#include <Parsers/ASTIdentifier.h>
#include <Parsers/ASTSelectWithUnionQuery.h>
#include <Parsers/ASTInsertQuery.h>

#include <Parsers/CommonParsers.h>
#include <Parsers/ExpressionElementParsers.h>
#include <Parsers/ExpressionListParsers.h>
#include <Parsers/ParserSelectWithUnionQuery.h>
#include <Parsers/ParserWatchQuery.h>
#include <Parsers/ParserInsertQuery.h>
#include <Parsers/ParserSetQuery.h>
#include <Parsers/InsertQuerySettingsPushDownVisitor.h>
#include <Common/typeid_cast.h>
#include "Parsers/IAST_fwd.h"


namespace DB
{

namespace ErrorCodes
{
    extern const int SYNTAX_ERROR;
}


bool ParserInsertQuery::parseImpl(Pos & pos, ASTPtr & node, Expected & expected)
{
    /// Create parsers
    ParserKeyword s_insert_into("INSERT INTO");
    ParserKeyword s_from_infile("FROM INFILE");
    ParserKeyword s_compression("COMPRESSION");
    ParserKeyword s_table("TABLE");
    ParserKeyword s_function("FUNCTION");
    ParserToken s_dot(TokenType::Dot);
    ParserKeyword s_values("VALUES");
    ParserKeyword s_format("FORMAT");
    ParserKeyword s_settings("SETTINGS");
    ParserKeyword s_select("SELECT");
    ParserKeyword s_watch("WATCH");
    ParserKeyword s_partition_by("PARTITION BY");
    ParserKeyword s_with("WITH");
    ParserToken s_lparen(TokenType::OpeningRoundBracket);
    ParserToken s_rparen(TokenType::ClosingRoundBracket);
    ParserIdentifier name_p(true);
    ParserList columns_p(std::make_unique<ParserInsertElement>(), std::make_unique<ParserToken>(TokenType::Comma), false);
    ParserFunction table_function_p{false};
    ParserStringLiteral infile_name_p;
    ParserExpressionWithOptionalAlias exp_elem_p(false);

    /// create ASTPtr variables (result of parsing will be put in them).
    /// They will be used to initialize ASTInsertQuery's fields.
    ASTPtr database;
    ASTPtr table;
    ASTPtr infile;
    ASTPtr columns;
    ASTPtr format;
    ASTPtr select;
    ASTPtr watch;
    ASTPtr table_function;
    ASTPtr settings_ast;
    ASTPtr partition_by_expr;
    ASTPtr compression;

    /// Insertion data
    const char * data = nullptr;

    /// Check for key words `INSERT INTO`. If it isn't found, the query can't be parsed as insert query.
    if (!s_insert_into.ignore(pos, expected))
        return false;

    /// try to find 'TABLE'
    s_table.ignore(pos, expected);

    /// Search for 'FUNCTION'. If this key word is in query, read fields for insertion into 'TABLE FUNCTION'.
    /// Word table is optional for table functions. (for example, s3 table function)
    /// Otherwise fill 'TABLE' fields.
    if (s_function.ignore(pos, expected))
    {
        /// Read function name
        if (!table_function_p.parse(pos, table_function, expected))
            return false;

        /// Support insertion values with partition by.
        if (s_partition_by.ignore(pos, expected))
        {
            if (!exp_elem_p.parse(pos, partition_by_expr, expected))
                return false;
        }
    }
    else
    {
        /// Read one word. It can be table or database name.
        if (!name_p.parse(pos, table, expected))
            return false;

        /// If there is a dot, previous name was database name,
        /// so read table name after dot.
        if (s_dot.ignore(pos, expected))
        {
            database = table;
            if (!name_p.parse(pos, table, expected))
                return false;
        }
    }

    /// Is there a list of columns
    if (s_lparen.ignore(pos, expected))
    {
        if (!columns_p.parse(pos, columns, expected))
            return false;

        if (!s_rparen.ignore(pos, expected))
            return false;
    }

    /// Check if file is a source of data.
    if (s_from_infile.ignore(pos, expected))
    {
        /// Read its name to process it later
        if (!infile_name_p.parse(pos, infile, expected))
            return false;

        /// Check for 'COMPRESSION' parameter (optional)
        if (s_compression.ignore(pos, expected))
        {
            /// Read compression name. Create parser for this purpose.
            ParserStringLiteral compression_p;
            if (!compression_p.parse(pos, compression, expected))
                return false;
        }
    }

