"""
Cares about the correct handling with ``needs.json`` files.

Creates, checks and imports ``needs.json`` files.
"""

from __future__ import annotations

import json
import os
import sys
from collections.abc import Iterable
from copy import deepcopy
from datetime import datetime
from functools import lru_cache
from typing import Any

from jsonschema import Draft7Validator
from sphinx.config import Config

from sphinx_needs.config import NeedsSphinxConfig
from sphinx_needs.data import NeedsCoreFields, NeedsInfoType
from sphinx_needs.logging import get_logger, log_warning

log = get_logger(__name__)


def generate_needs_schema(
    needs_config: NeedsSphinxConfig, exclude_properties: Iterable[str] = ()
) -> dict[str, Any]:
    """Generate a JSON schema for all fields in each need item.

    It is based on:
    * the core fields defined in NeedsCoreFields
    * the extra options defined dynamically
    * the global options defined dynamically
    * the extra links defined dynamically
    """
    properties: dict[str, Any] = {}

    for name, extra_params in needs_config.extra_options.items():
        properties[name] = {
            "type": "string",
            "description": extra_params.description,
            "field_type": "extra",
            "default": "",
        }

    # TODO currently extra options can overlap with core fields,
    # in which case they are ignored,
    # (this is the case for `type` added by the github service)
    # hence this is why we add the core options after the extra options
    for name, core_params in NeedsCoreFields.items():
        properties[name] = deepcopy(core_params["schema"])
        properties[name]["description"] = f"{core_params['description']}"
        properties[name]["field_type"] = "core"

    for link in needs_config.extra_links:
        properties[link["option"]] = {
            "type": "array",
            "items": {"type": "string"},
            "description": "Link field",
            "field_type": "links",
            "default": [],
        }
        properties[link["option"] + "_back"] = {
            "type": "array",
            "items": {"type": "string"},
            "description": "Backlink field",
            "field_type": "backlinks",
            "default": [],
        }

    for name in exclude_properties:
        if name in properties:
            del properties[name]

    return {
        "$schema": "http://json-schema.org/draft-07/schema#",
        "type": "object",
        "properties": properties,
    }


class NeedsList:
    def __init__(
        self,
        config: Config,
        outdir: str | os.PathLike[str],
        confdir: str | os.PathLike[str],
        add_schema: bool = True,
    ) -> None:
        self.config = config
        self.needs_config = NeedsSphinxConfig(config)
        self.outdir = outdir
        self.confdir = confdir
        self.current_version = config.version
        self.project = config.project
        self.needs_list = {
            "project": self.project,
            "current_version": self.current_version,
            "versions": {},
        }
        if not self.needs_config.reproducible_json:
            self.needs_list["created"] = ""
        self.log = log

        self._exclude_need_keys = set(self.needs_config.json_exclude_fields)

        self._schema = (
            generate_needs_schema(
                self.needs_config, exclude_properties=self._exclude_need_keys
            )
            if add_schema
            else None
        )
        self._need_defaults = (
            {
                name: value["default"]
                for name, value in self._schema["properties"].items()
                if "default" in value
            }
            if self._schema
            else {}
        )

    def update_or_add_version(self, version: str) -> None:
        from sphinx_needs import __version__

        if version not in self.needs_list["versions"]:
            self.needs_list["versions"][version] = {
                "needs_amount": 0,
                "needs": {},
                "creator": {
                    "program": "sphinx_needs",
                    "version": __version__,
                },
            }
            if self._schema:
                self.needs_list["versions"][version]["needs_schema"] = self._schema
            if self.needs_config.json_remove_defaults:
                self.needs_list["versions"][version]["needs_defaults_removed"] = True
            if not self.needs_config.reproducible_json:
                self.needs_list["versions"][version]["created"] = ""

        if "needs" not in self.needs_list["versions"][version]:
            self.needs_list["versions"][version]["needs"] = {}

        if not self.needs_config.reproducible_json:
            self.needs_list["versions"][version]["created"] = datetime.now().isoformat()

