#!/usr/bin/env python3

# Recursively read for all files
template_directory = './templates/'

# Written to when generation is done
out_directory = './out/'

# Applied in order, later files override earlier files
env_files = ['./vars.env', './local.env']

import jinja2
import re
import os

def main():
    key_value_store = create_key_value_store()
    template_files = find_all_templates()
    out_files = convert_templates_to_out_file(template_files)

    convert_all_templates(template_files, key_value_store, out_files)

def create_key_value_store():
    out = {}

    for env_file in env_files:
        with open(env_file) as file:
            data = file.read()

        for line in data.split('\n'):
            m = re.match(r'^([^={}]+)=([^={}\n]+)', line)
            if m is None:
                continue

            out[m.group(1)] = m.group(2)

    return out

def find_all_templates():
    files = []
    
    dirlist = [template_directory]
    
    while len(dirlist) > 0:
        for (dirpath, dirnames, filenames) in os.walk(dirlist.pop()):
            dirlist.extend(dirnames)
            files.extend(map(lambda n: os.path.join(*n), zip([dirpath] * len(filenames), filenames)))

    return files

def convert_templates_to_out_file(template_files):
    out_files = []

    real_template_dir = os.path.realpath(template_directory)
    real_out_dir = os.path.realpath(out_directory)

    for template_file in template_files:
        real_template_file = os.path.realpath(template_file)
        out_files += [real_template_file.replace(real_template_dir, real_out_dir)]

    return out_files

def convert_all_templates(template_files, key_value_store, out_files):
    env = jinja2.Environment()

    for (template, out) in zip(template_files, out_files):
        convert_template(env, template, key_value_store, out)

def convert_template(env, template, key_value_store, out):
    with open(template, 'r') as file:
        source = file.read()

    template = env.from_string(source)
    rendered = template.render(**key_value_store)

    out_dir_name = os.path.dirname(out)
    if not os.path.isdir(out_dir_name):
        os.makedirs(out_dir_name)

    with open(out, 'w') as file:
        file.write(rendered)

if __name__ == '__main__':
    main()