import React, { useState, useEffect, useRef } from "react";
import ReactMarkdown from "react-markdown";
import FileUploadCard from "./FileUploadCard";

const DeleteBinButton = ({ onClick }) => (
  <button className="delete-bin-btn" onClick={onClick} title="Delete chat">
    <svg viewBox="0 0 69 14" className="svgIcon bin-top">
      <path d="M20.8232 2.62734L19.9948 4.21304C19.8224 4.54309 19.4808 4.75 19.1085 4.75H4.92857C2.20246 4.75 0 6.87266 0 9.5C0 12.1273 2.20246 14.25 4.92857 14.25H64.0714C66.7975 14.25 69 12.1273 69 9.5C69 6.87266 66.7975 4.75 64.0714 4.75H49.8915C49.5192 4.75 49.1776 4.54309 49.0052 4.21305L48.1768 2.62734Z" />
    </svg>

    <svg viewBox="0 0 69 57" className="svgIcon bin-bottom">
      <path d="M64.0023 1.0648C64.0397 0.4882 63.5822 0 63.0044 0H5.99556C5.4178 0 4.96025 0.4882 4.99766 1.0648L8.19375 50.3203C8.44018 54.0758 11.6746 57 15.5712 57H53.4288C57.3254 57 60.5598 54.0758 60.8062 50.3203L64.0023 1.0648Z" />
    </svg>
  </button>
);

export default function App() {
  // <-- Set your backend URL here (the .hf.space backend)
  const API_BASE = "https://durga-7780-chatbot.hf.space";
  const [allChats, setAllChats] = useState({});
  const [messages, setMessages] = useState([]); // {id, role, text}
  const [input, setInput] = useState("");
  const [uploading, setUploading] = useState(false);
  const [files, setFiles] = useState([]);
  const [uploadProgress, setUploadProgress] = useState({});
  const [sessionId, setSessionId] = useState(() => {
    return localStorage.getItem("rag_session") || Math.random().toString(36).slice(2, 10);
  });
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState(null);
  const [isRecording, setIsRecording] = useState(false);
  const [isTranscribing, setIsTranscribing] = useState(false);
  const messagesEndRef = useRef(null);
  const mediaRecorderRef = useRef(null);
  const audioChunksRef = useRef([]);
  const justTranscribedRef = useRef(false);
  const [chatHistory, setChatHistory] = useState([]);
  const [warning, setWarning] = useState("");
  const [sttCooldown, setSttCooldown] = useState(false);
  useEffect(() => {
    const savedChats = JSON.parse(localStorage.getItem("allChats") || "{}");
    const savedHistory = JSON.parse(localStorage.getItem("chatHistory") || "[]");

  setAllChats(savedChats);
  setChatHistory(savedHistory);

  if (sessionId && savedChats[sessionId]) {
    setMessages(savedChats[sessionId]);
  }
  }, []);
  
  useEffect(() => {
    localStorage.setItem("allChats", JSON.stringify(allChats));
  }, [allChats]);
  
  useEffect(() => {
    localStorage.setItem("chatHistory", JSON.stringify(chatHistory));
  }, [chatHistory]);
  
  useEffect(() => {
    localStorage.setItem("rag_session", sessionId);
  }, [sessionId]);
  
  useEffect(() => {
    scrollToBottom();
  }, [messages, loading]);

  useEffect(() => {
    // Inject minimal CSS
    const css = `
      :root{ --bg:#0f1724; --card:#0b1220; --accent:#6ee7b7; --muted:#94a3b8; }
      *{box-sizing:border-box}
      html,body,#root{height:100%;}
      body{margin:0;font-family:Inter,ui-sans-serif,system-ui,-apple-system,'Segoe UI',Roboto,'Helvetica Neue',Arial;background:linear-gradient(180deg,#071029 0%, #071b2e 100%);color:#e6eef8}
      .app{display:flex;height:100vh;padding:24px;gap:24px}
      .left{width:360px;background:rgba(255,255,255,0.03);border-radius:12px;padding:16px;display:flex;flex-direction:column;gap:12px}
      .brand{font-weight:700;font-size:18px}
      .upload-area{background:rgba(255,255,255,0.02);padding:12px;border-radius:8px;border:1px dashed rgba(255,255,255,0.03);display:flex;flex-direction:column;gap:8px}
      .files-list{display:flex;flex-direction:column;gap:6px;max-height:220px;overflow:auto}
      .file-item{display:flex;justify-content:space-between;align-items:center;padding:8px;border-radius:8px;background:rgba(255,255,255,0.01)}
      .btn{background:var(--accent);color:#042024;padding:8px 12px;border-radius:8px;border:0;cursor:pointer;font-weight:600}
      .btn:disabled{opacity:0.5;cursor:not-allowed}

