import React, { useState } from "react";
import { History, X, RotateCcw } from "lucide-react";
import { Document } from "../../types";

interface VersionHistoryPanelProps {
  activeDoc: Document;
  editorText: string;
  setEditorText: (text: string) => void;
  createHistoryCheckpoint: (id: string, label?: string) => void;
  setDocuments: React.Dispatch<React.SetStateAction<Document[]>>;
  syncDocument: (id: string, text: string, flag: boolean) => Promise<void>;
  addLog: (text: string, type: "success" | "info" | "sync" | "error") => void;
  setToast: (toast: { show: boolean; message: string; timestamp: string }) => void;
  setShowVersionHistory: (show: boolean) => void;
  activeDocId: string;
}

export default function VersionHistoryPanel({
  activeDoc,
  editorText,
  setEditorText,
  createHistoryCheckpoint,
  setDocuments,
  syncDocument,
  addLog,
  setToast,
  setShowVersionHistory,
  activeDocId
}: VersionHistoryPanelProps) {
  const [checkpointLabelInput, setCheckpointLabelInput] = useState("");

  const handleSaveCheckpoint = () => {
    const val = checkpointLabelInput.trim() || "User Checkpoint";
    createHistoryCheckpoint(activeDocId, val);
    setCheckpointLabelInput("");
    setToast({
      show: true,
      message: "Manual snapshot saved 💾",
      timestamp: new Date().toLocaleTimeString([], { hour: "2-digit", minute: "2-digit" })
    });
  };

  const handleRestore = (hist: any) => {
    // Create safety backup of current content before swapping
    createHistoryCheckpoint(activeDocId, "Pre-Restore State Backup");
    // Swap text
    setEditorText(hist.content);
    // Mark document as edited and sync
    setDocuments((prevDocs) =>
      prevDocs.map((doc) => {
        if (doc.id === activeDocId) {
          return {
            ...doc,
            content: hist.content,
            isSynced: false,
            lastSaved: new Date().toISOString()
          };
        }
        return doc;
      })
    );
    syncDocument(activeDocId, hist.content, false);
    setToast({
      show: true,
      message: `Restored: ${hist.label || 'prior snapshot'}`,
      timestamp: new Date().toLocaleTimeString([], { hour: "2-digit", minute: "2-digit" })
    });
    addLog(`Restored "${activeDoc.title}" to state: "${hist.label}". Safety checkpoint captured.`, "success");
  };

  const historyList = activeDoc.history || [];

  return (
    <div className="w-[190px] sm:w-[220px] flex-shrink-0 bg-[#0F1115] rounded-lg border border-slate-805 p-2.5 flex flex-col min-h-0 text-left animate-slideLeft z-10">
      <div className="flex items-center justify-between border-b border-slate-800 pb-1.5 mb-2 flex-shrink-0">
        <span className="text-[9px] uppercase font-mono font-bold tracking-wider text-slate-400 flex items-center gap-1">
          <History className="h-3 w-3 text-indigo-400" /> History
        </span>
        <button
          type="button"
          onClick={() => setShowVersionHistory(false)}
          className="text-slate-500 hover:text-white transition p-0.5 rounded cursor-pointer"
        >
          <X className="h-3 w-3" />
        </button>
      </div>

      {/* Save Custom Checkpoint */}
      <div className="space-y-1 mb-2.5 pb-2.5 border-b border-slate-850 flex-shrink-0">
        <input
          type="text"
          value={checkpointLabelInput}
          onChange={(e) => setCheckpointLabelInput(e.target.value)}
          placeholder="Label (e.g. Pre-Proofread)"
          className="w-full text-[9px] font-mono px-2 py-1 bg-[#15181E] text-slate-205 border border-slate-800 rounded placeholder:text-slate-650 focus:outline-none focus:border-indigo-500"
        />
        <button
          type="button"
          onClick={handleSaveCheckpoint}
          className="w-full py-1 bg-indigo-650 hover:bg-indigo-600 text-[9px] text-white font-mono rounded transition duration-150 cursor-pointer text-center font-semibold"
        >
          + Save Checkpoint
        </button>
      </div>

      {/* List of past checkpoints */}
      <div className="flex-grow overflow-y-auto space-y-1.5 font-mono text-[9px] pr-1 scrollbar-thin">
        {historyList.length === 0 ? (
          <div className="text-slate-650 text-center py-10 text-[9px] font-mono leading-relaxed">
            No snapshots yet.<br/>Your keystrokes are saved automatically.
          </div>
        ) : (
          historyList.map((hist) => {
            const dateObj = new Date(hist.timestamp);
            const dateFormatted = dateObj.toLocaleDateString([], { month: "short", day: "numeric" });
            const timeFormatted = dateObj.toLocaleTimeString([], { hour: "2-digit", minute: "2-digit", second: "2-digit" });
            return (
              <div
                key={hist.id}
                className="p-2 rounded bg-[#15181E] border border-slate-800 hover:border-slate-705 transition flex flex-col gap-1 text-left relative duration-155"
              >
                <div className="flex items-center justify-between gap-1">
                  <span className="text-[9px] text-indigo-400 font-medium truncate max-w-[110px]" title={hist.label}>
                    {hist.label || "Snapshot"}
                  </span>
                  <span className="text-[8px] text-slate-500 font-mono">{dateFormatted}</span>
                </div>
                <div className="text-[8px] text-slate-550 leading-none font-mono">
                  {timeFormatted}
                </div>
                
                {/* Action row */}
                <div className="mt-1 flex items-center justify-between gap-1">
                  <span className="text-[8px] text-slate-605 font-mono">
                    {(hist.content.length / 1024).toFixed(2)} KB
                  </span>
                  <button
                    type="button"
                    onClick={() => handleRestore(hist)}
                    className="py-0.5 px-1 bg-[#0F1115] hover:bg-slate-800 text-slate-355 hover:text-white rounded text-[8px] transition border border-slate-800 flex items-center gap-0.5 cursor-pointer font-sans"
                    title="Restore document to this exact snapshot"
                  >
                    <RotateCcw className="h-2 w-2 text-indigo-400" /> Restore
                  </button>
                </div>
              </div>
            );
          })
        )}
      </div>
    </div>
  );
}