"use client";

import React, { useState, useEffect } from "react";
import { Sidebar } from "@/components/manual-label-scan/Sidebar";
import { Editor, ScanLabelFormData, AiPredictedData } from "@/components/manual-label-scan/Editor";
import { ImageViewer } from "@/components/manual-label-scan/ImageViewer";
import { getErrorMessage } from "@/utils/client-error";

export default function ManualLabelScanPage() {
  const [files, setFiles] = useState<{ url: string; filename: string }[]>([]);
  const [currentIndex, setCurrentIndex] = useState(-1);
  
  const [formData, setFormData] = useState<ScanLabelFormData>({
    filename: "",
    no_sku: "",
    nama_item: "",
    expiry_date: "",
    notes: ""
  });
  const [aiPredicted, setAiPredicted] = useState<AiPredictedData | null>(null);
  const [aiSource, setAiSource] = useState<{ type: "batch" | "live"; timestamp: string; method?: string; confidence?: number } | null>(null);

  const [skuList, setSkuList] = useState<Array<{ no_sku: string; nama_item: string }>>([]);
  const [isScanning, setIsScanning] = useState(false);
  const [savingGT, setSavingGT] = useState(false);

  const [toast, setToast] = useState({ message: "", show: false, isError: false });
  const showToast = (message: string, isError = false) => {
    setToast({ message, show: true, isError });
    setTimeout(() => setToast(p => ({ ...p, show: false })), 2500);
  };

  useEffect(() => {
    const fetchAllData = async () => {
      try {
        // Fetch Skus
        const skuRes = await fetch("/api/skus");
        if (skuRes.ok) {
          const skuData = await skuRes.json();
          setSkuList(skuData.skus || []);
        }

        // Fetch Test Images — the frozen 79-image Validation Set
        // (product-test-images-fixed/), the only set the accuracy harness
        // scores. Gallery/training photos (foto-kemasan-v2/) are not shown
        // here: they don't need per-photo ground truth, only correct
        // SKU-folder placement for classifier training.
        const testRes = await fetch("/api/product-images");
        let testFiles: { url: string; filename: string }[] = [];
        if (testRes.ok) {
          const testData = await testRes.json();
          testFiles = (testData.files || []).map((f: string) => ({
            url: `/api/product-images?filename=${encodeURIComponent(f)}`,
            filename: f
          }));
        }

        setFiles(testFiles);
        if (testFiles.length > 0) setCurrentIndex(0);

      } catch (err) {
        console.error("Error initializing page", err);
        showToast("Error loading dataset files", true);
      }
    };
    fetchAllData();
  }, []);

  useEffect(() => {
    if (currentIndex < 0 || currentIndex >= files.length) return;
    const file = files[currentIndex];
    
    const loadLabel = async () => {
      try {
        const res = await fetch(`/api/manual-label-scan?filename=${encodeURIComponent(file.filename)}`);
        if (res.ok) {
          const data = await res.json();
          setFormData({
            filename: data.filename || file.filename,
            no_sku: data.no_sku || "",
            nama_item: data.nama_item || "",
            expiry_date: data.expiry_date || "",
            notes: data.notes || ""
          });
        }
      } catch (err) {
        console.error("Error fetching label", err);
      }

      // Default-load the AI prediction from the last batch accuracy run
      // (not a live re-scan) so failures are visible immediately while
      // browsing - "Scan with AI" below can still be used to get a fresh
      // live result for this exact image.
      setAiPredicted(null);
      setAiSource(null);
      try {
        const aiRes = await fetch(`/api/product-scan-results?filename=${encodeURIComponent(file.filename)}`);
        if (aiRes.ok) {
          const aiData = await aiRes.json();
          if (aiData.found) {
            setAiPredicted({
              no_sku: aiData.no_sku,
              nama_item: aiData.nama_item,
              expiry_date: aiData.expiry_date
            });
            setAiSource({ type: "batch", timestamp: aiData.timestamp, method: aiData.method, confidence: aiData.confidence });
          }
        }
      } catch (err) {
        console.error("Error fetching batch AI result", err);
      }
    };
    loadLabel();
  }, [currentIndex, files]);

