import sys
from typing import Optional, Sequence
from urllib.parse import urljoin

import requests
import typer
from wasabi import msg

from .. import about
from ..util import (
    get_installed_models,
    get_minor_version,
    get_package_version,
    is_in_interactive,
    is_in_jupyter,
    is_package,
    is_prerelease_version,
    run_command,
)
from ._util import SDIST_SUFFIX, WHEEL_SUFFIX, Arg, Opt, app


@app.command(
    "download",
    context_settings={"allow_extra_args": True, "ignore_unknown_options": True},
)
def download_cli(
    # fmt: off
    ctx: typer.Context,
    model: str = Arg(..., help="Name of pipeline package to download"),
    direct: bool = Opt(False, "--direct", "-d", "-D", help="Force direct download of name + version"),
    sdist: bool = Opt(False, "--sdist", "-S", help="Download sdist (.tar.gz) archive instead of pre-built binary wheel"),
    # fmt: on
):
    """
    Download compatible trained pipeline from the default download path using
    pip. If --direct flag is set, the command expects the full package name with
    version. For direct downloads, the compatibility check will be skipped. All
    additional arguments provided to this command will be passed to `pip install`
    on package installation.

    DOCS: https://spacy.io/api/cli#download
    AVAILABLE PACKAGES: https://spacy.io/models
    """
    download(model, direct, sdist, *ctx.args)


def download(
    model: str,
    direct: bool = False,
    sdist: bool = False,
    *pip_args,
) -> None:
    if (
        not (is_package("spacy") or is_package("spacy-nightly"))
        and "--no-deps" not in pip_args
    ):
        msg.warn(
            "Skipping pipeline package dependencies and setting `--no-deps`. "
            "You don't seem to have the spaCy package itself installed "
            "(maybe because you've built from source?), so installing the "
            "package dependencies would cause spaCy to be downloaded, which "
            "probably isn't what you want. If the pipeline package has other "
            "dependencies, you'll have to install them manually."
        )
        pip_args = pip_args + ("--no-deps",)
    if direct:
        # Reject model names with '/', in order to prevent shenanigans.
        if "/" in model:
            msg.fail(
                title="Model download rejected",
                text=f"Cannot download model '{model}'. Models are expected to be file names, not URLs or fragments",
                exits=True,
            )
        components = model.split("-")
        model_name = "".join(components[:-1])
        version = components[-1]
    else:
        model_name = model
        compatibility = get_compatibility()
        version = get_version(model_name, compatibility)

    # If we already have this version installed, skip downloading
    installed = get_installed_models()
    if model_name in installed:
        installed_version = get_package_version(model_name)
        if installed_version == version:
            msg.warn(f"{model_name} v{version} already installed, skipping")
            return

    filename = get_model_filename(model_name, version, sdist)

    download_model(filename, pip_args)
    msg.good(
        "Download and installation successful",
        f"You can now load the package via spacy.load('{model_name}')",
    )
    if is_in_jupyter():
        reload_deps_msg = (
            "If you are in a Jupyter or Colab notebook, you may need to "
            "restart Python in order to load all the package's dependencies. "
            "You can do this by selecting the 'Restart kernel' or 'Restart "
            "runtime' option."
        )
        msg.warn(
            "Restart to reload dependencies",
            reload_deps_msg,
        )
    elif is_in_interactive():
        reload_deps_msg = (
            "If you are in an interactive Python session, you may need to "
            "exit and restart Python to load all the package's dependencies. "
            "You can exit with Ctrl-D (or Ctrl-Z and Enter on Windows)."
        )
        msg.warn(
            "Restart to reload dependencies",
            reload_deps_msg,
        )


def get_model_filename(model_name: str, version: str, sdist: bool = False) -> str:
    dl_tpl = "{m}-{v}/{m}-{v}{s}"
    suffix = SDIST_SUFFIX if sdist else WHEEL_SUFFIX
    filename = dl_tpl.format(m=model_name, v=version, s=suffix)
    return filename


def get_compatibility() -> dict:
    if is_prerelease_version(about.__version__):
        version: Optional[str] = about.__version__
    else:
        version = get_minor_version(about.__version__)
    r = requests.get(about.__compatibility__)
    if r.status_code != 200:
        msg.fail(
            f"Server error ({r.status_code})",
            f"Couldn't fetch compatibility table. Please find a package for your spaCy "
            f"installation (v{about.__version__}), and download it manually. "
            f"For more details, see the documentation: "
            f"https://spacy.io/usage/models",
            exits=1,
        )
    comp_table = r.json()
    comp = comp_table["spacy"]
    if version not in comp:
        msg.fail(f"No compatible packages found for v{version} of spaCy", exits=1)
    return comp[version]


def get_version(model: str, comp: dict) -> str:
    if model not in comp:
        msg.fail(
            f"No compatible package found for '{model}' (spaCy v{about.__version__})",
            exits=1,
        )
    return comp[model][0]


def get_latest_version(model: str) -> str:
    comp = get_compatibility()
    return get_version(model, comp)


def download_model(
    filename: str, user_pip_args: Optional[Sequence[str]] = None
) -> None:
    # Construct the download URL carefully. We need to make sure we don't
    # allow relative paths or other shenanigans to trick us into download
    # from outside our own repo.
    base_url = about.__download_url__
    # urljoin requires that the path ends with /, or the last path part will be dropped
    if not base_url.endswith("/"):
        base_url = about.__download_url__ + "/"
    download_url = urljoin(base_url, filename)
    if not download_url.startswith(about.__download_url__):
        raise ValueError(f"Download from {filename} rejected. Was it a relative path?")
    pip_args = list(user_pip_args) if user_pip_args is not None else []
    cmd = [sys.executable, "-m", "pip", "install"] + pip_args + [download_url]
    run_command(cmd)