Fixes some mycology test suite errors

4 files changed, 465 insertions, 20 deletions

diff --git a/pkg/field/blank.go b/pkg/field/blank.go
new file mode 100644
index 0000000..2c30b6e
--- /dev/null
+++ b/pkg/field/blank.go
@@ -0,0 +1,97 @@
+package field
+
+func (f *Field) Blank(x, y int) {
+	if !f.isIn(x, y) {
+		// outside the field, nothing to do
+		return
+	}
+	l := &f.lines[y-f.y]
+	if x < l.x || x >= l.x+l.l {
+		// outside the current line's columns
+		return
+	}
+	if x > l.x && x < l.x+l.l-1 {
+		// just set the value
+		l.columns[x-l.x] = ' '
+		return
+	}
+	// do we need to trim this line?
+	if l.l == 1 {
+		// this was the last character on the line
+		if y == f.y {
+			// We need to trim the leading lines
+			leadingLines := 1
+			for i := 1; i < f.ly; i++ {
+				if f.lines[i].l == 0 {
+					leadingLines++
+				} else {
+					break
+				}
+			}
+			f.y += leadingLines
+			f.ly -= leadingLines
+			lines := make([]Line, f.ly)
+			for i := 0; i < f.ly; i++ {
+				lines[i] = f.lines[leadingLines+i]
+			}
+			f.lines = lines
+		} else if y == f.y+f.ly-1 {
+			// We need to trim the trailing lines
+			trailingLines := 1
+			for i := f.ly + f.y - 2; i >= 0; i-- {
+				if f.lines[i].l == 0 {
+					trailingLines++
+				} else {
+					break
+				}
+			}
+			f.ly -= trailingLines
+			f.lines = f.lines[:f.ly]
+		} else {
+			// it was a line in the middle
+			l.l = 0
+			l.columns = make([]int, 0)
+		}
+	} else if x == l.x {
+		// We need to remove leading spaces
+		leadingSpaces := 1
+		for i := 1; i < l.l; i++ {
+			if l.columns[i] == ' ' {
+				leadingSpaces++
+			} else {
+				break
+			}
+		}
+		l.x += leadingSpaces
+		l.l -= leadingSpaces
+		columns := make([]int, l.l)
+		for i := 0; i < l.l; i++ {
+			columns[i] = l.columns[leadingSpaces+i]
+		}
+		l.columns = columns
+	} else if x == l.l+l.x-1 {
+		// we need to remove trailing spaces
+		trailingSpaces := 1
+		for i := l.l - 2; i >= 0; i-- {
+			if l.columns[i] == ' ' {
+				trailingSpaces++
+			} else {
+				break
+			}
+		}
+		l.l -= trailingSpaces
+		l.columns = l.columns[:l.l]
+	}
+	// we now need to find the new field limits
+	f.x = f.lines[0].x
+	x2 := f.lines[0].l + f.lines[0].x
+	for i := 1; i < f.ly; i++ {
+		if f.x > f.lines[i].x {
+			f.x = f.lines[i].x
+		}
+		if x2 < f.lines[i].x+f.lines[i].l {
+			x2 = f.lines[i].x + f.lines[i].l
+		}
+	}
+	f.lx = x2 - f.x
+}
diff --git a/pkg/field/blank_test.go b/pkg/field/blank_test.go
new file mode 100644
index 0000000..260c50b
--- /dev/null
+++ b/pkg/field/blank_test.go
@@ -0,0 +1,346 @@
+package field
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestBlankInside(t *testing.T) {
+	input := Field{
+		x:  0,
+		y:  0,
+		lx: 3,
+		ly: 1,
+		lines: []Line{
+			Line{x: 0, l: 3, columns: []int{'@', 'a', 'b'}},
+		},
+	}
+	expected := Field{
+		x:  0,
+		y:  0,
+		lx: 3,
+		ly: 1,
+		lines: []Line{
+			Line{x: 0, l: 3, columns: []int{'@', ' ', 'b'}},
+		},
+	}
+	// Test cases
+	testCases := []struct {
+		name     string
