#include "SqlFormattingUtils.h"
#include <QStringBuilder>

#include <cassert>
#include "PgKeywordList.h"

#include "PgConstraint.h"
#include "PgAttributeContainer.h"
#include "PgClass.h"
#include "PgClassContainer.h"
#include "PgNamespace.h"
#include "PgNamespaceContainer.h"
#include "PgDatabaseCatalog.h"

//inline QString u16(char16_t *utf16)

bool identNeedsQuotes(QString ident)
{
	if (ident[0].isDigit())
		return true;
	for (auto c : ident)
		if (c < 'a' && c > 'z' && c != '_')
			return true;

	auto kw = getPgsqlKeyword(ident);
	if (kw == nullptr)
		return false;
	else if (kw->getCategory() == UNRESERVED_KEYWORD)
		return false;
//	if (forTypes && sk->category == COL_NAME_KEYWORD)
//		return false;

	return true;
}

QString quoteIdent(QString ident)
{
	assert(ident.length() > 0);

	static const wchar_t dquote = L'"';

	if (identNeedsQuotes(ident)) {
		QString out;
		out += dquote;
		out += ident.replace("\"", "\"\"");
		out += dquote;
		return out;
	}
	else
		return ident;
}


QString genSchemaPrefix(const PgNamespace &ns)
{
	QString str;
	if (!ns.name.isEmpty()) {
		str = quoteIdent(ns.name) % QString::fromUtf16(u".");
	}
	return str;
}


QString genFQTableName(const PgDatabaseCatalog &catalog, const PgClass &cls)
{
	auto ns = catalog.namespaces()->getByKey(cls.relnamespace);

	return genSchemaPrefix(ns) % quoteIdent(cls.name);
}

QString genAlterTable(const PgDatabaseCatalog &catalog, const PgClass &cls)
{
	return "ALTER TABLE " % genFQTableName(catalog, cls);
}

QString getDropConstraintDefinition(const PgDatabaseCatalog &catalog, const PgConstraint &constraint)
{
	PgClass cls = catalog.classes()->getByKey(constraint.relid);
	return genAlterTable(catalog, cls) % " DROP CONSTRAINT " % quoteIdent(constraint.name) % ";";
}


/// Helper class that builds comma seperated identifier list
class IdentListString {
public:
	void add(QString ident)
	{
		if (!m_str.isEmpty())
			m_str += ",";
		m_str += quoteIdent(ident);
	}
	const QString& str() const { return m_str; }
private:
	QString m_str;
};

QString getColumnNameList(const PgDatabaseCatalog &catalog, Oid relid, const SmallAttNumVec<5> &attnums)
{
	IdentListString result;

	const auto ac = catalog.attributes();
	for (auto an : attnums) {
		result.add(ac->getByKey({ relid, an }).name);
	}
	return result.str();
}

QString getForeignKeyConstraintDefinition(const PgDatabaseCatalog &catalog, const PgConstraint &constraint)
{
	//PgClass cls = catalog.classes()->getByKey(constraint.relid);
	PgClass fcls = catalog.classes()->getByKey(constraint.frelid);
	QString deferrable;
	QString validated;
	if (!constraint.validated)
		validated += " NOT VALID";
	if (constraint.deferrable) {
		deferrable = QLatin1String(" DEFERRABLE INITIALLY ") % (constraint.deferred ? "DEFERRED" : "IMMEDIATE");
	}

	return "\n    FOREIGN KEY ("
			% getColumnNameList(catalog, constraint.relid, constraint.key) % ")\n    REFERENCES "
			% genFQTableName(catalog, fcls) % " ("
			% getColumnNameList(catalog, constraint.frelid, constraint.fkey) % ")\n    MATCH "
			% ForeignKeyMatchToString(constraint.fmatchtype)
			%  " ON UPDATE " % ForeignKeyActionToString(constraint.fupdtype)
			%  " ON DELETE " % ForeignKeyActionToString(constraint.fdeltype)
			% deferrable % validated % ";";


}

QString getPrimaryKeyConstraintDefinition(const PgDatabaseCatalog &catalog, const PgConstraint &constraint)
{
	QString ddl = " PRIMARY KEY ("
			% getColumnNameList(catalog, constraint.relid, constraint.key) % ");";

	return ddl;
}

QString getUniqueConstraintDefinition(const PgDatabaseCatalog &catalog, const PgConstraint &constraint)
{
	QString ddl = " UNIQUE ("
			% getColumnNameList(catalog, constraint.relid, constraint.key) % ");";

	return ddl;
}

QString getConstraintDefinition(const PgDatabaseCatalog &catalog, const PgConstraint &constraint)
{
	PgClass cls = catalog.classes()->getByKey(constraint.relid);
//	return genAlterTable(catalog, cls) % " ADD CONSTRAINT "
//			% quoteIdent(constraint.name) % " " % constraint.definition % ";";
	QString result = genAlterTable(catalog, cls) % "\n  ADD CONSTRAINT "
			% quoteIdent(constraint.name);
	switch (constraint.type) {
	case ConstraintType::ForeignKey:
		result += getForeignKeyConstraintDefinition(catalog, constraint);
		break;
	case ConstraintType::PrimaryKey:
		result += getPrimaryKeyConstraintDefinition(catalog, constraint);
		break;
	case ConstraintType::Unique:
		result += getUniqueConstraintDefinition(catalog, constraint);
		break;
	case ConstraintType::Check:
	default:
		result = result % " " % constraint.definition;
		break;
	}
	return result;
}


/*
wxString sql;

sql = wxT("(") + GetQuotedFkColumns()
	  +  wxT(")\n      REFERENCES ") + GetQuotedSchemaPrefix(GetRefSchema()) + qtIdent(GetReferences())
	  +  wxT(" (") + GetQuotedRefColumns()
	  +  wxT(")");

if (GetDatabase()->BackendMinimumVersion(7, 4) || GetMatch() == wxT("FULL"))
	sql += wxT(" MATCH ") + GetMatch();

sql += wxT("\n      ON UPDATE ") + GetOnUpdate()
	   +  wxT(" ON DELETE ") + GetOnDelete();
if (GetDeferrable())
{
	sql += wxT(" DEFERRABLE INITIALLY ");
	if (GetDeferred())
		sql += wxT("DEFERRED");
	else
		sql += wxT("IMMEDIATE");
}

if (GetDatabase()->BackendMinimumVersion(9, 1) && !GetValid())
	sql += wxT("\n      NOT VALID");

return sql;
*/