print("running extra script...")

import os
import sys
import inspect
import gzip
import shutil

Import("env")

GEN_DIR = 'lib/generated'
OWN_FILE = "extra_script.py"

INDEXJS = "index.js"
INDEXCSS = "index.css"

# embedded files definition is generated inside here
EMBEDDED_INCLUDE="embeddedfiles.h"

def basePath():
    #see: https://stackoverflow.com/questions/16771894/python-nameerror-global-name-file-is-not-defined
    return os.path.dirname(inspect.getfile(lambda: None))

def is_current(infile, outfile):
    if os.path.exists(outfile):
        otime = os.path.getmtime(outfile)
        itime = os.path.getmtime(infile)
        if (otime >= itime):
            own = os.path.join(basePath(), OWN_FILE)
            if os.path.exists(own):
                owntime = os.path.getmtime(own)
                if owntime > otime:
                    return False
            print(f"{outfile} is newer than {infile}, no need to recreate")
            return True
    return False

def compress_file(infile, outfile):
    if is_current(infile, outfile):
        return
    print(f"compressing {infile}")
    with open(infile, 'rb') as f_in:
        with gzip.open(outfile, 'wb') as f_out:
            shutil.copyfileobj(f_in, f_out)

def write_file_if_changed(filename, data):
    """
    Create or update file if it not contains data as content
    """
    if os.path.exists(filename):
        changetype = 'updating'
        with open(filename, 'r') as fh:
            if fh.read() == data:
                print(f"{filename} is up to date")
                return False
    else:
        changetype = 'generating'
    print(f"#{changetype} {filename}")
    with open(filename, 'w') as fh:
        fh.write(data)
    return True

def get_embedded_files(env):
    filelist = []
    efiles = env.GetProjectOption("board_build.embed_files")
    for f in efiles.split("\n"):
        if f == '':
            continue
        filelist.append(f)
    return filelist  

def get_content_type(fn):
    if (fn.endswith('.gz')):
        fn = fn[0:-3]
    if (fn.endswith('html')):
        return "text/html"
    if (fn.endswith('json')):
        return "application/json"
    if (fn.endswith('js')):
        return "text/javascript"
    if (fn.endswith('css')):
        return "text/css"
    if (fn.endswith('png')):
        return "image/png"
    if (fn.endswith('jpg') or fn.endswith('jpeg')):
        return "image/jpeg"
    return "application/octet-stream"

def join_files(target, filename, dirlist):
    """
    Join files named filename within different directories
    into one single gzip archive (located in generated dir)
    """
    print("joinfiles: {} into {} from dirs [{}]".format(filename, target, ','.join(dirlist)))
    flist = []
    for dir in dirlist:
        fn = os.path.join(dir, filename)
        if os.path.exists(fn):
            flist.append(fn)
    current = False
    if os.path.exists(target):
        current = True
        for f in flist:
            if not is_current(f, target):
                current = False
                break
    if current:
        print(f"{target} is up to date")
        return
    print(f"creating {target}")

    # add multiple files
    with gzip.open(target, "wb") as oh:
        for fn in flist:
            print("adding {} to {}".format(fn, target))
            with open(fn, "rb") as rh:
                shutil.copyfileobj(rh, oh)

def prebuild(env):
    print("#prebuild running")

    # directory for dynamically generated files
    gendir = os.path.join(basePath(), GEN_DIR)
    if not os.path.exists(gendir):
        os.makedirs(gendir)
    if not os.path.isdir(gendir):
        print("unable to create directory {}".format(gendir))
        sys.exit(1)

    # join static web server files

    # only useful for different task dirs with custom configs
    # join_files(os.path.join(gendir, INDEXJS+".gz"), INDEXJS, ["web"])
    # join_files(os.path.join(gendir, INDEXCSS+".gz"), INDEXCSS, ["web"])

    # platformio defined embedded files as list
    pio_embedded = get_embedded_files(env)

    filedefs = []
    for ef in pio_embedded:
        print(f"#checking embedded file {ef}")
        # files are defined with relative path to platformio.ini
        # the name can be with extension gz or without
        (dn, fn) = os.path.split(ef)
        pureName = fn
        if pureName.endswith('.gz'):
            pureName = pureName[0:-3]
        usname = ef.replace('/','_').replace('.','_') # sanitize filenames
        filedefs.append((pureName, usname, get_content_type(pureName)))
        infile = os.path.join(basePath(), "web", pureName)
        if os.path.exists(infile):
            compress_file(infile, ef)
        else:
            print("#WARNING: infile {infile} for {ef} not found")

    # generate c-header file for embedding zip files
    content = ""
    for entry in filedefs:
        content += 'EMBED_GZ_FILE("{}", {}, "{}");\n'.format(*entry)
    write_file_if_changed(os.path.join(gendir, EMBEDDED_INCLUDE), content)  

print("#prescript...")
prebuild(env)