#!/usr/bin/env python3

from pathlib import Path
import sys
import yaml
from jinja2 import Environment, FileSystemLoader, StrictUndefined

BASE = Path("/opt/homelab")
SERVICES_DIR = BASE / "services"
TEMPLATES_DIR = BASE / "templates"
OUTPUT_DIR = BASE / "generated" / "caddy"


def load_yaml(path: Path) -> dict:
    with path.open("r", encoding="utf-8") as f:
        data = yaml.safe_load(f) or {}
    return data


def validate_service(data: dict, source: Path) -> None:
    required_common = ["name", "type", "domain"]
    for key in required_common:
        if key not in data:
            raise ValueError(f"{source.name}: missing required key '{key}'")

    svc_type = data["type"]
    if svc_type not in {"static", "proxy"}:
        raise ValueError(f"{source.name}: unsupported type '{svc_type}'")

    if svc_type == "static" and "root" not in data:
        raise ValueError(f"{source.name}: static service requires 'root'")

    if svc_type == "proxy" and "backend" not in data:
        raise ValueError(f"{source.name}: proxy service requires 'backend'")


def render_service(env: Environment, data: dict) -> str:
    svc_type = data["type"]

    defaults = {
        "headers": False,
        "auth": False,
        "real_ip": False,
        "health_uri": None,
        "health_interval": None,
    }

    merged = {**defaults, **data}

    if svc_type == "static":
        template = env.get_template("static.caddy.j2")
        return template.render(**merged).strip() + "\n"

    reverse_proxy_block = any(
        [
            merged.get("real_ip"),
            merged.get("health_uri"),
            merged.get("health_interval"),
        ]
    )
    merged["reverse_proxy_block"] = reverse_proxy_block

    template = env.get_template("proxy.caddy.j2")
    return template.render(**merged).strip() + "\n"


def main() -> int:
    OUTPUT_DIR.mkdir(parents=True, exist_ok=True)

    env = Environment(
        loader=FileSystemLoader(str(TEMPLATES_DIR)),
        undefined=StrictUndefined,
        trim_blocks=True,
        lstrip_blocks=True,
    )

    rendered_files = []

    for svc_file in sorted(SERVICES_DIR.glob("*.yml")):
        data = load_yaml(svc_file)
        validate_service(data, svc_file)

        rendered = render_service(env, data)
        output_file = OUTPUT_DIR / f"{data['name']}.caddy"
        output_file.write_text(rendered, encoding="utf-8")
        rendered_files.append(output_file.name)

    print("Generated:")
    for name in rendered_files:
        print(f" - {name}")

    return 0


if __name__ == "__main__":
    sys.exit(main())