import { useCallback, useEffect, useState } from "react";
import { API } from "../config";

type PRScan = {
  id: number;
  pr_number: number;
  repo_name: string;
  pr_title: string;
  pr_url: string;
  source_branch: string;
  target_branch: string;
  author: string;
  state: "open" | "merged" | "closed";
  scan_status: "pending" | "completed";
  issues_count: number;
  security_issues: number;
  created_at: string;
};

type PRDetail = PRScan & {
  scan_result: Record<string, unknown>;
  scan_details_with_code: unknown[];
  ai_review: unknown;
  report_path: string;
};

type ChangedFile = {
  filename: string;
  status: string;
  additions: number;
  deletions: number;
};

type FileContent = {
  content: string;
  issues: Array<{
    line: number;
    severity: string;
    message: string;
    rule?: string;
  }>;
};

type View = "dashboard" | "pr-list" | "settings";

type QualityGateProps = {
  view: View;
};

const BASE = API.quality;

async function apiGet<T>(path: string): Promise<T> {
  const res = await fetch(`${BASE}${path}`);
  if (!res.ok) throw new Error(`${res.status} ${res.statusText}`);
  return res.json();
}

async function apiPost<T>(path: string): Promise<T> {
  const res = await fetch(`${BASE}${path}`, { method: "POST" });
  if (!res.ok) throw new Error(`${res.status} ${res.statusText}`);
  return res.json();
}

export default function QualityGate({ view }: QualityGateProps) {
  const [prs, setPrs] = useState<PRScan[]>([]);
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState("");
  const [filter, setFilter] = useState<"all" | "open" | "merged" | "closed">("all");

  const [selectedPR, setSelectedPR] = useState<PRDetail | null>(null);
  const [changedFiles, setChangedFiles] = useState<ChangedFile[]>([]);
  const [selectedFile, setSelectedFile] = useState<string>("");
  const [fileContent, setFileContent] = useState<FileContent | null>(null);
  const [modalOpen, setModalOpen] = useState(false);

  const fetchPRs = useCallback(async () => {
    setLoading(true);
    setError("");
    try {
      const query = filter === "all" ? "" : `?state=${filter}`;
      const data = await apiGet<{ prs: PRScan[] } | PRScan[]>(`/prs${query}`);
      setPrs(Array.isArray(data) ? data : data.prs || []);
    } catch (e) {
      setError((e as Error).message);
    } finally {
      setLoading(false);
    }
  }, [filter]);

  useEffect(() => {
    fetchPRs();
  }, [fetchPRs]);

  const openPRDetail = useCallback(async (prId: number) => {
    setLoading(true);
    setError("");
    try {
      const [detail, files] = await Promise.all([
        apiGet<PRDetail>(`/prs/${prId}`),
        apiGet<{ files: ChangedFile[] } | ChangedFile[]>(`/prs/${prId}/files`),
      ]);
      setSelectedPR(detail);
      const fileList = Array.isArray(files) ? files : files.files || [];
      setChangedFiles(fileList);
      if (fileList.length > 0) {
        setSelectedFile(fileList[0].filename);
      }
      setModalOpen(true);
    } catch (e) {
      setError((e as Error).message);
    } finally {
      setLoading(false);
    }
  }, []);

  useEffect(() => {
    if (!modalOpen || !selectedPR || !selectedFile) return;
    setFileContent(null);
    apiGet<FileContent>(`/prs/${selectedPR.id}/file?path=${encodeURIComponent(selectedFile)}`)
      .then(setFileContent)
      .catch(() => setFileContent({ content: "// Failed to load file", issues: [] }));
  }, [modalOpen, selectedPR, selectedFile]);

  const handleMerge = async () => {
    if (!selectedPR) return;
    setLoading(true);
    try {
      await apiPost(`/prs/${selectedPR.id}/merge`);
      setModalOpen(false);
      fetchPRs();
    } catch (e) {
      setError((e as Error).message);
    } finally {
      setLoading(false);
    }
  };