      .right{flex:1;display:flex;flex-direction:column;border-radius:12px;background:rgba(255,255,255,0.02);padding:12px;gap:12px}
      .chat-window{flex:1;overflow:auto;padding:12px;display:flex;flex-direction:column;gap:12px}
      .message-row{display:flex;width:100%}

      /* user RIGHT, ai LEFT */
      .message-row.user{justify-content:flex-end}
      .message-row.ai{justify-content:flex-start}

      .bubble {
        max-width: 70%;
        padding: 8px 10px;
        border-radius: 12px;
        box-shadow: 0 4px 14px rgba(2,6,23,0.6);
        line-height: 1.5;
        word-break: break-word;
      }

      /* user bubble appears on right (bright) */
      .bubble.user {
        background: #2563eb;
        color: white;
        margin-left: auto;
      }


      /* ai bubble appears on left (dark) */
      .bubble.ai{
        background:#0f1724;
        color:#e6eef8;
        border-top-right-radius:12px;
        border-top-left-radius:4px;
      }
    .text-input {
      flex: 1;
      min-height: 44px;
      max-height: 120px;
      padding: 12px 14px;
      border-radius: 10px;
      border: 1px solid rgba(255,255,255,0.12);
      background: rgba(255,255,255,0.06);
      color: #e6eef8;
      font-size: 14px;
      resize: none;
    }
    
    .text-input::placeholder {
      color: rgba(255,255,255,0.5);
    }
    .input-row {
      display: flex;
      align-items: flex-end;
      gap: 10px;
    }
    
    .switch {
      position: relative;
      width: 48px;
      height: 48px;
      display: flex;
      justify-content: center;
      align-items: center;
      background-color: rgb(60,64,67);
      color: #fff;
      border-radius: 50%;
      cursor: pointer;
      transition: all .3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    }
    
    .mic-on, .mic-off {
      width: 100%;
      height: 100%;
      display: flex;
      justify-content: center;
      align-items: center;
      transition: all .3s ease-in-out;
    }
    
    .mic-on { z-index: 4; }
    .mic-off {
      position: absolute;
      inset: 0;
      z-index: 5;
      opacity: 0;
    }
    
    .switch:hover {
      background-color: rgba(60,64,67,0.8);
    }
    
    #mic-toggle {
      display: none;
    }
    
    #mic-toggle:checked + .switch {
      background-color: red;
    }
    
    #mic-toggle:checked + .switch .mic-off {
      opacity: 1;
    }
    
    #mic-toggle:checked + .switch .mic-on {
      opacity: 0;
    }
    
    #mic-toggle:active + .switch {
      scale: 1.2;
    }
    .history-item {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 8px;
      padding: 8px;
      border-radius: 6px;
      margin-bottom: 6px;
      cursor: pointer;
      transition: background 0.2s ease;
    }
    
    .history-item:hover {
      background: rgba(255,255,255,0.08);
    }
    
    .history-title {
      flex: 1;
      font-size: 13px;
      white-space: nowrap;
      overflow: hidden;
      text-overflow: ellipsis;
    }
    
    .history-delete {
      flex-shrink: 0;
    }
    .history-item {
      min-height: 36px;
    }
    
    .history-title {
      flex: 1;
      overflow: hidden;
      white-space: nowrap;
      text-overflow: ellipsis;
    }

