#!/usr/bin/env python3
"""
Generates and updates snapshot test cases from packse scenarios.

Important:

    This script is the backend called by `./scripts/sync_scenarios.sh`, consider using that
    if not developing scenarios.

Requirements:

    $ uv pip install -r scripts/scenarios/pylock.toml

    Uses `git`, `rustfmt`, and `cargo insta test` requirements from the project.

Usage:

    Regenerate the scenario test files using the given scenarios:

        $ ./scripts/scenarios/generate.py <path>

    Scenarios can be developed locally with the following workflow:

        Serve scenarios on a local index using packse

        $ packse serve --no-hash <path to scenarios>

        Override the uv package index and update the tests

        $ UV_TEST_PACKSE_INDEX="http://localhost:3141" ./scripts/scenarios/generate.py <path to scenarios>

        If an editable version of packse is installed, this script will use its bundled scenarios by default.

"""

import argparse
import importlib.metadata
import logging
import os
import re
import subprocess
import sys
import textwrap
from enum import StrEnum, auto
from pathlib import Path
from typing import Any

TOOL_ROOT = Path(__file__).parent
TEMPLATES = TOOL_ROOT / "templates"
PACKSE = TOOL_ROOT / "packse-scenarios"
REQUIREMENTS = TOOL_ROOT / "pylock.toml"
PROJECT_ROOT = TOOL_ROOT.parent.parent
TESTS = PROJECT_ROOT / "crates" / "uv" / "tests" / "it"
TESTS_COMMON_MOD_RS = TESTS / "common" / "mod.rs"

try:
    import packse
    import packse.inspect
except ImportError:
    print(
        f"missing requirement `packse`: install the requirements at {REQUIREMENTS.relative_to(PROJECT_ROOT)}",
        file=sys.stderr,
    )
    exit(1)

try:
    import chevron_blue
except ImportError:
    print(
        f"missing requirement `chevron-blue`: install the requirements at {REQUIREMENTS.relative_to(PROJECT_ROOT)}",
        file=sys.stderr,
    )
    exit(1)


class TemplateKind(StrEnum):
    install = auto()
    compile = auto()
    lock = auto()

    def template_file(self) -> Path:
        return TEMPLATES / f"{self.name}.mustache"

    def test_file(self) -> Path:
        match self.value:
            case TemplateKind.install:
                return TESTS / "pip_install_scenarios.rs"
            case TemplateKind.compile:
                return TESTS / "pip_compile_scenarios.rs"
            case TemplateKind.lock:
                return TESTS / "lock_scenarios.rs"
            case _:
                raise NotImplementedError()


def main(
    scenarios: list[Path],
    template_kinds: list[TemplateKind],
    snapshot_update: bool = True,
):
    # Fetch packse version
    packse_version = importlib.metadata.version("packse")

    debug = logging.getLogger().getEffectiveLevel() <= logging.DEBUG

    # Don't update the version to `0.0.0` to preserve the `UV_TEST_PACKSE_URL`
    # in local tests.
    if packse_version != "0.0.0":
        update_common_mod_rs(packse_version)

    if not scenarios:
        if packse_version == "0.0.0":
            path = packse.__development_base_path__ / "scenarios"
            if path.exists():
                logging.info(
                    "Detected development version of packse, using scenarios from %s",
                    path,
                )
                scenarios = [path]
            else:
                logging.error(
                    "No scenarios provided. Found development version of packse but is missing scenarios. Is it installed as an editable?"
                )
                sys.exit(1)
        else:
            logging.error("No scenarios provided, nothing to do.")
            return

    targets = []
    for target in scenarios:
        if target.is_dir():
            targets.extend(target.glob("**/*.json"))
            targets.extend(target.glob("**/*.toml"))
            targets.extend(target.glob("**/*.yaml"))
        else:
            targets.append(target)

    logging.info("Loading scenario metadata...")
    data = packse.inspect.variables_for_templates(
        targets=targets,
        no_hash=True,
    )

    data["scenarios"] = [
        scenario
        for scenario in data["scenarios"]
        # Drop example scenarios
        if not scenario["name"].startswith("example")
    ]

    # We have a mixture of long singe-line descriptions (json scenarios) we need to
    # wrap and manually formatted markdown in toml and yaml scenarios we want to
    # preserve.
    for scenario in data["scenarios"]:
        if scenario["_textwrap"]:
            scenario["description"] = textwrap.wrap(scenario["description"], width=80)
        else:
            scenario["description"] = scenario["description"].splitlines()
        # Don't drop empty lines like chevron would.
        scenario["description"] = "\n/// ".join(scenario["description"])

    # Apply the same wrapping to the expected explanation
    for scenario in data["scenarios"]:
        expected = scenario["expected"]
        if explanation := expected["explanation"]:
            if scenario["_textwrap"]:
                expected["explanation"] = textwrap.wrap(explanation, width=80)
            else:
                expected["explanation"] = explanation.splitlines()
            expected["explanation"] = "\n// ".join(expected["explanation"])

    # Hack to track which scenarios require a specific Python patch version
    for scenario in data["scenarios"]:
        if "patch" in scenario["name"]:
            scenario["python_patch"] = True
        else:
            scenario["python_patch"] = False