+		input    *Field
+		inputX   int
+		inputY   int
+		expected *Field
+	}{
+		{"inside", &input, 1, 0, &expected},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			tc.input.Blank(tc.inputX, tc.inputY)
+			require.Equal(t, tc.expected, tc.input)
+		})
+	}
+}
+
+func TestBlankInsideLine(t *testing.T) {
+	input := Field{
+		x:  0,
+		y:  0,
+		lx: 3,
+		ly: 3,
+		lines: []Line{
+			Line{x: 0, l: 3, columns: []int{'@', 'a', 'b'}},
+			Line{x: 0, l: 1, columns: []int{'d'}},
+			Line{x: 0, l: 1, columns: []int{'c'}},
+		},
+	}
+	expected := Field{
+		x:  0,
+		y:  0,
+		lx: 3,
+		ly: 3,
+		lines: []Line{
+			Line{x: 0, l: 3, columns: []int{'@', 'a', 'b'}},
+			Line{columns: []int{}},
+			Line{x: 0, l: 1, columns: []int{'c'}},
+		},
+	}
+	// Test cases
+	testCases := []struct {
+		name     string
+		input    *Field
+		inputX   int
+		inputY   int
+		expected *Field
+	}{
+		{"inside", &input, 0, 1, &expected},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			tc.input.Blank(tc.inputX, tc.inputY)
+			require.Equal(t, tc.expected, tc.input)
+		})
+	}
+}
+
+func TestBlankOutside(t *testing.T) {
+	input := Field{
+		x:  0,
+		y:  0,
+		lx: 1,
+		ly: 1,
+		lines: []Line{
+			Line{x: 0, l: 1, columns: []int{'@'}},
+		},
+	}
+	expected := Field{
+		x:  0,
+		y:  0,
+		lx: 1,
+		ly: 1,
+		lines: []Line{
+			Line{x: 0, l: 1, columns: []int{'@'}},
+		},
+	}
+	// Test cases
+	testCases := []struct {
+		name     string
+		input    *Field
+		inputX   int
+		inputY   int
+		expected *Field
+	}{
+		{"xappend", &input, 1, 0, &expected},
+		{"xprepend", &input, -1, 0, &expected},
+		{"yappend", &input, 0, 1, &expected},
+		{"yprepend", &input, 0, -1, &expected},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			tc.input.Blank(tc.inputX, tc.inputY)
+			require.Equal(t, tc.expected, tc.input)
+		})
+	}
+}
+
+func TestBlankOutsideLine(t *testing.T) {
+	input := Field{
+		x:  -1,
+		y:  0,
+		lx: 3,
+		ly: 2,
+		lines: []Line{
+			Line{x: -1, l: 3, columns: []int{'@', '@', '@'}},
+			Line{x: 0, l: 1, columns: []int{'@'}},
+		},
+	}
+	expected := Field{
+		x:  -1,
+		y:  0,
+		lx: 3,
+		ly: 2,
+		lines: []Line{
+			Line{x: -1, l: 3, columns: []int{'@', '@', '@'}},
+			Line{x: -0, l: 1, columns: []int{'@'}},
+		},
+	}
+	// Test cases
+	testCases := []struct {
+		name     string
+		input    *Field
+		inputX   int
+		inputY   int
+		expected *Field
+	}{
+		{"xappend", &input, 1, 1, &expected},
+		{"xprepend", &input, -1, 1, &expected},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			tc.input.Blank(tc.inputX, tc.inputY)
+			require.Equal(t, tc.expected, tc.input)
+		})
+	}
+}
+
+func TestBlankLineTrim(t *testing.T) {
+	expected := Field{
+		x:  -1,
+		y:  0,
+		lx: 3,
+		ly: 1,
+		lines: []Line{
+			Line{x: -1, l: 3, columns: []int{'@', '@', '@'}},
+		},
+	}
+	bottomCenter := Field{
+		x:  -1,
+		y:  0,
+		lx: 3,
+		ly: 3,
+		lines: []Line{
+			Line{x: -1, l: 3, columns: []int{'@', '@', '@'}},
+			Line{},