    .delete-bin-btn {
        width: 28px;
        height: 28px;
        border-radius: 6px;
        border: none;
        background: rgba(255, 95, 95, 0.15);
        cursor: pointer;
        display: flex;
        flex-direction: column;
        align-items: center;
        justify-content: center;
        gap: 2px;
        padding: 0;
      }
      
      .delete-bin-btn:hover {
        background: rgba(255, 95, 95, 0.35);
      }
      
      .delete-bin-btn .svgIcon {
        width: 10px;
        transition: 0.3s;
      }
      
      .delete-bin-btn .svgIcon path {
        fill: white;
      }
      
      .delete-bin-btn .bin-top {
        transform-origin: bottom right;
      }
      
      .delete-bin-btn:hover .bin-top {
        transform: rotate(160deg);
      }
      .delete-bin-btn:focus-visible {
        outline: 2px solid #ff5f5f;
        outline-offset: 2px;
      }
      .delete-bin-btn {
        background: rgba(255, 0, 0, 0.25);
      }
      
      .delete-bin-btn:hover {
        background: rgba(255, 0, 0, 0.6);
      }
      
      .delete-bin-btn .svgIcon path {
        fill: #ff3b3b;
      }
      
      .delete-bin-btn:hover .svgIcon path {
        fill: #ffffff;
      }
.chat-history-scroll {
  overflow-y: auto;
  flex: 1;
  padding-right: 4px;
  max-height: calc(100vh - 420px);
}


    `;
    const style = document.createElement("style");
    style.innerHTML = css;
    document.head.appendChild(style);
    return () => {
      if (style && style.parentNode) style.parentNode.removeChild(style);
    };
  }, []);

  function scrollToBottom() {
    if (messagesEndRef.current) {
      messagesEndRef.current.scrollIntoView({ behavior: "smooth" });
    }
  }

  const handleFiles = (e) => {
    const fileList = Array.from(e.target.files);
    setFiles((prev) => [...prev, ...fileList]);
  };

  const removeFile = (index) => {
    setFiles((prev) => prev.filter((_, i) => i !== index));
  };
const loadChat = (id) => {
  setSessionId(id);

  const msgs = allChats[id] || [];
  setMessages(msgs);

  localStorage.setItem("rag_session", id);
};

  const uploadFiles = async () => {
  if (!files.length) return;
  setUploading(true);
  setError(null);

  try {
    const form = new FormData();
    files.forEach((f) => form.append("files", f));
    form.append("session_id", sessionId);

    const xhr = new XMLHttpRequest();
    xhr.open("POST", `${API_BASE}/api/upload`);

    xhr.upload.onprogress = (event) => {
      if (event.lengthComputable) {
        const percent = Math.round((event.loaded / event.total) * 100);
        // Update progress for all files equally (or enhance per-file)
        const newProgress = {};
        files.forEach((f) => {
          newProgress[f.name] = percent;
        });
        setUploadProgress(newProgress);
      }
    };

    xhr.onload = () => {
      if (xhr.status >= 200 && xhr.status < 300) {
        const data = JSON.parse(xhr.responseText);
        addSystemMessage(
          `Uploaded ${data.indexed_files?.length || files.length} file(s). Indexed successfully.`
        );
        setFiles([]);
        setUploadProgress({});
      } else {
        throw new Error(xhr.responseText || `HTTP ${xhr.status}`);
      }
      setUploading(false);
    };

    xhr.onerror = () => {
      setError("Upload failed");
      setUploading(false);
    };

    xhr.send(form);
  } catch (err) {
    console.error(err);
    setError(err.message || "Upload failed");
    setUploading(false);
  }
};


const addSystemMessage = (text) => {
  const msg = { id: Date.now() + Math.random(), role: "system", text };

  setMessages((m) => [...m, msg]);

  setAllChats(prev => ({
    ...prev,
    [sessionId]: [...(prev[sessionId] || []), msg]
  }));
};


const sendMessage = async () => {
  if (!input.trim()) {
    setWarning("Please enter a message before sending");

