package gudusoft.gsqlparser.catalog.diagnostic;

import gudusoft.gsqlparser.catalog.runtime.CatalogQualifiedName;

import java.util.Objects;
import java.util.Optional;

/**
 * One catalog diagnostic record (validator, reader, provider, or runtime).
 *
 * <p>Plan §7.3. Diagnostics are immutable value objects; build via {@link #builder()}.</p>
 *
 * <p>{@code location} is intentionally left as a free-form {@link String} until P1E
 * introduces a structured {@code SourceLocation} type — the JSON / DDL readers landing
 * in P1B and Phase 2.A have no shared shape worth committing to yet.</p>
 */
public final class CatalogDiagnostic {

    private final CatalogDiagnosticSeverity severity;
    private final CatalogDiagnosticCode code;
    private final String message;
    private final CatalogQualifiedName name;
    private final String location;
    private final String repairHint;

    private CatalogDiagnostic(Builder b) {
        if (b.severity == null) {
            throw new IllegalArgumentException("CatalogDiagnostic.severity is required");
        }
        if (b.code == null) {
            throw new IllegalArgumentException("CatalogDiagnostic.code is required");
        }
        if (b.message == null || b.message.isEmpty()) {
            throw new IllegalArgumentException("CatalogDiagnostic.message is required");
        }
        this.severity = b.severity;
        this.code = b.code;
        this.message = b.message;
        this.name = b.name;
        this.location = b.location;
        this.repairHint = b.repairHint;
    }

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

    /**
     * Convenience: build a diagnostic from severity + code + message only. Most
     * validator emissions don't have a qualified name or location yet.
     */
    public static CatalogDiagnostic of(CatalogDiagnosticSeverity severity,
                                       CatalogDiagnosticCode code,
                                       String message) {
        return builder().severity(severity).code(code).message(message).build();
    }

    public CatalogDiagnosticSeverity severity() {
        return severity;
    }

    public CatalogDiagnosticCode code() {
        return code;
    }

    public String message() {
        return message;
    }

    public Optional<CatalogQualifiedName> name() {
        return Optional.ofNullable(name);
    }

    public Optional<String> location() {
        return Optional.ofNullable(location);
    }

    public Optional<String> repairHint() {
        return Optional.ofNullable(repairHint);
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (!(o instanceof CatalogDiagnostic)) return false;
        CatalogDiagnostic that = (CatalogDiagnostic) o;
        return severity == that.severity
            && code == that.code
            && message.equals(that.message)
            && Objects.equals(name, that.name)
            && Objects.equals(location, that.location)
            && Objects.equals(repairHint, that.repairHint);
    }

    @Override
    public int hashCode() {
        return Objects.hash(severity, code, message, name, location, repairHint);
    }

    @Override
    public String toString() {
        return "CatalogDiagnostic{" + severity + " " + code + ": " + message
            + (name != null ? " name=" + name : "")
            + (location != null ? " at=" + location : "")
            + (repairHint != null ? " hint=" + repairHint : "")
            + '}';
    }

    public static final class Builder {

        private CatalogDiagnosticSeverity severity;
        private CatalogDiagnosticCode code;
        private String message;
        private CatalogQualifiedName name;
        private String location;
        private String repairHint;

        private Builder() {
        }

        public Builder severity(CatalogDiagnosticSeverity v) {
            this.severity = v;
            return this;
        }

        public Builder code(CatalogDiagnosticCode v) {
            this.code = v;
            return this;
        }

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

        public Builder name(CatalogQualifiedName v) {
            this.name = v;
            return this;
        }

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

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

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