import { useEffect, useRef, useState } from 'react';
import { rateLimitCooldownUntil, uploadScanCapture } from './scan-capture-upload.js';
import {
  buildScannedCardPayload,
  getScanAuthHeaders,
  identifyTrackedCardCapture,
  resolveDisambiguationRefineAction,
  resolveIdentifyOutcome,
  submitScanForReview,
  tryLayer0VisualIdentify,
  tryLayer1TextIdentify,
  VISION_RATE_LIMIT_MS,
  fetchVisionIdentify,
} from './scanner-card-identify.js';

/** Debug mode flag — set via localStorage or window global */
function isDebugMode() {
  if (typeof window === 'undefined') return false;
  return (
    window.__SCANNER_DEBUG === true ||
    localStorage.getItem('SCANNER_DEBUG') === 'true'
  );
}

function debugLog(emoji, message, data) {
  if (!isDebugMode()) return;
  const timestamp = new Date().toISOString().split('T')[1].slice(0, 12);
  if (data !== undefined) {
    console.log(`[Scanner Debug ${timestamp}] ${emoji} ${message}`, data);
  } else {
    console.log(`[Scanner Debug ${timestamp}] ${emoji} ${message}`);
  }
}

/**
 * Card identification, disambiguation, and review-submission flow for the scanner.
 * Camera refs and verify-card wiring are supplied by the parent + useCameraScanner.
 */
function readFileToImageData(file) {
  return new Promise((resolve, reject) => {
    const img = new Image();
    const url = URL.createObjectURL(file);

    img.onload = () => {
      const canvas = document.createElement('canvas');
      canvas.width = img.naturalWidth;
      canvas.height = img.naturalHeight;
      const ctx = canvas.getContext('2d', { willReadFrequently: true });
      ctx.drawImage(img, 0, 0);
      const imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
      URL.revokeObjectURL(url);
      resolve(imageData);
    };

    img.onerror = () => {
      URL.revokeObjectURL(url);
      reject(new Error('Failed to load image from gallery'));
    };

    img.src = url;
  });
}

export function useScannerIdentification({
  onCardScanned,
  onError,
  onTrackerComplete,
  onTrackerReset,
  videoRef,
  canvasRef,
  onVerifyCardRef,
  verificationPausedRef,
}) {
  const [disambiguation, setDisambiguation] = useState(null);
  const [isIdentifying, setIsIdentifying] = useState(false);
  const [scanNotice, setScanNotice] = useState(null);
  const [submittingReview, setSubmittingReview] = useState(false);

  const visionCooldownUntilRef = useRef(0);
  const activeVerificationRef = useRef(0);
  const lastErrorAtRef = useRef(0);
  const disambiguationRefineRef = useRef(null);

  useEffect(() => {
    if (verificationPausedRef) {
      verificationPausedRef.current = Boolean(disambiguation);
    }
  }, [disambiguation, verificationPausedRef]);

  const finishTrackedCard = (cardTracker) => {
    if (!cardTracker?.id) return;
    onTrackerComplete?.(cardTracker.id);
  };

  const emitScannedCard = async (cardTracker, imageData, finalCard, ocrMeta = {}) => {
    cardTracker.status = 'scanned';

    const originalTitle = document.title;
    document.title = `📸 ${finalCard.name} - Card Scanner`;
    setTimeout(() => {
      document.title = originalTitle;
    }, 3000);

    // Show result immediately — don't block on upload
    onCardScanned(buildScannedCardPayload(finalCard, { imageData, scanImageUrl: null, ocrMeta }));
    finishTrackedCard(cardTracker);

    // Upload capture in background (fire-and-forget)
    if (imageData) {
      uploadScanCapture(imageData)
        .then((url) => {
          if (debugLog && isDebugMode) {
            debugLog('📤', `Background upload complete: ${url ? 'success' : '429'}`);
          }
        })
        .catch((uploadError) => {
          console.warn('Scan image upload failed:', uploadError);
        });
    }
  };

  const showScanNotice = (message) => {
    setScanNotice(message);
    setTimeout(() => setScanNotice(null), 8000);
  };

  const handleReviewSubmitted = (cardTracker, message) => {
    if (cardTracker) {
      cardTracker.status = 'confirmed';
      finishTrackedCard(cardTracker);
    }
    setDisambiguation(null);
    disambiguationRefineRef.current = null;
    showScanNotice(message);
  };

  const handleDisambiguationPick = async (candidate) => {
    if (!disambiguation) return;
    const { cardTracker, imageData, ocrMeta } = disambiguation;
    await emitScannedCard(cardTracker, imageData, candidate, ocrMeta);
    setDisambiguation(null);
    disambiguationRefineRef.current = null;
  };

