import Utils from "./utils";
import Lexer from "./lexer";
import PrimitiveLiteral from "./primitiveLiteral";
import NameOrIdentifier from "./nameOrIdentifier";
import Expressions from "./expressions";

export namespace Query {
    export function queryOptions(value: Utils.SourceArray, index: number, metadataContext?: any): Lexer.Token {
        let token = Query.queryOption(value, index, metadataContext);
        if (!token) return;
        let start = index;
        index = token.next;

        let options = [];
        while (token) {
            options.push(token);
            // &
            if (value[index] !== 0x26) break;
            index++;

            token = Query.queryOption(value, index, metadataContext);
            if (!token) return;
            index = token.next;
        }

        return Lexer.tokenize(value, start, index, { options }, Lexer.TokenType.QueryOptions);
    }

    export function queryOption(value: Utils.SourceArray, index: number, metadataContext?: any): Lexer.Token {
        return Query.systemQueryOption(value, index, metadataContext) ||
            Query.aliasAndValue(value, index) ||
            Query.customQueryOption(value, index);
    }

    export function systemQueryOption(value: Utils.SourceArray, index: number, metadataContext?: any): Lexer.Token {
        return Query.expand(value, index, metadataContext) ||
            Query.filter(value, index) ||
            Query.format(value, index) ||
            Query.id(value, index) ||
            Query.inlinecount(value, index) ||
            Query.orderby(value, index) ||
            Query.search(value, index) ||
            Query.select(value, index) ||
            Query.skip(value, index) ||
            Query.skiptoken(value, index) ||
            Query.top(value, index);
    }

    export function customQueryOption(value: Utils.SourceArray, index: number): Lexer.Token {
      let key = NameOrIdentifier.odataIdentifier(value, index);
      if (!key) return;
      let start = index;
      index = key.next;

      let eq = Lexer.EQ(value, index);
      if (!eq) return;
      index = eq;

      while (value[index] !== 0x26 && index < value.length) index++;
      if (index === eq) return;

      return Lexer.tokenize(value, start, index, { key: key.raw, value: Utils.stringify(value, eq, index) }, Lexer.TokenType.CustomQueryOption);
    }

    export function id(value: Utils.SourceArray, index: number): Lexer.Token {
        let start = index;
        if (Utils.equals(value, index, "%24id")) {
            index += 5;
        }else
        if (Utils.equals(value, index, "$id")) {
            index += 3;
        }else return;

        let eq = Lexer.EQ(value, index);
        if (!eq) return;
        index = eq;

        while (value[index] !== 0x26 && index < value.length) index++;
        if (index === eq) return;

        return Lexer.tokenize(value, start, index, Utils.stringify(value, eq, index), Lexer.TokenType.Id);
    }

    export function expand(value: Utils.SourceArray, index: number, metadataContext?: any): Lexer.Token {
        let start = index;
        if (Utils.equals(value, index, "%24expand")) {
            index += 9;
        }else
        if (Utils.equals(value, index, "$expand")) {
            index += 7;
        }else return;

        let eq = Lexer.EQ(value, index);
        if (!eq) return;
        index = eq;

        let items = [];
        let token = Query.expandItem(value, index, metadataContext);
        if (!token) return;
        index = token.next;

        while (token) {
            items.push(token);

            let comma = Lexer.COMMA(value, index);
            if (comma) {
                index = comma;
                token = Query.expandItem(value, index, metadataContext);
                if (!token) return;
                index = token.next;
            }else break;
        }

        return Lexer.tokenize(value, start, index, { items }, Lexer.TokenType.Expand);
    }

    export function expandItem(value: Utils.SourceArray, index: number, metadataContext?: any): Lexer.Token {
        let start = index;
        let star = Lexer.STAR(value, index);
        if (star) {
            index = star;
            let ref = Expressions.refExpr(value, index);
            if (ref) {
                index = ref.next;
                return Lexer.tokenize(value, start, index, { path: "*", ref }, Lexer.TokenType.ExpandItem);
            } else {
                let open = Lexer.OPEN(value, index);
                if (open) {
                    index = open;
                    let token = Query.levels(value, index);
                    if (!token) return;
                    index = token.next;

                    let close = Lexer.CLOSE(value, index);
                    if (!close) return;
                    index = close;

                    return Lexer.tokenize(value, start, index, { path: "*", levels: token }, Lexer.TokenType.ExpandItem);
                }
            }
        }

        let path = Query.expandPath(value, index, metadataContext);
        if (!path) return;
        index = path.next;

        let tokenValue: any = { path };

        let ref = Expressions.refExpr(value, index);
        if (ref) {
            index = ref.next;
            tokenValue.ref = ref;

            let open = Lexer.OPEN(value, index);
            if (open) {
                index = open;

                let option = Query.expandRefOption(value, index);
                if (!option) return;

                let refOptions = [];
                while (option) {
                    refOptions.push(option);
                    index = option.next;

                    let semi = Lexer.SEMI(value, index);
                    if (semi) {
                        index = semi;

