import { useState, useRef, useEffect } from "react";
import { invoke } from "@tauri-apps/api/core";
import Markdown from "react-markdown";
import { Message, ProviderConfig } from "../types";

export function Chat() {
  const [messages, setMessages] = useState<Message[]>([]);
  const [input, setInput] = useState("");
  const [loading, setLoading] = useState(false);
  const [model, setModel] = useState("llama3.1"); // Default local model
  const messagesEndRef = useRef<HTMLDivElement>(null);

  const scrollToBottom = () => {
    messagesEndRef.current?.scrollIntoView({ behavior: "smooth" });
  };

  useEffect(scrollToBottom, [messages]);

  const sendMessage = async () => {
    if (!input.trim() || loading) return;

    const userMsg: Message = { role: "user", content: input };
    const newHistory = [...messages, userMsg];
    
    setMessages(newHistory);
    setInput("");
    setLoading(true);

    try {
      const config: ProviderConfig = {
        provider: "ollama",
        model: model,
        base_url: "http://localhost:11434",
      };

      // Invoke backend chat command
      // The backend returns the *new* messages (assistant response + tool outputs)
      const response = await invoke<Message[]>("chat", {
        messages: newHistory,
        config: config,
      });

      setMessages((prev) => [...prev, ...response]);
    } catch (e) {
      console.error(e);
      setMessages((prev) => [
        ...prev,
        { role: "assistant", content: `**Error:** ${e}` },
      ]);
    } finally {
      setLoading(false);
    }
  };

  return (
    <div className="chat-container" style={{ display: "flex", flexDirection: "column", height: "100%", maxWidth: "800px", margin: "0 auto" }}>
      {/* Settings Bar */}
      <div style={{ padding: "10px", borderBottom: "1px solid #ddd", display: "flex", gap: "10px", alignItems: "center" }}>
        <label>Ollama Model:</label>
        <input 
          value={model} 
          onChange={(e) => setModel(e.target.value)} 
          placeholder="e.g. llama3, mistral"
          style={{ padding: "5px" }}
        />
      </div>

      {/* Messages Area */}
      <div style={{ flex: 1, overflowY: "auto", padding: "20px", display: "flex", flexDirection: "column", gap: "15px" }}>
        {messages.map((msg, idx) => (
          <div 
            key={idx} 
            className={`message ${msg.role}`}
            style={{
              alignSelf: msg.role === "user" ? "flex-end" : "flex-start",
              maxWidth: "80%",
              padding: "10px 15px",
              borderRadius: "10px",
              background: msg.role === "user" ? "#007AFF" : msg.role === "tool" ? "#f0f0f0" : "#E5E5EA",
              color: msg.role === "user" ? "white" : "black",
              border: msg.role === "tool" ? "1px solid #ccc" : "none",
              fontFamily: msg.role === "tool" ? "monospace" : "inherit",
              fontSize: msg.role === "tool" ? "0.9em" : "1em",
              whiteSpace: msg.role === "tool" ? "pre-wrap" : "normal"
            }}
          >
            <strong>{msg.role === "user" ? "You" : msg.role === "tool" ? "Tool Output" : "Agent"}</strong>
            {msg.role === "tool" ? (
               <div style={{maxHeight: "200px", overflow: "auto"}}>{msg.content}</div>
            ) : (
              <Markdown>{msg.content}</Markdown>
            )}
            
            {/* Show Tool Calls if present */}
            {msg.tool_calls && (
              <div style={{ marginTop: "10px", fontSize: "0.85em", color: "#666" }}>
                {msg.tool_calls.map((tc, i) => (
                  <div key={i} style={{ background: "rgba(0,0,0,0.05)", padding: "5px", borderRadius: "4px" }}>
                    🛠 <code>{tc.function.name}({tc.function.arguments})</code>
                  </div>
                ))}
              </div>
            )}
          </div>
        ))}
        {loading && <div style={{ alignSelf: "flex-start", color: "#888" }}>Thinking...</div>}
        <div ref={messagesEndRef} />
      </div>

      {/* Input Area */}
      <div style={{ padding: "20px", borderTop: "1px solid #ddd", display: "flex", gap: "10px" }}>
        <input
          value={input}
          onChange={(e) => setInput(e.target.value)}
          onKeyDown={(e) => e.key === "Enter" && sendMessage()}
          placeholder="Ask the agent to do something..."
          style={{ flex: 1, padding: "10px", borderRadius: "4px", border: "1px solid #ccc" }}
          disabled={loading}
        />
        <button onClick={sendMessage} disabled={loading} style={{ padding: "10px 20px" }}>
          Send
        </button>
      </div>
    </div>
  );
}