    Pos before_values = pos;

    /// VALUES or FROM INFILE or FORMAT or SELECT
    if (!infile && s_values.ignore(pos, expected))
    {
        /// If VALUES is defined in query, everything except setting will be parsed as data
        data = pos->begin;
    }
    else if (s_format.ignore(pos, expected))
    {
        /// If FORMAT is defined, read format name
        if (!name_p.parse(pos, format, expected))
            return false;
    }
    else if (s_select.ignore(pos, expected) || s_with.ignore(pos,expected))
    {
        /// If SELECT is defined, return to position before select and parse
        /// rest of query as SELECT query.
        pos = before_values;
        ParserSelectWithUnionQuery select_p;
        select_p.parse(pos, select, expected);

        /// FORMAT section is expected if we have input() in SELECT part
        if (s_format.ignore(pos, expected) && !name_p.parse(pos, format, expected))
            return false;
    }
    else if (s_watch.ignore(pos, expected))
    {
        /// If WATCH is defined, return to position before WATCH and parse
        /// rest of query as WATCH query.
        pos = before_values;
        ParserWatchQuery watch_p;
        watch_p.parse(pos, watch, expected);

        /// FORMAT section is expected if we have input() in SELECT part
        if (s_format.ignore(pos, expected) && !name_p.parse(pos, format, expected))
            return false;
    }
    else
    {
        /// If all previous conditions were false, query is incorrect
        return false;
    }

    /// Read SETTINGS if they are defined
    if (s_settings.ignore(pos, expected))
    {
        /// Settings are written like SET query, so parse them with ParserSetQuery
        ParserSetQuery parser_settings(true);
        if (!parser_settings.parse(pos, settings_ast, expected))
            return false;
    }

    if (select)
    {
        /// Copy SETTINGS from the INSERT ... SELECT ... SETTINGS
        InsertQuerySettingsPushDownVisitor::Data visitor_data{settings_ast};
        InsertQuerySettingsPushDownVisitor(visitor_data).visit(select);
    }

    /// In case of defined format, data follows it.
    if (format && !infile)
    {
        Pos last_token = pos;
        --last_token;
        data = last_token->end;

        /// If format name is followed by ';' (end of query symbol) there is no data to insert.
        if (data < end && *data == ';')
            throw Exception("You have excessive ';' symbol before data for INSERT.\n"
                                    "Example:\n\n"
                                    "INSERT INTO t (x, y) FORMAT TabSeparated\n"
                                    ";\tHello\n"
                                    "2\tWorld\n"
                                    "\n"
                                    "Note that there is no ';' just after format name, "
                                    "you need to put at least one whitespace symbol before the data.", ErrorCodes::SYNTAX_ERROR);

        while (data < end && (*data == ' ' || *data == '\t' || *data == '\f'))
            ++data;

        /// Data starts after the first newline, if there is one, or after all the whitespace characters, otherwise.

        if (data < end && *data == '\r')
            ++data;

        if (data < end && *data == '\n')
            ++data;
    }

    /// Create query and fill its fields.
    auto query = std::make_shared<ASTInsertQuery>();
    node = query;

    if (infile)
    {
        query->infile = infile;
        if (compression)
            query->compression = compression;
    }

    if (table_function)
    {
        query->table_function = table_function;
        query->partition_by = partition_by_expr;
    }
    else
    {
        query->database = database;
        query->table = table;
    }

    tryGetIdentifierNameInto(format, query->format);

    query->columns = columns;
    query->select = select;
    query->watch = watch;
    query->settings_ast = settings_ast;
    query->data = data != end ? data : nullptr;
    query->end = end;

    if (database)
        query->children.push_back(database);
    if (table)
        query->children.push_back(table);
    if (columns)
        query->children.push_back(columns);
    if (select)
        query->children.push_back(select);
    if (watch)
        query->children.push_back(watch);
    if (settings_ast)
        query->children.push_back(settings_ast);

    return true;
}

bool ParserInsertElement::parseImpl(Pos & pos, ASTPtr & node, Expected & expected)
{
    return ParserColumnsMatcher().parse(pos, node, expected)
        || ParserQualifiedAsterisk().parse(pos, node, expected)
        || ParserAsterisk().parse(pos, node, expected)
        || ParserCompoundIdentifier().parse(pos, node, expected);
}

}