                        option = Query.expandRefOption(value, index);
                        if (!option) return;
                    }else break;
                }

                let close = Lexer.CLOSE(value, index);
                if (!close) return;
                index = close;

                tokenValue.options = refOptions;
            }
        } else {
            let count = Expressions.countExpr(value, index);
            if (count) {
                index = count.next;
                tokenValue.count = count;

                let open = Lexer.OPEN(value, index);
                if (open) {
                    index = open;

                    let option = Query.expandCountOption(value, index);
                    if (!option) return;

                    let countOptions = [];
                    while (option) {
                        countOptions.push(option);
                        index = option.next;

                        let semi = Lexer.SEMI(value, index);
                        if (semi) {
                            index = semi;

                            option = Query.expandCountOption(value, index);
                            if (!option) return;
                        }else break;
                    }

                    let close = Lexer.CLOSE(value, index);
                    if (!close) return;
                    index = close;
                    tokenValue.options = countOptions;
                }
            } else {
                let open = Lexer.OPEN(value, index);
                if (open) {
                    index = open;

                    let option = Query.expandOption(value, index);
                    if (!option) return;

                    let options = [];
                    while (option) {
                        options.push(option);
                        index = option.next;

                        let semi = Lexer.SEMI(value, index);
                        if (semi) {
                            index = semi;

                            option = Query.expandOption(value, index);
                            if (!option) return;
                        }else break;
                    }

                    let close = Lexer.CLOSE(value, index);
                    if (!close) return;
                    index = close;
                    tokenValue.options = options;
                }
            }
        }

        return Lexer.tokenize(value, start, index, tokenValue, Lexer.TokenType.ExpandItem);
    }

    export function expandCountOption(value: Utils.SourceArray, index: number): Lexer.Token {
        return Query.filter(value, index) ||
            Query.search(value, index);
    }

    export function expandRefOption(value: Utils.SourceArray, index: number): Lexer.Token {
        return Query.expandCountOption(value, index) ||
            Query.orderby(value, index) ||
            Query.skip(value, index) ||
            Query.top(value, index) ||
            Query.inlinecount(value, index);
    }

    export function expandOption(value: Utils.SourceArray, index: number): Lexer.Token {
        return Query.expandRefOption(value, index) ||
            Query.select(value, index) ||
            Query.expand(value, index) ||
            Query.levels(value, index);
    }

    export function expandPath(value: Utils.SourceArray, index: number, metadataContext?: any): Lexer.Token {
        let start = index;
        let path = [];

        let token = NameOrIdentifier.qualifiedEntityTypeName(value, index, metadataContext) ||
            NameOrIdentifier.qualifiedComplexTypeName(value, index, metadataContext);

        if (token) {
            index = token.next;
            path.push(token);
            if (value[index] !== 0x2f) return;
            index++;
            metadataContext = token.value.metadata;
            delete token.value.metadata;
        }

        let complex = NameOrIdentifier.complexProperty(value, index, metadataContext) ||
            NameOrIdentifier.complexColProperty(value, index, metadataContext);
        while (complex) {
            if (value[complex.next] === 0x2f) {
                index = complex.next + 1;
                path.push(complex);

                let complexTypeName = NameOrIdentifier.qualifiedComplexTypeName(value, index, metadataContext);
                if (complexTypeName) {
                    if (value[complexTypeName.next] === 0x2f) {
                        index = complexTypeName.next + 1;
                        path.push(complexTypeName);
                    }
                    metadataContext = complexTypeName.value.metadata;
                    delete complexTypeName.value.metadata;
                }

                complex = NameOrIdentifier.complexProperty(value, index, metadataContext) ||
                    NameOrIdentifier.complexColProperty(value, index, metadataContext);
            }else break;
        }

