__package__ = 'archivebox.index'

import os
import sys
import json as pyjson
from pathlib import Path

from datetime import datetime, timezone
from typing import List, Optional, Iterator, Any, Union

from archivebox.config import VERSION, DATA_DIR, CONSTANTS
from archivebox.config.common import SERVER_CONFIG, SHELL_CONFIG

from .schema import Link
from archivebox.misc.system import atomic_write
from archivebox.misc.util import enforce_types



@enforce_types
def generate_json_index_from_links(links: List[Link], with_headers: bool):
    from django.conf import settings
    
    MAIN_INDEX_HEADER = {
        'info': 'This is an index of site data archived by ArchiveBox: The self-hosted web archive.',
        'schema': 'archivebox.index.json',
        'copyright_info': SERVER_CONFIG.FOOTER_INFO,
        'meta': {
            'project': 'ArchiveBox',
            'version': VERSION,
            'git_sha': VERSION,  # not used anymore, but kept for backwards compatibility
            'website': 'https://ArchiveBox.io',
            'docs': 'https://github.com/ArchiveBox/ArchiveBox/wiki',
            'source': 'https://github.com/ArchiveBox/ArchiveBox',
            'issues': 'https://github.com/ArchiveBox/ArchiveBox/issues',
            'dependencies': settings.BINARIES.to_dict(),
        },
    }
    
    
    if with_headers:
        output = {
            **MAIN_INDEX_HEADER,
            'num_links': len(links),
            'updated': datetime.now(timezone.utc),
            'last_run_cmd': sys.argv,
            'links': links,
        }
    else:
        output = links
    return to_json(output, indent=4, sort_keys=True)


@enforce_types
def parse_json_main_index(out_dir: Path=DATA_DIR) -> Iterator[Link]:
    """parse an archive index json file and return the list of links"""

    index_path = Path(out_dir) / CONSTANTS.JSON_INDEX_FILENAME
    if index_path.exists():
        with open(index_path, 'r', encoding='utf-8') as f:
            try:
                links = pyjson.load(f)['links']
                if links:
                    Link.from_json(links[0])
            except Exception as err:
                print("    {lightyellow}! Found an index.json in the project root but couldn't load links from it: {} {}".format(
                    err.__class__.__name__,
                    err,
                    **SHELL_CONFIG.ANSI,
                ))
                return ()

            for link_json in links:
                try:
                    yield Link.from_json(link_json)
                except KeyError:
                    try:
                        detail_index_path = CONSTANTS.ARCHIVE_DIR / link_json['timestamp']
                        yield parse_json_link_details(str(detail_index_path))
                    except KeyError: 
                        # as a last effort, try to guess the missing values out of existing ones
                        try:
                            yield Link.from_json(link_json, guess=True)
                        except KeyError:
                            # print("    {lightyellow}! Failed to load the index.json from {}".format(detail_index_path, **ANSI))
                            continue
    return ()

### Link Details Index

@enforce_types
def write_json_link_details(link: Link, out_dir: Optional[str]=None) -> None:
    """write a json file with some info about the link"""
    
    out_dir = out_dir or link.link_dir
    path = Path(out_dir) / CONSTANTS.JSON_INDEX_FILENAME
    atomic_write(str(path), link._asdict(extended=True))


@enforce_types
def parse_json_link_details(out_dir: Union[Path, str], guess: bool=False) -> Optional[Link]:
    """load the json link index from a given directory"""
    
    existing_index = Path(out_dir) / CONSTANTS.JSON_INDEX_FILENAME
    if os.access(existing_index, os.F_OK):
        with open(existing_index, 'r', encoding='utf-8') as f:
            try:
                link_json = pyjson.load(f)
                return Link.from_json(link_json, guess)
            except pyjson.JSONDecodeError:
                pass
    return None


@enforce_types
def parse_json_links_details(out_dir: Union[Path, str]) -> Iterator[Link]:
    """read through all the archive data folders and return the parsed links"""


    for entry in os.scandir(CONSTANTS.ARCHIVE_DIR):
        if entry.is_dir(follow_symlinks=True):
            if os.access((Path(entry.path) / 'index.json'), os.F_OK):
                try:
                    link = parse_json_link_details(entry.path)
                except KeyError:
                    link = None
                if link:
                    yield link



### Helpers

class ExtendedEncoder(pyjson.JSONEncoder):
    """
    Extended json serializer that supports serializing several model
    fields and objects
    """

    def default(self, obj):
        cls_name = obj.__class__.__name__

        if hasattr(obj, '_asdict'):
            return obj._asdict()

        elif isinstance(obj, bytes):
            return obj.decode()

        elif isinstance(obj, datetime):
            return obj.isoformat()

        elif isinstance(obj, Exception):
            return '{}: {}'.format(obj.__class__.__name__, obj)

        elif cls_name in ('dict_items', 'dict_keys', 'dict_values'):
            return tuple(obj)

        return pyjson.JSONEncoder.default(self, obj)


@enforce_types
def to_json(obj: Any, indent: Optional[int]=4, sort_keys: bool=True, cls=ExtendedEncoder) -> str:
    return pyjson.dumps(obj, indent=indent, sort_keys=sort_keys, cls=ExtendedEncoder)