+			Line{x: 0, l: 1, columns: []int{'@'}},
+		},
+	}
+	bottomLeft := Field{
+		x:  -4,
+		y:  0,
+		lx: 6,
+		ly: 3,
+		lines: []Line{
+			Line{x: -1, l: 3, columns: []int{'@', '@', '@'}},
+			Line{},
+			Line{x: -4, l: 1, columns: []int{'@'}},
+		},
+	}
+	bottomRight := Field{
+		x:  -1,
+		y:  0,
+		lx: 6,
+		ly: 3,
+		lines: []Line{
+			Line{x: -1, l: 3, columns: []int{'@', '@', '@'}},
+			Line{},
+			Line{x: 4, l: 1, columns: []int{'@'}},
+		},
+	}
+	topCenter := Field{
+		x:  -1,
+		y:  -2,
+		lx: 3,
+		ly: 3,
+		lines: []Line{
+			Line{x: 0, l: 1, columns: []int{'@'}},
+			Line{},
+			Line{x: -1, l: 3, columns: []int{'@', '@', '@'}},
+		},
+	}
+	topLeft := Field{
+		x:  -4,
+		y:  -2,
+		lx: 6,
+		ly: 3,
+		lines: []Line{
+			Line{x: -4, l: 1, columns: []int{'@'}},
+			Line{},
+			Line{x: -1, l: 3, columns: []int{'@', '@', '@'}},
+		},
+	}
+	topRight := Field{
+		x:  -1,
+		y:  -2,
+		lx: 6,
+		ly: 3,
+		lines: []Line{
+			Line{x: 4, l: 1, columns: []int{'@'}},
+			Line{},
+			Line{x: -1, l: 3, columns: []int{'@', '@', '@'}},
+		},
+	}
+	// Test cases
+	testCases := []struct {
+		name     string
+		input    *Field
+		inputX   int
+		inputY   int
+		expected *Field
+	}{
+		{"bottomCenter", &bottomCenter, 0, 2, &expected},
+		{"bottomLeft", &bottomLeft, -4, 2, &expected},
+		{"bottomRight", &bottomRight, 4, 2, &expected},
+		{"topCenter", &topCenter, 0, -2, &expected},
+		{"topLeft", &topLeft, -4, -2, &expected},
+		{"topRight", &topRight, 4, -2, &expected},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			tc.input.Blank(tc.inputX, tc.inputY)
+			require.Equal(t, tc.expected, tc.input)
+		})
+	}
+}
+
+func TestBlankcolumnsTrim(t *testing.T) {
+	expectedBottom := Field{
+		x:  -1,
+		y:  0,
+		lx: 3,
+		ly: 2,
+		lines: []Line{
+			Line{x: -1, l: 3, columns: []int{'@', '@', '@'}},
+			Line{x: 0, l: 1, columns: []int{'@'}},
+		},
+	}
+	expectedTop := Field{
+		x:  -1,
+		y:  -1,
+		lx: 3,
+		ly: 2,
+		lines: []Line{
+			Line{x: 0, l: 1, columns: []int{'@'}},
+			Line{x: -1, l: 3, columns: []int{'@', '@', '@'}},
+		},
+	}
+	bottomLeft := Field{
+		x:  -4,
+		y:  0,
+		lx: 6,
+		ly: 2,
+		lines: []Line{
+			Line{x: -1, l: 3, columns: []int{'@', '@', '@'}},
+			Line{x: -4, l: 5, columns: []int{'@', ' ', ' ', ' ', '@'}},
+		},
+	}
+	bottomRight := Field{
+		x:  -1,
+		y:  0,
+		lx: 6,
+		ly: 2,
+		lines: []Line{
+			Line{x: -1, l: 3, columns: []int{'@', '@', '@'}},
+			Line{x: 0, l: 5, columns: []int{'@', ' ', ' ', ' ', '@'}},
+		},
+	}
+	topLeft := Field{
+		x:  -4,
+		y:  -1,
+		lx: 6,
+		ly: 2,
+		lines: []Line{
+			Line{x: -4, l: 5, columns: []int{'@', ' ', ' ', ' ', '@'}},
+			Line{x: -1, l: 3, columns: []int{'@', '@', '@'}},
+		},
+	}
+	topRight := Field{
+		x:  -1,
+		y:  -1,
+		lx: 6,
+		ly: 2,
+		lines: []Line{
+			Line{x: 0, l: 5, columns: []int{'@', ' ', ' ', ' ', '@'}},
+			Line{x: -1, l: 3, columns: []int{'@', '@', '@'}},
+		},
+	}
+	// Test cases
+	testCases := []struct {
+		name     string
+		input    *Field
+		inputX   int
