"use client";

import { useState, useCallback, useEffect } from "react";
import { StemeDBClient, type AuditResponse, ApiError } from "@/lib/api";
import type { PanelState } from "@/lib/types";
import { AUDIT_FETCH_LIMIT, TIME_RANGES_MS, type TimeRangeKey } from "@/lib/constants";
import { ErrorState } from "@/components/shared/error-state";
import { AuditList } from "./audit-list";
import { AuditLoadingSkeleton } from "./audit-loading-skeleton";
import { AuditEmptyState } from "./audit-empty-state";
import type { AuditFilterValues } from "./audit-filters";

interface AuditPanelProps {
  initialFilters?: Partial<AuditFilterValues>;
}

export function AuditPanel({ initialFilters }: AuditPanelProps) {
  const [state, setState] = useState<PanelState<AuditResponse>>({ status: "idle" });
  const [filters, setFilters] = useState<AuditFilterValues>({
    subject: initialFilters?.subject ?? "",
    predicate: initialFilters?.predicate ?? "",
    agentId: initialFilters?.agentId ?? "",
    action: initialFilters?.action ?? "",
    timeRange: initialFilters?.timeRange ?? "24h",
  });

  const fetchData = useCallback(async (currentFilters: AuditFilterValues) => {
    setState({ status: "loading" });
    try {
      const client = new StemeDBClient();

      // Convert time range to from/to timestamps
      let fromTs: number | undefined;
      let toTs: number | undefined;
      if (currentFilters.timeRange !== "all") {
        const now = Date.now();
        const rangeMs = TIME_RANGES_MS[currentFilters.timeRange as TimeRangeKey] ?? TIME_RANGES_MS["24h"];
        fromTs = now - rangeMs;
        toTs = now;
      }

      const data = await client.auditQueries({
        limit: AUDIT_FETCH_LIMIT,
        agentId: currentFilters.agentId || undefined,
        subject: currentFilters.subject || undefined,
        predicate: currentFilters.predicate || undefined,
        from: fromTs,
        to: toTs,
      });
      setState({ status: "success", data });
    } catch (err) {
      // 404 means no audit entries - treat as empty success
      if (err instanceof ApiError && err.status === 404) {
        setState({
          status: "success",
          data: { audits: [], total_count: 0 },
        });
        return;
      }
      const message =
        err instanceof ApiError
          ? err.userMessage
          : err instanceof Error
            ? err.message
            : "Unknown error";
      setState({ status: "error", error: message });
    }
  }, []);

  // Load data on mount
  useEffect(() => {
    fetchData(filters);
  }, [fetchData, filters]);

  const handleFilterChange = useCallback((newFilters: AuditFilterValues) => {
    setFilters(newFilters);
    // fetchData will be called by the useEffect above
  }, []);

  const handleRetry = useCallback(() => {
    fetchData(filters);
  }, [fetchData, filters]);

  const hasFilters =
    filters.subject !== "" ||
    filters.predicate !== "" ||
    filters.agentId !== "" ||
    filters.action !== "" ||
    filters.timeRange !== "24h";

  return (
    <div className="space-y-6">
      {/* Header */}
      <div className="rounded-lg border border-border bg-card p-6">
        <h2 className="text-lg font-medium text-card-foreground mb-2">
          Query & Action History
        </h2>
        <p className="text-sm text-muted-foreground">
          Browse the complete audit trail of queries and administrative actions.
          Filter by subject, predicate, agent, or time range. Export data as JSON or CSV.
        </p>
      </div>

      {/* Content */}
      <div className="rounded-lg border border-border bg-card p-6">
        {state.status === "idle" && <AuditLoadingSkeleton />}
        {state.status === "loading" && <AuditLoadingSkeleton />}

        {state.status === "error" && (
          <ErrorState
            title="Failed to Load Audit Trail"
            error={state.error}
            onRetry={handleRetry}
          />
        )}

        {state.status === "success" && (
          <>
            {state.data.audits.length === 0 && !hasFilters ? (
              <AuditEmptyState hasFilters={false} />
            ) : (
              <AuditList
                entries={state.data.audits}
                totalCount={state.data.total_count}
                filters={filters}
                onFilterChange={handleFilterChange}
              />
            )}
          </>
        )}
      </div>
    </div>
  );
}