  const cancelDisambiguation = () => {
    const { cardTracker } = disambiguation ?? {};
    if (cardTracker) {
      onTrackerReset?.(cardTracker.id);
    }
    setDisambiguation(null);
    disambiguationRefineRef.current = null;
  };

  const reportScannerError = (message) => {
    if (disambiguation) return;
    const now = Date.now();
    if (now - lastErrorAtRef.current < 4000) return;
    lastErrorAtRef.current = now;
    onError?.(message);
  };

  const applyIdentifyOutcome = async (cardTracker, imageData, outcome) => {
    switch (outcome.type) {
      case 'emit':
        cardTracker.status = outcome.cardStatus;
        await emitScannedCard(cardTracker, imageData, outcome.card, outcome.ocrMeta);
        break;
      case 'disambiguation':
        cardTracker.status = 'verifying';
        setDisambiguation({
          cardTracker,
          imageData,
          candidates: outcome.matches,
          ocrMeta: outcome.ocrMeta,
          message: outcome.message,
          fromLayer1: Boolean(outcome.fromLayer1),
          fromLayer0: Boolean(outcome.fromLayer0),
        });
        break;
      case 'notice':
        cardTracker.status = outcome.cardStatus;
        showScanNotice(outcome.message);
        finishTrackedCard(cardTracker);
        break;
      case 'error':
        cardTracker.status = outcome.cardStatus;
        cardTracker.negativeAt = Date.now();
        reportScannerError(outcome.message);
        break;
      default:
        break;
    }
  };

  const handleNotInCatalog = async () => {
    if (!disambiguation || submittingReview) return;
    setSubmittingReview(true);

    const { cardTracker, imageData, candidates, ocrMeta } = disambiguation;
    const guessedName =
      ocrMeta?.cardName ||
      ocrMeta?.query ||
      candidates?.[0]?.name ||
      null;

    try {
      const result = await submitScanForReview({
        imageData,
        name: guessedName,
        candidateCardIds: (candidates || []).map((c) => c.id),
        authHeaders: getScanAuthHeaders(),
      });

      if (result.rateLimited) {
        visionCooldownUntilRef.current = rateLimitCooldownUntil(VISION_RATE_LIMIT_MS);
        reportScannerError('Too many scan attempts. Please wait a moment and try again.');
        return;
      }

      handleReviewSubmitted(cardTracker, result.message);
    } catch (error) {
      reportScannerError(error.message || 'Failed to submit scan for review');
    } finally {
      setSubmittingReview(false);
    }
  };

  useEffect(() => {
    if (!disambiguation?.imageData) return;
    if (disambiguation.fromLayer1 || disambiguation.fromLayer0) return;
    if (Date.now() < visionCooldownUntilRef.current) return;

    const refineKey = disambiguation.cardTracker?.id ?? 'modal';
    if (disambiguationRefineRef.current === refineKey) return;
    disambiguationRefineRef.current = refineKey;

    let cancelled = false;

    (async () => {
      try {
        const authHeaders = getScanAuthHeaders();
        const vision = await fetchVisionIdentify(disambiguation.imageData, authHeaders);
        if (cancelled) return;

        if (vision.rateLimited) {
          visionCooldownUntilRef.current = Date.now() + VISION_RATE_LIMIT_MS;
          return;
        }

        const action = resolveDisambiguationRefineAction(vision.result, {
          candidates: disambiguation.candidates,
        });
        if (cancelled) return;

        switch (action.type) {
          case 'review_submitted':
            handleReviewSubmitted(disambiguation.cardTracker, action.message);
            break;
          case 'emit':
            await emitScannedCard(
              disambiguation.cardTracker,
              disambiguation.imageData,
              action.card,
              action.ocrMeta
            );
            setDisambiguation(null);
            disambiguationRefineRef.current = null;
            break;
          case 'pick':
            await handleDisambiguationPick(action.candidate);
            break;
          case 'catalog_gap':
            try {
              const submitResult = await submitScanForReview({
                imageData: disambiguation.imageData,
                ...action.submitPayload,
                authHeaders,
              });
              if (submitResult.ok) {
                handleReviewSubmitted(disambiguation.cardTracker, submitResult.message);
              }
            } catch {
              setDisambiguation((current) =>
                current
                  ? {
                      ...current,
                      visionHint: action.setHint,
                      message: action.hintMessage,
                    }
                  : current
              );
            }
            break;
          case 'narrow':
            setDisambiguation((current) =>
              current
                ? {
                    ...current,
                    candidates: action.filtered,
                    message: action.message,
                    visionHint: action.visionHint,
                  }
                : current
            );
            break;
          default:
            break;
        }
      } catch (error) {
        console.warn('Disambiguation vision refine failed:', error);
      }
    })();

    return () => {
      cancelled = true;
    };
    // eslint-disable-next-line react-hooks/exhaustive-deps -- refine runs per disambiguation session, not per handler identity
  }, [disambiguation?.cardTracker?.id, disambiguation?.imageData]);

