package gudusoft.gsqlparser.resolver2.enhancement;

import gudusoft.gsqlparser.nodes.TObjectName;
import gudusoft.gsqlparser.resolver2.model.ResolutionEvidence;
import gudusoft.gsqlparser.resolver2.model.SourceLocation;
import gudusoft.gsqlparser.resolver2.namespace.INamespace;

/**
 * Represents a column reference collected during resolution that needs
 * to be added to a namespace.
 *
 * This is used by the explicit namespace enhancement phase to track
 * which columns should be added to which namespaces between resolution passes.
 */
public class CollectedColumnRef {

    /** The column name to add */
    private final String columnName;

    /** The target namespace to add the column to */
    private final INamespace targetNamespace;

    /** The AST node that referenced this column */
    private final TObjectName sourceReference;

    /** The pass number when this was collected */
    private final int passNumber;

    /**
     * Confidence score for this column (0.0 to 1.0)
     * @deprecated Use {@link #evidenceDetail} instead
     */
    private final double confidence;

    /**
     * Evidence/reason for adding this column
     * @deprecated Use {@link #evidenceDetail} instead
     */
    private final String evidence;

    /** Structured evidence detail for this column reference */
    private final ResolutionEvidence evidenceDetail;

    /** Source location description (for debugging) */
    private final String sourceLocation;

    /**
     * Legacy constructor for backward compatibility.
     *
     * @deprecated Use {@link #CollectedColumnRef(String, INamespace, TObjectName, int, ResolutionEvidence)} instead
     */
    public CollectedColumnRef(String columnName,
                              INamespace targetNamespace,
                              TObjectName sourceReference,
                              int passNumber,
                              double confidence,
                              String evidence) {
        this.columnName = columnName;
        this.targetNamespace = targetNamespace;
        this.sourceReference = sourceReference;
        this.passNumber = passNumber;
        this.confidence = confidence;
        this.evidence = evidence;
        this.sourceLocation = formatLocation(sourceReference);
        // Create evidenceDetail from legacy parameters
        this.evidenceDetail = ResolutionEvidence.fromLegacyEvidence(evidence, confidence, sourceReference);
    }

    /**
     * Constructor with ResolutionEvidence (preferred for new code).
     *
     * @param columnName The column name to add
     * @param targetNamespace The target namespace
     * @param sourceReference The AST node that referenced this column
     * @param passNumber The resolution pass number
     * @param evidenceDetail Structured evidence detail
     */
    public CollectedColumnRef(String columnName,
                              INamespace targetNamespace,
                              TObjectName sourceReference,
                              int passNumber,
                              ResolutionEvidence evidenceDetail) {
        this.columnName = columnName;
        this.targetNamespace = targetNamespace;
        this.sourceReference = sourceReference;
        this.passNumber = passNumber;
        this.evidenceDetail = evidenceDetail;
        // Derive legacy fields from evidenceDetail
        this.confidence = evidenceDetail != null ? evidenceDetail.getWeight() : 0.5;
        this.evidence = evidenceDetail != null ? evidenceDetail.toLegacyEvidence() : null;
        this.sourceLocation = formatLocation(sourceReference);
    }

    private String formatLocation(TObjectName objName) {
        if (objName == null) return "unknown";
        return String.format("line %d, col %d",
            objName.getLineNo(), objName.getColumnNo());
    }

    public String getColumnName() {
        return columnName;
    }

    public INamespace getTargetNamespace() {
        return targetNamespace;
    }

    public TObjectName getSourceReference() {
        return sourceReference;
    }

    public int getPassNumber() {
        return passNumber;
    }

    public double getConfidence() {
        return confidence;
    }

    public String getEvidence() {
        return evidence;
    }

    /**
     * Get the structured evidence detail for this column reference.
     *
     * @return The structured evidence detail
     */
    public ResolutionEvidence getEvidenceDetail() {
        return evidenceDetail;
    }

    public String getSourceLocation() {
        return sourceLocation;
    }

    @Override
    public String toString() {
        return String.format("CollectedColumnRef{column='%s', namespace='%s', pass=%d, conf=%.2f, evidence='%s', loc=%s}",
            columnName,
            targetNamespace != null ? targetNamespace.getDisplayName() : "null",
            passNumber,
            confidence,
            evidence,
            sourceLocation);
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        CollectedColumnRef that = (CollectedColumnRef) o;

        if (!columnName.equalsIgnoreCase(that.columnName)) return false;
        return targetNamespace == that.targetNamespace; // Identity comparison for namespace
    }

    @Override
    public int hashCode() {
        int result = columnName.toLowerCase().hashCode();
        result = 31 * result + System.identityHashCode(targetNamespace);
        return result;
    }
}