        let nav = NameOrIdentifier.navigationProperty(value, index, metadataContext);

        if (!nav) return;
        index = nav.next;
        path.push(nav);
        metadataContext = nav.metadata;
        delete nav.metadata;

        if (value[index] === 0x2f) {
            let typeName = NameOrIdentifier.qualifiedEntityTypeName(value, index + 1, metadataContext);
            if (typeName) {
                index = typeName.next;
                path.push(typeName);
                metadataContext = typeName.value.metadata;
                delete typeName.value.metadata;
            }
        }

        return Lexer.tokenize(value, start, index, path, Lexer.TokenType.ExpandPath);
    }

    export function search(value: Utils.SourceArray, index: number): Lexer.Token {
        let start = index;
        if (Utils.equals(value, index, "%24search")) {
            index += 9;
        }else
        if (Utils.equals(value, index, "$search")) {
            index += 7;
        }else return;

        let eq = Lexer.EQ(value, index);
        if (!eq) return;
        index = eq;

        let expr = Query.searchExpr(value, index);
        if (!expr) return;
        index = expr.next;

        return Lexer.tokenize(value, start, index, expr, Lexer.TokenType.Search);
    }

    export function searchExpr(value: Utils.SourceArray, index: number): Lexer.Token {
        let token = Query.searchParenExpr(value, index) ||
            Query.searchTerm(value, index);

        if (!token) return;
        let start = index;
        index = token.next;

        let expr = Query.searchAndExpr(value, index) ||
            Query.searchOrExpr(value, index);

        if (expr) {
            const left = Lexer.clone(token);
            token.next = expr.value.next;
            token.value = {
                left: left,
                right: expr.value
            };
            token.type = expr.type;
            token.raw = Utils.stringify(value, token.position, token.next);

            if (token.type === Lexer.TokenType.SearchAndExpression && token.value.right.type === Lexer.TokenType.SearchOrExpression) {
                token.value.left = Lexer.tokenize(value, token.value.left.position, token.value.right.value.left.next, {
                    left: token.value.left,
                    right: token.value.right.value.left
                }, token.type);
                token.type = token.value.right.type;
                token.value.right = token.value.right.value.right;
            }
        }

        return token;
    }

    export function searchTerm(value: Utils.SourceArray, index: number): Lexer.Token {
        return Query.searchNotExpr(value, index) ||
            Query.searchPhrase(value, index) ||
            Query.searchWord(value, index);
    }

    export function searchNotExpr(value: Utils.SourceArray, index: number): Lexer.Token {
        let rws = Lexer.RWS(value, index);
        if (!Utils.equals(value, rws, "NOT")) return;
        let start = index;
        index = rws + 3;
        rws = Lexer.RWS(value, index);
        if (rws === index) return;
        index = rws;
        let expr = Query.searchPhrase(value, index) ||
            Query.searchWord(value, index);
        if (!expr) return;
        index = expr.next;

        return Lexer.tokenize(value, start, index, expr, Lexer.TokenType.SearchNotExpression);
    }

    export function searchOrExpr(value: Utils.SourceArray, index: number): Lexer.Token {
        let rws = Lexer.RWS(value, index);
        if (rws === index || !Utils.equals(value, rws, "OR")) return;
        let start = index;
        index = rws + 2;
        rws = Lexer.RWS(value, index);
        if (rws === index) return;
        index = rws;
        let token = Query.searchExpr(value, index);
        if (!token) return;
        index = token.next;

        return Lexer.tokenize(value, start, index, token, Lexer.TokenType.SearchOrExpression);
    }

    export function searchAndExpr(value: Utils.SourceArray, index: number): Lexer.Token {
        let rws = Lexer.RWS(value, index);
        if (rws === index || !Utils.equals(value, rws, "AND")) return;
        let start = index;
        index = rws + 3;
        rws = Lexer.RWS(value, index);
        if (rws === index) return;
        index = rws;
        let token = Query.searchExpr(value, index);
        if (!token) return;
        index = token.next;

        return Lexer.tokenize(value, start, index, token, Lexer.TokenType.SearchAndExpression);
    }

    export function searchPhrase(value: Utils.SourceArray, index: number): Lexer.Token {
        let mark = Lexer.quotationMark(value, index);
        if (mark === index) return;
        let start = index;
        index = mark;

