# Copyright (c) 2019, 2021 The Regents of the University of California
# All Rights Reserved.
#
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# met: redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer;
# redistributions in binary form must reproduce the above copyright
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# this software without specific prior written permission.
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"""File contains the Artifact class and helper functions
"""

import hashlib
from inspect import cleandoc
import json
from pathlib import Path
import subprocess
import time
from typing import Any, Dict, List, Union, Optional
from uuid import UUID, uuid4
import json

from ._artifactdb import getDBConnection


def getHash(path: Path) -> str:
    """
    Returns an md5 hash for the file in self.path.
    """
    BUF_SIZE = 65536
    md5 = hashlib.md5()
    with open(path, "rb") as f:
        while True:
            data = f.read(BUF_SIZE)
            if not data:
                break
            md5.update(data)

    return md5.hexdigest()


def getGit(path: Path) -> Dict[str, str]:
    """
    Returns dictionary with origin, current commit, and repo name for the
    base repository for `path`.
    An exception is generated if the repo is dirty or doesn't exist
    """
    path = path.resolve()  # Make absolute

    if path.is_file():
        path = path.parent

    command = [
        "git",
        "status",
        "--porcelain",
        "--ignore-submodules",
        "--untracked-files=no",
    ]
    res = subprocess.run(command, stdout=subprocess.PIPE, cwd=path)
    if res.returncode != 0:
        raise Exception("git repo doesn't exist for {}".format(path))
    if res.stdout:
        raise Exception("git repo dirty for {}".format(path))

    command = ["git", "remote", "get-url", "origin"]
    origin = subprocess.check_output(command, cwd=path)

    command = ["git", "log", "-n1", "--pretty=format:%H"]
    hsh = subprocess.check_output(command, cwd=path)

    command = ["git", "rev-parse", "--show-toplevel"]
    name = subprocess.check_output(command, cwd=path)

    return {
        "origin": str(origin.strip(), "utf-8"),
        "hash": str(hsh.strip(), "utf-8"),
        "name": str(name.strip(), "utf-8"),
    }


class Artifact:
    """
    A base artifact class.
    It holds following attributes of an artifact:

    1) name: name of the artifact
    2) command: bash command used to generate the artifact
    3) path: path of the location of the artifact
    4) time: time of creation of the artifact
    5) documentation: a string to describe the artifact
    6) ID: unique identifier of the artifact
    7) inputs: list of the input artifacts used to create this artifact stored
       as a list of uuids

    Optional fields:
    a) architecture: name of the ISA (e.g. x86, riscv) ("" by default)
    b) size: size of the artifact in bytes (None by default)
    c) is_zipped: True when the artifact must be decompressed before using,
       False otherwise (False by default)
    d) md5sum: the md5 checksum of the artifact, used for integrity checking
       ("" by default)
    e) url: URL to download the artifact ("" by default)
    f) supported_gem5_versions: a list of supported gem5 versions that the
       artifact should be used with (an empty list by default)
    g) version: version of the artifact, e.g. "v21-0" ("" by default)
    h) **kwargs: other fields, values must have __str__() defined.
    """

    _id: UUID
    name: str
    type: str
    documentation: str
    command: str
    path: Path
    hash: str
    time: float
    git: Dict[str, str]
    cwd: Path
    inputs: List["Artifact"]

    # Optional fields
    architecture: str
    size: Optional[int]
    is_zipped: bool
    md5sum: str
    url: str
    supported_gem5_versions: List[str]
    version: str

    extra: Dict[str, str]

    @classmethod
    def createArtifact(
        cls,
        command: str,
        name: str,
        cwd: str,
        typ: str,
        path: Union[str, Path],
        documentation: str,
        inputs: List["Artifact"] = [],
        architecture: str = "",
        size: Optional[int] = None,
        is_zipped: bool = False,
        md5sum: str = "",
        url: str = "",
        supported_gem5_versions: List[str] = [],
        version: str = "",
        **kwargs: str,
    ) -> "Artifact":

        """Constructs a new artifact without using the database.

