# Copyright Spack Project Developers. See COPYRIGHT file for details.
#
# SPDX-License-Identifier: (Apache-2.0 OR MIT)

import errno
import os
import re
import shutil
import sys
from pathlib import Path
from typing import Dict, List, Optional, Tuple

import spack.config
import spack.hash_types as ht
import spack.llnl.util.filesystem as fs
import spack.projections
import spack.spec
import spack.util.spack_json as sjson
from spack.error import SpackError
from spack.llnl.util.filesystem import readlink

default_projections = {
    "all": "{architecture.platform}-{architecture.target}/{name}-{version}-{hash}"
}


def _check_concrete(spec: "spack.spec.Spec") -> None:
    """If the spec is not concrete, raise a ValueError"""
    if not spec.concrete:
        raise ValueError("Specs passed to a DirectoryLayout must be concrete!")


def _get_spec(prefix: str) -> Optional["spack.spec.Spec"]:
    """Returns a spec if the prefix contains a spec file in the .spack subdir"""
    for f in ("spec.json", "spec.yaml"):
        try:
            return spack.spec.Spec.from_specfile(os.path.join(prefix, ".spack", f))
        except Exception:
            continue
    return None


def specs_from_metadata_dirs(root: str) -> List["spack.spec.Spec"]:
    stack = [root]
    specs = []

    while stack:
        prefix = stack.pop()

        spec = _get_spec(prefix)

        if spec:
            spec.set_prefix(prefix)
            specs.append(spec)
            continue

        try:
            scandir = os.scandir(prefix)
        except OSError:
            continue

        with scandir as entries:
            for entry in entries:
                if entry.is_dir(follow_symlinks=False):
                    stack.append(entry.path)
    return specs


class DirectoryLayout:
    """A directory layout is used to associate unique paths with specs. Different installations are
    going to want different layouts for their install, and they can use this to customize the
    nesting structure of spack installs. The default layout is:

    * <install root>/

      * <platform-os-target>/

        * <compiler>-<compiler version>/

          * <name>-<version>-<hash>

    The installation directory projections can be modified with the projections argument."""

    def __init__(
        self,
        root: str,
        *,
        projections: Optional[Dict[str, str]] = None,
        hash_length: Optional[int] = None,
    ) -> None:
        self.root = root
        projections = projections or default_projections
        self.projections = {key: projection.lower() for key, projection in projections.items()}

        # apply hash length as appropriate
        self.hash_length = hash_length
        if self.hash_length is not None:
            for when_spec, projection in self.projections.items():
                if "{hash}" not in projection:
                    raise InvalidDirectoryLayoutParametersError(
                        "Conflicting options for installation layout hash length"
                        if "{hash" in projection
                        else "Cannot specify hash length when the hash is not part of all "
                        "install_tree projections"
                    )
                self.projections[when_spec] = projection.replace(
                    "{hash}", "{hash:%d}" % self.hash_length
                )

        # If any of these paths change, downstream databases may not be able to
        # locate files in older upstream databases
        self.metadata_dir = ".spack"
        self.deprecated_dir = "deprecated"
        self.spec_file_name = "spec.json"
        # Use for checking yaml and deprecated types
        self._spec_file_name_yaml = "spec.yaml"
        self.extension_file_name = "extensions.yaml"
        self.packages_dir = "repos"  # archive of package.py files
        self.manifest_file_name = "install_manifest.json"

    @property
    def hidden_file_regexes(self) -> Tuple[str]:
        return ("^{0}$".format(re.escape(self.metadata_dir)),)

    def relative_path_for_spec(self, spec: "spack.spec.Spec") -> str:
        _check_concrete(spec)

        projection = spack.projections.get_projection(self.projections, spec)
        path = spec.format_path(projection)
        return str(Path(path))

    def write_spec(self, spec: "spack.spec.Spec", path: str) -> None:
        """Write a spec out to a file."""
        _check_concrete(spec)
        with open(path, "w", encoding="utf-8") as f:
            # The hash of the projection is the DAG hash which contains
            # the full provenance, so it's available if we want it later
            spec.to_json(f, hash=ht.dag_hash)

    def write_host_environment(self, spec: "spack.spec.Spec") -> None:
        """The host environment is a json file with os, kernel, and spack
        versioning. We use it in the case that an analysis later needs to
        easily access this information.
        """
        env_file = self.env_metadata_path(spec)
        environ = spack.spec.get_host_environment_metadata()
        with open(env_file, "w", encoding="utf-8") as fd:
            sjson.dump(environ, fd)

    def read_spec(self, path: str) -> "spack.spec.Spec":
        """Read the contents of a file and parse them as a spec"""
        try:
            with open(path, encoding="utf-8") as f:
                extension = os.path.splitext(path)[-1].lower()
                if extension == ".json":
                    spec = spack.spec.Spec.from_json(f)
                elif extension == ".yaml":
                    # Too late for conversion; spec_file_path() already called.
                    spec = spack.spec.Spec.from_yaml(f)
                else:
                    raise SpecReadError(f"Did not recognize spec file extension: {extension}")
        except Exception as e:
            if spack.config.get("config:debug"):
                raise
            raise SpecReadError(f"Unable to read file: {path}", f"Cause: {e}")

