"use client";

import React, { useState, useRef, useEffect } from "react";

interface Message {
  role: "user" | "assistant" | "system";
  content: string | any[];
  reasoning_content?: string;
  files?: Array<{ name: string; type: string; dataUrl?: string }>;
}

export default function AetherisChatPage() {
  const [messages, setMessages] = useState<Message[]>([]);
  const [inputValue, setInputValue] = useState("");
  const [selectedModel, setSelectedModel] = useState("auto/best-coding");
  const [isGenerating, setIsGenerating] = useState(false);
  const [attachedFiles, setAttachedFiles] = useState<
    Array<{ name: string; type: string; dataUrl?: string; textContent?: string }>
  >([]);
  const [showModelsDropdown, setShowModelsDropdown] = useState(false);

  const messagesEndRef = useRef<HTMLDivElement>(null);
  const fileInputRef = useRef<HTMLInputElement>(null);
  const textareaRef = useRef<HTMLTextAreaElement>(null);

  const models = [
    { id: "auto/best-coding", name: "Best Coding", desc: "Top-tier coding, logic, and debugging" },
    {
      id: "auto/best-reasoning",
      name: "Best Reasoning",
      desc: "Collapsible thinking, logic, math",
    },
    { id: "auto/best-free", name: "Best Free", desc: "100% free, unlimited scaling models" },
    {
      id: "auto/best-chat",
      name: "Best Conversational",
      desc: "Fast, natural dialogues and answers",
    },
  ];

  // Auto-scroll to bottom of chat
  useEffect(() => {
    messagesEndRef.current?.scrollIntoView({ behavior: "smooth" });
  }, [messages, isGenerating]);

  // Auto-resize textarea height
  useEffect(() => {
    if (textareaRef.current) {
      textareaRef.current.style.height = "auto";
      textareaRef.current.style.height = `${Math.min(textareaRef.current.scrollHeight, 200)}px`;
    }
  }, [inputValue]);

  const handleFileUpload = (e: React.ChangeEvent<HTMLInputElement>) => {
    const files = e.target.files;
    if (!files) return;

    Array.from(files).forEach((file) => {
      const reader = new FileReader();
      if (file.type.startsWith("image/")) {
        reader.onload = (event) => {
          setAttachedFiles((prev) => [
            ...prev,
            { name: file.name, type: file.type, dataUrl: event.target?.result as string },
          ]);
        };
        reader.readAsDataURL(file);
      } else {
        // Read text files directly as text content
        reader.onload = (event) => {
          setAttachedFiles((prev) => [
            ...prev,
            { name: file.name, type: file.type, textContent: event.target?.result as string },
          ]);
        };
        reader.readAsText(file);
      }
    });

    if (fileInputRef.current) fileInputRef.current.value = "";
  };

  const removeAttachedFile = (index: number) => {
    setAttachedFiles((prev) => prev.filter((_, i) => i !== index));
  };

  const executeQuickAction = (promptText: string) => {
    if (isGenerating) return;
    sendMessage(promptText, []);
  };

  const handleSend = () => {
    if (isGenerating) return;
    const text = inputValue.trim();
    if (!text && attachedFiles.length === 0) return;

    sendMessage(text, attachedFiles);
    setInputValue("");
    setAttachedFiles([]);
  };

  const sendMessage = async (text: string, files: typeof attachedFiles) => {
    setIsGenerating(true);

    // Prepare message payload content
    let userMsgContent: string | any[] = text;

    // Check if there are attached images for multimodal OpenAI compatibility
    const attachedImages = files.filter((f) => f.type.startsWith("image/"));
    const attachedTexts = files.filter((f) => !f.type.startsWith("image/"));

    if (attachedImages.length > 0) {
      const parts: any[] = [{ type: "text", text }];
      attachedImages.forEach((img) => {
        parts.push({
          type: "image_url",
          image_url: { url: img.dataUrl },
        });
      });
      userMsgContent = parts;
    } else if (attachedTexts.length > 0) {
      // Append text file content straight to the prompt
      let textFilesPrompt = "";
      attachedTexts.forEach((file) => {
        textFilesPrompt += `[Attached File: ${file.name}]\n\`\`\`\n${file.textContent}\n\`\`\`\n\n`;
      });
      userMsgContent = textFilesPrompt + text;
    }

    const newUserMessage: Message = {
      role: "user",
      content: userMsgContent,
      files: files.map((f) => ({ name: f.name, type: f.type, dataUrl: f.dataUrl })),
    };

    const newMessages = [...messages, newUserMessage];
    setMessages(newMessages);

