package gudusoft.gsqlparser.lineage2.contract;

/**
 * Contract {@code Endpoint} (lineage2-contract.md §4.1).
 *
 * <p>Physical endpoints are always emitted fully expanded
 * ({@code database}/{@code schema}/{@code object} all non-empty, D-15);
 * endpoints that cannot be fully qualified get a non-RESOLVED
 * {@link ResolutionStatus} and the surface name observed.
 *
 * <p>Location emission is tri-state, mirroring the gold-fixture
 * conventions: a non-null {@code sourceLocation} is emitted as-is; a null
 * location with a {@link LocationNullReason} is emitted as
 * {@code "sourceLocation": null} plus the reason; when both are absent the
 * keys are omitted entirely.
 *
 * <p>Internal API: not part of the public gsqlparser surface.
 */
public final class Endpoint {

    private final String database;
    private final String schema;
    private final String object;
    private final String column;
    private final ObjectKind objectKind;
    private final ResolutionStatus resolutionStatus;
    private final ScopeKind scopeKind;
    private final Integer definedAtStatementIndex;
    private final SourceLocation sourceLocation;
    private final LocationNullReason locationNullReason;

    private Endpoint(Builder b) {
        if (b.object == null) {
            throw new IllegalArgumentException("object must not be null");
        }
        if (b.objectKind == null || b.resolutionStatus == null) {
            throw new IllegalArgumentException(
                    "objectKind and resolutionStatus must not be null");
        }
        this.database = b.database;
        this.schema = b.schema;
        this.object = b.object;
        this.column = b.column;
        this.objectKind = b.objectKind;
        this.resolutionStatus = b.resolutionStatus;
        this.scopeKind = b.scopeKind;
        this.definedAtStatementIndex = b.definedAtStatementIndex;
        this.sourceLocation = b.sourceLocation;
        this.locationNullReason = b.locationNullReason;
    }

    public static Builder builder(String object) {
        return new Builder(object);
    }

    public String getDatabase() {
        return database;
    }

    public String getSchema() {
        return schema;
    }

    public String getObject() {
        return object;
    }

    public String getColumn() {
        return column;
    }

    public ObjectKind getObjectKind() {
        return objectKind;
    }

    public ResolutionStatus getResolutionStatus() {
        return resolutionStatus;
    }

    /** Nullable — only set for temp/variable/cursor endpoints (D-11). */
    public ScopeKind getScopeKind() {
        return scopeKind;
    }

    /** Nullable — only set for temp/variable/cursor endpoints (D-11). */
    public Integer getDefinedAtStatementIndex() {
        return definedAtStatementIndex;
    }

    /** Nullable. */
    public SourceLocation getSourceLocation() {
        return sourceLocation;
    }

    /** Nullable — set only when {@code sourceLocation} is null. */
    public LocationNullReason getLocationNullReason() {
        return locationNullReason;
    }

    public static final class Builder {
        private String database;
        private String schema;
        private final String object;
        private String column;
        private ObjectKind objectKind = ObjectKind.UNKNOWN;
        private ResolutionStatus resolutionStatus = ResolutionStatus.RESOLVED;
        private ScopeKind scopeKind;
        private Integer definedAtStatementIndex;
        private SourceLocation sourceLocation;
        private LocationNullReason locationNullReason;

        private Builder(String object) {
            this.object = object;
        }

        public Builder database(String database) {
            this.database = database;
            return this;
        }

        public Builder schema(String schema) {
            this.schema = schema;
            return this;
        }

        public Builder column(String column) {
            this.column = column;
            return this;
        }

        public Builder objectKind(ObjectKind objectKind) {
            this.objectKind = objectKind;
            return this;
        }

        public Builder resolutionStatus(ResolutionStatus resolutionStatus) {
            this.resolutionStatus = resolutionStatus;
            return this;
        }

        public Builder scopeKind(ScopeKind scopeKind) {
            this.scopeKind = scopeKind;
            return this;
        }

        public Builder definedAtStatementIndex(Integer definedAtStatementIndex) {
            this.definedAtStatementIndex = definedAtStatementIndex;
            return this;
        }

        public Builder sourceLocation(SourceLocation sourceLocation) {
            this.sourceLocation = sourceLocation;
            return this;
        }

        public Builder locationNullReason(LocationNullReason reason) {
            this.locationNullReason = reason;
            return this;
        }

        public Endpoint build() {
            return new Endpoint(this);
        }
    }
}