+		inputY   int
+		expected *Field
+	}{
+		{"bottomLeft", &bottomLeft, -4, 1, &expectedBottom},
+		{"bottomRight", &bottomRight, 4, 1, &expectedBottom},
+		{"topLeft", &topLeft, -4, -1, &expectedTop},
+		{"topRight", &topRight, 4, -1, &expectedTop},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			tc.input.Blank(tc.inputX, tc.inputY)
+			require.Equal(t, tc.expected, tc.input)
+		})
+	}
+}
diff --git a/pkg/field/field.go b/pkg/field/field.go
index fbe987a..a31f4da 100644
--- a/pkg/field/field.go
+++ b/pkg/field/field.go
@@ -41,8 +41,8 @@ func Load(fd io.Reader) (*Field, error) {
 				}
 				if l.l > 0 {
 					f.ly++
-					if f.lx < l.l {
-						f.lx = l.l
+					if f.lx-f.x < l.l-l.x {
+						f.lx = l.l - l.x + f.x
 					}
 					f.lines = append(f.lines, *l)
 				}
diff --git a/pkg/field/utils.go b/pkg/field/utils.go
index 1bd2b2b..c513d96 100644
--- a/pkg/field/utils.go
+++ b/pkg/field/utils.go
@@ -15,6 +15,10 @@ func (f Field) isIn(x, y int) bool {
 }
 
 func (f *Field) Set(x, y, v int) {
+	if v == ' ' {
+		f.Blank(x, y)
+		return
+	}
 	if y >= f.y {
 		if y < f.y+f.ly {
 			l := &f.lines[y-f.y]
@@ -29,13 +33,13 @@ func (f *Field) Set(x, y, v int) {
 					l.columns[x-l.x] = v
 				} else {
 					// append columns
-					newL := l.l + x - l.x
+					newL := x - l.x + 1
 					for i := l.l; i < newL-1; i++ {
 						l.columns = append(l.columns, ' ')
 					}
 					l.columns = append(l.columns, v)
 					l.l = newL
-					if f.lx < l.l-l.x {
+					if f.lx-f.x < l.l-l.x {
 						f.lx = l.l - l.x
 					}
 				}
@@ -44,18 +48,18 @@ func (f *Field) Set(x, y, v int) {
 				newL := l.l + l.x - x
 				c := make([]int, newL)
 				c[0] = v
-				for i := 0; i < l.x-x; i++ {
-					c[i+1] = ' '
+				for i := 1; i < l.x-x; i++ {
+					c[i] = ' '
 				}
-				for j := 0; j < l.l; j++ {
-					c[j+l.x-x] = l.columns[j]
+				for i := l.x - x; i < newL; i++ {
+					c[i] = l.columns[i-l.x+x]
 				}
 				l.columns = c
 				l.x = x
 				l.l = newL
 				if f.x > x {
+					f.lx = f.lx + f.x - x
 					f.x = x
-					f.lx = newL
 				}
 			}
 		} else {
@@ -67,9 +71,10 @@ func (f *Field) Set(x, y, v int) {
 			f.lines = append(f.lines, Line{x: x, l: 1, columns: []int{v}})
 			f.ly = newLy
 			if f.x > x {
-				f.lx += f.x - x
+				f.lx = f.lx + f.x - x
 				f.x = x
-			} else if f.lx-f.x < x {
+			}
+			if f.lx-f.x < x {
 				f.lx = x - f.x
 			}
 		}
@@ -77,21 +82,18 @@ func (f *Field) Set(x, y, v int) {
 		// prepend lines
 		newLy := f.ly + f.y - y
 		lines := make([]Line, newLy)
-		lines[0] = Line{
-			x:       x,
-			l:       1,
-			columns: []int{v},
-		}
-		for j := 0; j < f.ly; j++ {
-			lines[j+f.y-y] = f.lines[j]
+		lines[0] = Line{x: x, l: 1, columns: []int{v}}
+		for j := f.y - y; j < newLy; j++ {
+			lines[j] = f.lines[j-f.y+y]
 		}
 		f.lines = lines
 		f.y = y
 		f.ly = newLy
 		if f.x > x {
-			f.lx += f.x - x
+			f.lx = f.lx + f.x - x
 			f.x = x
-		} else if f.lx-f.x < x {
+		}
+		if f.lx-f.x < x {
 			f.lx = x - f.x + 1
 		}
 	}