from __future__ import annotations

import importlib.util
import json
from pathlib import Path


PROJECT_ROOT = Path(__file__).resolve().parents[2]
SCRIPT_PATH = (
    PROJECT_ROOT
    / "agentkit"
    / "skills"
    / "builtin"
    / "o11y-alert-rule-lookup"
    / "scripts"
    / "find_alert_rule.py"
)


def _load_module():
    spec = importlib.util.spec_from_file_location("find_alert_rule", SCRIPT_PATH)
    assert spec and spec.loader
    module = importlib.util.module_from_spec(spec)
    spec.loader.exec_module(module)
    return module


def test_find_alert_rule_returns_exact_match(tmp_path, capsys):
    module = _load_module()
    runbooks_dir = tmp_path / "runbooks"
    rules_dir = runbooks_dir / "rules" / "tidb"
    rules_dir.mkdir(parents=True)
    (rules_dir / "cpu.yaml").write_text(
        """
groups:
  - name: tidb.rules
    rules:
      - alert: HighCPUUsage
        expr: sum(rate(process_cpu_seconds_total[5m])) > 0.8
        for: 10m
        annotations:
          summary: CPU is high
      - alert: HighMemoryUsage
        expr: process_resident_memory_bytes > 1024
""".strip()
    )

    code = module.main(["--alert-name", "HighCPUUsage", "--runbooks-dir", str(runbooks_dir)])
    captured = capsys.readouterr()
    payload = json.loads(captured.out)

    assert code == 0
    assert payload["status"] == "ok"
    assert payload["searched_files"] == 1
    assert payload["top_match"]["alert"] == "HighCPUUsage"
    assert len(payload["exact_matches"]) == 1
    assert payload["exact_matches"][0]["alert"] == "HighCPUUsage"
    assert payload["exact_matches"][0]["file"] == "rules/tidb/cpu.yaml"
    assert payload["exact_matches"][0]["for"] == "10m"
    assert "process_cpu_seconds_total" in payload["exact_matches"][0]["expr"]


def test_find_alert_rule_returns_fuzzy_candidates_when_exact_missing(tmp_path, capsys):
    module = _load_module()
    runbooks_dir = tmp_path / "runbooks"
    rules_dir = runbooks_dir / "rules" / "tidb"
    rules_dir.mkdir(parents=True)
    (rules_dir / "cpu.yaml").write_text(
        """
groups:
  - name: tidb.rules
    rules:
      - alert: TiDBHighCPUUsage
        expr: sum(rate(process_cpu_seconds_total[5m])) > 0.8
""".strip()
    )

    code = module.main(["--alert-name", "HighCPUUsage", "--runbooks-dir", str(runbooks_dir)])
    captured = capsys.readouterr()
    payload = json.loads(captured.out)

    assert code == 0
    assert payload["status"] == "ok"
    assert payload["exact_matches"] == []
    assert len(payload["fuzzy_matches"]) == 1
    assert payload["top_match"]["alert"] == "TiDBHighCPUUsage"
    assert payload["fuzzy_matches"][0]["alert"] == "TiDBHighCPUUsage"
    assert payload["fuzzy_matches"][0]["match_type"] in {"substring", "token_overlap"}


def test_find_alert_rule_uses_component_and_messages_to_rank_same_name_matches(tmp_path, capsys):
    module = _load_module()
    runbooks_dir = tmp_path / "runbooks"
    rules_dir = runbooks_dir / "rules"
    (rules_dir / "tidb").mkdir(parents=True)
    (rules_dir / "tikv").mkdir(parents=True)
    (rules_dir / "tidb" / "cpu.yaml").write_text(
        """
groups:
  - name: tidb.rules
    rules:
      - alert: HighCPUUsage
        expr: tidb_server_cpu_usage > 0.8
        annotations:
          summary: tidb cpu is high
          message: executor busy
""".strip()
    )
    (rules_dir / "tikv" / "cpu.yaml").write_text(
        """
groups:
  - name: tikv.rules
    rules:
      - alert: HighCPUUsage
        expr: tikv_thread_cpu_seconds_total > 0.8
        annotations:
          summary: tikv raftstore cpu is high
          message: raftstore busy
""".strip()
    )

    code = module.main(
        [
            "--alert-name",
            "HighCPUUsage",
            "--component",
            "tikv",
            "--message",
            "raftstore busy",
            "--runbooks-dir",
            str(runbooks_dir),
        ]
    )
    captured = capsys.readouterr()
    payload = json.loads(captured.out)

    assert code == 0
    assert payload["status"] == "ok"
    assert len(payload["exact_matches"]) == 2
    assert payload["top_match"]["file"] == "rules/tikv/cpu.yaml"
    assert payload["exact_matches"][0]["context_score"] > payload["exact_matches"][1]["context_score"]


def test_find_alert_rule_extracts_multiline_expr_blocks(tmp_path, capsys):
    module = _load_module()
    runbooks_dir = tmp_path / "runbooks"
    rules_dir = runbooks_dir / "rules" / "tidb"
    rules_dir.mkdir(parents=True)
    (rules_dir / "cpu.yaml").write_text(
        """
groups:
  - name: tidb.rules
    rules:
      - alert: TiDBCPUCoreUsageOver75ForBig3
        expr: |
          100 * max by (tenant, cluster_id, cluster) (
            sum(rate(node_cpu_seconds_total{component=~"tidb"}[1m]))
          ) > 75
        for: 5m
""".strip()
    )

    code = module.main(
        [
            "--alert-name",
            "TiDBCPUCoreUsageOver75ForBig3",
            "--runbooks-dir",
            str(runbooks_dir),
        ]
    )
    captured = capsys.readouterr()
    payload = json.loads(captured.out)

    assert code == 0
    assert payload["top_match"]["for"] == "5m"
    assert "100 * max by" in payload["top_match"]["expr"]
    assert "sum(rate(node_cpu_seconds_total" in payload["top_match"]["expr"]
    assert payload["top_match"]["expr"] != "|"


def test_find_alert_rule_reports_missing_runbooks_dir(capsys):
    module = _load_module()

    code = module.main(["--alert-name", "HighCPUUsage", "--runbooks-dir", "/tmp/does-not-exist"])
    captured = capsys.readouterr()
    payload = json.loads(captured.out)

    assert code == 2
    assert payload["status"] == "error"
    assert "rules/" in payload["error"]