#!/usr/bin/env python

import sys
import importlib
import os

# Nuclex SCons libraries
sys.path.append('../../BuildSystem/scons')
nuclex = importlib.import_module('nuclex')
archive = importlib.import_module('archive')

# ----------------------------------------------------------------------------------------------- #

universal_webp_target_name = 'webp'

environment = nuclex.create_cplusplus_environment()
#environment['ENV'] = os.environ
#environment['CXX'] = 'clang++'

# ----------------------------------------------------------------------------------------------- #
# Step 0: preparatory work

# Fetch the list of headers used when compiling
webp_headers_file = environment.File('webp-headers')
webp_header_files = archive.split_lines(webp_headers_file.get_text_contents())

# Fetch the list of sources to compile webp
webp_sources_file = environment.File('webp-sources')
webp_source_files = archive.split_lines(webp_sources_file.get_text_contents())

# ----------------------------------------------------------------------------------------------- #
# Step 1: Download the current release

# Fetch the available download URLs from a file
download_url_file = environment.File('webp-download-urls')
download_urls = archive.split_lines(download_url_file.get_text_contents())

# Determine the target filename for the download (below 'downloads' folder)
archive_filename = os.path.basename(download_urls[0])
archive_file = environment.File(os.path.join('downloads', archive_filename))

# Tell SCons how to "produce" the downloaded archive (by calling wget)
if not archive_file.exists():
    download_archive = environment.Command(
        source = download_url_file,
        #action = 'wget ' + download_urls[0] + ' --output-document=$TARGET',
        action = archive.download_url_in_urlfile,
        target = archive_file
    )

# ----------------------------------------------------------------------------------------------- #
# Step 2: Extract the release into the build directory

def extract_compressed_tarball(target, source, env):
    """Extracts the distribution .tar.gz archive and applies a patch that ensures
    the same headers will work on Windows and average Linux distributions.

    @param  target  Output files, not used by the function but passed along so
                    SCons can look at them and knows its dependency tree
    @param  source  Source files, expected to be an array containing the .tar.gz
                    path and the unified diff path
    @param  env     SCons build environment"""

    archive.extract_compressed_tarball(str(source[0]), 'build', 1)

# Tell SCons how to "produce" the sources & headers (by calling tar)
extract_archive = environment.Command(
    source = archive_file,
    #action = 'tar --extract --gzip --strip-components=1 --file=$SOURCE --directory=build',
    action = extract_compressed_tarball,
    target = webp_source_files + webp_header_files
)

# ----------------------------------------------------------------------------------------------- #
# Step 3: Compile the webp library

webp_environment = environment.Clone()

del webp_environment['SOURCE_DIRECTORY'] # We define the sources ourselves
webp_environment['HEADER_DIRECTORY'] = 'build'

#webp_environment.add_preprocessor_constant('XML_POOR_ENTROPY')
#webp_environment.add_preprocessor_constant('XML_STATIC')

webp_environment.add_source_directory(
    'build/src',
    webp_source_files,
    scons_issue_2908_workaround_needed = True
)

compile_webp_library = webp_environment.build_library(
    universal_webp_target_name,
    static = True
)

# ----------------------------------------------------------------------------------------------- #
# Step 4: Put the header in the main package directory

for header in webp_header_files:
    if header.startswith('build/src/'):
        install_path = os.path.join('Include/webp', header[10:])
        environment.InstallAs(install_path, header)

# ----------------------------------------------------------------------------------------------- #