#include "CondFormat.h"
#include "Settings.h"
#include "Data.h"

CondFormat::CondFormat(const QString& filter, const QColor& foreground, const QColor& background, const QString& encoding)
 : m_filter(filter),
 m_bgColor(background),
 m_fgColor(foreground)
{
 if (!filter.isEmpty())
 m_sqlCondition = filterToSqlCondition(filter, encoding);
}

QString CondFormat::filterToSqlCondition(const QString& value, const QString& encoding)
{
 // Check for any special comparison operators at the beginning of the value string. If there are none default to LIKE.
 QString op = "LIKE";
 QString val, val2;
 QString escape;
 bool numeric = false, ok = false;

 // range/BETWEEN operator
 if (value.contains("~")) {
 int sepIdx = value.indexOf('~');
 val = value.mid(0, sepIdx);
 val2 = value.mid(sepIdx+1);
 float valf = val.toFloat(&ok);
 if (ok) {
 float val2f = val2.toFloat(&ok);
 ok = ok && (valf < val2f);
 }
 }
 if (ok) {
 op = "BETWEEN";
 numeric = true;
 } else {
 val.clear();
 val2.clear();
 if(value.left(2) == ">=" || value.left(2) == "<=" || value.left(2) == "<>")
 {
 // Check if we're filtering for '<> NULL'. In this case we need a special comparison operator.
 if(value.left(2) == "<>" && value.mid(2) == "NULL")
 {
 // We are filtering for '<>NULL'. Override the comparison operator to search for NULL values in this column. Also treat search value (NULL) as number,
 // in order to avoid putting quotes around it.
 op = "IS NOT";
 numeric = true;
 val = "NULL";
 } else if(value.left(2) == "<>" && value.mid(2) == "''") {
 // We are filtering for "<>''", i.e. for everything which is not an empty string
 op = "<>";
 numeric = true;
 val = "''";
 } else {
 value.mid(2).toFloat(&numeric);
 op = value.left(2);
 val = value.mid(2);
 }
 } else if(value.left(1) == ">" || value.left(1) == "<") {
 value.mid(1).toFloat(&numeric);
 op = value.left(1);
 val = value.mid(1);
 } else if(value.left(1) == "=") {
 val = value.mid(1);

 // Check if value to compare with is 'NULL'
 if(val != "NULL")
 {
 // It's not, so just compare normally to the value, whatever it is.
 op = "=";
 } else {
 // It is NULL. Override the comparison operator to search for NULL values in this column. Also treat search value (NULL) as number,
 // in order to avoid putting quotes around it.
 op = "IS";
 numeric = true;
 }
 } else if(value.left(1) == "/" && value.right(1) == "/" && value.length() > 2) {
 val = value.mid(1, value.length() - 2);
 op = "REGEXP";
 numeric = false;
 } else {
 // Keep the default LIKE operator

 // Set the escape character if one has been specified in the settings dialog
 QString escape_character = Settings::getValue("databrowser", "filter_escape").toString();
 if(escape_character == "'") escape_character = "''";
 if(escape_character.length())
 escape = QString("ESCAPE '%1'").arg(escape_character);

 // Add % wildcards at the start and at the beginning of the filter query, but only if there weren't set any
 // wildcards manually. The idea is to assume that a user who's just typing characters expects the wildcards to
 // be added but a user who adds them herself knows what she's doing and doesn't want us to mess up her query.
 if(!value.contains("%"))
 {
 val = value;
 val.prepend('%');
 val.append('%');
 }
 }
 }
 if(val.isEmpty())
 val = value;

 if(val == "" || val == "%" || val == "%%")
 return QString();
 else {
 // Quote and escape value, but only if it's not numeric and not the empty string sequence
 if(!numeric && val != "''")
 val = QString("'%1'").arg(val.replace("'", "''"));

 QString whereClause(op + " " + QString(encodeString(val.toUtf8(), encoding)));
 if (!val2.isEmpty())
 whereClause += " AND " + QString(encodeString(val2.toUtf8(), encoding));
 whereClause += " " + escape;
 return whereClause;
 }
}