  const handleClose = async () => {
    if (!selectedPR) return;
    setLoading(true);
    try {
      await apiPost(`/prs/${selectedPR.id}/close`);
      setModalOpen(false);
      fetchPRs();
    } catch (e) {
      setError((e as Error).message);
    } finally {
      setLoading(false);
    }
  };

  const stats = {
    pending: prs.filter((p) => p.state === "open").length,
    passed: prs.filter((p) => p.state === "merged").length,
    rejected: prs.filter((p) => p.state === "closed").length,
    totalIssues: prs.reduce((s, p) => s + p.issues_count, 0),
  };

  return (
    <div className="h-full overflow-y-auto p-8">
      {error && (
        <div className="mb-4 px-4 py-2 bg-red-50 text-red-700 text-sm flex justify-between items-center rounded-xl border border-red-200">
          {error}
          <button className="font-bold text-red-400 hover:text-red-600" onClick={() => setError("")}>✕</button>
        </div>
      )}

      {view === "dashboard" && (
        <>
          <h2 className="text-xl font-extrabold mb-6">Overview</h2>

          <div className="grid grid-cols-4 gap-5 mb-8">
            {[
              { label: "Open PRs", value: stats.pending, color: "text-yellow-600", bg: "bg-yellow-50" },
              { label: "Merged", value: stats.passed, color: "text-green-600", bg: "bg-green-50" },
              { label: "Rejected", value: stats.rejected, color: "text-red-600", bg: "bg-red-50" },
              { label: "Total Issues", value: stats.totalIssues, color: "text-magenta", bg: "bg-magenta-50" },
            ].map((s) => (
              <div key={s.label} className={`${s.bg} p-6 border border-border rounded-2xl shadow-[0_4px_16px_rgba(0,0,0,0.04)]`}>
                <div className={`text-3xl font-extrabold ${s.color}`}>{s.value}</div>
                <div className="text-sm font-bold text-txt-muted mt-2">{s.label}</div>
              </div>
            ))}
          </div>

          <h3 className="text-lg font-extrabold mb-4">Recent Pull Requests</h3>
          <PRTable prs={prs.slice(0, 8)} loading={loading} onView={(pr) => openPRDetail(pr.id)} />
        </>
      )}

      {view === "pr-list" && (
        <>
          <div className="flex items-center justify-between mb-6">
            <h2 className="text-xl font-extrabold">Pull Request List</h2>
            <div className="flex gap-2">
              {(["all", "open", "merged", "closed"] as const).map((f) => (
                <button
                  key={f}
                  onClick={() => setFilter(f)}
                  className={`px-3 py-1.5 text-xs font-bold border rounded-lg transition-colors ${
                    filter === f
                      ? "border-magenta text-magenta bg-magenta-50"
                      : "border-border text-txt-muted hover:border-magenta"
                  }`}
                >
                  {f === "all" ? "All" : f === "open" ? "Open" : f === "merged" ? "Merged" : "Closed"}
                </button>
              ))}
              <button className="btn-outline text-xs px-3 py-1.5" onClick={fetchPRs}>
                Refresh
              </button>
            </div>
          </div>
          <PRTable prs={prs} loading={loading} onView={(pr) => openPRDetail(pr.id)} />
        </>
      )}

      {view === "settings" && (
        <div className="max-w-xl">
          <h2 className="text-xl font-extrabold mb-6">Settings</h2>
          <div className="card mb-4">
            <h3 className="font-bold mb-2">Webhook Configuration</h3>
            <p className="text-sm text-txt-muted mb-3">Add this URL to your Gitea repository webhook settings:</p>
            <code className="block bg-surface-muted p-3 text-sm font-mono break-all rounded-lg">
              POST {window.location.origin}/quality-api/webhook/gitea
            </code>
          </div>
          <div className="card">
            <h3 className="font-bold mb-2">Quick Notes</h3>
            <ul className="text-sm text-txt-muted list-disc list-inside space-y-1">
              <li>Supports Gitea Push and Pull Request events</li>
              <li>Runs Pylint, Flake8, ESLint, and Bandit automatically</li>
              <li>Optional AI review using DeepSeek-V3</li>
              <li>Scan summary can be pushed to Feishu channels</li>
            </ul>
          </div>
        </div>
      )}

