#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
Utility script to create a pypi-like directory structure (localpi)
from a number of Python packages in a directory of the local filesystem.

  DIRECTORY STRUCTURE (before):
      +-- downloads/
           +-- alice-1.0.zip
           +-- alice-1.0.tar.gz
           +-- bob-1.3.0.tar.gz
           +-- bob-1.4.2.tar.gz
           +-- charly-1.0.tar.bz2

  DIRECTORY STRUCTURE (afterwards):
      +-- downloads/
           +-- simple/
           |      +-- alice/index.html   --> ../../alice-*.*
           |      +-- bob/index.html     --> ../../bob-*.*
           |      +-- charly/index.html  --> ../../charly-*.*
           |      +-- index.html  --> alice/, bob/, ...
           +-- alice-1.0.zip
           +-- alice-1.0.tar.gz
           +-- bob-1.3.0.tar.gz
           +-- bob-1.4.2.tar.gz
           +-- charly-1.0.tar.bz2

USAGE EXAMPLE:

    mkdir -p /tmp/downloads
    pip install --download=/tmp/downloads argparse Jinja2
    make_localpi.py /tmp/downloads
    pip install --index-url=file:///tmp/downloads/simple argparse Jinja2

ALTERNATIVE:

    pip install --download=/tmp/downloads argparse Jinja2
    pip install --find-links=/tmp/downloads --no-index argparse Jinja2
"""

from __future__ import with_statement, print_function
from fnmatch import fnmatch
import os.path
import shutil
import sys


__author__  = "Jens Engel"
__version__ = "0.2"
__license__ = "BSD"
__copyright__ = "(c) 2013 by Jens Engel"


class Package(object):
    """
    Package entity that keeps track of:
      * one or more versions of this package
      * one or more archive types
    """
    PATTERNS = [
        "*.egg", "*.exe", "*.whl", "*.zip", "*.tar.gz", "*.tar.bz2", "*.7z"
    ]

    def __init__(self, filename, name=None):
        if not name and filename:
            name = self.get_pkgname(filename)
        self.name  = name
        self.files = []
        if filename:
            self.files.append(filename)

    @property
    def versions(self):
        versions_info = [ self.get_pkgversion(p) for p in self.files ]
        return versions_info

    @classmethod
    def get_pkgversion(cls, filename):
        parts = os.path.basename(filename).rsplit("-", 1)
        version = ""
        if len(parts) >= 2:
            version = parts[1]
        for pattern in cls.PATTERNS:
            assert pattern.startswith("*")
            suffix = pattern[1:]
            if version.endswith(suffix):
                version = version[:-len(suffix)]
                break
        return version

    @staticmethod
    def get_pkgname(filename):
        name = os.path.basename(filename).rsplit("-", 1)[0]
        if name.startswith("http%3A") or name.startswith("https%3A"):
            # -- PIP DOWNLOAD-CACHE PACKAGE FILE NAME SCHEMA:
            pos = name.rfind("%2F")
            name = name[pos+3:]
        return name

    @staticmethod
    def splitext(filename):
        fname = os.path.splitext(filename)[0]
        if fname.endswith(".tar"):
            fname = os.path.splitext(fname)[0]
        return fname

    @classmethod
    def isa(cls, filename):
        basename = os.path.basename(filename)
        if basename.startswith("."):
            return False
        for pattern in cls.PATTERNS:
            if fnmatch(filename, pattern):
                return True
        return False


def make_index_for(package, index_dir, verbose=True):
    """
    Create an 'index.html' for one package.