  const verifyCardShape = async (cardTracker) => {
    if (!videoRef.current || !canvasRef.current || cardTracker.status !== 'detecting') return;
    if (disambiguation) return;
    if (activeVerificationRef.current >= 1) return;

    const verifyStartMs = Date.now();
    debugLog('🎯', `Shutter pressed (tracker-${cardTracker.id}, attempt ${cardTracker.scanAttempts + 1})`);

    activeVerificationRef.current += 1;
    cardTracker.status = 'verifying';
    setIsIdentifying(true);

    try {
      cardTracker.scanAttempts++;

      const identification = await identifyTrackedCardCapture({
        video: videoRef.current,
        canvas: canvasRef.current,
        cardTracker,
        authHeaders: getScanAuthHeaders(),
        visionCooldownUntilMs: visionCooldownUntilRef.current,
      });

      if (identification.retry) {
        debugLog('⏸️', `Verification skipped (cooldown active) → ${Date.now() - verifyStartMs}ms`);
        cardTracker.status = 'detecting';
        return;
      }

      if (identification.rateLimited) {
        visionCooldownUntilRef.current = Date.now() + VISION_RATE_LIMIT_MS;
        const cooldownUntil = new Date(visionCooldownUntilRef.current).toISOString().split('T')[1].slice(0, 8);
        debugLog('🚫', `Rate limit hit (15/min) — cooldown until ${cooldownUntil} → ${Date.now() - verifyStartMs}ms`);
        reportScannerError('Too many scan attempts. Please wait a moment and try again.');
        cardTracker.status = 'negative';
        cardTracker.negativeAt = Date.now();
        return;
      }

      if (identification.handled && identification.outcome) {
        cardTracker.status = 'confirmed';
        debugLog('✅', `Card verified successfully → ${Date.now() - verifyStartMs}ms total`, { outcome: identification.outcome.type });
        await applyIdentifyOutcome(cardTracker, identification.imageData, identification.outcome);
      } else {
        debugLog('❌', `Verification failed (no outcome) → ${Date.now() - verifyStartMs}ms`);
        cardTracker.status = 'negative';
        cardTracker.negativeAt = Date.now();
      }
    } catch (error) {
      console.error(`Error verifying card ${cardTracker.id}:`, error);
      debugLog('💥', `Verification exception → ${Date.now() - verifyStartMs}ms`, { error: error.message });
      cardTracker.status = 'negative';
      cardTracker.negativeAt = Date.now();
      reportScannerError(error.message || 'Scan failed');
    } finally {
      activeVerificationRef.current = Math.max(0, activeVerificationRef.current - 1);
      setIsIdentifying(activeVerificationRef.current > 0);
    }
  };

  useEffect(() => {
    if (onVerifyCardRef) {
      onVerifyCardRef.current = verifyCardShape;
    }
  });

  const identifyFromGalleryFile = async (file) => {
    if (!file || verificationPausedRef?.current) return;

    setIsIdentifying(true);
    try {
      const imageData = await readFileToImageData(file);
      const authHeaders = getScanAuthHeaders();
      const syntheticTracker = { id: `gallery-${Date.now()}`, status: 'verifying' };

      const l0 = await tryLayer0VisualIdentify(imageData, authHeaders);
      if (l0.handled && l0.outcome) {
        await applyIdentifyOutcome(syntheticTracker, imageData, l0.outcome);
        return;
      }

      const result = await tryLayer1TextIdentify(imageData, authHeaders);

      if (result.handled && result.outcome) {
        await applyIdentifyOutcome(syntheticTracker, imageData, result.outcome);
        return;
      }

      if (Date.now() < visionCooldownUntilRef.current) {
        reportScannerError('Too many scan attempts. Please wait a moment and try again.');
        return;
      }

      const vision = await fetchVisionIdentify(imageData, authHeaders);
      if (vision.rateLimited) {
        visionCooldownUntilRef.current = Date.now() + VISION_RATE_LIMIT_MS;
        reportScannerError('Too many scan attempts. Please wait a moment and try again.');
        return;
      }

      if (vision.ok && vision.result) {
        await applyIdentifyOutcome(
          syntheticTracker,
          imageData,
          resolveIdentifyOutcome(vision.result)
        );
        return;
      }

      reportScannerError('Could not identify card from gallery image');
    } catch (error) {
      reportScannerError(error.message || 'Gallery identify failed');
    } finally {
      setIsIdentifying(activeVerificationRef.current > 0);
    }
  };

  return {
    disambiguation,
    isIdentifying,
    scanNotice,
    submittingReview,
    handleDisambiguationPick,
    handleNotInCatalog,
    cancelDisambiguation,
    identifyFromGalleryFile,
  };
}