"use client";

import { useMemo, useState } from "react";
import { useTenant } from "@/contexts/TenantContext";

type Message = {
  role: "user" | "assistant" | "system";
  content: string;
  meta?: string;
};

const API_BASE =
  process.env.NEXT_PUBLIC_API_URL?.replace(/\/$/, "") || "http://localhost:8000";

export function ChatPanel() {
  const { tenantId } = useTenant();
  const [message, setMessage] = useState("");
  const [isSending, setIsSending] = useState(false);
  const [history, setHistory] = useState<Message[]>([
    {
      role: "assistant",
      content:
        "Hi there! I’m the IntegraChat orchestrator. Ask anything about your tenant data and I will route the right MCP tools.",
      meta: "Agent ready",
    },
  ]);
  const [lastDecision, setLastDecision] = useState<string | null>(null);

  const conversationPayload = useMemo(
    () =>
      history
        .filter((m) => m.role !== "system")
        .map((m) => ({
          role: m.role,
          content: m.content,
        })),
    [history],
  );

  async function handleSend() {
    if (!message.trim() || isSending) return;
    const userMessage: Message = { role: "user", content: message.trim() };
    const optimisticHistory = [...history, userMessage];
    setHistory(optimisticHistory);
    setMessage("");
    setIsSending(true);

    try {
      const response = await fetch(`${API_BASE}/agent/message`, {
        method: "POST",
        headers: {
          "Content-Type": "application/json",
        },
        body: JSON.stringify({
          tenant_id: tenantId,
          message: userMessage.content,
          conversation_history: conversationPayload,
          temperature: 0,
        }),
      });

      if (!response.ok) {
        throw new Error(
          `API error (${response.status}) – check backend/api/main.py`,
        );
      }

      const data = await response.json();
      const assistantText =
        data?.text ??
        "Agent responded but text field was empty. Inspect FastAPI logs for clues.";
      setHistory((prev) => [
        ...prev,
        {
          role: "assistant",
          content: assistantText,
          meta: data?.decision?.reason ?? "response",
        },
      ]);
      setLastDecision(
        data?.decision
          ? `${data.decision.action} · ${data.decision.tool ?? "llm"}`
          : null,
      );
    } catch (err) {
      console.error(err);
      setHistory((prev) => [
        ...prev,
        {
          role: "assistant",
          content:
            err instanceof Error
              ? err.message
              : "Failed to reach the FastAPI gateway.",
          meta: "error",
        },
      ]);
      setLastDecision("error");
    } finally {
      setIsSending(false);
    }
  }

  return (
    <section
      id="chat"
      className="gradient-border relative rounded-[28px] p-1 text-white"
    >
      <div className="glass-panel relative rounded-[26px] p-6">
        <div>
          <p className="text-sm uppercase tracking-[0.5em] text-cyan-200/70">
            Orchestrator Console
          </p>
          <h2 className="mt-2 text-3xl font-semibold">
            Talk to your enterprise agent
          </h2>
        </div>
        <div className="mt-6 h-[360px] space-y-3 overflow-y-auto rounded-2xl border border-white/10 bg-slate-950/40 p-4 scrollArea">
          {history.map((msg, idx) => (
            <div
              key={`${msg.role}-${idx}`}
              className={`flex gap-3 rounded-2xl px-4 py-3 ${
                msg.role === "user"
                  ? "bg-slate-900/70 text-slate-100"
                  : "bg-cyan-500/10 text-slate-100"
              }`}
            >
              <span className="text-xs font-semibold uppercase tracking-widest text-cyan-200/80">
                {msg.role}
              </span>
              <div className="space-y-1 text-sm">
                <p>{msg.content}</p>
                {msg.meta && (
                  <p className="text-xs text-slate-400">{msg.meta}</p>
                )}
              </div>
            </div>
          ))}
        </div>

        <div className="mt-5 flex flex-col gap-3 md:flex-row">
          <textarea
            placeholder="Ask about policies, knowledge base hits, or route through RAG/Web/Admin..."
            value={message}
            onChange={(e) => setMessage(e.target.value)}
            className="flex-1 rounded-2xl border border-white/10 bg-white/5 px-4 py-3 text-sm text-white outline-none focus:border-cyan-200/80"
            rows={3}
          />
          <button
            onClick={handleSend}
            disabled={isSending}
            className="min-w-[160px] rounded-2xl bg-gradient-to-r from-sky-400 to-cyan-500 px-6 py-3 font-semibold text-slate-950 shadow-lg shadow-cyan-500/30 transition hover:-translate-y-0.5 disabled:cursor-not-allowed disabled:opacity-60"
          >
            {isSending ? "Routing…" : "Send to MCP"}
          </button>
        </div>

        <div className="mt-4 flex items-center gap-3 text-sm text-slate-300">
          <span className="h-2 w-2 rounded-full bg-emerald-400 shadow-[0_0_12px_#34d399]" />
          {lastDecision
            ? `Last decision: ${lastDecision}`
            : "No tool invocation yet"}
        </div>
      </div>
    </section>
  );
}