import { useEffect, useState } from "react";
import { useNavigate, useParams } from "react-router-dom";
import Markdown from "react-markdown";
import remarkGfm from "remark-gfm";
import {
  applyFixToBranch,
  cancelTicket,
  deleteWorktreeCmd,
  getTicketResult,
  getWorktreeDiff,
  retryTicket,
} from "../../lib/api";
import { getErrorMessage } from "../../lib/errors";
import type { ProcessedTicket, Worktree } from "../../lib/types";
import ConfirmModal from "../ui/ConfirmModal";

function statusBadgeClass(status: string): string {
  switch (status) {
    case "Pending":
      return "bg-yellow-100 text-yellow-700";
    case "Analyzing":
      return "bg-blue-100 text-blue-700";
    case "Developing":
      return "bg-purple-100 text-purple-700";
    case "Done":
      return "bg-green-100 text-green-700";
    case "Error":
      return "bg-red-100 text-red-700";
    case "Cancelled":
      return "bg-gray-100 text-gray-500";
    default:
      return "bg-gray-100 text-gray-700";
  }
}

function DiffViewer({ diff }: { diff: string }) {
  if (!diff) {
    return <div className="py-4 text-center text-sm text-gray-400">No changes detected.</div>;
  }

  const lines = diff.split("\n");
  return (
    <pre className="max-h-[600px] overflow-auto rounded-lg bg-gray-900 p-4 font-mono text-xs text-gray-100">
      {lines.map((line, i) => {
        let cls = "";
        if (line.startsWith("+++") || line.startsWith("---")) cls = "text-gray-400";
        else if (line.startsWith("+")) cls = "bg-green-900/20 text-green-400";
        else if (line.startsWith("-")) cls = "bg-red-900/20 text-red-400";
        else if (line.startsWith("@@")) cls = "text-blue-400";
        else if (line.startsWith("diff ")) cls = "font-bold text-yellow-400";
        return (
          <div key={i} className={cls}>
            {line}
          </div>
        );
      })}
    </pre>
  );
}

export default function TicketDetail() {
  const { ticketId } = useParams();
  const navigate = useNavigate();
  const [ticket, setTicket] = useState<ProcessedTicket | null>(null);
  const [worktree, setWorktree] = useState<Worktree | null>(null);
  const [diff, setDiff] = useState<string | null>(null);
  const [targetBranch, setTargetBranch] = useState("");
  const [tab, setTab] = useState<"info" | "analyst" | "developer" | "diff">("info");
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState("");
  const [isDeleteWorktreeModalOpen, setIsDeleteWorktreeModalOpen] = useState(false);

  async function loadData() {
    if (!ticketId) return;
    try {
      const result = await getTicketResult(ticketId);
      setTicket(result.ticket);
      setWorktree(result.worktree);

      if (result.ticket.developer_report) setTab("developer");
      else if (result.ticket.analyst_report) setTab("analyst");

      if (result.worktree && result.worktree.status === "Active") {
        try {
          const d = await getWorktreeDiff(result.worktree.id);
          setDiff(d);
        } catch {
          setDiff(null);
        }
      } else {
        setDiff(null);
      }
    } catch (err) {
      setError(getErrorMessage(err));
    }
  }

  useEffect(() => {
    loadData();
  }, [ticketId]);

  async function handleRetry() {
    if (!ticketId) return;
    setLoading(true);
    try {
      await retryTicket(ticketId);
      await loadData();
    } catch (err) {
      setError(getErrorMessage(err));
    }
    setLoading(false);
  }

  async function handleCancel() {
    if (!ticketId) return;
    setLoading(true);
    try {
      await cancelTicket(ticketId);
      await loadData();
    } catch (err) {
      setError(getErrorMessage(err));
    }
    setLoading(false);
  }

  async function handleApplyFix() {
    if (!worktree || !targetBranch) return;
    setLoading(true);
    setError("");
    try {
      await applyFixToBranch(worktree.id, targetBranch);
      await loadData();
    } catch (err) {
      setError(getErrorMessage(err));
    }
    setLoading(false);
  }

  async function handleDeleteWorktree() {
    if (!worktree) return;
    setIsDeleteWorktreeModalOpen(false);
    setLoading(true);
    try {
      await deleteWorktreeCmd(worktree.id);
      setWorktree(null);
      setDiff(null);
    } catch (err) {
      setError(getErrorMessage(err));
    }
    setLoading(false);
  }

  if (!ticket) {
    return <div className="p-8 text-gray-400">Loading...</div>;
  }

  const tabs = [
    { key: "info" as const, label: "Info" },
    {
      key: "analyst" as const,
      label: "Analyst Report",
      disabled: !ticket.analyst_report,
    },
    {
      key: "developer" as const,
      label: "Developer Report",
      disabled: !ticket.developer_report,
    },
    { key: "diff" as const, label: "Diff", disabled: !diff && !worktree },
  ];