    def add_need(self, version: str, need_info: NeedsInfoType) -> None:
        self.update_or_add_version(version)
        writable_needs = {
            key: value
            for key, value in need_info.items()
            if key not in self._exclude_need_keys
        }
        if self.needs_config.json_remove_defaults:
            writable_needs = {
                key: value
                for key, value in writable_needs.items()
                if not (
                    key in self._need_defaults and value == self._need_defaults[key]
                )
            }
        self.needs_list["versions"][version]["needs"][need_info["id"]] = writable_needs
        self.needs_list["versions"][version]["needs_amount"] = len(
            self.needs_list["versions"][version]["needs"]
        )

    def wipe_version(self, version: str) -> None:
        if version in self.needs_list["versions"]:
            del self.needs_list["versions"][version]

    def _finalise(self) -> None:
        # We need to rewrite some data, because this kind of data gets overwritten during needs.json import
        if not self.needs_config.reproducible_json:
            self.needs_list["created"] = datetime.now().isoformat()
        else:
            self.needs_list.pop("created", None)
        self.needs_list["current_version"] = self.current_version
        self.needs_list["project"] = self.project

    def write_json(self, needs_file: str = "needs.json", needs_path: str = "") -> None:
        self._finalise()
        needs_dir = needs_path if needs_path else self.outdir
        with open(os.path.join(needs_dir, needs_file), "w") as f:
            json.dump(self.needs_list, f, sort_keys=True)

    def dump_json(self) -> str:
        self._finalise()
        return json.dumps(self.needs_list, sort_keys=True)

    def load_json(self, file: str) -> None:
        if not os.path.isabs(file):
            file = os.path.join(self.confdir, file)

        if not os.path.exists(file):
            log_warning(
                self.log, f"Could not load needs json file {file}", "json_load", None
            )
        else:
            errors = check_needs_file(file)
            # We only care for schema errors here, all other possible errors
            # are not important for need-imports.
            if errors.schema:
                self.log.info(f"Schema validation errors detected in file {file}:")
                for error in errors.schema:
                    self.log.info(f"  {error.message} -> {'.'.join(error.path)}")

            with open(file) as needs_file:
                try:
                    needs_list = json.load(needs_file)
                except json.JSONDecodeError:
                    log_warning(
                        self.log,
                        f"Could not decode json file {file}",
                        "json_load",
                        None,
                    )
                else:
                    self.needs_list = needs_list

            self.log.debug(f"needs.json file loaded: {file}")


class Errors:
    def __init__(self, schema_errors: list[Any]):
        self.schema = schema_errors


def check_needs_file(path: str) -> Errors:
    """
    Checks a given json-file, if it passes our needs.json structure tests.

    Current checks:
    * Schema validation

    :param path: File path to a needs.json file
    :return: Dict, with error reports
    """
    with open(path) as needs_file:
        try:
            data = json.load(needs_file)
        except json.JSONDecodeError as e:
            raise SphinxNeedsFileException(
                f'Problems loading json file "{path}". '
                f"Maybe it is empty or has an invalid json format. Original exception: {e}"
            )
    return check_needs_data(data)


@lru_cache
def _load_schema() -> dict[str, Any]:
    schema_path = os.path.join(os.path.dirname(__file__), "needsfile.json")
    with open(schema_path) as schema_file:
        return json.load(schema_file)  # type: ignore[no-any-return]


def check_needs_data(data: Any) -> Errors:
    """
    Checks a given json-file, if it passes our needs.json structure tests.

    Current checks:
    * Schema validation

    :param data: Loaded needs.json file
    :return: Dict, with error reports
    """
    needs_schema = _load_schema()

    validator = Draft7Validator(needs_schema)
    schema_errors = list(validator.iter_errors(data))

    # In future there may be additional types of validations.
    # So lets already use a class for all errors
    return Errors(schema_errors)


if "main" in __name__:
    """
    Allows a simple call via CLI::

        python needsfile.py docs/needs/needs.json
    """
    try:
        needs_file = sys.argv[1]
    except IndexError:
        needs_file = "needs.json"
    check_needs_file(needs_file)


class SphinxNeedsFileException(BaseException):
    """Exception for any file handling problems inside Sphinx-Needs"""