import { useMemo, useState } from "react";
import { getApiErrorMessage, useSchemeAuditQuery } from "../../api/queries";
import { ApiErrorView } from "../../shared/ui/ApiErrorView";
import { StatCard } from "../../shared/ui/StatCard";

type Props = {
  schemeId: string;
};

type AuditGroup = "all" | "lifecycle" | "pricing" | "versioning" | "upload";

function valueText(value: unknown): string {
  if (value === null || value === undefined || value === "") {
    return "—";
  }
  return String(value);
}

function detectGroup(eventType: string | null | undefined): AuditGroup {
  const value = (eventType || "").toLowerCase();

  if (value.includes("pricing.")) return "pricing";
  if (value.includes("version")) return "versioning";
  if (value.includes("upload") || value.includes("import")) return "upload";
  if (
    value.includes("published") ||
    value.includes("unpublished") ||
    value.includes("rolled_back") ||
    value.includes("scheme.created")
  ) {
    return "lifecycle";
  }

  return "all";
}

function groupLabel(group: AuditGroup): string {
  if (group === "all") return "Все";
  if (group === "lifecycle") return "Жизненный цикл";
  if (group === "pricing") return "Тарифы";
  if (group === "versioning") return "Версионирование";
  return "Загрузка / импорт";
}

function prettyDetails(value: unknown): string {
  if (value === null || value === undefined) {
    return "null";
  }

  if (typeof value === "string") {
    try {
      const parsed = JSON.parse(value);
      return JSON.stringify(parsed, null, 2);
    } catch {
      return value;
    }
  }

  try {
    return JSON.stringify(value, null, 2);
  } catch {
    return String(value);
  }
}

export function SchemeAuditTab({ schemeId }: Props) {
  const auditQuery = useSchemeAuditQuery(schemeId);
  const [selectedGroup, setSelectedGroup] = useState<AuditGroup>("all");
  const [expandedRows, setExpandedRows] = useState<Record<string, boolean>>({});

  const items = useMemo(() => {
    const raw = auditQuery.data ?? [];
    return [...raw].sort((a, b) => {
      const left = new Date(a.created_at || 0).getTime();
      const right = new Date(b.created_at || 0).getTime();
      return right - left;
    });
  }, [auditQuery.data]);

  const counts = useMemo(() => {
    return {
      all: items.length,
      lifecycle: items.filter((item) => detectGroup(item.event_type) === "lifecycle").length,
      pricing: items.filter((item) => detectGroup(item.event_type) === "pricing").length,
      versioning: items.filter((item) => detectGroup(item.event_type) === "versioning").length,
      upload: items.filter((item) => detectGroup(item.event_type) === "upload").length
    };
  }, [items]);

  const filtered = useMemo(() => {
    if (selectedGroup === "all") {
      return items;
    }
    return items.filter((item) => detectGroup(item.event_type) === selectedGroup);
  }, [items, selectedGroup]);

  const detailsMap = useMemo(() => {
    const result: Record<string, string> = {};

    filtered.forEach((item, index) => {
      const key = item.audit_event_id || `${item.event_type || "event"}-${index}`;
      result[key] = prettyDetails(item.details_json);
    });

    return result;
  }, [filtered]);

  if (auditQuery.isLoading) {
    return <div className="panel">Загрузка аудита...</div>;
  }

  if (auditQuery.isError) {
    return <ApiErrorView title="Ошибка загрузки аудита" message={getApiErrorMessage(auditQuery.error)} />;
  }

  return (
    <div className="detail-grid">
      <div className="panel">
        <h3>Аудит схемы</h3>
        <p className="muted">
          История событий по схеме. Список отсортирован от новых к старым.
        </p>

        <div className="stats-grid">
          <StatCard label="Всего событий" value={counts.all} />
          <StatCard label="Жизненный цикл" value={counts.lifecycle} />
          <StatCard label="Тарифы" value={counts.pricing} />
          <StatCard label="Версионирование" value={counts.versioning} />
        </div>
      </div>

      <div className="panel">
        <div className="toolbar">
          <button
            type="button"
            className={`btn ${selectedGroup === "all" ? "btn-primary" : "btn-secondary"}`}
            onClick={() => setSelectedGroup("all")}
          >
            Все ({counts.all})
          </button>

          <button
            type="button"
            className={`btn ${selectedGroup === "lifecycle" ? "btn-primary" : "btn-secondary"}`}
            onClick={() => setSelectedGroup("lifecycle")}
          >
            Жизненный цикл ({counts.lifecycle})
          </button>

          <button
            type="button"
            className={`btn ${selectedGroup === "pricing" ? "btn-primary" : "btn-secondary"}`}
            onClick={() => setSelectedGroup("pricing")}
          >
            Тарифы ({counts.pricing})
          </button>

          <button
            type="button"
            className={`btn ${selectedGroup === "versioning" ? "btn-primary" : "btn-secondary"}`}
            onClick={() => setSelectedGroup("versioning")}
          >
            Версионирование ({counts.versioning})
          </button>

          <button
            type="button"
            className={`btn ${selectedGroup === "upload" ? "btn-primary" : "btn-secondary"}`}
            onClick={() => setSelectedGroup("upload")}
          >
            Загрузка / импорт ({counts.upload})
          </button>
        </div>
      </div>

      <div className="panel">
        <h3>События</h3>

        {filtered.length === 0 ? (
          <p className="muted">Событий для выбранной группы нет.</p>
        ) : (
          <div className="audit-list">
            {filtered.map((item, index) => {
              const rowKey = item.audit_event_id || `${item.event_type || "event"}-${index}`;
              const isOpen = expandedRows[rowKey] === true;
              const details = detailsMap[rowKey] || "{}";

              return (
                <div key={rowKey} className="audit-card">
                  <div className="audit-card-head">
                    <div>
                      <div className="audit-title">{valueText(item.event_type)}</div>
                      <div className="muted">
                        Группа: {groupLabel(detectGroup(item.event_type))} · Создано: {valueText(item.created_at)}
                      </div>
                    </div>

                    <div className="toolbar">
                      <button
                        type="button"
                        className="btn btn-secondary"
                        onClick={() =>
                          setExpandedRows((prev) => ({
                            ...prev,
                            [rowKey]: !prev[rowKey]
                          }))
                        }
                      >
                        {isOpen ? "Скрыть details_json" : "Показать details_json"}
                      </button>
                    </div>
                  </div>

                  <div className="audit-meta-grid">
                    <div><strong>Тип объекта:</strong> {valueText(item.object_type)}</div>
                    <div><strong>Ссылка на объект:</strong> {valueText(item.object_ref)}</div>
                    <div><strong>ID события:</strong> <span className="mono-cell">{valueText(item.audit_event_id)}</span></div>
                  </div>

                  {isOpen ? (
                    <div className="code-box" style={{ marginTop: 12 }}>
                      {details}
                    </div>
                  ) : null}
                </div>
              );
            })}
          </div>
        )}
      </div>
    </div>
  );
}