load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

def _helm_import_impl(ctx):
    if ctx.attr.url.startswith("oci://"):
        # Use the python script to pull
        output_file = "chart.tgz"

        # We need a python interpreter. We'll assume 'python3' is in the path for now.
        # In a strict build, we should probably use the python toolchain, but that's hard in a repo rule.

        # Locate the helper script.
        # Since this is a repo rule, we can't easily access the source tree files unless we use `exports_files` and `ctx.path`.
        # But `tools/helm_pull.py` is in the main repo.
        # We can copy the content of the script into the rule or the repo.

        # Let's assume the script content is passed or available.
        # Actually, reading it from the label is cleaner if possible.
        script_path = ctx.path(Label("//tools:helm_pull.py"))

        cmd = [
            "python3",
            script_path,
            "--url",
            ctx.attr.url,
            "--version",
            ctx.attr.version,
            "--output",
            output_file,
        ]

        if ctx.attr.sha256:
            cmd.extend(["--digest", ctx.attr.sha256])

        result = ctx.execute(cmd)
        if result.return_code != 0:
            fail("Failed to pull OCI chart: \n%s\n%s" % (result.stdout, result.stderr))

        # Extract
        ctx.extract(output_file, stripPrefix = ctx.attr.strip_prefix)
        ctx.delete(output_file)

    else:
        # HTTP fallback (simulating http_archive logic partially)
        ctx.download_and_extract(
            url = ctx.attr.url,
            sha256 = ctx.attr.sha256,
            stripPrefix = ctx.attr.strip_prefix,
        )

    # Build file
    ctx.file("BUILD.bazel", ctx.attr.build_file_content)

helm_import = repository_rule(
    implementation = _helm_import_impl,
    attrs = {
        "url": attr.string(mandatory = True),
        "version": attr.string(),
        "sha256": attr.string(),
        "strip_prefix": attr.string(),
        "build_file_content": attr.string(),
    },
)

def _helm_deps_impl(ctx):
    # 1. Read the lockfile
    lockfile_content = ctx.read(ctx.path(Label("//third_party/helm:chartfile.lock.json")))
    lock = json.decode(lockfile_content)

    # 2. Iterate over charts
    for name, info in lock.get("charts", {}).items():
        # name is like "grafana/grafana"
        # repo_name will be "helm_grafana_grafana"
        repo_name = "helm_" + name.replace("/", "_").replace("-", "_")
        chart_name = name.split("/")[1]

        helm_import(
            name = repo_name,
            url = info["url"],
            version = info.get("version", ""),  # Version needed for OCI
            sha256 = info["digest"],
            strip_prefix = chart_name,
            build_file_content = """
filegroup(
    name = "chart",
    srcs = glob(["**"]),
    visibility = ["//visibility:public"],
)
""",
        )

helm_deps = module_extension(
    implementation = _helm_deps_impl,
)