    // Create a placeholder for the assistant response
    const assistantMessageIndex = newMessages.length;
    setMessages((prev) => [...prev, { role: "assistant", content: "", reasoning_content: "" }]);

    try {
      // Structure chat messages list for completions payload
      const chatHistory = newMessages.map((msg) => ({
        role: msg.role,
        content: msg.content,
      }));

      const response = await fetch("/api/public-chat", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({
          model: selectedModel,
          messages: chatHistory,
          stream: true,
        }),
      });

      if (!response.ok) {
        throw new Error(`Server returned error: ${response.status}`);
      }

      const reader = response.body?.getReader();
      const decoder = new TextDecoder();
      if (!reader) throw new Error("ReadableStream is not supported by the response.");

      let assistantText = "";
      let reasoningText = "";

      while (true) {
        const { value, done } = await reader.read();
        if (done) break;

        const chunk = decoder.decode(value);
        const lines = chunk.split("\n");

        for (const line of lines) {
          if (line.startsWith("data: ")) {
            const dataStr = line.slice(6).trim();
            if (dataStr === "[DONE]") continue;

            try {
              const dataObj = JSON.parse(dataStr);
              const delta = dataObj.choices?.[0]?.delta;

              if (delta) {
                if (delta.reasoning_content) {
                  reasoningText += delta.reasoning_content;
                }
                if (delta.content) {
                  assistantText += delta.content;
                }

                setMessages((prev) => {
                  const updated = [...prev];
                  updated[assistantMessageIndex] = {
                    role: "assistant",
                    content: assistantText,
                    reasoning_content: reasoningText,
                  };
                  return updated;
                });
              }
            } catch {
              // Ignore parse errors from malformed SSE chunks
            }
          }
        }
      }
    } catch (err: any) {
      console.error(err);
      setMessages((prev) => {
        const updated = [...prev];
        updated[assistantMessageIndex] = {
          role: "assistant",
          content: `⚠️ Error: ${err.message || "Failed to generate response"}`,
        };
        return updated;
      });
    } finally {
      setIsGenerating(false);
    }
  };

  // Helper to parse markdown-like code blocks and lists
  const renderMessageContent = (msg: Message) => {
    let text = "";
    if (typeof msg.content === "string") {
      text = msg.content;
    } else if (Array.isArray(msg.content)) {
      const textPart = msg.content.find((p: any) => p.type === "text");
      text = textPart ? textPart.text : "";
    }

    if (!text) return null;

    // Split content by code blocks
    const parts = text.split(/(```[\s\S]*?```)/g);

    return parts.map((part, idx) => {
      if (part.startsWith("```") && part.endsWith("```")) {
        const lines = part.split("\n");
        const header = lines[0].slice(3).trim();
        const code = lines.slice(1, -1).join("\n");

        return (
          <div
            key={idx}
            className="my-4 border border-zinc-800 rounded-lg overflow-hidden bg-zinc-950 font-mono text-sm"
          >
            <div className="flex justify-between items-center px-4 py-2 bg-zinc-900 border-b border-zinc-800 text-zinc-400 select-none">
              <span>{header || "code"}</span>
              <button
                onClick={() => navigator.clipboard.writeText(code)}
                className="flex items-center gap-1 hover:text-zinc-200 transition-colors text-xs"
              >
                <span className="material-symbols-outlined text-sm">content_copy</span> Copy
              </button>
            </div>
            <pre className="p-4 overflow-x-auto text-zinc-300">
              <code>{code}</code>
            </pre>
          </div>
        );
      }

      // Handle simple formatting like lists and paragraphs
      return (
        <div key={idx} className="whitespace-pre-wrap leading-relaxed break-words">
          {part.split("\n").map((line, lIdx) => {
            if (line.startsWith("- ") || line.startsWith("* ")) {
              return (
                <ul key={lIdx} className="list-disc pl-6 my-1">
                  <li>{line.slice(2)}</li>
                </ul>
              );
            }
            if (/^\d+\.\s/.test(line)) {
              const numEnd = line.indexOf(" ");
              return (
                <ol key={lIdx} className="list-decimal pl-6 my-1">
                  <li>{line.slice(numEnd + 1)}</li>
                </ol>
              );
            }
            return (
              <p key={lIdx} className={line.trim() === "" ? "h-2" : "my-1"}>
                {line}
              </p>
            );
          })}
        </div>
      );
    });
  };