        let valueStart = index;
        let ch = Lexer.qcharNoAMPDQUOTE(value, index);
        while (ch > index && !Lexer.OPEN(value, index) && !Lexer.CLOSE(value, index)) {
            index = ch;
            ch = Lexer.qcharNoAMPDQUOTE(value, index);
        }
        let valueEnd = index;

        mark = Lexer.quotationMark(value, index);
        if (!mark) return;
        index = mark;

        return Lexer.tokenize(value, start, index, Utils.stringify(value, valueStart, valueEnd), Lexer.TokenType.SearchPhrase);
    }

    export function searchWord(value: Utils.SourceArray, index: number): Lexer.Token {
        let next = Utils.required(value, index, Lexer.ALPHA, 1);
        if (!next) return;
        let start = index;
        index = next;

        let token = Lexer.tokenize(value, start, index, null, Lexer.TokenType.SearchWord);
        token.value = token.raw;
        return token;
    }

    export function searchParenExpr(value: Utils.SourceArray, index: number): Lexer.Token {
        let open = Lexer.OPEN(value, index);
        if (!open) return;
        let start = index;
        index = open;
        index = Lexer.BWS(value, index);

        let expr = Query.searchExpr(value, index);
        if (!expr) return;
        index = expr.next;

        index = Lexer.BWS(value, index);
        let close = Lexer.CLOSE(value, index);
        if (!close) return;
        index = close;

        return Lexer.tokenize(value, start, index, expr, Lexer.TokenType.SearchParenExpression);
    }

    export function levels(value: Utils.SourceArray, index: number): Lexer.Token {
        let start = index;
        if (Utils.equals(value, index, "%24levels")) {
            index += 9;
        }else
        if (Utils.equals(value, index, "$levels")) {
            index += 7;
        }else return;

        let eq = Lexer.EQ(value, index);
        if (!eq) return;
        index = eq;

        let level;
        if (Utils.equals(value, index, "max")) {
            level = "max";
            index += 3;
        } else {
            let token = PrimitiveLiteral.int32Value(value, index);
            if (!token) return;
            level = token.raw;
            index = token.next;
        }

        return Lexer.tokenize(value, start, index, level, Lexer.TokenType.Levels);
    }

    export function filter(value: Utils.SourceArray, index: number): Lexer.Token {
        let start = index;
        if (Utils.equals(value, index, "%24filter")) {
            index += 9;
        }else
        if (Utils.equals(value, index, "$filter")) {
            index += 7;
        }else return;

        let eq = Lexer.EQ(value, index);
        if (!eq) return;
        index = eq;

        let expr = Expressions.boolCommonExpr(value, index);
        if (!expr) return;
        index = expr.next;

        return Lexer.tokenize(value, start, index, expr, Lexer.TokenType.Filter);
    }

    export function orderby(value: Utils.SourceArray, index: number): Lexer.Token {
        let start = index;
        if (Utils.equals(value, index, "%24orderby")) {
            index += 10;
        }else
        if (Utils.equals(value, index, "$orderby")) {
            index += 8;
        }else return;

        let eq = Lexer.EQ(value, index);
        if (!eq) return;
        index = eq;

        let items = [];
        let token = Query.orderbyItem(value, index);
        if (!token) return;
        index = token.next;

        while (token) {
            items.push(token);

            let comma = Lexer.COMMA(value, index);
            if (comma) {
                index = comma;
                token = Query.orderbyItem(value, index);
                if (!token) return;
                index = token.next;
            }else break;
        }

        return Lexer.tokenize(value, start, index, { items }, Lexer.TokenType.OrderBy);
    }

    export function orderbyItem(value: Utils.SourceArray, index: number): Lexer.Token {
        let expr = Expressions.commonExpr(value, index);
        if (!expr) return;
        let start = index;
        index = expr.next;

        let direction = 1;
        let rws = Lexer.RWS(value, index);
        if (rws > index) {
            index = rws;
            if (Utils.equals(value, index, "asc")) index += 3;
            else if (Utils.equals(value, index, "desc")) {
                index += 4;
                direction = -1;
            }else return;
        }

        return Lexer.tokenize(value, start, index, { expr, direction }, Lexer.TokenType.OrderByItem);
    }

    export function skip(value: Utils.SourceArray, index: number): Lexer.Token {
        let start = index;
        if (Utils.equals(value, index, "%24skip")) {
            index += 7;
        }else
        if (Utils.equals(value, index, "$skip")) {
            index += 5;
        }else return;

