Fin/writer.go

package fin

/*
	writer.go
	Copyright 2025 Sharkk, sharkk.net
	Authors: Sky Johnson
*/

import (
	"fmt"
	"io"
	"strconv"
)

// Write serializes the data to the provided writer
func (d *Data) Write(w io.Writer) error {
	return writeMap(w, d.data, 0)
}

func Save(w io.Writer, d *Data) error {
	return d.Write(w)
}

// Helper for writing indentation
func writeIndent(w io.Writer, level int) error {
	for range level {
		if _, err := w.Write([]byte{'\t'}); err != nil {
			return err
		}
	}
	return nil
}

// Helper for writing numbers using pooled buffers
func writeNumber(w io.Writer, val any) error {
	buffer := GetByteSlice()
	defer PutByteSlice(buffer)

	switch v := val.(type) {
	case int:
		*buffer = strconv.AppendInt((*buffer)[:0], int64(v), 10)
	case float64:
		*buffer = strconv.AppendFloat((*buffer)[:0], v, 'g', -1, 64)
	default:
		return fmt.Errorf("not a number type")
	}

	_, err := w.Write(*buffer)
	return err
}

// Consolidated string writing with escaping
func writeString(w io.Writer, s string, quote bool) error {
	if quote {
		if _, err := io.WriteString(w, "\""); err != nil {
			return err
		}
	}

	for i := range len(s) {
		c := s[i]
		var escaped string
		switch c {
		case '"':
			escaped = "\\\""
		case '\\':
			escaped = "\\\\"
		case '\n':
			escaped = "\\n"
		case '\t':
			escaped = "\\t"
		default:
			if _, err := w.Write([]byte{c}); err != nil {
				return err
			}
			continue
		}
		if _, err := io.WriteString(w, escaped); err != nil {
			return err
		}
	}

	if quote {
		if _, err := io.WriteString(w, "\""); err != nil {
			return err
		}
	}
	return nil
}

// Unified value writing logic
func writeValue(w io.Writer, value any, level int, addSpace, addNewline bool) error {
	if addSpace {
		if _, err := w.Write([]byte{' '}); err != nil {
			return err
		}
	}

	switch v := value.(type) {
	case nil:
		// Do nothing for nil
	case string:
		if err := writeString(w, v, true); err != nil {
			return err
		}
	case int, float64:
		if err := writeNumber(w, v); err != nil {
			return err
		}
	case bool:
		val := "false"
		if v {
			val = "true"
		}
		if _, err := io.WriteString(w, val); err != nil {
			return err
		}
	case map[string]any:
		if _, err := io.WriteString(w, "{\n"); err != nil {
			return err
		}
		if err := writeMap(w, v, level+1); err != nil {
			return err
		}
		if err := writeIndent(w, level); err != nil {
			return err
		}
		if _, err := io.WriteString(w, "}"); err != nil {
			return err
		}
	case []any:
		if _, err := io.WriteString(w, "{\n"); err != nil {
			return err
		}
		if err := writeArray(w, v, level+1); err != nil {
			return err
		}
		if err := writeIndent(w, level); err != nil {
			return err
		}
		if _, err := io.WriteString(w, "}"); err != nil {
			return err
		}
	}

	if addNewline {
		if _, err := io.WriteString(w, "\n"); err != nil {
			return err
		}
	}
	return nil
}

func writeMap(w io.Writer, data map[string]any, level int) error {
	for key, value := range data {
		if err := writeIndent(w, level); err != nil {
			return err
		}
		if _, err := io.WriteString(w, key); err != nil {
			return err
		}

		// Handle combined value+object case
		if m, ok := value.(map[string]any); ok && len(m) > 1 {
			if simpleValue, hasValue := m["value"]; hasValue {
				if err := writeValue(w, simpleValue, level, true, false); err != nil {
					return err
				}
				if _, err := io.WriteString(w, " {\n"); err != nil {
					return err
				}
				for k, v := range m {
					if k != "value" {
						if err := writeIndent(w, level+1); err != nil {
							return err
						}
						if _, err := io.WriteString(w, k); err != nil {
							return err
						}
						if err := writeValue(w, v, level+1, true, true); err != nil {
							return err
						}
					}
				}
				if err := writeIndent(w, level); err != nil {
					return err
				}
				if _, err := io.WriteString(w, "}\n"); err != nil {
					return err
				}
				continue
			}
		}

		if err := writeValue(w, value, level, true, true); err != nil {
			return err
		}
	}
	return nil
}

func writeArray(w io.Writer, array []any, level int) error {
	for _, item := range array {
		if err := writeIndent(w, level); err != nil {
			return err
		}
		if err := writeValue(w, item, level, true, true); err != nil {
			return err
		}
	}
	return nil
}