        Different from registerArtifact(), this method won't use database.
        As a result, this method won't check whether the artifact has
        already existed in the database, as well as it won't add the artifact
        to the database.
        """

        # Dictionary with all of the kwargs for construction.
        data: Dict[str, Any] = {}

        data["name"] = name
        data["type"] = typ
        data["documentation"] = cleandoc(documentation)
        if len(data["documentation"]) < 10:  # 10 characters is arbitrary
            raise Exception(
                cleandoc(
                    """Must provide longer documentation!
                This documentation is how your future data will remember what
                this artifact is and how it was created."""
                )
            )

        data["command"] = cleandoc(command)

        data["time"] = time.time()

        ppath = Path(path)
        data["path"] = ppath
        if ppath.is_file():
            data["hash"] = getHash(ppath)
            data["git"] = {}
        elif ppath.is_dir():
            data["git"] = getGit(ppath)
            data["hash"] = data["git"]["hash"]
        else:
            raise Exception("Path {} doesn't exist".format(ppath))

        pcwd = Path(cwd)
        data["cwd"] = pcwd
        if not pcwd.exists():
            raise Exception("cwd {} doesn't exist.".format(pcwd))
        if not pcwd.is_dir():
            raise Exception("cwd {} is not a directory".format(pcwd))

        data["inputs"] = [i._id for i in inputs]

        data["architecture"] = architecture
        data["size"] = size
        data["is_zipped"] = is_zipped
        data["md5sum"] = md5sum
        data["url"] = url
        data["supported_gem5_versions"] = supported_gem5_versions[:]
        data["version"] = version

        data["extra"] = kwargs

        data["_id"] = uuid4()

        # Now that we have a complete object, construct it
        self = cls(data)

        return self

    @classmethod
    def registerArtifact(
        cls,
        command: str,
        name: str,
        cwd: str,
        typ: str,
        path: Union[str, Path],
        documentation: str,
        inputs: List["Artifact"] = [],
        architecture: str = "",
        size: Optional[int] = None,
        is_zipped: bool = False,
        md5sum: str = "",
        url: str = "",
        supported_gem5_versions: List[str] = [],
        version: str = "",
        **kwargs: str,
    ) -> "Artifact":
        """Constructs a new artifact and adds to the database.

        This assume either it's not in the database or it is the exact same as
        when it was added to the database
        """

        self = cls.createArtifact(
            command,
            name,
            cwd,
            typ,
            path,
            documentation,
            inputs,
            architecture,
            size,
            is_zipped,
            md5sum,
            url,
            supported_gem5_versions,
            version,
            **kwargs,
        )

        _db = getDBConnection()

        if self.hash in _db:
            old_artifact = Artifact(_db.get(self.hash))
            self._id = old_artifact._id

            self._checkSimilar(old_artifact)

        else:
            # Upload the file if there is one.
            if self.path.is_file():
                _db.upload(self._id, self.path)

            # Putting the artifact to the database
            _db.put(self._id, self._getSerializable())

        return self

    def __init__(self, other: Union[str, UUID, Dict[str, Any]]) -> None:
        """Constructs an artifact object from the database based on a UUID or
        dictionary from the database. Note that if the variable `other` is of
        type `Dict[str, Any]`, this function will not try to establish a
        connection to the database.
        """
        if not isinstance(other, Dict):
            _db = getDBConnection()
            if isinstance(other, str):
                other = UUID(other)
            if isinstance(other, UUID):
                other = _db.get(other)

        if not other:
            raise Exception("Cannot construct artifact")

        if isinstance(other["_id"], str):
            other["_id"] = UUID(other["_id"])  # type: ignore
        assert isinstance(other["_id"], UUID)
        self._id = other["_id"]
        self.name = other["name"]
        self.type = other["type"]
        self.documentation = other["documentation"]
        self.command = other["command"]
        self.path = Path(other["path"])
        self.hash = other["hash"]
        assert isinstance(other["git"], dict)
        self.git = other["git"]
        self.cwd = Path(other["cwd"])
        self.inputs = [Artifact(i) for i in other["inputs"]]

