From 4fbb8ef399a356e0b1a7393311c22ca68c50a14d Mon Sep 17 00:00:00 2001
From: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
Date: Sun, 30 Sep 2018 16:06:17 +0200
Subject: Dive list: hand-code the DiveTripModel

The dive list is fed data by means of a sorted "DiveTripModel".
There are two modes: list and tree. This was implemented rather
elegantly with a general "TreeModel", which can represent trees
of arbitrary depths.

Nevertheless, we have at most two levels and on the second level
only dives can reside. Implementing proper model-semantics
(insert, delete, move) will be quite a challenge and implementing
it under the umbrella of a very general model will not make it
easier.

Therefore, for now, hardcode the model:
At the top-level there are items which may either be a trip
(can contain multiple dives) or a dive (contains exactly one dive).

Thus, we can completely de-virutalize the DiveItem and TripItem
classes, which are now trivial wrappers around dive * and dive_trip *.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
---
 qt-models/divetripmodel.h | 47 +++++++++++++++++++++++++++++++++++++----------
 1 file changed, 37 insertions(+), 10 deletions(-)

(limited to 'qt-models/divetripmodel.h')

diff --git a/qt-models/divetripmodel.h b/qt-models/divetripmodel.h
index d33df2143..f6125d196 100644
--- a/qt-models/divetripmodel.h
+++ b/qt-models/divetripmodel.h
@@ -2,12 +2,12 @@
 #ifndef DIVETRIPMODEL_H
 #define DIVETRIPMODEL_H
 
-#include "treemodel.h"
 #include "core/dive.h"
-#include <string>
+#include <QAbstractItemModel>
+#include <QCoreApplication>		// For Q_DECLARE_TR_FUNCTIONS
 
-struct DiveItem : public TreeItem {
-	Q_DECLARE_TR_FUNCTIONS(TripItem)
+struct DiveItem {
+	Q_DECLARE_TR_FUNCTIONS(TripItem)		// Is that TripItem on purpose?
 public:
 	enum Column {
 		NR,
@@ -31,10 +31,10 @@ public:
 		COLUMNS
 	};
 
-	QVariant data(int column, int role) const override;
+	QVariant data(int column, int role) const;
 	dive *d;
-	bool setData(const QModelIndex &index, const QVariant &value, int role = Qt::EditRole) override;
-	Qt::ItemFlags flags(const QModelIndex &index) const override;
+	DiveItem(dive *dIn) : d(dIn) {}			// Trivial constructor
+	bool setData(const QModelIndex &index, const QVariant &value, int role = Qt::EditRole);
 	QString displayDate() const;
 	QString displayDuration() const;
 	QString displayDepth() const;
@@ -50,14 +50,15 @@ public:
 	int weight() const;
 };
 
-struct TripItem : public TreeItem {
+struct TripItem {
 	Q_DECLARE_TR_FUNCTIONS(TripItem)
 public:
-	QVariant data(int column, int role) const override;
+	QVariant data(int column, int role) const;
 	dive_trip_t *trip;
+	TripItem(dive_trip_t *tIn) : trip(tIn) {}	// Trivial constructor
 };
 
-class DiveTripModel : public TreeModel {
+class DiveTripModel : public QAbstractItemModel {
 	Q_OBJECT
 public:
 	enum Column {
@@ -102,9 +103,35 @@ public:
 	DiveTripModel(QObject *parent = 0);
 	Layout layout() const;
 	void setLayout(Layout layout);
+	QVariant data(const QModelIndex &index, int role) const;
+	int columnCount(const QModelIndex&) const;
+	int rowCount(const QModelIndex &parent) const;
+	QModelIndex index(int row, int column, const QModelIndex &parent) const;
+	QModelIndex parent(const QModelIndex &index) const;
 
 private:
+	// The model has up to two levels. At the top level, we have either trips or dives
+	// that do not belong to trips. Such a top-level item is represented by the "Item"
+	// struct. Two cases two consider:
+	// 1) If "trip" is non-null, then this is a dive-trip and the dives are collected
+	// in the dives vector.  Note that in principle we could also get the dives in a
+	// trip from the backend, but there they are collected in a linked-list, which is
+	// quite inconvenient to access.
+	// 2) If "trip" is null, this is a dive and dives is supposed to contain exactly
+	// one element, which is the corresponding dive.
+	struct Item {
+		dive_trip		*trip;
+		QVector<dive *>		 dives;
+		Item(dive_trip *t, dive *d);	// Initialize a trip with one dive
+		Item(dive *d);			// Initialize a top-level dive
+	};
+
+	dive *diveOrNull(const QModelIndex &index) const;	// Returns a dive if this index represents a dive, null otherwise
+	QPair<dive_trip *, dive *> tripOrDive(const QModelIndex &index) const;
+								// Returns either a pointer to a trip or a dive, or twice null of index is invalid
+								// null, something is really wrong
 	void setupModelData();
+	std::vector<Item> items;				// Use std::vector for convenience of emplace_back()
 	Layout currentLayout;
 };
 
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