      {modalOpen && selectedPR && (
        <div className="fixed inset-0 z-50 flex items-center justify-center bg-black/40">
          <div className="bg-white w-[92vw] h-[88vh] flex flex-col rounded-2xl overflow-hidden shadow-[0_20px_60px_rgba(0,0,0,0.2)]">
            <div className="flex items-center justify-between px-6 py-4 border-b border-border shrink-0">
              <div>
                <h2 className="text-lg font-extrabold">
                  #{selectedPR.pr_number} {selectedPR.pr_title}
                </h2>
                <p className="text-xs text-txt-muted mt-1">
                  {selectedPR.author} · {selectedPR.source_branch} → {selectedPR.target_branch} · {selectedPR.repo_name}
                </p>
              </div>
              <button
                className="w-8 h-8 flex items-center justify-center text-txt-muted hover:text-txt font-bold text-lg"
                onClick={() => setModalOpen(false)}
              >
                ✕
              </button>
            </div>

            <div className="flex flex-1 min-h-0">
              <div className="w-[260px] shrink-0 border-r border-border overflow-y-auto p-4 bg-surface-muted/35">
                <h3 className="text-xs font-bold text-txt-muted uppercase mb-3">Changed Files</h3>
                {changedFiles.map((f) => (
                  <button
                    key={f.filename}
                    className={`block w-full text-left px-3 py-2 text-sm truncate transition-colors rounded-lg ${
                      selectedFile === f.filename
                        ? "bg-magenta-50 text-magenta font-bold"
                        : "text-txt hover:bg-surface-muted"
                    }`}
                    onClick={() => setSelectedFile(f.filename)}
                  >
                    <span className={`inline-block w-4 mr-1 text-xs font-bold ${
                      f.status === "added" ? "text-green-600" : f.status === "removed" ? "text-red-600" : "text-yellow-600"
                    }`}>
                      {f.status === "added" ? "A" : f.status === "removed" ? "D" : "M"}
                    </span>
                    {f.filename.split("/").pop()}
                    <span className="text-xs text-txt-muted ml-1 block truncate">{f.filename}</span>
                  </button>
                ))}
              </div>

              <div className="flex-1 overflow-auto bg-white">
                {fileContent ? (
                  <pre className="text-sm font-mono leading-6 p-4">
                    {fileContent.content.split("\n").map((line, i) => {
                      const lineNum = i + 1;
                      const issues = fileContent.issues.filter((iss) => iss.line === lineNum);
                      return (
                        <div key={i} className={`flex ${issues.length > 0 ? "bg-red-50/80" : ""}`}>
                          <span className="w-12 shrink-0 text-right pr-4 text-txt-muted select-none text-xs leading-6">
                            {lineNum}
                          </span>
                          <span className="flex-1 whitespace-pre-wrap">{line}</span>
                          {issues.length > 0 && (
                            <span className="shrink-0 px-2 text-xs text-red-600 max-w-xs truncate" title={issues[0].message}>
                              ● {issues[0].message}
                            </span>
                          )}
                        </div>
                      );
                    })}
                  </pre>
                ) : (
                  <div className="flex items-center justify-center h-full text-txt-muted text-sm">
                    {selectedFile ? "Loading file..." : "Select a file to inspect"}
                  </div>
                )}
              </div>

              <div className="w-[220px] shrink-0 border-l border-border overflow-y-auto p-4 bg-surface-muted/60">
                <h3 className="text-xs font-bold text-txt-muted uppercase mb-3">Issue Panel</h3>
                {fileContent?.issues.length === 0 && (
                  <p className="text-xs text-txt-muted">No issues</p>
                )}
                {fileContent?.issues.map((iss, i) => (
                  <div key={i} className="mb-3 p-2 bg-white border border-border text-xs rounded-lg">
                    <div className="flex items-center gap-1 mb-1">
                      <span className={`font-bold ${
                        iss.severity === "error" ? "text-red-600" : iss.severity === "warning" ? "text-yellow-600" : "text-blue-600"
                      }`}>
                        {iss.severity === "error" ? "❌" : iss.severity === "warning" ? "⚠️" : "ℹ️"}
                      </span>
                      <span className="text-txt-muted">L{iss.line}</span>
                    </div>
                    <p className="text-txt">{iss.message}</p>
                    {iss.rule && <p className="text-txt-muted mt-0.5">{iss.rule}</p>}
                  </div>
                ))}
              </div>
            </div>

