#!/usr/bin/env python3

from pathlib import Path
import argparse
import zipfile
import ast
import json
import logging
from utils import *

log = logging.getLogger(__name__)

REQUIRED_KEYS = set(['name', 'blender', 'version'])
SCHEMA_VERSION = 1

class BadAddon(Exception):
    pass

def iter_addons(path: Path) -> (Path, dict):
    """
    Generator, yields (path, bl_info) of blender addons in `path`.
    """
    pass
    for item in path.iterdir():
        try:
            yield(item, extract_blinfo(item))
        except BadAddon as err:
            log.debug("Skipping '{}': {}".format(item.name, err))

def parse_blinfo(source: str) -> dict:
    """Parse a python file and return its bl_info dict, if there is one (else return None)"""

    try:
        tree = ast.parse(source)
    except SyntaxError as e:
        raise BadAddon("Syntax error") from e

    for body in tree.body:
        if body.__class__ != ast.Assign:
            continue
        if len(body.targets) != 1:
            continue
        if getattr(body.targets[0], 'id', '') != 'bl_info':
            continue

        return ast.literal_eval(body.value)

    raise BadAddon('No bl_info found')


def extract_blinfo(item: Path) -> dict:
    """
    Extract bl_info dict from addon at path (can be single file, python package, or zip)
    """

    blinfo = None
    addon_name = item.name
    
    if not item.exists():
        raise FileNotFoundError("Cannot extract blinfo from '%s'; no such file or directory" % item)

    if item.is_dir():
        fname = item / '__init__.py'
        try:
            with fname.open("r") as f:
                blinfo = parse_blinfo(f.read())
        except FileNotFoundError as err:
            # directory with no __init__.py: not an addon
            raise BadAddon("Directory '%s' doesn't contain __init__.py; not a python package" % item) from err
    
    elif item.is_file():
        try:
            with zipfile.ZipFile(str(item), 'r') as z:
                if len(z.namelist()) == 1:
                    # zipfile with one item: just read that item
                    blinfo = parse_blinfo(z.read(z.namelist()[0]))
                else:
                    # zipfile with multiple items: try all __init__.py files
                    for fname in z.namelist():
                        # TODO: zips with multiple bl_infos might be a problem,
                        # not sure how such cases should be handled (if at all)
                        # for now we just break after the first one
                        if fname.endswith('__init__.py'):
                            try:
                                blinfo = parse_blinfo(z.read(fname))
                                break
                            except BadAddon:
                                continue
                    if blinfo is None:
                        raise BadAddon("Zipfile '%s' doesn't contain a readable bl_info dict" % item)

        except zipfile.BadZipFile:
            # If it's not a valid zip, assume file is just a normal file
            # TODO: this probably blows up inelegantly on corrupted zips
            with item.open() as f:
                blinfo = parse_blinfo(f.read())

    # This should not happen
    if blinfo == None:
        raise RuntimeError("Could not read addon '%s'" % addon_name)

    return blinfo



def make_repo(path: Path):
    """Make repo.json for files in directory 'path'"""

    repo_data = {}
    package_data = []

    if not path.is_dir():
        raise FileNotFoundError(path)

    for addon, bl_info in iter_addons(path):
        package_datum = {}

        if not REQUIRED_KEYS.issubset(set(bl_info)):
            log.warning(
                    "Required key(s) '{}' not found in bl_info of '{}'".format(
                        "', '".join(REQUIRED_KEYS.difference(set(bl_info))), addon)
                    )

        package_datum['bl_info'] = bl_info
        package_datum['type'] = 'addon'
        package_data.append(package_datum)

    repo_data['packages'] = package_data

    log.info("Repository generation successful")
    cwd = Path.cwd()
    dump_repo(cwd, repo_data)
    log.info("repo.json written to %s" % cwd)


def main():
    parser = argparse.ArgumentParser(description='Generate a blender package repository from a directory of addons')

    parser.add_argument('-v', '--verbose',
            help="Increase verbosity (can be used multiple times)",
            action="count",
            default=0)
    parser.add_argument('path',
            type=Path,
            nargs='?',
            default=Path.cwd(),
            help="Path to addon directory")

    args = parser.parse_args()
    log.level = args.verbose
    logging.basicConfig(level=logging.INFO,
            format='%(levelname)8s: %(message)s')

    make_repo(args.path)

if __name__ == '__main__':
    main()