"""
This program is free software: you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License,
or (at your option) any later version.


This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
See the GNU General Public License for more details.


You should have received a copy of the GNU General Public License
 along with this program.  If not, see <https://www.gnu.org/licenses/>.

Copyright © 2019 Cloud Linux Software Inc.

This software is also available under ImunifyAV commercial license,
see <https://www.imunify360.com/legal/eula>
"""
import abc
import json
import os
from collections import defaultdict
from dataclasses import dataclass, field
from typing import NamedTuple, Optional

from .db import DB, PatchDependencyMatch, VersionMatch
from .utils import HashCalculator, get_base_dir


class FileIdentifier(NamedTuple):
    rel_path: str
    hash: str
    vuln_id: Optional[int] = None
    vuln_type: Optional[int] = None


@dataclass
class VersionIdentifier:
    id: int
    hash: str
    file_identifiers: list[FileIdentifier]
    # one identifier can match multiple base_dirs, need to keep track of them to avoid duplicate scanning
    matched_base_dirs: set = field(default_factory=set)


@dataclass
class PatchDependency:
    files: list[FileIdentifier]


class Matcher(abc.ABC):
    def __init__(self, input_file: str):
        self.dict_of_identifiers = self._parse_input(input_file)

    @abc.abstractmethod
    def _parse_input(self, file_path: str) -> dict[str, list[tuple]]:
        pass


class VersionsMatcher(Matcher):
    @staticmethod
    def _parse_path_hash_pairs(file_hashes: str) -> list[FileIdentifier]:
        # accepts file_hashes string like [<file_hash>|<file_path>|]*n
        # returns list of FileIdentifier objects
        parts = file_hashes.strip().split("|")
        return [
            FileIdentifier(rel_path, hash_)
            for rel_path, hash_ in zip(parts[1::2], parts[::2])
        ]

    def _parse_line(self, line: str) -> Optional[VersionIdentifier]:
        # each line is made up as <state>:<id>:<reporting_hash>:[file_hashes]
        # and <file_hashes> is a list of "<file_hash>|<file_path>|" pairs
        state, id_, hash_, file_hashes = line.strip().split(":")
        if state != "+":
            return None
        return VersionIdentifier(
            id_, hash_, self._parse_path_hash_pairs(file_hashes)
        )

    def _parse_input(
        self, file_path: str
    ) -> dict[str, list[VersionIdentifier]]:
        # reads file version_identifiers with contents like
        # +:10831:38ed3878c51c61af938cd4fd9228b23b:ad8d2ec0797fbe584a2f5c1e0985b188|classes/Product.php|e890fa7432bbe7bee4dcbbff1009ca4b|app/AppKernel.php|
        plugins_identifiers_by_path: dict[
            str, list[VersionIdentifier]
        ] = defaultdict(list)
        with open(file_path, "r") as file:
            for line in file:
                if new_identifier := self._parse_line(line):
                    plugins_identifiers_by_path[
                        new_identifier.file_identifiers[0].rel_path
                    ].append(new_identifier)
        return plugins_identifiers_by_path

    def has_full_match(
        self,
        plugin_identifier: VersionIdentifier,
        base_dir: str,
        hash_calculator: HashCalculator,
    ) -> bool:
        # 1) check that all files from file_identifiers exist in their paths relative to base_dir
        for file_identifier in plugin_identifier.file_identifiers:
            if not os.path.isfile(
                os.path.join(base_dir, file_identifier.rel_path)
            ):
                return False
        # 2) all files exist, now check their hashes
        for file_identifier in plugin_identifier.file_identifiers:
            if (
                hash_calculator.calc_hash(
                    os.path.join(base_dir, file_identifier.rel_path),
                    apply_normalization=True,
                )
                != file_identifier.hash
            ):
                return False
        return True

    def match_and_save(
        self,
        full_path: str,
        relative_path: str,
        db: DB,
        hash_calculator: HashCalculator,
    ):
        is_matched = False
        # check if we have any version_identifier matching given path
        for plugin_identifier in self.dict_of_identifiers.get(
            relative_path, []
        ):
            base_dir = get_base_dir(full_path, relative_path)
            # skip if we already have matched this base_dir with this plugin_identifier
            if (
                base_dir not in plugin_identifier.matched_base_dirs
                and self.has_full_match(
                    plugin_identifier, base_dir, hash_calculator
                )
            ):
                plugin_identifier.matched_base_dirs.add(base_dir)
                db.versions_matches.buffered_insert(
                    VersionMatch(
                        id=plugin_identifier.id,
                        path=base_dir,
                        hash=plugin_identifier.hash,
                    )
                )
                is_matched = True
        return is_matched


class PatchDependenciesMatcher(Matcher):
    def _parse_input(self, file_path: str) -> dict[str, list[PatchDependency]]:
        # read patch_dependencies file
        # each line represent a patch dependency and is made of a list of FileToPatch objects, like:
        # +[{"hash": "(...)", "checksum": "(...)", "vulnerability_type": 10, "vulnerability_id": 4346, \
        # "filename": "popup-builder/com/helpers/AdminHelper.php"}, \
        # {"hash": "(...)", "checksum": "(...)", "vulnerability_type": 10, "vulnerability_id": 4347, \
        # "filename": "popup-builder/com/classes/Ajax.php"}]
        # we should consider only those lines starting with "+"
        patch_deps: dict[str, list[PatchDependency]] = defaultdict(list)
        with open(file_path, "r") as file:
            for line in file:
                state, data = line[0], line[1:]
                if state != "+":
                    continue
                patch_dependency = PatchDependency(
                    files=[
                        FileIdentifier(
                            rel_path=_["filename"],
                            hash=_["hash"],
                            vuln_id=_["vulnerability_id"],
                            vuln_type=_["vulnerability_type"],
                        )
                        for _ in json.loads(data)
                    ]
                )
                for file_identifier in patch_dependency.files:
                    patch_deps[file_identifier.rel_path].append(
                        patch_dependency
                    )
        return patch_deps

    def match_and_save(
        self,
        full_path: str,
        relative_path: str,
        db: DB,
        hash_calculator: HashCalculator,
    ):
        is_matched = False
        for patch_dependency in self.dict_of_identifiers.get(
            relative_path, []
        ):
            base_dir = get_base_dir(full_path, relative_path)
            # for each matching file add PatchDependencyMatch to db
            # if all files matching patch_dependency are found, set dependencies_met=True to all of them
            matches_to_insert = []  # [(path, hash, vuln_id, vuln_type), ...]
            for file_identifier in patch_dependency.files:
                if (
                    file_identifier.rel_path == relative_path
                    and hash_calculator.calc_hash(
                        os.path.join(base_dir, file_identifier.rel_path),
                    )
                    == file_identifier.hash
                ):
                    # todo: fix duplicates in PatchDependencyMatch table: add a constraint in table
                    #  and make a common dict for all the file_identifiers to eliminate duplicates in ram
                    matches_to_insert.append(
                        (
                            os.path.join(base_dir, file_identifier.rel_path),
                            file_identifier.hash,
                            file_identifier.vuln_id,
                            file_identifier.vuln_type,
                        )
                    )
                    is_matched = True
            # if all files matched, set dependencies_met=True
            matches_to_insert = [
                PatchDependencyMatch(
                    *row,
                    dependencies_met=(
                        len(matches_to_insert) == len(patch_dependency.files)
                    ),
                )
                for row in matches_to_insert
            ]
            [
                db.patch_dependencies.buffered_insert(match)
                for match in matches_to_insert
            ]
        return is_matched