        let eq = Lexer.EQ(value, index);
        if (!eq) return;
        index = eq;

        let token = PrimitiveLiteral.int32Value(value, index);
        if (!token) return;
        index = token.next;

        return Lexer.tokenize(value, start, index, token, Lexer.TokenType.Skip);
    }

    export function top(value: Utils.SourceArray, index: number): Lexer.Token {
        let start = index;
        if (Utils.equals(value, index, "%24top")) {
            index += 6;
        }else
        if (Utils.equals(value, index, "$top")) {
            index += 4;
        }else return;

        let eq = Lexer.EQ(value, index);
        if (!eq) return;
        index = eq;

        let token = PrimitiveLiteral.int32Value(value, index);
        if (!token) return;
        index = token.next;

        return Lexer.tokenize(value, start, index, token, Lexer.TokenType.Top);
    }

    export function format(value: Utils.SourceArray, index: number): Lexer.Token {
        let start = index;
        if (Utils.equals(value, index, "%24format")) {
            index += 9;
        }else
        if (Utils.equals(value, index, "$format")) {
            index += 7;
        }else return;

        let eq = Lexer.EQ(value, index);
        if (!eq) return;
        index = eq;

        let format;
        if (Utils.equals(value, index, "atom")) {
            format = "atom";
            index += 4;
        }else if (Utils.equals(value, index, "json")) {
            format = "json";
            index += 4;
        }else if (Utils.equals(value, index, "xml")) {
            format = "xml";
            index += 3;
        }

        if (format) return Lexer.tokenize(value, start, index, { format }, Lexer.TokenType.Format);
    }

    export function inlinecount(value: Utils.SourceArray, index: number): Lexer.Token {
        let start = index;
        if (Utils.equals(value, index, "%24count")) {
            index += 8;
        }else
        if (Utils.equals(value, index, "$count")) {
            index += 6;
        }else return;

        let eq = Lexer.EQ(value, index);
        if (!eq) return;
        index = eq;

        let token = PrimitiveLiteral.booleanValue(value, index);
        if (!token) return;
        index = token.next;

        return Lexer.tokenize(value, start, index, token, Lexer.TokenType.InlineCount);
    }

    export function select(value: Utils.SourceArray, index: number): Lexer.Token {
        let start = index;
        if (Utils.equals(value, index, "%24select")) {
            index += 9;
        }else
        if (Utils.equals(value, index, "$select")) {
            index += 7;
        }else return;

        let eq = Lexer.EQ(value, index);
        if (!eq) return;
        index = eq;

        let items = [];
        let token = Query.selectItem(value, index);
        if (!token) return;
        while (token) {
            items.push(token);
            index = token.next;

            let comma = Lexer.COMMA(value, index);
            if (comma) {
                index = comma;
                token = Query.selectItem(value, index);
                if (!token) return;
            }else break;
        }

        return Lexer.tokenize(value, start, index, { items }, Lexer.TokenType.Select);
    }

    export function selectItem(value: Utils.SourceArray, index: number): Lexer.Token {
        let start = index;
        let item;
        let op = Query.allOperationsInSchema(value, index);
        let star = Lexer.STAR(value, index);
        if (op > index) {
            item = { namespace: Utils.stringify(value, index, op - 2), value: "*" };
            index = op;
        }else if (star) {
            item = { value: "*" };
            index = star;
        } else {
            item = {};
            let name = NameOrIdentifier.qualifiedEntityTypeName(value, index) ||
                NameOrIdentifier.qualifiedComplexTypeName(value, index);

            if (name && value[name.next] !== 0x2f) return;
            else if (name && value[name.next] === 0x2f) {
                index++;
                item.name = name;
            }

            let select = Query.selectProperty(value, index) ||
                Query.qualifiedActionName(value, index) ||
                Query.qualifiedFunctionName(value, index);
            if (!select) return;
            index = select.next;

            item = name ? { name, select } : select;
        }

        if (index > start) return Lexer.tokenize(value, start, index, item, Lexer.TokenType.SelectItem);
    }

    export function allOperationsInSchema(value: Utils.SourceArray, index: number): number {
        let namespaceNext = NameOrIdentifier.namespace(value, index);
        let star = Lexer.STAR(value, namespaceNext + 1);
        if (namespaceNext > index && value[namespaceNext] === 0x2e && star) return star;
        return index;
    }

