import { useState, useEffect, useRef } from "react";
import Editor from "@monaco-editor/react";
import { askAgent } from "./agent/assistant";
import { runCode } from "./agent/runner";
import {
  loadTree,
  saveTree,
  addFile,
  addFolder,
  renameNode,
  deleteNode,
  getNodeByPath,
  updateFileContent,
  searchTree,
} from "./fileStore";
import { downloadProjectZip } from "./zipExport";
import { parseProblems } from "./problemParser";
import "./App.css";

// =================== SUPPORTED LANGUAGES ===================
const LANGUAGE_OPTIONS = [
  { id: "python", ext: ".py", icon: "🐍", monaco: "python" },
  { id: "javascript", ext: ".js", icon: "🟨", monaco: "javascript" },
  { id: "typescript", ext: ".ts", icon: "🟦", monaco: "typescript" },
  { id: "cpp", ext: ".cpp", icon: "💠", monaco: "cpp" },
  { id: "c", ext: ".c", icon: "🔷", monaco: "c" },
  { id: "java", ext: ".java", icon: "☕", monaco: "java" },
  { id: "html", ext: ".html", icon: "🌐", monaco: "html" },
  { id: "css", ext: ".css", icon: "🎨", monaco: "css" },
  { id: "json", ext: ".json", icon: "🧾", monaco: "json" },
];

const RUNNABLE_LANGS = ["python", "javascript", "java"];

// =================== APP ===================
function App() {
  const [tree, setTree] = useState(loadTree());
  const [activePath, setActivePath] = useState("main.py");
  const [output, setOutput] = useState("");
  const [prompt, setPrompt] = useState("");
  const [explanation, setExplanation] = useState("");
  const [stdin, setStdin] = useState("");
  const [problems, setProblems] = useState([]);
  const [theme, setTheme] = useState("vs-dark");
  const [searchOpen, setSearchOpen] = useState(false);
  const [searchQuery, setSearchQuery] = useState("");
  const [aiSuggestions, setAiSuggestions] = useState([]);
  const [contextMenu, setContextMenu] = useState(null); // right-click menu
  const editorRef = useRef(null);

  const currentFile = getNodeByPath(tree, activePath);
  const langMeta =
    LANGUAGE_OPTIONS.find((l) => currentFile?.name.endsWith(l.ext)) ||
    LANGUAGE_OPTIONS[0];

  // Save after tree change
  useEffect(() => {
    saveTree(tree);
  }, [tree]);

  // =================== FILE ACTIONS ===================
  const handleNewFile = () => {
    const name = window.prompt("Filename (with extension):");
    if (!name) return;
    setTree(addFile(tree, name));
  };

  const handleNewFolder = () => {
    const name = window.prompt("Folder name:");
    if (!name) return;
    setTree(addFolder(tree, name));
  };

  const handleRename = () => {
    if (!activePath) return;
    const newName = window.prompt("New name:", currentFile.name);
    if (!newName) return;
    setTree(renameNode(tree, activePath, newName));
    setActivePath(newName);
  };

  const handleDelete = () => {
    if (!activePath) return;
    setTree(deleteNode(tree, activePath));
    setActivePath(""); // unselect
  };

  const downloadFile = () => {
    if (!currentFile?.content) return;
    const blob = new Blob([currentFile.content], {
      type: "text/plain;charset=utf-8",
    });
    const a = document.createElement("a");
    a.href = URL.createObjectURL(blob);
    a.download = currentFile.name;
    a.click();
  };

  // =================== RUN ===================
  const handleRun = async () => {
    if (!currentFile?.content) return;

    const selectedLang = langMeta.id;
    if (!RUNNABLE_LANGS.includes(selectedLang)) {
      setOutput(`⚠️ Cannot run ${selectedLang}.`);
      return;
    }

    const res = await runCode(currentFile.content, selectedLang, stdin);
    setOutput(res.output || "");
    setProblems(res.error ? parseProblems(res.output) : []);
  };

  // =================== AI ===================
  const handleAskFix = async () => {
    if (!currentFile) return;
    const userHint = prompt.trim() ? `User request: ${prompt}` : "";
    const reply = await askAgent(
      `Improve, debug, or refactor this ${langMeta.id} file.
${userHint}
Return ONLY updated code, no explanation.

CODE:
${currentFile.content}`
    );
    updateActiveFileContent(reply);
  };

  const handleExplainSelection = async () => {
    if (!currentFile) return;
    const editor = editorRef.current;
    const selected = editor
      .getModel()
      .getValueInRange(editor.getSelection());
    const code = selected.trim() || currentFile.content;

    const userHint = prompt.trim()
      ? `Focus on: ${prompt}`
      : "Give a clear and simple explanation.";

    const reply = await askAgent(
      `Explain what this ${langMeta.id} code does, any risks, and improvements.
${userHint}

CODE:
${code}`
    );
    setExplanation(reply);
  };

  const updateActiveFileContent = (value) => {
    const updated = updateFileContent(tree, activePath, value);
    setTree(updated);
  };

  // ===== AI Autocomplete Suggestions (Popup) =====
  const fetchAiSuggestions = async (code) => {
    if (!code?.trim()) return;
    const reply = await askAgent(
      `Suggest possible next lines for continuation. Return 3 short snippets.\n${code}`
    );
    setAiSuggestions(reply.split("\n").filter((l) => l.trim()));
  };

  // =================== SEARCH ===================
  const handleSearchToggle = () => setSearchOpen(!searchOpen);

  const handleSearchNow = () => {
    if (!searchQuery) return;
    alert(
      `Found occurrences:\n${JSON.stringify(
        searchTree(tree, searchQuery),
        null,
        2
      )}`
    );
  };