    setTimeout(() => {
      setWarning("");
    }, 2000);

    return;
  }


  // add user message locally immediately
  const userMsg = { id: Date.now() + Math.random(), role: "user", text: input };
  setMessages((m) => [...m, userMsg]);
  setAllChats(prev => ({
  ...prev,
  [sessionId]: [...(prev[sessionId] || []), userMsg]
}));

  const query = input;
  setInput("");
  setLoading(true);
  setError(null);

  try {
    // include recent history so backend can handle follow-ups
    const recentHistory = messages.slice(-8).map((m) => {
      return { role: m.role, text: m.text };
    });

    const form = new FormData();
    form.append("session_id", sessionId);
    form.append("message", query);
    form.append("top_k", "6");
    form.append("history", JSON.stringify(recentHistory));
    
    setChatHistory(prev => {
      if (prev.some(c => c.id === sessionId)) {
        return prev;
      }
    
      return [
        {
          id: sessionId,
          title: query.trim().slice(0, 40)
        },
        ...prev
      ];
    });



  const res = await fetch(`${API_BASE}/api/chat`, {
      method: "POST",
      body: form,
    });

    if (!res.ok) {
      const contentType = res.headers.get("content-type") || "";
      let text = await res.text();
      try {
        if (contentType.includes("application/json")) {
          const j = JSON.parse(text);
          text = j.message || JSON.stringify(j);
        }
      } catch (e) {
        /* ignore */
      }
      throw new Error(text || `HTTP ${res.status}`);
    }

    const data = await res.json();
    const aiMsg = {
      id: Date.now() + Math.random(),
      role: "ai",
      text: data.answer || data.result || "No answer.",
    };

    setMessages((m) => [...m, aiMsg]);
    setAllChats(prev => ({
  ...prev,
  [sessionId]: [...(prev[sessionId] || []), aiMsg]
}));

  } catch (err) {
    console.error(err);
    setError(err.message || "Chat failed");
    addSystemMessage(`Error: ${err.message || "Chat failed"}`);
  } finally {
    setLoading(false);
  }
};


const handleKeyDown = (e) => {
  if (justTranscribedRef.current) {
    justTranscribedRef.current = false;
    return;
  }

  if (e.key === "Enter" && !e.shiftKey) {
    e.preventDefault();
    sendMessage();
  }
};


  const startRecording = async () => {
    try {
      const stream = await navigator.mediaDevices.getUserMedia({ audio: true });
      const mediaRecorder = new MediaRecorder(stream);
      mediaRecorderRef.current = mediaRecorder;
      audioChunksRef.current = [];

      mediaRecorder.ondataavailable = (event) => {
        if (event.data.size > 0) {
          audioChunksRef.current.push(event.data);
        }
      };

      mediaRecorder.onstop = async () => {
        const audioBlob = new Blob(audioChunksRef.current, { type: "audio/webm" });
        await transcribeAudio(audioBlob);
        stream.getTracks().forEach((track) => track.stop());
      };

      mediaRecorder.start();
      setIsRecording(true);
      setError(null);
    } catch (err) {
      console.error("Error accessing microphone:", err);
      setError("Microphone access denied. Please allow microphone permissions.");
      addSystemMessage("Error: Microphone access denied");
    }
  };

  const stopRecording = () => {
    if (mediaRecorderRef.current && isRecording) {
      mediaRecorderRef.current.stop();
      setIsRecording(false);
    }
  };

  const transcribeAudio = async (audioBlob) => {
    setIsTranscribing(true);
    setError(null);
  
    try {
      const form = new FormData();
      form.append("audio", audioBlob, "recording.webm");
      form.append("session_id", sessionId);
  
      const res = await fetch(`${API_BASE}/api/stt`, {
        method: "POST",
        body: form,
      });
  
      if (!res.ok) {
        const contentType = res.headers.get("content-type") || "";
        let text = await res.text();
        try {
          if (contentType.includes("application/json")) {
            const j = JSON.parse(text);
            text = j.message || j.error || JSON.stringify(j);
          }
        } catch (_) {}
        throw new Error(text || `HTTP ${res.status}`);
      }
  
