Class UTIL.Ens.HL7Validator Extends EnsLib.HL7.Util.Validator
{

/// Adds option 'q' (quick) to perform a minimal, DocType-agnostic HL7 syntax check:
///  - message must start with MSH
///  - MSH-1 must exist, be exactly one char, and equal the message FS
///  - each segment name must match [A-Z[A-Z0-9]{2}
///  - each segment must support retrieving field 1 (implies FS present)
///  - all segments use the same FS as MSH
/// 
/// Behavior:
///  - If pValSpec contains only 'q' (optionally with 'x'/'-x'), only quick-check runs.
///  - If pValSpec contains 'q' alongside other flas, quick-check runs first,
///    then remaining flas run via superclass validator.
///  - Honors 'x' (stop on first error) if present (unless overriden with '-x').
ClassMethod Validate(pDoc As EnsLib.HL7.Message, pValSpec As %String = 1) As %Status
{
    #dim tSC As %Status = $$$OK
    #dim scQuick As %Status = $$$OK
    #dim scOther As %Status = $$$OK

    // Normalize stop-on-first flag the same way base code expects: 'x' means stop early (default)
    // '-x' means scan all. For our purposes, we treat presence of "-x" as scall all.
    #dim stopOnFirst As %Boolean = 1
    If (pValSpec["-x") Set StopOnFirst = 0
    Else  If (pValSpec["x") Set stopOnFirst = 1

    #dim doQuick As %Boolean = (pValSpec["q")!(pValSpec["Q")
    If doQuick {
        Set scQuick = ..QuickSyntax(pDoc, stopOnFirst)

        // If the spec is only 'q' (+optional x/-x), exit now
        #dim trimmed As %String = $TR(pValSpec,"qQxX-")
        if trimmed="" Quit scQuick

        // Otherwise, remove q/Q and continue with remaining specs
        Set pValSpec = $TR(pValSpec,"qQ")
        If $$$ISERR(scQuick) & stopOnFirst Quit scQuick
    }

    // If anything remains, run the base validator on the rest
    If pValSpec'="" {
        Set scOther = ##super(pDoc, pValSpec)
    }

    Quit $$$ADDSC(scOther, scQuick)
}

/// Minimal HL7 syntax checks
ClassMethod QuickSyntax(pDoc As EnsLib.HL7.Message, stopOnFirst As %Boolean = 1) As %Status
{
    #dim tSC As %Status = $$$OK
    #dim s As %Status = $$$OK
    #dim seg As EnsLib.HL7.Segment
    #dim i As %Integer
    #dim fs, fsSeg, mshi, name as %String

    // 1) Must have at least one segment and it must be MSH
    Set seg = pDoc.GetSegmentAt(1, .s)
    If $$$ISERR(s) {
        Set tSC = $$$ADDSC(tSC, $$$ERROR($$$EnsErrGeneral, "Basic HL7 syntax: message contains no segments (missing MSH)."))
        Quit tSC
    }
    If seg.Name'="MSH" {
        Set tSC = $$$ADDSC(tSC, $$$ERROR($$$EnsErrGeneral, "Basic HL7 syntax: message must begin with MSH segment. Found '"_seg.Name_"'."))
        Quit tSC
    }

    // 2) MSH-1 must exist, be exactly 1 char, and equal FS
    Set fs = $$$FSSEP(seg.Separators)
    Set msh1 = seg.GetValueAt(1, seg.Separators, .s)
    If $$$ISERR(s) {
        Set tSC = $$$ADDSC(tSC, $$$ERROR($$$EnsErrGeneral, "Basic HL7 syntax: unable to read MSH-1 (Field Separator)."))
        Quit tSC
    }
    If (msh1="")!(+$L(msh1)'=1) {
        Set tSC = $$$ADDSC(tSC, $$$ERROR($$$EnsErrGeneral, "Basic HL7 syntax: MSH-1 (Field Separator) must be exactly one character."))
        Quit tSC
    }
    If (msh1'=fs) {
        Set tSC = $$$ADDSC(tSC, $$$ERROR($$$EnsErrGeneral, "Basic HL7 syntax: MSH-1 ('"_msh1_"') must match the message field separator ('"_fs_"')."))
        Quit tSC
    }

    // 3) Every segment:
    //    - name matches [A-Z[A-Z0-9]{2}
    //    - field 1 can be accessed (imples FS present after name)
    For i=1:1:pDoc.SegCount {
        Set seg = pDoc.GetSegmentAt(i, .s)
        If $$$ISERR(s) {
            Set tSC = $$$ADDSC(tSC, $$$ERROR($$$EnsErrGeneral, "Basic HL7 syntax: unable to retrieve segment #"_i_"."))
            If stopOnFirst {
                Break
            }
        }

        Set name = seg.Name
        If '(name?1U1(1U,1N)1(1(1U,1N))) {
            Set tSC = $$$ADDSC(tSC, $$$ERROR($$$EnsErrGeneral, "Basic HL7 syntax: invalid segment name '"_name_"' at position "_i_"; expected pattern [A-Z][A-Z0-9]{2}."))
            If stopOnFirst {
                Break
            }
        }

        // Attempt to get field 1; if this fails, it's effectively missing FS after tag
        #dim dummy As %String
        Set dummy = seg.GetValueAt(1, seg.Separators, .s)
        If $$$ISERR(s) {
            Set tSC = $$$ADDSC(tSC, $$$ERROR($$$EnsErrGeneral, "Basic HL7 syntax: no field separator after segment '"_name_"' as position "_i_"."))
            If stopOnFirst {
                Break
            }
        }
    }
    Quit tSC
}

}