        # Optional fields
        self.architecture = other.get("architecture", "")
        if "size" in other:
            if isinstance(other["size"], int):
                self.size = other["size"]
            else:
                self.size = None
        self.is_zipped = bool(other.get("is_zipped", False))
        self.md5sum = other.get("md5sum", "")
        self.url = other.get("url", "")
        self.supported_gem5_versions = []
        if "supported_gem5_versions" in other:
            if isinstance(other["supported_gem5_versions"], list):
                self.supported_gem5_versions = other[
                    "supported_gem5_versions"
                ][:]
            elif isinstance(other["supported_gem5_versions"], str):
                self.supported_gem5_versions = json.loads(
                    other["supported_gem5_versions"]
                )
        self.version = other.get("version", "")

        self.extra = {}
        if "extra" in other:
            if isinstance(other["extra"], dict):
                self.extra = {k: v for k, v in other["extra"].items()}
            elif isinstance(other["extra"], str):
                self.extra = json.loads(other["extra"])

    def __str__(self) -> str:
        inputs = ", ".join([i.name + ":" + str(i._id) for i in self.inputs])
        return "\n    ".join(
            [
                self.name,
                f"id: {self._id}",
                f"type: {self.type}",
                f"path: {self.path}",
                f"inputs: {inputs}",
                self.documentation,
            ]
        )

    def __repr__(self) -> str:
        return vars(self).__repr__()

    def _getSerializable(self) -> Dict[str, Union[str, UUID]]:
        data = vars(self).copy()
        data["inputs"] = [input._id for input in self.inputs]
        data["cwd"] = str(data["cwd"])
        data["path"] = str(data["path"])
        data["supported_gem5_versions"] = json.dumps(
            self.supported_gem5_versions
        )
        data["extra"] = json.dumps(self.extra)
        return data

    def __eq__(self, other: object) -> bool:
        """checks if two artifacts are the same.

        Two artifacts are the same if they have the same UUID and the same
        hash. We emit a warning if other fields are different. If other fields
        are different and the hash is the same, this is suggestive that the
        user is doing something wrong.
        """
        if not isinstance(other, Artifact):
            return NotImplemented

        if self.hash == other.hash and self._id == other._id:
            self._checkSimilar(other)
            return True
        else:
            return False

    def _checkSimilar(self, other: "Artifact"):
        """Prints warnings if other is simlar, but not the same as self.
        These mismatches may or may not be a problem. It's up to the user to
        make this decision.
        """
        if self.name != other.name:
            print(
                f"WARNING: name mismatch for {self.name}! "
                f"{self.name} != {other.name}"
            )
        if self.documentation != other.documentation:
            print(
                f"WARNING: documentation mismatch for {self.name}! "
                f"{self.documentation} != {other.documentation}"
            )
        if self.command != other.command:
            print(
                f"WARNING: command mismatch for {self.name}! "
                f"{self.command} != {other.command}"
            )
        if self.path != other.path:
            print(
                f"WARNING: path mismatch for {self.name}! "
                f"{self.path} != {other.path}"
            )
        if self.cwd != other.cwd:
            print(
                f"WARNING: cwd mismatch for {self.name}! "
                f"{self.cwd} != {other.cwd}"
            )
        if self.git != other.git:
            print(
                f"WARNING: git mismatch for {self.name}! "
                f"{self.git} != {other.git}"
            )
        mismatch = set(self.inputs).symmetric_difference(other.inputs)
        if mismatch:
            print(f"WARNING: input mismatch for {self.name}! {mismatch}")

    def __hash__(self) -> int:
        return self._id.int