  return (
    <div className="min-h-screen bg-zinc-950 text-zinc-100 flex flex-col font-sans">
      {/* Premium Glassmorphic Header */}
      <header className="sticky top-0 z-40 bg-zinc-950/70 backdrop-blur-xl border-b border-zinc-900 px-6 py-4 flex items-center justify-between">
        <div className="flex items-center gap-3">
          <div className="w-10 h-10 rounded-xl bg-gradient-to-tr from-indigo-500 via-purple-500 to-pink-500 flex items-center justify-center shadow-lg shadow-indigo-500/20">
            <span className="material-symbols-outlined text-white text-2xl font-semibold select-none">
              auto_awesome
            </span>
          </div>
          <div>
            <h1 className="text-xl font-bold tracking-tight bg-gradient-to-r from-zinc-100 via-zinc-200 to-purple-400 bg-clip-text text-transparent">
              Aetheris AI
            </h1>
            <p className="text-[10px] text-zinc-500 font-mono tracking-wide uppercase">
              Unified Router
            </p>
          </div>
        </div>

        {/* Model Selection Dropdown */}
        <div className="relative">
          <button
            onClick={() => setShowModelsDropdown(!showModelsDropdown)}
            className="flex items-center gap-2 bg-zinc-900 border border-zinc-800 hover:border-zinc-700 hover:bg-zinc-800/80 px-4 py-2 rounded-xl text-sm transition-all shadow-sm cursor-pointer select-none"
          >
            <span className="material-symbols-outlined text-purple-400 text-lg">smart_toy</span>
            <span className="font-semibold text-zinc-300">
              {models.find((m) => m.id === selectedModel)?.name}
            </span>
            <span className="material-symbols-outlined text-zinc-500 text-sm">
              {showModelsDropdown ? "keyboard_arrow_up" : "keyboard_arrow_down"}
            </span>
          </button>

          {showModelsDropdown && (
            <div className="absolute right-0 mt-2 w-72 bg-zinc-900 border border-zinc-800 rounded-2xl shadow-xl overflow-hidden z-50 py-1">
              {models.map((model) => (
                <button
                  key={model.id}
                  onClick={() => {
                    setSelectedModel(model.id);
                    setShowModelsDropdown(false);
                  }}
                  className="w-full text-left px-4 py-3 hover:bg-zinc-800 flex flex-col transition-colors cursor-pointer"
                >
                  <span className="font-semibold text-zinc-200 text-sm">{model.name}</span>
                  <span className="text-xs text-zinc-500 mt-0.5">{model.desc}</span>
                </button>
              ))}
            </div>
          )}
        </div>
      </header>

      {/* Main Chat Interface */}
      <main className="flex-1 overflow-y-auto px-4 md:px-8 py-6 max-w-4xl mx-auto w-full flex flex-col justify-between">
        {messages.length === 0 ? (
          /* Empty / Landing Hero State */
          <div className="flex-1 flex flex-col items-center justify-center py-20">
            <div className="w-24 h-24 rounded-3xl bg-gradient-to-tr from-indigo-500 via-purple-500 to-pink-500 flex items-center justify-center shadow-2xl shadow-indigo-500/25 mb-8 animate-pulse">
              <span className="material-symbols-outlined text-white text-6xl font-semibold select-none">
                auto_awesome
              </span>
            </div>
            <h2 className="text-4xl font-extrabold tracking-tight text-center bg-gradient-to-r from-zinc-50 via-zinc-100 to-purple-300 bg-clip-text text-transparent">
              How can Aetheris help you?
            </h2>
            <p className="text-zinc-400 mt-3 text-center max-w-md text-sm leading-relaxed">
              Experience unified intelligence routing across multiple AI models dynamically. Upload
              code, text, or ask a question.
            </p>

            {/* Quick Action Suggestion Cards */}
            <div className="grid grid-cols-1 md:grid-cols-3 gap-4 mt-12 w-full max-w-3xl">
              <button
                onClick={() =>
                  executeQuickAction(
                    "Write a clean, responsive landing page using HTML and Tailwind CSS."
                  )
                }
                className="bg-zinc-900/40 border border-zinc-900 hover:border-zinc-800 hover:bg-zinc-900/80 p-5 rounded-2xl text-left transition-all hover:scale-[1.02] flex flex-col items-start cursor-pointer"
              >
                <div className="w-8 h-8 rounded-lg bg-indigo-500/10 flex items-center justify-center mb-3">
                  <span className="material-symbols-outlined text-indigo-400 text-xl">code</span>
                </div>
                <span className="font-semibold text-zinc-200 text-sm">Write Code</span>
                <span className="text-xs text-zinc-500 mt-2">
                  Write a clean landing page with Tailwind CSS.
                </span>
              </button>

