkinter import Tk, N, W, E, S, StringVar
from tkinter import ttk
from PIL import ImageTk, Image

__version__ = "0.2"

DEF_W = 16
DEF_H = 16
DEF_F = 0
DEF_D = 600
DEF_S = 10


class Preview(object):
    def __init__(self, spritesheet, frame_w, frame_h, error_fn):
        self.spritesheet = spritesheet
        self.error = error_fn
        self.frames = []
        self.current = 0
        self.next_step = None
        self.delay_v = DEF_D

        self.root = Tk()
        self.root.title("SpriteSheet Animation Preview")
        self.root.columnconfigure(0, weight=1)
        self.root.rowconfigure(0, weight=1)

        mainframe = ttk.Frame(self.root, padding="10 10 10 10")
        mainframe.grid(column=0, row=0, sticky=(N, W, E, S))

        self.img = ttk.Label(mainframe, text="Preview", padding="0 10 10 10")
        self.img.grid(column=0, row=0, columnspan=2, sticky=N, padx=10)

        self.frame_w = StringVar()
        self.frame_w.set(frame_w)

        self.frame_h = StringVar()
        self.frame_h.set(frame_h)

        self.frame_list = StringVar()
        self.frame_list.set(DEF_F)

        self.delay = StringVar()
        self.delay.set(DEF_D)

        self.scale = StringVar()
        self.scale.set(DEF_S)

        ttk.Label(mainframe, text="Width (px)").grid(column=0, row=3, sticky=E, padx=10)
        entry_w = ttk.Entry(mainframe, width=8, textvariable=self.frame_w)
        entry_w.grid(column=1, row=3, sticky=(W, E))

        ttk.Label(mainframe, text="Height (px)").grid(
            column=0, row=4, sticky=E, padx=10
        )
        entry_h = ttk.Entry(mainframe, width=8, textvariable=self.frame_h)
        entry_h.grid(column=1, row=4, sticky=(W, E))

        ttk.Label(mainframe, text="Frames").grid(column=0, row=5, sticky=E, padx=10)
        entry_f = ttk.Entry(mainframe, width=16, textvariable=self.frame_list)
        entry_f.grid(column=1, row=5, sticky=(W, E))

        ttk.Label(mainframe, text="Delay (ms)").grid(column=0, row=6, sticky=E, padx=10)
        entry_d = ttk.Entry(mainframe, width=16, textvariable=self.delay)
        entry_d.grid(column=1, row=6, sticky=(W, E))

        ttk.Label(mainframe, text="Scale").grid(column=0, row=7, sticky=E, padx=10)
        entry_s = ttk.Entry(mainframe, width=16, textvariable=self.scale)
        entry_s.grid(column=1, row=7, sticky=(W, E))

        bf = ttk.Frame(mainframe, padding="0 10 0 10")
        bf.grid(column=1, row=8, sticky=(N, W, E, S))
        ttk.Button(bf, text="Update", command=self.update).grid(
            column=0, row=0, sticky=W
        )
        ttk.Button(bf, text="Quit", command=lambda *x: self.root.quit()).grid(
            column=1, row=0, sticky=W
        )

        self.update()

    def step(self, next):
        if not self.frames:
            self.next_step = None
            return

        self.current = next
        if self.current == len(self.frames):
            self.current = 0
        self.img.image = ImageTk.PhotoImage(self.frames[self.current])
        self.img["image"] = self.img.image
        self.next_step = self.root.after(
            self.delay_v, lambda: self.step(self.current + 1)
        )

    def update(self, *args):
        self.frames = []
        self.current = 0

        if self.next_step is not None:
            self.root.after_cancel(self.next_step)

        with Image.open(self.spritesheet) as image:
            try:
                width = int(self.frame_w.get())
            except Exception:
                self.error("Invalid width")

            try:
                height = int(self.frame_h.get())
            except Exception:
                self.error("Invalid height")

            try:
                scale = self.scale.get()
                if "," in scale:
                    scale = scale.split(",")
                    if len(scale) != 2:
                        self.error("Invalid x,y scale factor")
                else:
                    scale = (scale, scale)
                scale = [int(x) for x in scale]
            except Exception:
                self.error("Invalid scale")

            try:
                frame_list = [int(f) for f in self.frame_list.get().split()]
            except Exception:
                self.error("Invalid frame")

            try:
                self.delay_v = int(self.delay.get())
            except Exception:
                self.error("Invalid delay")

            (w, h) = image.size

            if w % width or h % height:
                self.error(
                    f"{self.spritesheet} size is not multiple of frame size ({width}, {height})"
                )

            frames = []
            for y in range(0, h, height):
                for x in range(0, w, width):
                    frames.append(
                        image.crop((x, y, x + width, y + height)).resize(
                            (width * scale[0], height * scale[1]), None
                        )
                    )

            for f in frame_list:
                self.frames.append(frames[f])

            self.step(0)

    def run(self):
        self.root.mainloop()


if __name__ == "__main__":
    parser = ArgumentParser(description="SpriteSheet Animation Preview")

    parser.add_argument(
        "--version", action="version", version="%(prog)s " + __version__
    )
    parser.add_argument("--width", dest="w", default=DEF_W, type=int,
                        help="frame width (default: %s)" % DEF_W)
    parser.add_argument("--height", dest="h", default=DEF_H, type=int,
                        help="frame height (default: %s)" % DEF_H)

    parser.add_argument("image", help="spritesheet to ipreview")

    args = parser.parse_args()

    Preview(args.image, args.w, args.h, parser.error).run()