# Copied from https://github.com/godotengine/godot/blob/c3b0a92c3cd9a219c1b1776b48c147f1d0602f07/methods.py#L1049-L1172
def show_progress(env):
    import os
    import sys
    import glob
    from SCons.Script import Progress, Command, AlwaysBuild

    screen = sys.stdout
    # Progress reporting is not available in non-TTY environments since it
    # messes with the output (for example, when writing to a file)
    show_progress = env["progress"] and sys.stdout.isatty()
    node_count = 0
    node_count_max = 0
    node_count_interval = 1
    node_count_fname = str(env.Dir("#")) + "/.scons_node_count"

    import time, math

    class cache_progress:
        # The default is 1 GB cache and 12 hours half life
        def __init__(self, path=None, limit=1073741824, half_life=43200):
            self.path = path
            self.limit = limit
            self.exponent_scale = math.log(2) / half_life
            if env["verbose"] and path != None:
                screen.write(
                    "Current cache limit is {} (used: {})\n".format(
                        self.convert_size(limit), self.convert_size(self.get_size(path))
                    )
                )
            self.delete(self.file_list())

        def __call__(self, node, *args, **kw):
            nonlocal node_count, node_count_max, node_count_interval, node_count_fname, show_progress
            if show_progress:
                # Print the progress percentage
                node_count += node_count_interval
                if node_count_max > 0 and node_count <= node_count_max:
                    screen.write("\r[%3d%%] " % (node_count * 100 / node_count_max))
                    screen.flush()
                elif node_count_max > 0 and node_count > node_count_max:
                    screen.write("\r[100%] ")
                    screen.flush()
                else:
                    screen.write("\r[Initial build] ")
                    screen.flush()

        def delete(self, files):
            if len(files) == 0:
                return
            if env["verbose"]:
                # Utter something
                screen.write("\rPurging %d %s from cache...\n" % (len(files), len(files) > 1 and "files" or "file"))
            [os.remove(f) for f in files]

        def file_list(self):
            if self.path is None:
                # Nothing to do
                return []
            # Gather a list of (filename, (size, atime)) within the
            # cache directory
            file_stat = [(x, os.stat(x)[6:8]) for x in glob.glob(os.path.join(self.path, "*", "*"))]
            if file_stat == []:
                # Nothing to do
                return []
            # Weight the cache files by size (assumed to be roughly
            # proportional to the recompilation time) times an exponential
            # decay since the ctime, and return a list with the entries
            # (filename, size, weight).
            current_time = time.time()
            file_stat = [(x[0], x[1][0], (current_time - x[1][1])) for x in file_stat]
            # Sort by the most recently accessed files (most sensible to keep) first
            file_stat.sort(key=lambda x: x[2])
            # Search for the first entry where the storage limit is
            # reached
            sum, mark = 0, None
            for i, x in enumerate(file_stat):
                sum += x[1]
                if sum > self.limit:
                    mark = i
                    break
            if mark is None:
                return []
            else:
                return [x[0] for x in file_stat[mark:]]

        def convert_size(self, size_bytes):
            if size_bytes == 0:
                return "0 bytes"
            size_name = ("bytes", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB")
            i = int(math.floor(math.log(size_bytes, 1024)))
            p = math.pow(1024, i)
            s = round(size_bytes / p, 2)
            return "%s %s" % (int(s) if i == 0 else s, size_name[i])

        def get_size(self, start_path="."):
            total_size = 0
            for dirpath, dirnames, filenames in os.walk(start_path):
                for f in filenames:
                    fp = os.path.join(dirpath, f)
                    total_size += os.path.getsize(fp)
            return total_size

    def progress_finish(target, source, env):
        nonlocal node_count, progressor
        try:
            with open(node_count_fname, "w") as f:
                f.write("%d\n" % node_count)
            progressor.delete(progressor.file_list())
        except Exception:
            pass

    try:
        with open(node_count_fname) as f:
            node_count_max = int(f.readline())
    except Exception:
        pass

    cache_directory = os.environ.get("SCONS_CACHE")
    # Simple cache pruning, attached to SCons' progress callback. Trim the
    # cache directory to a size not larger than cache_limit.
    cache_limit = float(os.getenv("SCONS_CACHE_LIMIT", 1024)) * 1024 * 1024
    progressor = cache_progress(cache_directory, cache_limit)
    Progress(progressor, interval=node_count_interval)

    progress_finish_command = Command("progress_finish", [], progress_finish)
    AlwaysBuild(progress_finish_command)