import { useEffect, useState } from "react";
import { FileText, Loader2, Maximize2, Minimize2, PanelRightClose } from "lucide-react";
import {
  AgenticApiError,
  generateReport,
  getReportVersion,
  listReportVersions,
  type ReportDetail,
  type ReportSummary,
} from "@/services/agenticApi";
import type { Analysis } from "@/services/orchestrationApi";
import { MarkdownContent } from "./MarkdownContent";
import { ReportVersionSelector } from "./ReportVersionSelector";
import { EmptyState, ErrorState } from "./AnalysisStates";
import { formatDateTime } from "./utils";

interface ReportSidebarProps {
  analysis: Analysis | null;
  userId?: string;
  onCollapse?: () => void;
  fullscreen?: boolean;
  onToggleFullscreen?: () => void;
}

export function ReportSidebar({ analysis, userId, onCollapse, fullscreen = false, onToggleFullscreen }: ReportSidebarProps) {
  const [versions, setVersions] = useState<ReportSummary[]>([]);
  const [selectedVersion, setSelectedVersion] = useState<number | undefined>();
  const [detail, setDetail] = useState<ReportDetail | null>(null);
  const [loadingVersions, setLoadingVersions] = useState(false);
  const [loadingDetail, setLoadingDetail] = useState(false);
  const [generating, setGenerating] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const [precondition, setPrecondition] = useState<string | null>(null);

  const loadVersions = async (analysisId: string, options: { silent?: boolean } = {}) => {
    setLoadingVersions(true);
    setError(null);
    try {
      const list = await listReportVersions(analysisId);
      setVersions(list);
      const latest = [...list].sort((a, b) => b.version - a.version)[0];
      setSelectedVersion(latest?.version);
    } catch (err) {
      setVersions([]);
      setSelectedVersion(undefined);
      const isMissingReportCollection = err instanceof AgenticApiError && err.status === 404;
      if (!options.silent && !isMissingReportCollection) {
        setError(err instanceof Error ? err.message : "Failed to load report versions");
      }
    } finally {
      setLoadingVersions(false);
    }
  };

  useEffect(() => {
    setDetail(null);
    setPrecondition(null);
    setVersions([]);
    setSelectedVersion(undefined);
    if (analysis?.id) loadVersions(analysis.id, { silent: true });
  }, [analysis?.id]);

  useEffect(() => {
    const loadDetail = async () => {
      if (!analysis?.id || selectedVersion == null) return;
      setLoadingDetail(true);
      setError(null);
      try {
        setDetail(await getReportVersion(analysis.id, selectedVersion));
      } catch (err) {
        setError(err instanceof Error ? err.message : "Failed to load report");
      } finally {
        setLoadingDetail(false);
      }
    };
    loadDetail();
  }, [selectedVersion]);

  const handleGenerate = async () => {
    if (!analysis?.id || !userId) return;
    setGenerating(true);
    setError(null);
    setPrecondition(null);
    try {
      const report = await generateReport(analysis.id, userId);
      setDetail(report);
      await loadVersions(analysis.id, { silent: true });
      setSelectedVersion(report.version);
    } catch (err) {
      if (err instanceof AgenticApiError && err.status === 409) {
        setPrecondition(err.message);
      } else {
        setError(err instanceof Error ? err.message : "Failed to generate report");
      }
    } finally {
      setGenerating(false);
    }
  };

