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import parser
import record
import utils

import pegs
import sequtils
import sets
import streams
import strutils
import tables
import times

type
    FieldKind* {.pure.} = enum
        Integer
        Real
        String

    FieldDescriptor* = ref object
        kind*: FieldKind

    RecordSet* = ref object
        kind*: string
        doc*: string
        fields*: TableRef[string, FieldDescriptor]
        mandatory*: HashSet[string]
        allowed*: HashSet[string]
        prohibited*: HashSet[string]

    IntegrityError* = object of Exception

proc addFieldDescriptor(recordSet: RecordSet, name: string): FieldDescriptor =
    if name in recordSet.fields:
        return recordSet.fields[name]
    new(result)
    recordSet.fields[name] = result

proc newRecordSet*(record: Record): RecordSet =
    new(result)

    init(result.mandatory)
    init(result.prohibited)
    init(result.allowed)

    result.kind = record["%rec"]

    if "%doc" in record:
        result.doc = record["%doc"]

    result.fields = newTable[string, FieldDescriptor]()

    for value in values(record, "%mandatory"):
        for field in split(value):
            incl(result.mandatory, field)
            incl(result.allowed, field)
            if field in result.prohibited:
                raise newException(Exception, "a field cannot be mandatory and prohibited at the same time")

    for value in values(record, "%prohibit"):
        for field in split(value):
            if field in result.mandatory:
                raise newException(Exception, "a field cannot be mandatory and prohibited at the same time")
            if field in result.allowed:
                raise newException(Exception, "a field cannot be allowed and prohibited at the same time")
            incl(result.prohibited, field)

    for value in values(record, "%allowed"):
        for field in split(value):
            if field in result.prohibited:
                raise newException(Exception, "a field cannot be allowed and prohibited at the same time")
            incl(result.allowed, field)

    for value in values(record, "%type"):
        let parts = split(value)
        let label = parts[0]
        let kind = parts[1]
        let desc = addFieldDescriptor(result, label)
        case kind
        of "int": desc.kind = FieldKind.Integer
        of "real": desc.kind = FieldKind.Real
        else: desc.kind = FieldKind.String

let integerPeg = peg"^ '-'? ('0' / ([1-9] \d*)) $"

# This should correspond to the JSON Number spec at the moment
let realPeg = peg"^ '-'? ('0' / ([1-9] \d*)) ('.' \d+)? ([Ee] [+-]? \d+)? $"

proc validate*(record: Record, recordSet: RecordSet) =
    let labels = toSet(toSeq(labels(record)))

    for label in labels(record):
        if len(recordSet.allowed) > 0:
            if label notin recordSet.allowed:
                raise newException(IntegrityError, format("not allowed: $1", label))

        if label in recordSet.prohibited:
            raise newException(IntegrityError, format("prohibited: $1", label))

    for mandatoryLabel in recordSet.mandatory:
        if mandatoryLabel notin labels:
            raise newException(IntegrityError, format("mandatory: $1",
                mandatoryLabel))

    for label, value in record:
        if label notin recordSet.fields:
            continue

        let desc = recordSet.fields[label]

        case desc.kind
        of FieldKind.Integer:
            if not (value =~ integerPeg):
                raise newException(IntegrityError, format("integer expected"))
        of FieldKind.Real:
            if not (value =~ realPeg):
                raise newException(IntegrityError, format("real expected"))
        else: discard

iterator recordsInSet*(stream: Stream, kind: string): Record =
    var
        currentSet: RecordSet = nil

    for record in records(stream):
        if currentSet == nil:
            if "%rec" in record and record["%rec"] == kind:
                currentSet = newRecordSet(record)
            continue
        else:
            if "%rec" in record and record["%rec"] == kind:
                currentSet = newRecordSet(record)
                continue
            elif "%rec" in record:
                currentSet = nil
                continue

        validate(record, currentSet)

        yield record