              <button
                onClick={() =>
                  executeQuickAction(
                    "Design a SQL schema for a modern e-commerce checkout flow with order history."
                  )
                }
                className="bg-zinc-900/40 border border-zinc-900 hover:border-zinc-800 hover:bg-zinc-900/80 p-5 rounded-2xl text-left transition-all hover:scale-[1.02] flex flex-col items-start cursor-pointer"
              >
                <div className="w-8 h-8 rounded-lg bg-purple-500/10 flex items-center justify-center mb-3">
                  <span className="material-symbols-outlined text-purple-400 text-xl">
                    database
                  </span>
                </div>
                <span className="font-semibold text-zinc-200 text-sm">DB Schema</span>
                <span className="text-xs text-zinc-500 mt-2">
                  Design a SQL schema for a checkout flow.
                </span>
              </button>

              <button
                onClick={() =>
                  executeQuickAction(
                    "Explain how quantum computing and superposition work using a simple coin analogy."
                  )
                }
                className="bg-zinc-900/40 border border-zinc-900 hover:border-zinc-800 hover:bg-zinc-900/80 p-5 rounded-2xl text-left transition-all hover:scale-[1.02] flex flex-col items-start cursor-pointer"
              >
                <div className="w-8 h-8 rounded-lg bg-pink-500/10 flex items-center justify-center mb-3">
                  <span className="material-symbols-outlined text-pink-400 text-xl">school</span>
                </div>
                <span className="font-semibold text-zinc-200 text-sm">Explain Concepts</span>
                <span className="text-xs text-zinc-500 mt-2">
                  Explain quantum computing using a coin analogy.
                </span>
              </button>
            </div>
          </div>
        ) : (
          /* Messages Feed */
          <div className="flex-1 flex flex-col gap-6 py-4">
            {messages.map((msg, index) => (
              <div key={index} className="flex flex-col gap-2">
                <div
                  className={`flex gap-4 items-start ${msg.role === "user" ? "justify-end" : ""}`}
                >
                  {msg.role !== "user" && (
                    <div className="w-8 h-8 rounded-lg bg-gradient-to-tr from-indigo-500 to-purple-500 flex items-center justify-center shadow-md select-none shrink-0">
                      <span className="material-symbols-outlined text-white text-lg">
                        auto_awesome
                      </span>
                    </div>
                  )}

                  <div
                    className={`max-w-[85%] rounded-2xl p-4 text-[15px] shadow-sm flex flex-col gap-2 ${
                      msg.role === "user"
                        ? "bg-purple-600/10 border border-purple-500/20 text-purple-50"
                        : "bg-zinc-900/60 border border-zinc-900 text-zinc-100"
                    }`}
                  >
                    {/* Attached files preview in history */}
                    {msg.files && msg.files.length > 0 && (
                      <div className="flex flex-wrap gap-2 mb-2">
                        {msg.files.map((file, fIdx) => (
                          <div
                            key={fIdx}
                            className="flex items-center gap-1.5 bg-zinc-950 border border-zinc-800 rounded-lg p-1.5 pr-2.5 text-xs select-none"
                          >
                            {file.type.startsWith("image/") ? (
                              <img
                                src={file.dataUrl}
                                className="w-8 h-8 object-cover rounded"
                                alt="uploaded"
                              />
                            ) : (
                              <span className="material-symbols-outlined text-zinc-500 text-base">
                                description
                              </span>
                            )}
                            <span className="text-zinc-400 truncate max-w-[120px] font-mono">
                              {file.name}
                            </span>
                          </div>
                        ))}
                      </div>
                    )}

                    {/* Rendering thinking process block for assistant responses */}
                    {msg.role === "assistant" && msg.reasoning_content && (
                      <details open className="group border-l-2 border-purple-500/30 pl-3 my-1">
                        <summary className="text-xs text-purple-400 font-semibold cursor-pointer select-none outline-none hover:text-purple-300 flex items-center gap-1.5">
                          <span className="w-1.5 h-1.5 bg-purple-500 rounded-full group-open:animate-none animate-ping"></span>
                          Thinking Process
                        </summary>
                        <div className="text-xs text-zinc-500 font-mono mt-2 bg-zinc-950/40 p-2.5 rounded-lg border border-zinc-900/60 whitespace-pre-wrap leading-relaxed">
                          {msg.reasoning_content}
                        </div>
                      </details>
                    )}