  return (
    <section className="space-y-4">
      <div className="flex items-center justify-between gap-3">
        <div className="flex min-w-0 items-center gap-2">
          <FileText className="h-4 w-4 flex-shrink-0 text-slate-600" />
          <div className="min-w-0">
            <h3 className="text-sm font-semibold text-slate-900">Report</h3>
            <p className="truncate text-xs text-slate-500">Generate and preview report versions.</p>
          </div>
        </div>
        <div className="flex flex-shrink-0 items-center gap-1.5">
          {onToggleFullscreen && (
            <button
              type="button"
              title={fullscreen ? "Exit fullscreen" : "Expand report to fullscreen"}
              aria-label={fullscreen ? "Exit fullscreen" : "Expand report to fullscreen"}
              onClick={onToggleFullscreen}
              className="rounded-md p-2 text-slate-500 hover:bg-slate-100 hover:text-slate-900"
            >
              {fullscreen ? <Minimize2 className="h-4 w-4" /> : <Maximize2 className="h-4 w-4" />}
            </button>
          )}
          {onCollapse && !fullscreen && (
            <button
              type="button"
              title="Collapse report sidebar"
              aria-label="Collapse report sidebar"
              onClick={onCollapse}
              className="rounded-md p-2 text-slate-500 hover:bg-slate-100 hover:text-slate-900"
            >
              <PanelRightClose className="h-4 w-4" />
            </button>
          )}
          <button
            type="button"
            aria-label="Generate report"
            title="Generate a new report version with the Python report skill"
            onClick={handleGenerate}
            disabled={!analysis || !userId || generating}
            className="inline-flex items-center gap-2 rounded-md bg-slate-900 px-3 py-2 text-xs font-medium text-white hover:bg-slate-800 disabled:cursor-not-allowed disabled:opacity-50"
          >
            {generating && <Loader2 className="h-3.5 w-3.5 animate-spin" />}
            Generate
          </button>
        </div>
      </div>

      {!analysis ? (
        <EmptyState title="Select an analysis" description="Reports are generated per analysis." />
      ) : (
        <>
          <ReportVersionSelector versions={versions} selectedVersion={selectedVersion} disabled={loadingVersions || loadingDetail} onSelect={setSelectedVersion} />
          {precondition && <p className="rounded-md border border-amber-200 bg-amber-50 px-3 py-2 text-xs leading-5 text-amber-800">{precondition}</p>}
          {error && <ErrorState title="Report error" message={error} />}
          {loadingDetail ? (
            <div className="flex items-center justify-center gap-2 rounded-lg border border-slate-200 bg-white py-8 text-sm text-slate-500">
              <Loader2 className="h-4 w-4 animate-spin" /> Loading report
            </div>
          ) : detail ? (
            <article className="rounded-lg border border-slate-200 bg-white p-4">
              <div className="mb-3 text-xs text-slate-500">v{detail.version} generated {formatDateTime(detail.generated_at)}</div>
              {detail.rendered_markdown ? (
                <MarkdownContent content={detail.rendered_markdown} />
              ) : (
                <div className="space-y-4 text-sm leading-6 text-slate-700">
                  {detail.executive_summary && <p>{detail.executive_summary}</p>}
                  {detail.findings && detail.findings.length > 0 && (
                    <div>
                      <p className="font-medium text-slate-900">Findings</p>
                      <ul className="mt-1 list-disc space-y-1 pl-5">
                        {detail.findings.map((item, index) => <li key={index}>{item.text}</li>)}
                      </ul>
                    </div>
                  )}
                  {detail.caveats && detail.caveats.length > 0 && (
                    <div>
                      <p className="font-medium text-slate-900">Caveats</p>
                      <ul className="mt-1 list-disc space-y-1 pl-5">
                        {detail.caveats.map((item, index) => <li key={index}>{item.text}</li>)}
                      </ul>
                    </div>
                  )}
                  {detail.open_questions && detail.open_questions.length > 0 && (
                    <div>
                      <p className="font-medium text-slate-900">Open questions</p>
                      <ul className="mt-1 list-disc space-y-1 pl-5">
                        {detail.open_questions.map((item, index) => <li key={index}>{item.text}</li>)}
                      </ul>
                    </div>
                  )}
                </div>
              )}
            </article>
          ) : (
            <EmptyState title="No report selected" description="Generate a report or select an existing version." />
          )}
        </>
      )}
    </section>
  );
}