From b8e473b069d9c81e2f6a471fa7636c27cee63fae Mon Sep 17 00:00:00 2001
From: historia <[not public]>
Date: Tue, 23 Jun 2026 04:38:06 -0400
Subject: initial commit

---
 io.go | 222 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 222 insertions(+)
 create mode 100644 io.go

(limited to 'io.go')

diff --git a/io.go b/io.go
new file mode 100644
index 0000000..1b2fd5d
--- /dev/null
+++ b/io.go
@@ -0,0 +1,222 @@
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"gopkg.in/yaml.v3"
+)
+
+// Save format is YAML header with metadata, then the text grid below.
+// Format:
+// ---
+// <yaml metadata>
+// ...
+// <grid lines>
+
+type SaveData struct {
+	Name       string      `yaml:"name"`
+	Width      int         `yaml:"width"`
+	Height     int         `yaml:"height"`
+	Palette    []Terrain   `yaml:"palette"`
+	GridBody   string      `yaml:"grid_body,omitempty"`
+	GridColors []string    `yaml:"grid_colors,omitempty"`
+	TextLabels []TextLabel `yaml:"text_labels,omitempty"`
+	Submaps    []SubmapRef `yaml:"submaps,omitempty"`
+}
+
+type SubmapRef struct {
+	X    int       `yaml:"x"`
+	Y    int       `yaml:"y"`
+	Data SaveData  `yaml:"data"`
+}
+
+// SerializeMap serializes the map to the save format.
+func SerializeMap(m *Map, path string) error {
+	data := buildSaveData(m)
+
+	yamlBytes, err := yaml.Marshal(data)
+	if err != nil {
+		return err
+	}
+
+	var buf bytes.Buffer
+	buf.WriteString("---\n")
+	buf.Write(yamlBytes)
+	buf.WriteString("...\n")
+
+	for _, row := range m.Grid {
+		for _, cell := range row {
+			if cell.Terrain < 0 || cell.Terrain >= len(m.Palette) {
+				buf.WriteByte(' ')
+			} else {
+				buf.WriteString(m.Palette[cell.Terrain].ASCII)
+			}
+		}
+		buf.WriteByte('\n')
+	}
+
+	dir := filepath.Dir(path)
+	if err := os.MkdirAll(dir, 0755); err != nil {
+		return err
+	}
+	return os.WriteFile(path, buf.Bytes(), 0644)
+}
+
+func buildSaveData(m *Map) SaveData {
+	sd := SaveData{
+		Name:    m.Name,
+		Width:   m.Width,
+		Height:  m.Height,
+		Palette: m.Palette,
+	}
+	// Build grid body (only stored in YAML for submaps)
+	var gb strings.Builder
+	for _, row := range m.Grid {
+		for _, cell := range row {
+			if cell.Terrain < 0 || cell.Terrain >= len(m.Palette) {
+				gb.WriteByte(' ')
+			} else {
+				gb.WriteString(m.Palette[cell.Terrain].ASCII)
+			}
+		}
+		gb.WriteByte('\n')
+	}
+	if m.Parent != nil {
+		sd.GridBody = gb.String()
+	}
+
+	for y := range m.Grid {
+		for x := range m.Grid[y] {
+			c := m.Grid[y][x]
+			if c.Color != "" {
+				sd.GridColors = append(sd.GridColors, fmt.Sprintf("%d,%d,%s", x, y, c.Color))
+			}
+		}
+	}
+	for _, tl := range m.TextLabels {
+		sd.TextLabels = append(sd.TextLabels, tl)
+	}
+	for pt, sub := range m.Submaps {
+		sd.Submaps = append(sd.Submaps, SubmapRef{
+			X: pt.X, Y: pt.Y,
+			Data: buildSaveData(sub),
+		})
+	}
+	return sd
+}
+
+// DeserializeMap reads a saved map file.
+func DeserializeMap(path string) (*Map, error) {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+	content := string(data)
+
+	if !strings.HasPrefix(content, "---\n") {
+		return nil, fmt.Errorf("invalid save file: missing YAML header")
+	}
+
+	endIdx := strings.Index(content, "\n...\n")
+	if endIdx < 0 {
+		return nil, fmt.Errorf("invalid save file: missing ... terminator")
+	}
+
+	yamlPart := content[4:endIdx]
+	gridPart := content[endIdx+5:]
+
+	var sd SaveData
+	if err := yaml.Unmarshal([]byte(yamlPart), &sd); err != nil {
+		return nil, fmt.Errorf("invalid YAML header: %w", err)
+	}
+
+	m := NewMap(sd.Name, sd.Width, sd.Height, sd.Palette)
+	m.Filename = path
+
+	// Restore colors
+	for _, entry := range sd.GridColors {
+		var x, y int
+		var c string
+		if n, _ := fmt.Sscanf(entry, "%d,%d,%s", &x, &y, &c); n == 3 {
+			if y >= 0 && y < m.Height && x >= 0 && x < m.Width {
+				m.Grid[y][x].Color = c
+			}
+		}
+	}
+
+	lines := strings.Split(strings.TrimRight(gridPart, "\n"), "\n")
+	for y, line := range lines {
+		if y >= m.Height {
+			break
+		}
+		for x, ch := range line {
+			if x >= m.Width {
+				break
+			}
+			for i, t := range m.Palette {
+				if string(ch) == t.ASCII {
+					m.Grid[y][x].Terrain = i
+					break
+				}
+			}
+		}
+	}
+
+	for _, tl := range sd.TextLabels {
+		PlaceTextLabel(m, tl.Start, tl.Text, tl.Color)
+	}
+
+	for _, sr := range sd.Submaps {
+		sub := restoreMap(&sr.Data, m)
+		m.Submaps[Point{sr.X, sr.Y}] = sub
+	}
+
+	return m, nil
+}
+
+func restoreMap(sd *SaveData, parent *Map) *Map {
+	m := NewMap(sd.Name, sd.Width, sd.Height, sd.Palette)
+	m.Parent = parent
+	// Restore colors
+	for _, entry := range sd.GridColors {
+		var x, y int
+		var c string
+		if n, _ := fmt.Sscanf(entry, "%d,%d,%s", &x, &y, &c); n == 3 {
+			if y >= 0 && y < m.Height && x >= 0 && x < m.Width {
+				m.Grid[y][x].Color = c
+			}
+		}
+	}
+	// Restore grid from GridBody
+	if sd.GridBody != "" {
+		lines := strings.Split(strings.TrimRight(sd.GridBody, "\n"), "\n")
+		for y, line := range lines {
+			if y >= m.Height {
+				break
+			}
+			for x, ch := range line {
+				if x >= m.Width {
+					break
+				}
+				for i, t := range m.Palette {
+					if string(ch) == t.ASCII {
+						m.Grid[y][x].Terrain = i
+						break
+					}
+				}
+			}
+		}
+	}
+	for _, tl := range sd.TextLabels {
+		PlaceTextLabel(m, tl.Start, tl.Text, tl.Color)
+	}
+	for _, sr := range sd.Submaps {
+		sub := restoreMap(&sr.Data, m)
+		m.Submaps[Point{sr.X, sr.Y}] = sub
+	}
+	return m
+}
-- 
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