        # Specs read from actual installations are always concrete
        spec._mark_concrete()
        return spec

    def spec_file_path(self, spec: "spack.spec.Spec") -> str:
        """Gets full path to spec file"""
        _check_concrete(spec)
        yaml_path = os.path.join(self.metadata_path(spec), self._spec_file_name_yaml)
        json_path = os.path.join(self.metadata_path(spec), self.spec_file_name)
        return yaml_path if os.path.exists(yaml_path) else json_path

    def deprecated_file_path(
        self,
        deprecated_spec: "spack.spec.Spec",
        deprecator_spec: Optional["spack.spec.Spec"] = None,
    ) -> str:
        """Gets full path to spec file for deprecated spec

        If the deprecator_spec is provided, use that. Otherwise, assume
        deprecated_spec is already deprecated and its prefix links to the
        prefix of its deprecator."""
        _check_concrete(deprecated_spec)
        if deprecator_spec:
            _check_concrete(deprecator_spec)

        # If deprecator spec is None, assume deprecated_spec already deprecated
        # and use its link to find the file.
        base_dir = (
            self.path_for_spec(deprecator_spec)
            if deprecator_spec
            else readlink(deprecated_spec.prefix)
        )

        yaml_path = os.path.join(
            base_dir,
            self.metadata_dir,
            self.deprecated_dir,
            deprecated_spec.dag_hash() + "_" + self._spec_file_name_yaml,
        )

        json_path = os.path.join(
            base_dir,
            self.metadata_dir,
            self.deprecated_dir,
            deprecated_spec.dag_hash() + "_" + self.spec_file_name,
        )

        return yaml_path if os.path.exists(yaml_path) else json_path

    def metadata_path(self, spec: "spack.spec.Spec") -> str:
        return os.path.join(spec.prefix, self.metadata_dir)

    def env_metadata_path(self, spec: "spack.spec.Spec") -> str:
        return os.path.join(self.metadata_path(spec), "install_environment.json")

    def build_packages_path(self, spec: "spack.spec.Spec") -> str:
        return os.path.join(self.metadata_path(spec), self.packages_dir)

    def create_install_directory(self, spec: "spack.spec.Spec") -> None:
        _check_concrete(spec)

        # Create install directory with properly configured permissions
        # Cannot import at top of file
        from spack.package_prefs import get_package_dir_permissions, get_package_group

        # Each package folder can have its own specific permissions, while
        # intermediate folders (arch/compiler) are set with access permissions
        # equivalent to the root permissions of the layout.
        group = get_package_group(spec)
        perms = get_package_dir_permissions(spec)

        fs.mkdirp(spec.prefix, mode=perms, group=group, default_perms="parents")
        fs.mkdirp(self.metadata_path(spec), mode=perms, group=group)  # in prefix

        self.write_spec(spec, self.spec_file_path(spec))

    def ensure_installed(self, spec: "spack.spec.Spec") -> None:
        """
        Throws InconsistentInstallDirectoryError if:
        1. spec prefix does not exist
        2. spec prefix does not contain a spec file, or
        3. We read a spec with the wrong DAG hash out of an existing install directory.
        """
        _check_concrete(spec)
        path = self.path_for_spec(spec)
        spec_file_path = self.spec_file_path(spec)

        if not os.path.isdir(path):
            raise InconsistentInstallDirectoryError(
                "Install prefix {0} does not exist.".format(path)
            )

        if not os.path.isfile(spec_file_path):
            raise InconsistentInstallDirectoryError(
                "Install prefix exists but contains no spec.json:", "  " + path
            )

        installed_spec = self.read_spec(spec_file_path)
        if installed_spec.dag_hash() != spec.dag_hash():
            raise InconsistentInstallDirectoryError(
                "Spec file in %s does not match hash!" % spec_file_path
            )

    def path_for_spec(self, spec: "spack.spec.Spec") -> str:
        """Return absolute path from the root to a directory for the spec."""
        _check_concrete(spec)