                    {renderMessageContent(msg)}
                  </div>

                  {msg.role === "user" && (
                    <div className="w-8 h-8 rounded-lg bg-zinc-800 flex items-center justify-center shrink-0 select-none">
                      <span className="material-symbols-outlined text-zinc-400 text-lg">
                        person
                      </span>
                    </div>
                  )}
                </div>
              </div>
            ))}
            <div ref={messagesEndRef} />
          </div>
        )}
      </main>

      {/* Floating Input Panel */}
      <footer className="w-full max-w-4xl mx-auto px-4 pb-6 mt-auto">
        <div className="bg-zinc-900/80 backdrop-blur-md border border-zinc-800 rounded-2xl overflow-hidden shadow-xl p-3 flex flex-col gap-2">
          {/* File Previews List inside the input container */}
          {attachedFiles.length > 0 && (
            <div className="flex flex-wrap gap-2 px-2 pb-2 border-b border-zinc-800/60">
              {attachedFiles.map((file, idx) => (
                <div
                  key={idx}
                  className="relative group flex items-center gap-2 bg-zinc-950 border border-zinc-800 rounded-xl p-2 text-xs select-none"
                >
                  {file.type.startsWith("image/") ? (
                    <img
                      src={file.dataUrl}
                      className="w-10 h-10 object-cover rounded-lg"
                      alt="preview"
                    />
                  ) : (
                    <span className="material-symbols-outlined text-zinc-400 text-2xl">
                      description
                    </span>
                  )}
                  <div className="flex flex-col truncate max-w-[120px]">
                    <span className="text-zinc-300 font-mono truncate">{file.name}</span>
                    <span className="text-[10px] text-zinc-500 font-mono">
                      {(file.type.split("/")[1] || "text").toUpperCase()}
                    </span>
                  </div>
                  <button
                    onClick={() => removeAttachedFile(idx)}
                    className="absolute -top-1.5 -right-1.5 bg-zinc-800 hover:bg-zinc-700 text-zinc-300 rounded-full w-5 h-5 flex items-center justify-center border border-zinc-700 shadow-md cursor-pointer transition-transform group-hover:scale-110"
                  >
                    <span className="material-symbols-outlined text-[10px] font-bold">close</span>
                  </button>
                </div>
              ))}
            </div>
          )}

          {/* Prompt Form */}
          <div className="flex items-end gap-2.5">
            <button
              onClick={() => fileInputRef.current?.click()}
              className="p-2.5 text-zinc-400 hover:text-zinc-200 hover:bg-zinc-800/80 rounded-xl transition-all cursor-pointer select-none"
              title="Attach images or code files"
            >
              <span className="material-symbols-outlined text-2xl">attach_file</span>
            </button>
            <input
              type="file"
              ref={fileInputRef}
              onChange={handleFileUpload}
              className="hidden"
              multiple
              accept="image/*,.txt,.md,.js,.ts,.json,.csv,.py,.sh,.css,.html"
            />

            <textarea
              ref={textareaRef}
              value={inputValue}
              onChange={(e) => setInputValue(e.target.value)}
              onKeyDown={(e) => {
                if (e.key === "Enter" && !e.shiftKey) {
                  e.preventDefault();
                  handleSend();
                }
              }}
              placeholder="Ask Aetheris anything..."
              className="flex-1 bg-transparent border-0 outline-none text-zinc-100 text-sm py-2 px-1 resize-none placeholder-zinc-500 max-h-48 min-h-[36px]"
              rows={1}
            />

            <button
              onClick={handleSend}
              disabled={isGenerating || (!inputValue.trim() && attachedFiles.length === 0)}
              className={`p-2.5 rounded-xl transition-all flex items-center justify-center select-none cursor-pointer ${
                isGenerating || (!inputValue.trim() && attachedFiles.length === 0)
                  ? "bg-zinc-800 text-zinc-600"
                  : "bg-purple-600 hover:bg-purple-500 text-white shadow-md shadow-purple-500/10 active:scale-95"
              }`}
            >
              {isGenerating ? (
                <div className="w-5 h-5 border-2 border-white/20 border-t-white rounded-full animate-spin"></div>
              ) : (
                <span className="material-symbols-outlined text-xl">send</span>
              )}
            </button>
          </div>
        </div>
        <p className="text-[10px] text-zinc-600 text-center mt-2.5 font-mono select-none">
          Aetheris AI is powered by OmniRoute &bull; Free keyless and active load-balanced
          connections
        </p>
      </footer>
    </div>
  );
}