import { useEffect } from "react";
import { useParams, Link } from "react-router-dom";
import { useQuery, useMutation, useQueryClient } from "@tanstack/react-query";
import { issuesApi } from "../api/issues";
import { useCompany } from "../context/CompanyContext";
import { usePanel } from "../context/PanelContext";
import { useBreadcrumbs } from "../context/BreadcrumbContext";
import { queryKeys } from "../lib/queryKeys";
import { InlineEditor } from "../components/InlineEditor";
import { CommentThread } from "../components/CommentThread";
import { IssueProperties } from "../components/IssueProperties";
import { StatusIcon } from "../components/StatusIcon";
import { PriorityIcon } from "../components/PriorityIcon";
import { Separator } from "@/components/ui/separator";
import { ChevronRight } from "lucide-react";

export function IssueDetail() {
  const { issueId } = useParams<{ issueId: string }>();
  const { selectedCompanyId } = useCompany();
  const { openPanel, closePanel } = usePanel();
  const { setBreadcrumbs } = useBreadcrumbs();
  const queryClient = useQueryClient();

  const { data: issue, isLoading, error } = useQuery({
    queryKey: queryKeys.issues.detail(issueId!),
    queryFn: () => issuesApi.get(issueId!),
    enabled: !!issueId,
  });

  const { data: comments } = useQuery({
    queryKey: queryKeys.issues.comments(issueId!),
    queryFn: () => issuesApi.listComments(issueId!),
    enabled: !!issueId,
  });

  const updateIssue = useMutation({
    mutationFn: (data: Record<string, unknown>) => issuesApi.update(issueId!, data),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: queryKeys.issues.detail(issueId!) });
      if (selectedCompanyId) {
        queryClient.invalidateQueries({ queryKey: queryKeys.issues.list(selectedCompanyId) });
      }
    },
  });

  const addComment = useMutation({
    mutationFn: (body: string) => issuesApi.addComment(issueId!, body),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: queryKeys.issues.comments(issueId!) });
    },
  });

  useEffect(() => {
    setBreadcrumbs([
      { label: "Issues", href: "/issues" },
      { label: issue?.title ?? issueId ?? "Issue" },
    ]);
  }, [setBreadcrumbs, issue, issueId]);

  useEffect(() => {
    if (issue) {
      openPanel(
        <IssueProperties issue={issue} onUpdate={(data) => updateIssue.mutate(data)} />
      );
    }
    return () => closePanel();
  }, [issue]); // eslint-disable-line react-hooks/exhaustive-deps

  if (isLoading) return <p className="text-sm text-muted-foreground">Loading...</p>;
  if (error) return <p className="text-sm text-destructive">{error.message}</p>;
  if (!issue) return null;

  // Ancestors are returned oldest-first from the server (root at end, immediate parent at start)
  const ancestors = issue.ancestors ?? [];

  return (
    <div className="max-w-2xl space-y-6">
      {/* Parent chain breadcrumb */}
      {ancestors.length > 0 && (
        <nav className="flex items-center gap-1 text-xs text-muted-foreground flex-wrap">
          {[...ancestors].reverse().map((ancestor, i) => (
            <span key={ancestor.id} className="flex items-center gap-1">
              {i > 0 && <ChevronRight className="h-3 w-3 shrink-0" />}
              <Link
                to={`/issues/${ancestor.id}`}
                className="hover:text-foreground transition-colors truncate max-w-[200px]"
                title={ancestor.title}
              >
                {ancestor.title}
              </Link>
            </span>
          ))}
          <ChevronRight className="h-3 w-3 shrink-0" />
          <span className="text-foreground/60 truncate max-w-[200px]">{issue.title}</span>
        </nav>
      )}

      <div className="space-y-3">
        <div className="flex items-center gap-2">
          <StatusIcon
            status={issue.status}
            onChange={(status) => updateIssue.mutate({ status })}
          />
          <PriorityIcon
            priority={issue.priority}
            onChange={(priority) => updateIssue.mutate({ priority })}
          />
          <span className="text-xs font-mono text-muted-foreground">{issue.id.slice(0, 8)}</span>
        </div>

        <InlineEditor
          value={issue.title}
          onSave={(title) => updateIssue.mutate({ title })}
          as="h2"
          className="text-xl font-bold"
        />

        <InlineEditor
          value={issue.description ?? ""}
          onSave={(description) => updateIssue.mutate({ description })}
          as="p"
          className="text-sm text-muted-foreground"
          placeholder="Add a description..."
          multiline
        />
      </div>

      <Separator />

      <CommentThread
        comments={comments ?? []}
        onAdd={async (body) => {
          await addComment.mutateAsync(body);
        }}
      />
    </div>
  );
}