        if spec.external:
            return spec.external_path

        path = self.relative_path_for_spec(spec)
        assert not path.startswith(self.root)
        return os.path.join(self.root, path)

    def remove_install_directory(self, spec: "spack.spec.Spec", deprecated: bool = False) -> None:
        """Removes a prefix and any empty parent directories from the root.
        Raised RemoveFailedError if something goes wrong.
        """
        path = self.path_for_spec(spec)
        assert path.startswith(self.root), (
            "Attempted to remove dir outside Spack's install tree. PATH: {path}, ROOT: {self.root}"
        )

        if deprecated:
            if os.path.exists(path):
                try:
                    metapath = self.deprecated_file_path(spec)
                    os.unlink(path)
                    os.remove(metapath)
                except OSError as e:
                    raise RemoveFailedError(spec, path, e) from e
        elif os.path.exists(path):
            try:
                if sys.platform == "win32":
                    # Windows readonly files cannot be removed by Python
                    # directly, change permissions before attempting to remove
                    shutil.rmtree(
                        path,
                        ignore_errors=False,
                        onerror=fs.readonly_file_handler(ignore_errors=False),
                    )
                else:
                    shutil.rmtree(path)
            except OSError as e:
                raise RemoveFailedError(spec, path, e) from e

        path = os.path.dirname(path)
        while path != self.root:
            if os.path.isdir(path):
                try:
                    os.rmdir(path)
                except OSError as e:
                    if e.errno == errno.ENOENT:
                        # already deleted, continue with parent
                        pass
                    elif e.errno == errno.ENOTEMPTY:
                        # directory wasn't empty, done
                        return
                    else:
                        raise e
            path = os.path.dirname(path)

    def all_specs(self) -> List["spack.spec.Spec"]:
        """Returns a list of all specs detected in self.root, detected by ``.spack`` directories.
        Their prefix is set to the directory containing the ``.spack`` directory. Note that these
        specs may follow a different layout than the current layout if it was changed after
        installation."""
        return specs_from_metadata_dirs(self.root)

    def deprecated_for(
        self, specs: List["spack.spec.Spec"]
    ) -> List[Tuple["spack.spec.Spec", "spack.spec.Spec"]]:
        """Returns a list of tuples of specs (new, old) where new is deprecated for old"""
        spec_with_deprecated = []
        for spec in specs:
            try:
                deprecated = os.scandir(
                    os.path.join(str(spec.prefix), self.metadata_dir, self.deprecated_dir)
                )
            except OSError:
                continue

            with deprecated as entries:
                for entry in entries:
                    try:
                        deprecated_spec = spack.spec.Spec.from_specfile(entry.path)
                        spec_with_deprecated.append((spec, deprecated_spec))
                    except Exception:
                        continue
        return spec_with_deprecated


class DirectoryLayoutError(SpackError):
    """Superclass for directory layout errors."""

    def __init__(self, message, long_msg=None):
        super().__init__(message, long_msg)


class RemoveFailedError(DirectoryLayoutError):
    """Raised when a DirectoryLayout cannot remove an install prefix."""

    def __init__(self, installed_spec, prefix, error):
        super().__init__(
            "Could not remove prefix %s for %s : %s" % (prefix, installed_spec.short_spec, error)
        )
        self.cause = error


class InconsistentInstallDirectoryError(DirectoryLayoutError):
    """Raised when a package seems to be installed to the wrong place."""

    def __init__(self, message, long_msg=None):
        super().__init__(message, long_msg)


class SpecReadError(DirectoryLayoutError):
    """Raised when directory layout can't read a spec."""


class InvalidDirectoryLayoutParametersError(DirectoryLayoutError):
    """Raised when a invalid directory layout parameters are supplied"""

    def __init__(self, message, long_msg=None):
        super().__init__(message, long_msg)


class InvalidExtensionSpecError(DirectoryLayoutError):
    """Raised when an extension file has a bad spec in it."""


class ExtensionAlreadyInstalledError(DirectoryLayoutError):
    """Raised when an extension is added to a package that already has it."""

    def __init__(self, spec, ext_spec):
        super().__init__("%s is already installed in %s" % (ext_spec.short_spec, spec.short_spec))


class ExtensionConflictError(DirectoryLayoutError):
    """Raised when an extension is added to a package that already has it."""

    def __init__(self, spec, ext_spec, conflict):
        super().__init__(
            "%s cannot be installed in %s because it conflicts with %s"
            % (ext_spec.short_spec, spec.short_spec, conflict.short_spec)
        )
