"""Exports data from beets"""

from __future__ import annotations

import codecs
import csv
import json
import sys
from datetime import date, datetime
from typing import TYPE_CHECKING, Literal, Protocol, get_args
from xml.etree import ElementTree

import mediafile

from beets import ui, util
from beets.plugins import BeetsPlugin
from beetsplug.info import library_data, tag_data

if TYPE_CHECKING:
    from beets.library import Library

Format = Literal["json", "jsonlines", "csv", "xml"]


class ExportCLIOpts(Protocol):
    library: bool | None
    album: bool
    append: bool
    included_keys: list[str]
    output: str | None
    format: Format | None


class ExportEncoder(json.JSONEncoder):
    """Deals with dates because JSON doesn't have a standard"""

    def default(self, o):
        if isinstance(o, (datetime, date)):
            return o.isoformat()
        return json.JSONEncoder.default(self, o)


class ExportPlugin(BeetsPlugin):
    def __init__(self):
        super().__init__()

        self.config.add(
            {
                "default_format": "json",
                "json": {
                    # JSON module formatting options.
                    "formatting": {
                        "ensure_ascii": False,
                        "indent": 4,
                        "separators": (",", ": "),
                        "sort_keys": True,
                    }
                },
                "jsonlines": {
                    # JSON Lines formatting options.
                    "formatting": {
                        "ensure_ascii": False,
                        "separators": (",", ": "),
                        "sort_keys": True,
                    }
                },
                "csv": {
                    # CSV module formatting options.
                    "formatting": {
                        # The delimiter used to separate columns.
                        "delimiter": ",",
                        # The dialect to use when formatting the file output.
                        "dialect": "excel",
                    }
                },
                "xml": {
                    # XML module formatting options.
                    "formatting": {}
                },
                # TODO: Use something like the edit plugin
                # 'item_fields': []
            }
        )

    def commands(self):
        cmd = ui.Subcommand("export", help="export data from beets")
        cmd.func = self.run
        cmd.parser.add_album_option()
        cmd.parser.add_option(
            "-l",
            "--library",
            action="store_true",
            help="show library fields instead of tags",
        )
        cmd.parser.add_option(
            "--append",
            action="store_true",
            default=False,
            help="if should append data to the file",
        )
        cmd.parser.add_option(
            "-i",
            "--include-keys",
            default=[],
            action="append",
            dest="included_keys",
            help="comma separated list of keys to show",
        )
        cmd.parser.add_option(
            "-o",
            "--output",
            help="path for the output file. If not given, will print the data",
        )
        cmd.parser.add_option(
            "-f",
            "--format",
            default="json",
            help="the output format: json (default), jsonlines, csv, or xml",
        )
        return [cmd]

    def run(self, lib: Library, opts: ExportCLIOpts, args: list[str]) -> None:
        file_path = opts.output
        file_mode = "a" if opts.append else "w"
        default_format: Format = self.config["default_format"].as_choice(
            get_args(Format)
        )
        file_format = opts.format or default_format
        file_format_is_line_based = file_format == "jsonlines"
        format_options = self.config[file_format]["formatting"].get(dict)

        export_format = ExportFormat.factory(
            file_type=file_format, file_path=file_path, file_mode=file_mode
        )

        if opts.library or opts.album:
            data_collector = library_data
        else:
            data_collector = tag_data

        included_keys = []
        for keys in opts.included_keys:
            included_keys.extend(keys.split(","))

        items = []
        for data_emitter in data_collector(lib, args, album=opts.album):
            try:
                data, _ = data_emitter(included_keys or "*")
            except (mediafile.UnreadableFileError, OSError) as ex:
                self._log.error("cannot read file: {}", ex)
                continue

            for key, value in data.items():
                if isinstance(value, bytes):
                    data[key] = util.displayable_path(value)

            if file_format_is_line_based:
                export_format.export(data, **format_options)
            else:
                items += [data]

        if not file_format_is_line_based:
            export_format.export(items, **format_options)


class ExportFormat:
    """The output format type"""

    def __init__(self, file_path, file_mode="w", encoding="utf-8"):
        self.path = file_path
        self.mode = file_mode
        self.encoding = encoding
        # creates a file object to write/append or sets to stdout
        self.out_stream = (
            codecs.open(self.path, self.mode, self.encoding)
            if self.path
            else sys.stdout
        )

    @classmethod
    def factory(cls, file_type, **kwargs):
        if file_type in ["json", "jsonlines"]:
            return JsonFormat(**kwargs)
        if file_type == "csv":
            return CSVFormat(**kwargs)
        if file_type == "xml":
            return XMLFormat(**kwargs)
        raise NotImplementedError()

    def export(self, data, **kwargs):
        raise NotImplementedError()


class JsonFormat(ExportFormat):
    """Saves in a json file"""

    def __init__(self, file_path, file_mode="w", encoding="utf-8"):
        super().__init__(file_path, file_mode, encoding)

    def export(self, data, **kwargs):
        json.dump(data, self.out_stream, cls=ExportEncoder, **kwargs)
        self.out_stream.write("\n")


class CSVFormat(ExportFormat):
    """Saves in a csv file"""

    def __init__(self, file_path, file_mode="w", encoding="utf-8"):
        super().__init__(file_path, file_mode, encoding)

    def export(self, data, **kwargs):
        header = list(data[0].keys()) if data else []
        writer = csv.DictWriter(self.out_stream, fieldnames=header, **kwargs)
        writer.writeheader()
        writer.writerows(data)


class XMLFormat(ExportFormat):
    """Saves in a xml file"""

    def __init__(self, file_path, file_mode="w", encoding="utf-8"):
        super().__init__(file_path, file_mode, encoding)

    def export(self, data, **kwargs):
        # Creates the XML file structure.
        library = ElementTree.Element("library")
        tracks = ElementTree.SubElement(library, "tracks")
        if data and isinstance(data[0], dict):
            for index, item in enumerate(data):
                track = ElementTree.SubElement(tracks, "track")
                for key, value in item.items():
                    track_details = ElementTree.SubElement(track, key)
                    track_details.text = value
        # Depending on the version of python the encoding needs to change
        try:
            data = ElementTree.tostring(library, encoding="unicode", **kwargs)
        except LookupError:
            data = ElementTree.tostring(library, encoding="utf-8", **kwargs)

        self.out_stream.write(data)