import os
import re
from SCons.Script import *

_REPO_NAME = 'zlib'
_REPO_URL = 'https://github.com/madler/zlib.git'
_TAG_PATTERN = re.compile(r'^v([0-9]+)\.([0-9]+)(?:\.([0-9]+))?$')
_VERSION_SOURCE = '''
    #include <zlib.h>
    #include <stdio.h>
    
    int main(int, char**)
    {
        puts(ZLIB_VERSION);
        return 0;
    }
'''

def _build_lib_name(env: Environment) -> str:
    if os.name == 'posix':
        return 'z'
    elif os.name == 'nt':
        return {
            'debug': 'zlibstaticd'
        }.get(env['BUILD_TYPE'], 'zlibstatic')
    else:
        raise Exception('libpng is not supported yet on this OS')

def versions(env: Environment, update: bool = False, options: dict = {}):
    tags = env.GitTags(repo_name = _REPO_NAME, remote_url = _REPO_URL, force_fetch=update)
    result = []

    if options.get('use_system_library'):
        version = env.VersionFromSource('pkgconf --cflags-only-I zlib', _VERSION_SOURCE)
        if version:
            env['SYSTEM_ZLIB_VERSION'] = version
            result.append(version)
    else:
        for tag in tags:
            match = _TAG_PATTERN.match(tag)
            if match:
                result.append((int(match.groups()[0]), int(match.groups()[1]), int(match.groups()[2] or 0)))
    return result

def dependencies(env: Environment, version) -> 'dict':
    return {}

def cook(env: Environment, version, options: dict = {}) -> dict:
    if options.get('use_system_library'):
        return env.PkgCook('pkgconf --cflags --libs zlib')
    
    git_ref = f'refs/tags/v{version[0]}.{version[1]}'
    if version[2] != 0:
        git_ref = git_ref + f'.{version[2]}'
    repo = env.GitBranch(repo_name = _REPO_NAME, remote_url = _REPO_URL, git_ref = git_ref)
    checkout_root = repo['checkout_root']
    build_result = env.CMakeProject(project_root=checkout_root)
    include_dir = os.path.join(build_result['install_dir'], 'include')
    lib_name = _build_lib_name(env)
    lib_file = env.FindLib(lib_name, paths=build_result['LIBPATH'])
    return {
        'CPPPATH': [include_dir],
        'LIBS': [lib_file],
        'CMAKE_VARS': {
            'ZLIB_LIBRARY': lib_file,
            'ZLIB_INCLUDE_DIR': include_dir
        }
    }