  // =================== UI ===================
  return (
    <div
      className={`ide-root ${
        theme === "vs-dark" ? "ide-dark" : "ide-light"
      }`}
    >
      {/* ==== TOP BAR ==== */}
      <div className="ide-menubar">
        <div className="ide-menubar-left">
          <span className="ide-logo">⚙️ DevMate IDE</span>

          <button onClick={handleNewFile}>📄 New File</button>
          <button onClick={handleNewFolder}>📁 New Folder</button>
          <button onClick={handleRename}>✏️ Rename</button>
          <button onClick={downloadFile}>📥 Download</button>
          <button onClick={downloadProjectZip}>📦 ZIP</button>
        </div>

        <div className="ide-menubar-right">
          <button onClick={handleSearchToggle}>🔍 Search</button>
          <button onClick={handleRun}>▶ Run</button>
          <button onClick={handleAskFix}>🤖 Fix</button>
          <button onClick={handleExplainSelection}>📖 Explain</button>
          <button
            onClick={() =>
              setTheme(theme === "vs-dark" ? "light" : "vs-dark")
            }
          >
            {theme === "vs-dark" ? "☀️" : "🌙"}
          </button>
        </div>
      </div>

      {/* ==== BODY ==== */}
      <div className="ide-body">
        {/* ==== TREE VIEW (LEFT) ==== */}
        <div className="ide-sidebar">
          {renderTree(tree, setActivePath, setContextMenu)}
        </div>

        {/* ==== MAIN CENTER (EDITOR + OUTPUT) ==== */}
        <div className="ide-main">
          <div className="ide-editor-wrapper">
            <Editor
              height="100%"
              theme={theme}
              language={langMeta.monaco}
              value={currentFile?.content || ""}
              onChange={updateActiveFileContent}
              onMount={(editor) => (editorRef.current = editor)}
              onBlur={() => fetchAiSuggestions(currentFile?.content)}
            />
          </div>

          {/* AI Suggestions Tooltip */}
          {aiSuggestions.length > 0 && (
            <div className="ai-popup">
              {aiSuggestions.map((s, i) => (
                <div
                  key={i}
                  className="ai-suggest"
                  onClick={() =>
                    updateActiveFileContent(
                      (currentFile?.content || "") + "\n" + s
                    )
                  }
                >
                  {s}
                </div>
              ))}
            </div>
          )}

          {/* Bottom Panels: Output + stdin + Problems */}
          <div className="ide-panels">
            <pre className="ide-output">{output}</pre>

            <input
              className="ide-input-box"
              placeholder="Program input..."
              value={stdin}
              onChange={(e) => setStdin(e.target.value)}
            />

            {problems.length > 0 && (
              <div className="ide-problems-panel">
                <div>🚨 Problems ({problems.length})</div>
                {problems.map((p, i) => (
                  <div key={i}>
                    {p.file}:{p.line} — {p.message}
                  </div>
                ))}
              </div>
            )}
          </div>
        </div>

        {/* ==== RIGHT AI PANEL ==== */}
        <div className="ide-right-panel">
          <div className="ide-ai-header">🤖 AI Assistant</div>

          <div className="ide-ai-section">
            <label className="ide-ai-label">Instruction</label>
            <textarea
              className="ide-agent-textarea"
              placeholder="Ask the AI (e.g., 'optimize this function', 'add comments', 'convert to JS'...)"
              value={prompt}
              onChange={(e) => setPrompt(e.target.value)}
            />
          </div>

          <div className="ide-ai-buttons">
            <button onClick={handleAskFix}>💡 Apply Fix</button>
            <button onClick={handleExplainSelection}>📖 Explain Code</button>
          </div>

          {explanation && (
            <div className="ide-ai-section">
              <label className="ide-ai-label">Explanation</label>
              <div className="ide-explain">{explanation}</div>
            </div>
          )}
        </div>
      </div>

      {/* ==== SEARCH PANEL ==== */}
      {searchOpen && (
        <div className="search-dialog">
          <input
            placeholder="Search text..."
            onChange={(e) => setSearchQuery(e.target.value)}
          />
          <button onClick={handleSearchNow}>Search</button>
        </div>
      )}

      {/* ==== RIGHT-CLICK CONTEXT MENU ==== */}
      {contextMenu && (
        <div
          className="ide-context-menu"
          style={{ top: contextMenu.y, left: contextMenu.x }}
          onMouseLeave={() => setContextMenu(null)}
        >
          <div onClick={handleRename}>✏️ Rename</div>
          <div onClick={handleDelete}>🗑 Delete</div>
          <div onClick={downloadFile}>📥 Download</div>
        </div>
      )}
    </div>
  );
}

// =======================================================
// Tree Renderer UI
// =======================================================
function renderTree(node, setActivePath, setContextMenu, depth = 0) {
  return (
    <div key={node.name} style={{ paddingLeft: depth * 10 }}>
      <div
        className={`tree-item ${node.type}`}
        onClick={() => node.type === "file" && setActivePath(node.path)}
        onContextMenu={(e) => {
          e.preventDefault();
          setContextMenu({ x: e.pageX, y: e.pageY, file: node.path });
        }}
      >
        {node.type === "folder" ? "📁" : "📄"} {node.name}
      </div>
      {node.children &&
        node.children.map((child) =>
          renderTree(child, setActivePath, setContextMenu, depth + 1)
        )}
    </div>
  );
}

export default App;