"""Generate a Dockerfile from in.Dockerfile and a version JSON file, and write version info."""

import re
from pathlib import Path
from textwrap import dedent

from scripts import python_version

DOCKERFILE_TEMPLATE = Path("scripts/in.Dockerfile").read_text("utf-8")
DOCKERFILE = Path("Dockerfile")
JAIL_CONFIG = Path("config/snekbox.cfg")

versions, main_version = python_version.get_all_versions()

# Download and copy multiple python images into one layer
python_build = ""
jail_mounts = ""
previous_layer = "first"

for version in versions:
    # Configure NSJail mounts
    jail_mounts += dedent(
        f"""
        mount {{
            src: "/usr/local/bin/python{version.version_name}"
            dst: "/usr/local/bin/python{version.version_name}"
            is_bind: true
            rw: false
        }}
    """
    )

    if version.is_main:
        # Main is handled separately later
        continue

    # Add the current version to the Dockerfile
    layer_name = version.version_name.replace(".", "-")  # Dots aren't valid in layer names
    python_build += dedent(
        f"""
        FROM python:{version.image_tag} as base-{layer_name}
        COPY --from=base-{previous_layer} / /
    """
    )
    previous_layer = layer_name

# Main version is installed twice, once at the very beginning to make sure
# its files aren't overwritten, and once at the end which actually makes use of the version
python_build = f"FROM python:{main_version.image_tag} as base-first\n" + python_build

# Update mounts for python binaries in the NSJail config
new_config = re.sub(
    r"(?<=# mount-section-key)[\s\S]+(?=# mount-section-key-end)",
    jail_mounts,
    JAIL_CONFIG.read_text("utf-8"),
)
JAIL_CONFIG.write_text(new_config, "utf-8")

# Write new dockerfile
DOCKERFILE.write_text(
    "# THIS FILE IS AUTOGENERATED, DO NOT MODIFY! #\n"
    + DOCKERFILE_TEMPLATE.replace("{python_install_commands}", python_build)
    .replace("{final_base}", previous_layer)
    .replace("{main_version_tag}", main_version.image_tag),
    "utf-8",
)

print("Finished!")