1 files changed, 212 insertions, 0 deletions
diff --git a/qml/javascript/goban_util.js b/qml/javascript/goban_util.js
new file mode 100644
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+++ b/qml/javascript/goban_util.js
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+.pragma library
+
+/**
+ * Check if the case on the grid belongs to the first column.
+ */
+function isFirstCol(index, cols) {
+    return index % cols == 0;
+}
+
+/**
+ * Check if the case on the grid belongs to the last column.
+ */
+function isLastCol(index, cols) {
+    return  index % cols == cols - 1;
+}
+
+/**
+ * Check if the case on the grid belongs to the first row
+ */
+function isFirstRow(index, cols) {
+    return index < cols;
+}
+
+/**
+ * Check if the case on the grid belongs to the last row.
+ */
+function isLastRow(index, cols, rows) {
+    return cols * (rows - 1) <= index;
+}
+
+/**
+ * Get all the neighbors for a given position.
+ */
+function getNeighbors(index, cols, rows) {
+
+    var neighbors = [];
+    if (!isFirstCol(index, cols)) {
+        neighbors.push(index - 1)
+    }
+
+    if (!isLastCol(index, cols)) {
+        neighbors.push(index + 1)
+    }
+
+    if (!isFirstRow(index, cols)) {
+        neighbors.push(index - cols)
+    }
+
+    if (!isLastRow(index, cols, rows)) {
+        neighbors.push(index + cols)
+    }
+
+    return neighbors;
+}
+
+function getChainToRemove(index, grid, filter) {
+
+    var piecesToCheck = [];
+    var piecesToRemove = [];
+
+    /*
+     * filter wich keep only free places.
+     */
+    function freePlaces(x) {
+        return grid.getElementAtIndex(x).getType() === "";
+    }
+
+    var piece = index;
+    while (piece !== undefined) {
+
+        /* if the case has already been marked, do not check it again.
+         */
+        if (!grid.getElementAtIndex(piece).mark) {
+            grid.getElementAtIndex(piece).mark = true;
+            piecesToRemove.push(piece);
+
+            var neighbors = getNeighbors(piece, grid.columns, grid.rows);
+
+            if (neighbors.length !== 0) {
+                /*
+                 * If the place has liberty, return empty list.
+                 */
+                if (neighbors.some(freePlaces)) {
+                    return [];
+                }
+
+                /*
+                 * Now update the check list.
+                 */
+                neighbors.filter(filter).forEach(function(x) {
+                    piecesToCheck.push(x)
+                });
+
+            }
+        } else {
+            /*
+             * The piece may have been marked outside of this call.
+             * (We try to check chain in each direction, and return as soon as
+             * we find an empty place).
+             * If the piece is marked, but does not belongs to the piecesToRemove,
+             * we assume the piece is connected to a living chain, and
+             * subsequently this chain too.
+             */
+            if (! piecesToRemove.some(function(x) { return x === piece})) {
+                return [];
+            }
+        }
+
+        piece = piecesToCheck.pop();
+    }
+    return piecesToRemove;
+
+}
+
+/**
+ * Add a new stone on the goban.
+ *
+ * Check if there are dead chained and remove them from the goban.
+ *
+ * index(int):          the index where put the stone.
+ * grid(object):        the grid where to put the stone:
+ *  - grid.rows:        number of rows in the grid
+ *  - grid.columns:     number of columes in the grid
+ *  - grid.getElementAtIndex(index) should return the stone a the given index
+ * currentPlayer(bool): player color
+ * animation(bool):     should we add animation on the goban
+ * allowSuicide(bool):  if suicide an autorized action
+ *
+ * return true if the movement has been allowed.
+ */
+function addPiece(index, grid, currentPlayer, animation, allowSuicide, allowOveride) {
+
+    var point = grid.getElementAtIndex(index);
+    var elementType = point.getType();
+
+    if (!allowOveride && elementType !== "") {
+        return false;
+    }
+
+    var neighbors = getNeighbors(index, grid.columns, grid.rows);
+
+    function isPlayer(x) {
+        return grid.getElementAtIndex(x).getType() === (currentPlayer ? "white" : "black");
+    }
+
+    function isOponnent(x) {
+        return grid.getElementAtIndex(x).getType() === (currentPlayer ? "black" : "white");
+    }
+
+    function freeOrChain(x) {
+        var pointType = grid.getElementAtIndex(x).getType();
+        return pointType === "" || pointType === (currentPlayer ? "white" : "black");
+    }
+
+    point.put(currentPlayer, animation);
+
+    if (neighbors.length === 0) {
+        return true;
+    }
+
+    var somethingToRemove = false;
+    var movementAutorized = true;
+
+    /*
+     * Check for pieces to remove.
+     */
+    neighbors.filter(isOponnent).forEach(function(neighbor) {
+
+        var piecesToRemove = getChainToRemove(neighbor, grid, isOponnent);
+        if (piecesToRemove.length !== 0) {
+            somethingToRemove = true;
+        }
+        piecesToRemove.forEach(function(x) {
+            grid.getElementAtIndex(x).remove(animation);
+        })
+    });
+
+    /*
+     * Check for suicide.
+     */
+    if (!somethingToRemove) {
+        var suicides = getChainToRemove(index, grid, isPlayer);
+        if (suicides.length !== 0) {
+            if (allowSuicide) {
+                suicides.forEach(function(x) {
+                    grid.getElementAtIndex(x).remove(animation);
+                });
+            } else {
+                point.remove(false);
+                movementAutorized = false;
+            }
+        }
+
+    }
+
+    /*
+     * Remove the marks in the cases.
+     *
+     * The call to getChainToRemove add marks on the cases in order to
+     * prevent infinite looping. We need to clean the cases before any new
+     * click.
+     *
+     * We do not need to remove them before as we are not filtering the
+     * same pieces.
+     */
+    for (var i = 0; i < grid.columns * grid.rows; i++) {
+        grid.getElementAtIndex(i).mark = false;
+    }
+
+    return movementAutorized;
+
+}