      const data = await res.json();
      const transcribedText =
        data.text || data.transcription || data.result || "";
  
      if (transcribedText.trim()) {
        justTranscribedRef.current = true;

        setInput((prev) =>
          prev ? `${prev} ${transcribedText}` : transcribedText
        );
  
        setSttCooldown(true);
        setTimeout(() => setSttCooldown(false), 500);
      }
    } catch (err) {
      console.error("Transcription error:", err);
      setError(err.message || "Transcription failed");
      addSystemMessage(`Error: ${err.message || "Transcription failed"}`);
    } finally {
      setIsTranscribing(false);
    }
  };

  const toggleRecording = () => {
    if (isRecording) {
      stopRecording();
    } else {
      startRecording();
    }
  };

const deleteChat = (id) => {
  setChatHistory(prev => prev.filter(c => c.id !== id));

  setAllChats(prev => {
    const copy = { ...prev };
    delete copy[id];
    return copy;
  });

  if (sessionId === id) {
    setMessages([]);
  }
};

  
const startNewChat = () => {
  const newSession = Math.random().toString(36).slice(2, 10);

  setSessionId(newSession);
  setMessages([]);
  setInput("");

  setChatHistory(prev => [
    {
      id: newSession,
      title: "New Chat"
    },
    ...prev
  ]);

  localStorage.setItem("rag_session", newSession);
};

  return (
  <div className="app">
    {/* ================= LEFT PANEL ================= */}
    {/* 🔴 WARNING OVERLAY – PLACE HERE */}
    {warning && (
      <div
        style={{
          position: "fixed",
          inset: 0,
          display: "flex",
          alignItems: "center",
          justifyContent: "center",
          zIndex: 9999,
          background: "rgba(0,0,0,0.35)",
        }}
      >
        <div
          style={{
            display: "flex",
            alignItems: "center",
            gap: "10px",
            padding: "14px 18px",
            borderRadius: "10px",
            border: "2px solid #ff3b3b",
            background: "rgba(255,59,59,0.12)",
            color: "#ff3b3b",
            boxShadow: "0 0 0 1px rgba(255,59,59,.6), 0 12px 30px rgba(255,59,59,.4)",
            fontWeight: 600,
          }}
        >
          <svg
            stroke="currentColor"
            fill="none"
            strokeWidth="2"
            viewBox="0 0 24 24"
            width="26"
            height="26"
          >
            <path d="m21.73 18-8-14a2 2 0 0 0-3.48 0l-8 14A2 2 0 0 0 4 21h16a2 2 0 0 0 1.73-3Z" />
            <path d="M12 9v4" />
            <path d="M12 17h.01" />
          </svg>
          {warning}
        </div>
      </div>
    )}
    <div className="left">
     <button
      onClick={startNewChat}
      style={{
        marginTop: "8px",
        marginBottom: "12px",
        padding: "10px",
        borderRadius: "8px",
        background: "rgba(255,255,255,0.08)",
        color: "white",
        border: "1px solid rgba(255,255,255,0.12)",
        cursor: "pointer",
        fontWeight: 600
      }}
    >
       New Chat
    </button>
      <div className="brand">AskMate</div>

      {/* -------- Upload Area -------- */}
      <div className="upload-area">
        <FileUploadCard
          files={files}
          onFilesChange={setFiles}
          uploadProgress={uploadProgress}
          uploading={uploading}
          onUpload={uploadFiles}
        />


      </div>

      {/* -------- Chat History -------- */}
     
<div style={{ marginTop: 16, display: "flex", flexDirection: "column", flex: 1 }}>
  <div style={{ fontWeight: 600, marginBottom: 8 }}>
    Chat History
  </div>

  <div className="chat-history-scroll">
    {chatHistory.length === 0 && (
      <div className="small">No chats yet</div>
    )}

    {chatHistory.map((chat) => (
      <div
        key={chat.id}
        className="history-item"
        style={{
          background:
            chat.id === sessionId
              ? "rgba(110,231,183,0.2)"
              : "rgba(255,255,255,0.05)",
        }}
      >
        <span
          className="history-title"
          onClick={() => loadChat(chat.id)}
        >
          {chat.title}
        </span>

