#!/usr/bin/env python3
import argparse

from common import (
    build_common_arg_parser,
    clinic_cluster_meta,
    clinic_metrics_query,
    clinic_session,
    find_metric_definition,
    inject_expression_variables,
    parse_clinic_link,
    remove_label_matcher,
    series_last_values,
    write_json,
)


def main() -> int:
    parser = build_common_arg_parser(
        "Fetch metric values from a Clinic link by loading dashboard/panel expressions from tidb-perf-diagnosis knowledge"
    )
    parser.add_argument("--dashboard-title", required=True, help="Dashboard title from tidb-perf-diagnosis knowledge")
    parser.add_argument("--panel-title", required=True, help="Panel title from tidb-perf-diagnosis knowledge")
    parser.add_argument("--expression-index", type=int, default=0, help="Expression index within the selected panel")
    parser.add_argument("--instance", default=".*", help="Regex for $instance / ${instance:regex}")
    parser.add_argument("--k8s-cluster", default="", help="Override $k8s_cluster; default empty")
    parser.add_argument("--step", default="60s", help="Query step")
    args = parser.parse_args()

    clinic_context = parse_clinic_link(args.link)
    session = clinic_session(base_url=args.base_url, profile_name=args.profile)
    cluster_meta = clinic_cluster_meta(session, clinic_context)
    metric_def = find_metric_definition(args.dashboard_title, args.panel_title)

    expressions = metric_def["expressions"]
    if args.expression_index < 0 or args.expression_index >= len(expressions):
        raise ValueError(f"expression_index out of range: {args.expression_index}")

    raw_expr = expressions[args.expression_index]
    final_expr = inject_expression_variables(
        raw_expr,
        clinic_context,
        variable_rules={
            "k8s_cluster": args.k8s_cluster,
            "instance": args.instance,
        },
    )
    attempted_promqls = [final_expr]
    fallback_notes = []
    metrics_payload = clinic_metrics_query(session, clinic_context, final_expr, step=args.step)

    result = (((metrics_payload or {}).get("data") or {}).get("result")) or []
    fallback_expr = ""
    if not result and 'scope="' in final_expr:
        fallback_expr = remove_label_matcher(final_expr, "scope")
        if fallback_expr != final_expr:
            fallback_notes.append(
                "Primary query returned no series; retried once after removing the hard-coded scope matcher."
            )
            attempted_promqls.append(fallback_expr)
            metrics_payload = clinic_metrics_query(session, clinic_context, fallback_expr, step=args.step)

    write_json(
        {
            "clinic_context": clinic_context,
            "cluster_meta": {
                "id": cluster_meta.get("id"),
                "name": cluster_meta.get("name"),
                "version": cluster_meta.get("version"),
                "deployType": cluster_meta.get("deployType"),
                "deployTypeV2": cluster_meta.get("deployTypeV2"),
                "topology": cluster_meta.get("topology"),
                "status": cluster_meta.get("status"),
            },
            "knowledge_file": metric_def["knowledge_file"],
            "dashboard_title": metric_def["dashboard_title"],
            "panel_title": metric_def["panel_title"],
            "raw_expression": raw_expr,
            "final_promql": attempted_promqls[-1],
            "attempted_promqls": attempted_promqls,
            "fallback_notes": fallback_notes,
            "raw_series": metrics_payload,
            "last_values": series_last_values(metrics_payload),
        }
    )
    return 0


if __name__ == "__main__":
    raise SystemExit(main())