  // Handle Ctrl+S keyboard shortcut
  useEffect(() => {
    const handleKeyDown = (e: KeyboardEvent) => {
      if ((e.ctrlKey || e.metaKey) && e.key === "s") {
        e.preventDefault();
        handleSave();
      }
    };
    window.addEventListener("keydown", handleKeyDown);
    return () => window.removeEventListener("keydown", handleKeyDown);
  }, [formData]);

  const handleChange = (field: keyof ScanLabelFormData, value: string) => {
    setFormData(prev => ({ ...prev, [field]: value }));
  };

  const handleScanWithAi = async () => {
    if (currentIndex < 0) return;
    const currentFile = files[currentIndex];
    setIsScanning(true);
    try {
      // Fetch image as base64
      const imgRes = await fetch(currentFile.url);
      const blob = await imgRes.blob();
      const base64 = await new Promise<string>((resolve) => {
        const reader = new FileReader();
        reader.onloadend = () => resolve(reader.result as string);
        reader.readAsDataURL(blob);
      });

      const scanRes = await fetch("/api/scan-pfm", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ image: base64 })
      });
      
      if (!scanRes.ok) throw new Error("Pipeline API error");
      const scanData = await scanRes.json();

      // Compare against the sku_master-resolved best match (what the app
      // actually shows/saves as nama_item, and what the accuracy harness
      // scores), not classification.top1_name - that's the classifier's raw
      // internal class label (e.g. the foto-kemasan-v2 folder name), which
      // structurally never matches a sku_master-style ground truth string
      // even when the classification itself is correct.
      const bestMatch = (scanData.possibleMatches || []).find((m: { isBestMatch?: boolean }) => m.isBestMatch);

      setAiPredicted({
        no_sku: bestMatch?.no_sku,
        nama_item: bestMatch?.nama_item,
        expiry_date: scanData.ocr?.extracted_expired_date
      });
      setAiSource({
        type: "live",
        timestamp: new Date().toISOString(),
        method: scanData.classification?.method,
        confidence: scanData.classification?.top1_confidence
      });

      showToast("AI Scan complete!");
    } catch (err) {
      showToast(getErrorMessage(err, undefined, "AI Scan failed"), true);
    } finally {
      setIsScanning(false);
    }
  };

  const handleSave = async () => {
    setSavingGT(true);
    try {
      const res = await fetch("/api/manual-label-scan", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify(formData)
      });
      
      if (res.ok) {
        showToast("Ground truth saved successfully!");
        if (currentIndex < files.length - 1) {
          setCurrentIndex(prev => prev + 1);
        } else {
          showToast("All images completed!");
        }
      } else {
        const errData = await res.json().catch(() => ({}));
        showToast(getErrorMessage(null, errData, "Save failed"), true);
      }
    } catch (err) {
      showToast(getErrorMessage(err, undefined, "Save failed"), true);
    } finally {
      setSavingGT(false);
    }
  };

  return (
    <div className="h-screen w-screen flex flex-col bg-slate-950 font-sans overflow-hidden">
      {/* Header */}
      <header className="h-14 border-b border-slate-800 bg-slate-900/80 backdrop-blur-md flex items-center justify-between px-6 shrink-0 z-10">
        <div className="flex items-center gap-3">
          <div className="w-8 h-8 rounded-lg bg-gradient-to-tr from-teal-500 to-cyan-500 flex items-center justify-center font-bold text-white text-xs shadow-md">
            SP
          </div>
          <span className="text-sm font-bold text-slate-100">Product Scan Annotation</span>
        </div>
        <div className="text-xs">
          <a href="/scan-pfm" className="text-slate-400 hover:text-slate-100 transition">← Back to Scanner</a>
        </div>
      </header>

      {/* Main Body */}
      <div className="flex-1 flex overflow-hidden">
        <Sidebar
          files={files.map(f => f.filename)}
          currentIndex={currentIndex}
          onSelect={setCurrentIndex}
        />
        <ImageViewer src={currentIndex >= 0 ? files[currentIndex].url : null} />
        <Editor
          formData={formData}
          aiPredicted={aiPredicted}
          aiSource={aiSource}
          skuList={skuList}
          isScanning={isScanning}
          onScanWithAi={handleScanWithAi}
          onChange={handleChange}
          onSave={handleSave}
          savingGT={savingGT}
        />
      </div>

      {/* Toast */}
      <div className={`fixed bottom-6 left-1/2 -translate-x-1/2 px-5 py-3 rounded-lg flex items-center gap-2.5 shadow-2xl font-medium z-[100] transition duration-300 ${toast.show ? "translate-y-0 opacity-100 scale-100" : "translate-y-12 opacity-0 scale-95 pointer-events-none"} ${toast.isError ? "bg-rose-600 text-white" : "bg-emerald-600 text-white"}`}>
        <span>{toast.isError ? "❌" : "✅"}</span>
        <span className="text-sm">{toast.message}</span>
      </div>
    </div>
  );
}