import { useState } from "react";
import { useQuery, useMutation, useQueryClient } from "@tanstack/react-query";
import {
  ExternalLink,
  Link2,
  RefreshCw,
  Search,
  Trash2,
  Loader2,
  Plus,
  X,
} from "lucide-react";
import {
  listJiraLinks,
  searchJiraIssues,
  createJiraLink,
  syncJiraLink,
  deleteJiraLink,
  type JiraLink,
  type JiraLinkEntityType,
  type JiraIssueResult,
} from "../api/jira";
import { useDebounce } from "../hooks/useDebounce";

interface JiraLinkPanelProps {
  entityType: JiraLinkEntityType;
  entityId: string;
}

const priorityColors: Record<string, string> = {
  Highest: "text-red-400",
  High: "text-orange-400",
  Medium: "text-yellow-400",
  Low: "text-cyan-400",
  Lowest: "text-gray-400",
};

const statusColors: Record<string, string> = {
  "To Do": "bg-gray-700 text-gray-300",
  "In Progress": "bg-blue-900/50 text-blue-400",
  "Done": "bg-green-900/50 text-green-400",
};

export default function JiraLinkPanel({ entityType, entityId }: JiraLinkPanelProps) {
  const queryClient = useQueryClient();
  const [showSearch, setShowSearch] = useState(false);
  const [searchQuery, setSearchQuery] = useState("");
  const debouncedQuery = useDebounce(searchQuery, 400);

  // ── Queries ─────────────────────────────────────────────────────

  const { data: links = [], isLoading: isLoadingLinks } = useQuery({
    queryKey: ["jira-links", entityType, entityId],
    queryFn: () => listJiraLinks({ entity_type: entityType, entity_id: entityId }),
  });

  const { data: searchResults = [], isFetching: isSearching } = useQuery({
    queryKey: ["jira-search", debouncedQuery],
    queryFn: () => searchJiraIssues(debouncedQuery),
    enabled: debouncedQuery.length >= 2,
  });

  // ── Mutations ───────────────────────────────────────────────────

  const invalidate = () => {
    queryClient.invalidateQueries({
      queryKey: ["jira-links", entityType, entityId],
    });
  };

  const linkMutation = useMutation({
    mutationFn: (issueKey: string) =>
      createJiraLink({
        entity_type: entityType,
        entity_id: entityId,
        jira_issue_key: issueKey,
      }),
    onSuccess: () => {
      invalidate();
      setShowSearch(false);
      setSearchQuery("");
    },
  });

  const syncMutation = useMutation({
    mutationFn: (linkId: string) => syncJiraLink(linkId),
    onSuccess: invalidate,
  });

  const deleteMutation = useMutation({
    mutationFn: (linkId: string) => deleteJiraLink(linkId),
    onSuccess: invalidate,
  });

  // ── Render helpers ──────────────────────────────────────────────

  const formatDate = (dateStr: string | null) => {
    if (!dateStr) return null;
    return new Date(dateStr).toLocaleDateString("en-US", {
      month: "short",
      day: "numeric",
      hour: "2-digit",
      minute: "2-digit",
    });
  };

  const getStatusClass = (status: string | null) => {
    if (!status) return "bg-gray-700 text-gray-400";
    return statusColors[status] || "bg-gray-700 text-gray-300";
  };

  return (
    <div className="rounded-xl border border-gray-800 bg-gray-900 p-6">
      <div className="mb-4 flex items-center justify-between">
        <h2 className="flex items-center gap-2 text-lg font-semibold text-white">
          <Link2 className="h-5 w-5 text-blue-400" />
          Jira
        </h2>
        <button
          onClick={() => setShowSearch(!showSearch)}
          className="flex items-center gap-1 rounded-lg border border-gray-700 px-3 py-1.5 text-xs text-gray-300 hover:border-blue-500/50 hover:text-blue-400 transition-colors"
        >
          {showSearch ? (
            <>
              <X className="h-3.5 w-3.5" /> Cancel
            </>
          ) : (
            <>
              <Plus className="h-3.5 w-3.5" /> Link Issue
            </>
          )}
        </button>
      </div>

      {/* Search panel */}
      {showSearch && (
        <div className="mb-4 rounded-lg border border-gray-700 bg-gray-800/50 p-3 space-y-3">
          <div className="relative">
            <Search className="absolute left-3 top-1/2 h-4 w-4 -translate-y-1/2 text-gray-500" />
            <input
              type="text"
              value={searchQuery}
              onChange={(e) => setSearchQuery(e.target.value)}
              placeholder="Search Jira issues (e.g. SEC-1234 or keyword)..."
              className="w-full rounded-lg border border-gray-700 bg-gray-900 py-2 pl-10 pr-3 text-sm text-gray-200 placeholder-gray-500 focus:border-blue-500 focus:outline-none"
              autoFocus
            />
            {isSearching && (
              <Loader2 className="absolute right-3 top-1/2 h-4 w-4 -translate-y-1/2 animate-spin text-gray-500" />
            )}
          </div>