    # Split scenarios into `install`, `compile` and `lock` cases
    install_scenarios = []
    compile_scenarios = []
    lock_scenarios = []

    for scenario in data["scenarios"]:
        resolver_options = scenario["resolver_options"] or {}
        # Avoid writing the empty `required-environments = []`
        resolver_options["has_required_environments"] = bool(
            resolver_options["required_environments"]
        )
        if resolver_options.get("universal"):
            lock_scenarios.append(scenario)
        elif resolver_options.get("python") is not None:
            compile_scenarios.append(scenario)
        else:
            install_scenarios.append(scenario)

    template_kinds_and_scenarios: list[tuple[TemplateKind, list[Any]]] = [
        (TemplateKind.install, install_scenarios),
        (TemplateKind.compile, compile_scenarios),
        (TemplateKind.lock, lock_scenarios),
    ]
    for template_kind, scenarios in template_kinds_and_scenarios:
        if template_kind not in template_kinds:
            continue

        data = {"scenarios": scenarios}

        ref = "HEAD" if packse_version == "0.0.0" else packse_version

        # Add generated metadata
        data["generated_from"] = (
            f"https://github.com/astral-sh/packse/tree/{ref}/scenarios"
        )
        data["generated_with"] = "./scripts/sync_scenarios.sh"
        data["vendor_links"] = (
            f"https://raw.githubusercontent.com/astral-sh/packse/{ref}/vendor/links.html"
        )

        data["index_url"] = (
            os.environ.get(
                "UV_TEST_PACKSE_INDEX",
                f"https://astral-sh.github.io/packse/{ref}",
            )
            + "/simple-html"
        )

        # Render the template
        logging.info(f"Rendering template {template_kind.name}")
        output = chevron_blue.render(
            template=template_kind.template_file().read_text(),
            data=data,
            no_escape=True,
            warn=True,
        )

        # Update the test files
        logging.info(
            f"Updating test file at `{template_kind.test_file().relative_to(PROJECT_ROOT)}`...",
        )
        with open(template_kind.test_file(), "w") as test_file:
            test_file.write(output)

        # Format
        logging.info(
            "Formatting test file...",
        )
        subprocess.check_call(
            ["rustfmt", template_kind.test_file()],
            stderr=subprocess.STDOUT,
            stdout=sys.stderr if debug else subprocess.DEVNULL,
        )

        # Update snapshots
        if snapshot_update:
            logging.info("Updating snapshots...")
            env = os.environ.copy()
            command = [
                "cargo",
                "insta",
                "test",
                "--features",
                "pypi,python,python-patch",
                "--accept",
                "--test-runner",
                "nextest",
                "--test",
                "it",
                "--",
                template_kind.test_file().with_suffix("").name,
            ]
            logging.debug(f"Running {' '.join(command)}")
            exit_code = subprocess.call(
                command,
                cwd=PROJECT_ROOT,
                stderr=subprocess.STDOUT,
                stdout=sys.stderr if debug else subprocess.DEVNULL,
                env=env,
            )
            if exit_code != 0:
                logging.warning(
                    f"Snapshot update failed with exit code {exit_code} (use -v to show details)"
                )
        else:
            logging.info("Skipping snapshot update")

    logging.info("Done!")


def update_common_mod_rs(packse_version: str):
    """Update the value of `PACKSE_VERSION` used in non-scenario tests.

    Example:
    ```rust
    pub const PACKSE_VERSION: &str = "0.3.30";
    ```
    """
    test_common = TESTS_COMMON_MOD_RS.read_text()
    before_version = 'pub const PACKSE_VERSION: &str = "'
    after_version = '";'
    build_vendor_links_url = f"{before_version}{packse_version}{after_version}"
    if build_vendor_links_url in test_common:
        logging.info(f"Up-to-date: {TESTS_COMMON_MOD_RS}")
    else:
        logging.info(f"Updating: {TESTS_COMMON_MOD_RS}")
        url_matcher = re.compile(
            re.escape(before_version) + '[^"]+' + re.escape(after_version)
        )
        assert len(url_matcher.findall(test_common)) == 1, (
            f"PACKSE_VERSION not found in {TESTS_COMMON_MOD_RS}"
        )
        test_common = url_matcher.sub(build_vendor_links_url, test_common)
        TESTS_COMMON_MOD_RS.write_text(test_common)


if __name__ == "__main__":
    parser = argparse.ArgumentParser(
        description="Generates and updates snapshot test cases from packse scenarios.",
    )
    parser.add_argument(
        "scenarios",
        type=Path,
        nargs="*",
        help="The scenario files to use",
    )
    parser.add_argument(
        "--templates",
        type=TemplateKind,
        choices=list(TemplateKind),
        default=list(TemplateKind),
        nargs="*",
        help="The templates to render. By default, all templates are rendered",
    )
    parser.add_argument(
        "-v",
        "--verbose",
        action="store_true",
        help="Enable debug logging",
    )
    parser.add_argument(
        "-q",
        "--quiet",
        action="store_true",
        help="Disable logging",
    )

    parser.add_argument(
        "--no-snapshot-update",
        action="store_true",
        help="Disable automatic snapshot updates",
    )

    args = parser.parse_args()
    if args.quiet:
        log_level = logging.CRITICAL
    elif args.verbose:
        log_level = logging.DEBUG
    else:
        log_level = logging.INFO

    logging.basicConfig(level=log_level, format="%(message)s")

    main(args.scenarios, args.templates, snapshot_update=not args.no_snapshot_update)