    export function selectProperty(value: Utils.SourceArray, index: number): Lexer.Token {
        let token = Query.selectPath(value, index) ||
            NameOrIdentifier.primitiveProperty(value, index) ||
            NameOrIdentifier.primitiveColProperty(value, index) ||
            NameOrIdentifier.navigationProperty(value, index);
        if (!token) return;
        let start = index;
        index = token.next;

        if (token.type === Lexer.TokenType.SelectPath) {
            if (value[index] === 0x2f) {
                index++;
                let prop = Query.selectProperty(value, index);

                if (!prop) return;
                let path = Lexer.clone(token);
                token.next = prop.next;
                token.raw = Utils.stringify(value, start, token.next);
                token.value = { path, next: prop };
            }
        }

        return token;
    }

    export function selectPath(value: Utils.SourceArray, index: number): Lexer.Token {
        let token = NameOrIdentifier.complexProperty(value, index) ||
            NameOrIdentifier.complexColProperty(value, index);

        if (!token) return;
        let start = index;
        index = token.next;

        let tokenValue: any = token;
        if (value[index] === 0x2f) {
            let name = NameOrIdentifier.qualifiedComplexTypeName(value, index + 1);
            if (name) {
                index = name.next;
                tokenValue = { prop: token, name };
            }
        }

        return Lexer.tokenize(value, start, index, tokenValue, Lexer.TokenType.SelectPath);
    }

    export function qualifiedActionName(value: Utils.SourceArray, index: number): Lexer.Token {
        let namespaceNext = NameOrIdentifier.namespace(value, index);
        if (namespaceNext === index || value[namespaceNext] !== 0x2e) return;
        let start = index;
        index = namespaceNext + 1;

        let action = NameOrIdentifier.action(value, index);
        if (!action) return;
        action.value.namespace = Utils.stringify(value, start, namespaceNext);

        return Lexer.tokenize(value, start, action.next, action, Lexer.TokenType.Action);
    }

    export function qualifiedFunctionName(value: Utils.SourceArray, index: number): Lexer.Token {
        let namespaceNext = NameOrIdentifier.namespace(value, index);
        if (namespaceNext === index || value[namespaceNext] !== 0x2e) return;
        let start = index;
        index = namespaceNext + 1;

        let fn = NameOrIdentifier.odataFunction(value, index);
        if (!fn) return;
        fn.value.namespace = Utils.stringify(value, start, namespaceNext);
        index = fn.next;
        let tokenValue: any = { name: fn };

        let open = Lexer.OPEN(value, index);
        if (open) {
            index = open;
            tokenValue.parameters = [];
            let param = Expressions.parameterName(value, index);
            if (!param) return;

            while (param) {
                index = param.next;
                tokenValue.parameters.push(param);

                let comma = Lexer.COMMA(value, index);
                if (comma) {
                    index = comma;
                    let param = Expressions.parameterName(value, index);
                    if (!param) return;
                }else break;
            }

            let close = Lexer.CLOSE(value, index);
            if (!close) return;
            index = close;
        }

        return Lexer.tokenize(value, start, index, tokenValue, Lexer.TokenType.Function);
    }

    export function skiptoken(value: Utils.SourceArray, index: number): Lexer.Token {
        let start = index;
        if (Utils.equals(value, index, "%24skiptoken")) {
            index += 12;
        }else
        if (Utils.equals(value, index, "$skiptoken")) {
            index += 10;
        }else return;

        let eq = Lexer.EQ(value, index);
        if (!eq) return;
        index = eq;

        let ch = Lexer.qcharNoAMP(value, index);
        if (!ch) return;
        let valueStart = index;

        while (ch > index) {
            index = ch;
            ch = Lexer.qcharNoAMP(value, index);
        }

        return Lexer.tokenize(value, start, index, Utils.stringify(value, valueStart, index), Lexer.TokenType.SkipToken);
    }

    export function aliasAndValue(value: Utils.SourceArray, index: number): Lexer.Token {
        let alias = Expressions.parameterAlias(value, index);
        if (!alias) return;
        let start = index;
        index = alias.next;

        let eq = Lexer.EQ(value, index);
        if (!eq) return;
        index = eq;

        let paramValue = Expressions.parameterValue(value, index);
        if (!paramValue) return;
        index = paramValue.next;

        return Lexer.tokenize(value, start, index, {
            alias,
            value: paramValue
        }, Lexer.TokenType.AliasAndValue);
    }
}

export default Query;