          {searchResults.length > 0 && (
            <div className="max-h-48 space-y-1 overflow-y-auto">
              {searchResults.map((issue: JiraIssueResult) => (
                <button
                  key={issue.issue_key}
                  onClick={() => linkMutation.mutate(issue.issue_key)}
                  disabled={linkMutation.isPending}
                  className="flex w-full items-center justify-between rounded-lg px-3 py-2 text-left text-sm hover:bg-gray-700/50 transition-colors"
                >
                  <div className="flex-1 min-w-0">
                    <div className="flex items-center gap-2">
                      <span className="font-mono text-xs text-blue-400">
                        {issue.issue_key}
                      </span>
                      <span className={`text-xs ${priorityColors[issue.priority || ""] || "text-gray-500"}`}>
                        {issue.priority}
                      </span>
                    </div>
                    <p className="mt-0.5 truncate text-xs text-gray-300">
                      {issue.summary}
                    </p>
                  </div>
                  <span className={`ml-2 shrink-0 rounded px-2 py-0.5 text-xs ${getStatusClass(issue.status)}`}>
                    {issue.status}
                  </span>
                </button>
              ))}
            </div>
          )}

          {debouncedQuery.length >= 2 && !isSearching && searchResults.length === 0 && (
            <p className="text-center text-xs text-gray-500">No issues found</p>
          )}
        </div>
      )}

      {/* Linked issues */}
      {isLoadingLinks ? (
        <div className="flex justify-center py-4">
          <Loader2 className="h-5 w-5 animate-spin text-gray-500" />
        </div>
      ) : links.length === 0 ? (
        <p className="text-center text-sm text-gray-500 py-4">
          No Jira issues linked
        </p>
      ) : (
        <div className="space-y-2">
          {links.map((link: JiraLink) => (
            <div
              key={link.id}
              className="rounded-lg border border-gray-700 bg-gray-800/30 p-3"
            >
              <div className="flex items-start justify-between gap-2">
                <div className="flex-1 min-w-0">
                  <div className="flex items-center gap-2 flex-wrap">
                    <span className="font-mono text-sm font-medium text-blue-400">
                      {link.jira_issue_key}
                    </span>
                    {link.jira_status && (
                      <span
                        className={`rounded px-1.5 py-0.5 text-xs ${getStatusClass(link.jira_status)}`}
                      >
                        {link.jira_status}
                      </span>
                    )}
                    {link.jira_priority && (
                      <span
                        className={`text-xs ${priorityColors[link.jira_priority] || "text-gray-500"}`}
                      >
                        {link.jira_priority}
                      </span>
                    )}
                  </div>
                  {link.jira_assignee && (
                    <p className="mt-1 text-xs text-gray-400">
                      Assignee: {link.jira_assignee}
                    </p>
                  )}
                  {link.last_synced_at && (
                    <p className="mt-0.5 text-xs text-gray-500">
                      Synced: {formatDate(link.last_synced_at)}
                    </p>
                  )}
                </div>

                <div className="flex shrink-0 items-center gap-1">
                  <button
                    onClick={() => syncMutation.mutate(link.id)}
                    disabled={syncMutation.isPending}
                    title="Sync from Jira"
                    className="rounded p-1 text-gray-500 hover:bg-gray-700 hover:text-blue-400 transition-colors"
                  >
                    <RefreshCw
                      className={`h-3.5 w-3.5 ${syncMutation.isPending ? "animate-spin" : ""}`}
                    />
                  </button>
                  <a
                    href={`https://jira.atlassian.com/browse/${link.jira_issue_key}`}
                    target="_blank"
                    rel="noopener noreferrer"
                    title="Open in Jira"
                    className="rounded p-1 text-gray-500 hover:bg-gray-700 hover:text-blue-400 transition-colors"
                  >
                    <ExternalLink className="h-3.5 w-3.5" />
                  </a>
                  <button
                    onClick={() => deleteMutation.mutate(link.id)}
                    disabled={deleteMutation.isPending}
                    title="Unlink"
                    className="rounded p-1 text-gray-500 hover:bg-gray-700 hover:text-red-400 transition-colors"
                  >
                    <Trash2 className="h-3.5 w-3.5" />
                  </button>
                </div>
              </div>
            </div>
          ))}
        </div>
      )}
    </div>
  );
}