refactor decode (#62)

* refactoring and writing some tests

* add javadoc

Author: Invokedzz

src/main/java/dev/toonformat/jtoon/decoder/ArrayDecoder.java

@@ -0,0 +1,293 @@
+package dev.toonformat.jtoon.decoder;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.regex.Matcher;
+
+import static dev.toonformat.jtoon.util.Headers.ARRAY_HEADER_PATTERN;
+import static dev.toonformat.jtoon.util.Headers.TABULAR_HEADER_PATTERN;
+
+/**
+ * Handles decoding of TOON arrays to JSON format.
+ */
+public class ArrayDecoder {
+
+    private ArrayDecoder() {
+        throw new UnsupportedOperationException("Utility class cannot be instantiated");
+    }
+
+    /**
+     * Parses array from header string and following lines.
+     * Detects array type (tabular, list, or primitive) and routes accordingly.
+     * @param header the header string to parse
+     * @param depth the depth of array
+     * @param context decode object in order to deal with lines, delimiter and options
+     * @return parsed array with delimiter
+     */
+    protected static List<Object> parseArray(String header, int depth, DecodeContext context) {
+        String arrayDelimiter = extractDelimiterFromHeader(header, context);
+
+        return parseArrayWithDelimiter(header, depth, arrayDelimiter, context);
+    }
+
+    /**
+     * Extracts delimiter from array header.
+     * Returns tab, pipe, or comma (default) based on header pattern.
+     * @param header the header string to parse
+     * @param context decode object in order to deal with lines, delimiter and options
+     * @return extracted delimiter from header
+     */
+    protected static String extractDelimiterFromHeader(String header, DecodeContext context) {
+        Matcher matcher = ARRAY_HEADER_PATTERN.matcher(header);
+        if (matcher.find() && matcher.groupCount() == 3) {
+            String delimChar = matcher.group(3);
+            if (delimChar != null) {
+                if ("\t".equals(delimChar)) {
+                    return "\t";
+                } else if ("|".equals(delimChar)) {
+                    return "|";
+                }
+            }
+        }
+        // Default to comma
+        return context.delimiter;
+    }
+
+    /**
+     * Parses array from header string and following lines with a specific
+     * delimiter.
+     * Detects array type (tabular, list, or primitive) and routes accordingly.
+     * @param header the header string to parse
+     * @param depth depth of array
+     * @param arrayDelimiter array delimiter
+     * @param context decode object in order to deal with lines, delimiter and options
+     * @return parsed array
+     */
+    protected static List<Object> parseArrayWithDelimiter(String header, int depth, String arrayDelimiter, DecodeContext context) {
+        Matcher tabularMatcher = TABULAR_HEADER_PATTERN.matcher(header);
+        Matcher arrayMatcher = ARRAY_HEADER_PATTERN.matcher(header);
+
+        if (tabularMatcher.find()) {
+            return TabularArrayDecoder.parseTabularArray(header, depth, arrayDelimiter, context);
+        }
+
+        if (arrayMatcher.find()) {
+            int headerEndIdx = arrayMatcher.end();
+            String afterHeader = header.substring(headerEndIdx).trim();
+
+            if (afterHeader.startsWith(":")) {
+                String inlineContent = afterHeader.substring(1).trim();
+
+                if (!inlineContent.isEmpty()) {
+                    List<Object> result = parseArrayValues(inlineContent, arrayDelimiter);
+                    validateArrayLength(header, result.size());
+                    context.currentLine++;
+                    return result;
+                }
+            }
+
+            context.currentLine++;
+            if (context.currentLine < context.lines.length) {
+                String nextLine = context.lines[context.currentLine];
+                int nextDepth = DecodeHelper.getDepth(nextLine, context);
+                String nextContent = nextLine.substring(nextDepth * context.options.indent());
+
+                if (nextDepth <= depth) {
+                    // The next line is not a child of this array,
+                    // the array is empty
+                    validateArrayLength(header, 0);
+                    return Collections.emptyList();
+                }
+
+                if (nextContent.startsWith("- ")) {
+                    context.currentLine--;
+                    return parseListArray(depth, header, context);