        <DeleteBinButton onClick={() => deleteChat(chat.id)} />
      </div>
    ))}
  </div>
</div>

{/* -------- Chat History -------- */}

      <div
        style={{
          marginTop: "auto",
          fontSize: 13,
          color: "var(--muted)",
        }}
      >
        Tip: Upload your lecture PDFs first. Then ask focused questions.
      </div>
    </div>

    {/* ================= RIGHT PANEL ================= */}
    <div className="right">
      <div
        style={{
          display: "flex",
          justifyContent: "space-between",
          alignItems: "center",
        }}
      >
        <div style={{ fontWeight: 700 }}>Chat</div>
        <div className="small">AskMate</div>
      </div>

      <div className="chat-window">
        {messages.map((m) => (
          <div
            key={m.id}
            className={`message-row ${
              m.role === "user"
                ? "user"
                : m.role === "ai"
                ? "ai"
                : "system"
            }`}
          >
            <div
              className={`bubble ${
                m.role === "user" ? "user" : m.role === "ai" ? "ai" : ""
              }`}
            >
              <ReactMarkdown>{m.text}</ReactMarkdown>
              {m.role === "system" && (
                <div className="meta">{m.text}</div>
              )}
            </div>
          </div>
        ))}
        <div ref={messagesEndRef} />
      </div>

      <div style={{ display: "flex", flexDirection: "column", gap: 8 }}>
        <div className="input-row">
          <textarea
            className="text-input"
            rows={2}
            placeholder="Ask a question (Shift+Enter for new line)"
            value={input}
            onChange={(e) => setInput(e.target.value)}
            onKeyDown={handleKeyDown}
          />
          <input
            type="checkbox"
            id="mic-toggle"
            checked={isRecording}
            readOnly
          />
          
          <label
            htmlFor="mic-toggle"
            className="switch"
            onClick={toggleRecording}
            title={isRecording ? "Stop recording" : "Start recording"}
          style={{ opacity: isTranscribing ? 0.5 : 1, pointerEvents: isTranscribing ? "none" : "auto" }}
          >
            {/* Mic ON */}
            <div className="mic-on">
              <svg
                xmlns="http://www.w3.org/2000/svg"
                width="22"
                height="22"
                fill="currentColor"
                viewBox="0 0 16 16"
              >
                <path d="M5 3a3 3 0 0 1 6 0v5a3 3 0 0 1-6 0V3z" />
                <path d="M3.5 6.5A.5.5 0 0 1 4 7v1a4 4 0 0 0 8 0V7a.5.5 0 0 1 1 0v1a5 5 0 0 1-4.5 4.975V15h3a.5.5 0 0 1 0 1h-7a.5.5 0 0 1 0-1h3v-2.025A5 5 0 0 1 3 8V7a.5.5 0 0 1 .5-.5z" />
              </svg>
            </div>
          
            {/* Mic OFF / Recording */}
            <div className="mic-off">
              <svg
                xmlns="http://www.w3.org/2000/svg"
                width="22"
                height="22"
                fill="currentColor"
                viewBox="0 0 16 16"
              >
                <path d="M13 8c0 .564-.094 1.107-.266 1.613l-.814-.814A4.02 4.02 0 0 0 12 8V7a.5.5 0 0 1 1 0v1z" />
                <path d="M9.486 10.607 5 6.12V8a3 3 0 0 0 4.486 2.607z" />
                <path d="M11 3v4.879L5.158 2.037A3.001 3.001 0 0 1 11 3z" />
                <path d="M1.646 1.646l12 12 .708-.708-12-12-.708.708z" />
              </svg>
            </div>
          </label>


          <button
            className="btn"
            disabled={loading || isRecording || sttCooldown}
            onClick={sendMessage}
          >
            {loading ? "Thinking..." : "Send"}
          </button>
        </div>
      </div>
    </div>
  </div>
);

}