  return (
    <div className="p-8">
      <div className="mb-6 flex items-center justify-between">
        <div>
          <button onClick={() => navigate(-1)} className="mb-1 text-sm text-blue-600 hover:underline">
            Back
          </button>
          <h2 className="flex items-center gap-3 text-xl font-bold">
            <span className="font-mono text-base text-gray-400">#{ticket.artifact_id}</span>
            {ticket.artifact_title}
            <span
              className={`rounded-full px-2 py-0.5 text-xs font-medium ${statusBadgeClass(
                ticket.status
              )}`}
            >
              {ticket.status}
            </span>
          </h2>
        </div>
        <div className="flex gap-2">
          {(ticket.status === "Error" || ticket.status === "Done" || ticket.status === "Cancelled") && (
            <button
              onClick={handleRetry}
              disabled={loading}
              className="rounded bg-blue-600 px-3 py-1 text-sm text-white hover:bg-blue-700 disabled:opacity-50"
            >
              Retry
            </button>
          )}
          {(ticket.status === "Pending" ||
            ticket.status === "Analyzing" ||
            ticket.status === "Developing") && (
            <button
              onClick={handleCancel}
              disabled={loading}
              className="rounded bg-red-100 px-3 py-1 text-sm text-red-700 hover:bg-red-200 disabled:opacity-50"
            >
              Cancel
            </button>
          )}
        </div>
      </div>

      {error && (
        <div className="mb-4 rounded border border-red-200 bg-red-50 p-3 text-sm text-red-700">{error}</div>
      )}

      <div className="mb-6 flex gap-1 border-b border-gray-200">
        {tabs.map((t) => (
          <button
            key={t.key}
            onClick={() => setTab(t.key)}
            disabled={t.disabled}
            className={`-mb-px border-b-2 px-4 py-2 text-sm font-medium transition-colors ${
              tab === t.key
                ? "border-blue-600 text-blue-600"
                : t.disabled
                ? "cursor-not-allowed border-transparent text-gray-300"
                : "border-transparent text-gray-500 hover:text-gray-700"
            }`}
          >
            {t.label}
          </button>
        ))}
      </div>

      {tab === "info" && (
        <div className="space-y-4">
          <div className="space-y-3 rounded-lg border border-gray-200 bg-white p-4">
            <div>
              <span className="text-sm text-gray-500">Status:</span>
              <span className="ml-2 text-sm">{ticket.status}</span>
            </div>
            <div>
              <span className="text-sm text-gray-500">Detected:</span>
              <span className="ml-2 text-sm">{new Date(ticket.detected_at).toLocaleString()}</span>
            </div>
            {ticket.processed_at && (
              <div>
                <span className="text-sm text-gray-500">Processed:</span>
                <span className="ml-2 text-sm">{new Date(ticket.processed_at).toLocaleString()}</span>
              </div>
            )}
            {worktree && (
              <div>
                <span className="text-sm text-gray-500">Worktree:</span>
                <span className="ml-2 font-mono text-sm">{worktree.branch_name}</span>
                <span
                  className={`ml-2 rounded-full px-2 py-0.5 text-xs ${
                    worktree.status === "Active"
                      ? "bg-green-100 text-green-700"
                      : worktree.status === "Merged"
                      ? "bg-blue-100 text-blue-700"
                      : "bg-gray-100 text-gray-500"
                  }`}
                >
                  {worktree.status}
                </span>
              </div>
            )}
          </div>

          {worktree && worktree.status === "Active" && (
            <div className="rounded-lg border border-gray-200 bg-white p-4">
              <h3 className="mb-3 text-sm font-semibold">Worktree Actions</h3>
              <div className="mb-3 flex items-center gap-2">
                <input
                  type="text"
                  placeholder="Target branch (e.g. feature/login)"
                  value={targetBranch}
                  onChange={(e) => setTargetBranch(e.target.value)}
                  className="flex-1 rounded border border-gray-300 px-3 py-1.5 text-sm focus:border-transparent focus:ring-2 focus:ring-blue-500"
                />
                <button
                  onClick={handleApplyFix}
                  disabled={loading || !targetBranch}
                  className="rounded bg-green-600 px-3 py-1.5 text-sm text-white hover:bg-green-700 disabled:opacity-50"
                >
                  Apply fix
                </button>
              </div>
              <button
                onClick={() => setIsDeleteWorktreeModalOpen(true)}
                disabled={loading}
                className="text-sm text-red-600 hover:underline"
              >
                Delete worktree
              </button>
            </div>
          )}

          {worktree && worktree.status === "Merged" && (
            <div className="rounded border border-blue-200 bg-blue-50 p-3 text-sm text-blue-700">
              Fix applied to branch: {worktree.merged_into}
            </div>
          )}
        </div>
      )}

      {tab === "analyst" && ticket.analyst_report && (
        <div className="prose prose-sm max-w-none rounded-lg border border-gray-200 bg-white p-6">
          <Markdown remarkPlugins={[remarkGfm]}>{ticket.analyst_report}</Markdown>
        </div>
      )}

      {tab === "developer" && ticket.developer_report && (
        <div className="prose prose-sm max-w-none rounded-lg border border-gray-200 bg-white p-6">
          <Markdown remarkPlugins={[remarkGfm]}>{ticket.developer_report}</Markdown>
        </div>
      )}

      {tab === "diff" && <DiffViewer diff={diff || ""} />}

      <ConfirmModal
        isOpen={isDeleteWorktreeModalOpen}
        confirmDisabled={loading}
        onCancel={() => setIsDeleteWorktreeModalOpen(false)}
        onConfirm={() => void handleDeleteWorktree()}
      />
    </div>
  );
}