            <div className="flex justify-end gap-3 px-6 py-4 border-t border-border shrink-0">
              <button className="btn-outline" onClick={() => setModalOpen(false)}>
                Close
              </button>
              <button
                className="bg-red-600 text-white font-bold text-sm px-6 py-2.5 border-none cursor-pointer hover:opacity-90 disabled:opacity-50 rounded-xl"
                onClick={handleClose}
                disabled={loading || selectedPR.state !== "open"}
              >
                Reject
              </button>
              <button
                className="btn-magenta"
                onClick={handleMerge}
                disabled={loading || selectedPR.state !== "open"}
              >
                Approve & Merge
              </button>
            </div>
          </div>
        </div>
      )}
    </div>
  );
}

function PRTable({
  prs,
  loading,
  onView,
}: {
  prs: PRScan[];
  loading: boolean;
  onView: (pr: PRScan) => void;
}) {
  if (loading && prs.length === 0) {
    return <div className="text-center py-8 text-txt-muted text-sm">Loading...</div>;
  }

  if (prs.length === 0) {
    return <div className="text-center py-8 text-txt-muted text-sm">No PR records found</div>;
  }

  return (
    <div className="overflow-x-auto rounded-2xl border border-border bg-white shadow-[0_6px_22px_rgba(0,0,0,0.04)]">
      <table className="w-full text-sm">
        <thead>
          <tr className="bg-surface-muted text-left">
            <th className="px-4 py-3 border-b border-border font-bold">PR#</th>
            <th className="px-4 py-3 border-b border-border font-bold">Title</th>
            <th className="px-4 py-3 border-b border-border font-bold">Repository</th>
            <th className="px-4 py-3 border-b border-border font-bold">Author</th>
            <th className="px-4 py-3 border-b border-border font-bold">Branch</th>
            <th className="px-4 py-3 border-b border-border font-bold">State</th>
            <th className="px-4 py-3 border-b border-border font-bold">Issues</th>
            <th className="px-4 py-3 border-b border-border font-bold">Created</th>
            <th className="px-4 py-3 border-b border-border font-bold">Action</th>
          </tr>
        </thead>
        <tbody>
          {prs.map((pr) => (
            <tr key={pr.id} className="border-b border-border hover:bg-surface-muted/50 transition-colors">
              <td className="px-4 py-3 font-mono text-xs">#{pr.pr_number}</td>
              <td className="px-4 py-3 font-bold max-w-[220px] truncate">{pr.pr_title}</td>
              <td className="px-4 py-3 text-txt-muted text-xs">{pr.repo_name}</td>
              <td className="px-4 py-3 text-txt-muted">{pr.author}</td>
              <td className="px-4 py-3 text-xs font-mono text-txt-muted">
                {pr.source_branch} → {pr.target_branch}
              </td>
              <td className="px-4 py-3">
                <span className={`badge ${
                  pr.state === "open"
                    ? "bg-yellow-100 text-yellow-700"
                    : pr.state === "merged"
                      ? "bg-green-100 text-green-700"
                      : "bg-red-100 text-red-700"
                }`}>
                  {pr.state === "open" ? "Open" : pr.state === "merged" ? "Merged" : "Closed"}
                </span>
              </td>
              <td className="px-4 py-3">
                <span className={`font-bold ${pr.issues_count > 0 ? "text-red-600" : "text-green-600"}`}>
                  {pr.issues_count}
                </span>
              </td>
              <td className="px-4 py-3 text-xs text-txt-muted">
                {new Date(pr.created_at).toLocaleString("en-US")}
              </td>
              <td className="px-4 py-3">
                <button
                  className="text-magenta font-bold text-xs hover:underline"
                  onClick={() => onView(pr)}
                >
                  Inspect →
                </button>
              </td>
            </tr>
          ))}
        </tbody>
      </table>
    </div>
  );
}