    :param package:   Package object to use.
    :param index_dir: Where 'index.html' should be created.
    """
    index_template = """\
<html>
<head><title>{title}</title></head>
<body>
<h1>{title}</h1>
<ul>
{packages}
</ul>
</body>
</html>
"""
    item_template = '<li><a href="{1}">{0}</a></li>'
    index_filename = os.path.join(index_dir, "index.html")
    if not os.path.isdir(index_dir):
        os.makedirs(index_dir)

    parts = []
    for pkg_filename in package.files:
        pkg_name = os.path.basename(pkg_filename)
        if pkg_name == "index.html":
            # -- ROOT-INDEX:
            pkg_name = os.path.basename(os.path.dirname(pkg_filename))
        else:
            pkg_name = package.splitext(pkg_name)
        pkg_relpath_to = os.path.relpath(pkg_filename, index_dir)
        parts.append(item_template.format(pkg_name, pkg_relpath_to))

    if not parts:
        print("OOPS: Package %s has no files" % package.name)
        return

    if verbose:
        root_index = not Package.isa(package.files[0])
        if root_index:
            info = "with %d package(s)" % len(package.files)
        else:
            package_versions = sorted(set(package.versions))
            info = ", ".join(reversed(package_versions))
        message = "%-30s  %s" % (package.name, info)
        print(message)

    with open(index_filename, "w") as f:
        packages = "\n".join(parts)
        text = index_template.format(title=package.name, packages=packages)
        f.write(text.strip())
        f.close()


def make_package_index(download_dir):
    """
    Create a pypi server like file structure below download directory.

    :param download_dir:    Download directory with packages.

    EXAMPLE BEFORE:
      +-- downloads/
           +-- alice-1.0.zip
           +-- alice-1.0.tar.gz
           +-- bob-1.3.0.tar.gz
           +-- bob-1.4.2.tar.gz
           +-- charly-1.0.tar.bz2

    EXAMPLE AFTERWARDS:
      +-- downloads/
           +-- simple/
           |      +-- alice/index.html   --> ../../alice-*.*
           |      +-- bob/index.html     --> ../../bob-*.*
           |      +-- charly/index.html  --> ../../charly-*.*
           |      +-- index.html  --> alice/index.html, bob/index.html, ...
           +-- alice-1.0.zip
           +-- alice-1.0.tar.gz
           +-- bob-1.3.0.tar.gz
           +-- bob-1.4.2.tar.gz
           +-- charly-1.0.tar.bz2
    """
    if not os.path.isdir(download_dir):
        raise ValueError("No such directory: %r" % download_dir)

    pkg_rootdir = os.path.join(download_dir, "simple")
    if os.path.isdir(pkg_rootdir):
        shutil.rmtree(pkg_rootdir, ignore_errors=True)
    os.mkdir(pkg_rootdir)

    # -- STEP: Collect all packages.
    package_map = {}
    packages = []
    for filename in sorted(os.listdir(download_dir)):
        if not Package.isa(filename):
            continue
        pkg_filepath = os.path.join(download_dir, filename)
        package_name = Package.get_pkgname(pkg_filepath)
        package = package_map.get(package_name, None)
        if not package:
            # -- NEW PACKAGE DETECTED: Store/register package.
            package = Package(pkg_filepath)
            package_map[package.name] = package
            packages.append(package)
        else:
            # -- SAME PACKAGE: Collect other variant/version.
            package.files.append(pkg_filepath)

    # -- STEP: Make local PYTHON PACKAGE INDEX.
    root_package = Package(None, "Python Package Index")
    root_package.files = [ os.path.join(pkg_rootdir, pkg.name, "index.html")
                           for pkg in packages ]
    make_index_for(root_package, pkg_rootdir)
    for package in packages:
        index_dir = os.path.join(pkg_rootdir, package.name)
        make_index_for(package, index_dir)


# -----------------------------------------------------------------------------
# MAIN:
# -----------------------------------------------------------------------------
if __name__ == "__main__":
    if (len(sys.argv) != 2) or "-h" in sys.argv[1:] or "--help" in sys.argv[1:]:
        print("USAGE: %s DOWNLOAD_DIR" % os.path.basename(sys.argv[0]))
        print(__doc__)
        sys.exit(1)
    make_package_index(sys.argv[1])