+                } else {
+                    context.currentLine++;
+                    List<Object> result = parseArrayValues(nextContent, arrayDelimiter);
+                    validateArrayLength(header, result.size());
+                    return result;
+                }
+            }
+            List<Object> empty = new ArrayList<>();
+            validateArrayLength(header, 0);
+            return empty;
+        }
+
+        if (context.options.strict()) {
+            throw new IllegalArgumentException("Invalid array header: " + header);
+        }
+        return Collections.emptyList();
+    }
+
+    /**
+     * Validates array length if declared in header.
+     * @param header header
+     * @param actualLength actual length
+     */
+    protected static void validateArrayLength(String header, int actualLength) {
+        Integer declaredLength = extractLengthFromHeader(header);
+        if (declaredLength != null && declaredLength != actualLength) {
+            throw new IllegalArgumentException(
+                String.format("Array length mismatch: declared %d, found %d", declaredLength, actualLength));
+        }
+    }
+
+    /**
+     * Extracts declared length from array header.
+     * Returns the number specified in [n] or null if not found.
+     */
+    private static Integer extractLengthFromHeader(String header) {
+        Matcher matcher = ARRAY_HEADER_PATTERN.matcher(header);
+        if (matcher.find()) {
+            try {
+                return Integer.parseInt(matcher.group(2));
+            } catch (NumberFormatException e) {
+                return null;
+            }
+        }
+        return null;
+    }
+
+    /**
+     * Parses array values from a delimiter-separated string.
+     * @param values the values string to parse
+     * @param arrayDelimiter array delimiter
+     * @return parsed array values
+     */
+    protected static List<Object> parseArrayValues(String values, String arrayDelimiter) {
+        List<Object> result = new ArrayList<>();
+        List<String> rawValues = parseDelimitedValues(values, arrayDelimiter);
+        for (String value : rawValues) {
+            result.add(PrimitiveDecoder.parse(value));
+        }
+        return result;
+    }
+
+    /**
+     * Splits a string by delimiter, respecting quoted sections.
+     * Whitespace around delimiters is tolerated and trimmed.
+     * @param input the input string to parse
+     * @param arrayDelimiter array delimiter
+     * @return parsed delimited values
+     */
+    protected static List<String> parseDelimitedValues(String input, String arrayDelimiter) {
+        List<String> result = new ArrayList<>();
+        StringBuilder current = new StringBuilder();
+        boolean inQuotes = false;
+        boolean escaped = false;
+        char delimChar = arrayDelimiter.charAt(0);
+
+        int i = 0;
+        while (i < input.length()) {
+            char c = input.charAt(i);
+
+            if (escaped) {
+                current.append(c);
+                escaped = false;
+                i++;
+            } else if (c == '\\') {
+                current.append(c);
+                escaped = true;
+                i++;
+            } else if (c == '"') {
+                current.append(c);
+                inQuotes = !inQuotes;
+                i++;
+            } else if (c == delimChar && !inQuotes) {
+                // Found delimiter - add current value (trimmed) and reset
+                String value = current.toString().trim();
+                result.add(value);
+                current = new StringBuilder();
+                // Skip whitespace after delimiter
+                do {
+                    i++;
+                } while (i < input.length() && Character.isWhitespace(input.charAt(i)));
+            } else {
+                current.append(c);
+                i++;
+            }
+        }
+
+        // Add final value
+        if (!current.isEmpty() || input.endsWith(arrayDelimiter)) {
+            result.add(current.toString().trim());
+        }
+
+        return result;
+    }
+
+    /**
+     * Parses list array format where items are prefixed with "- ".
+     * Example: items[2]:\n - item1\n - item2
+     */
+    private static List<Object> parseListArray(int depth, String header, DecodeContext context) {
+        List<Object> result = new ArrayList<>();
+        context.currentLine++;
+
+        boolean shouldContinue = true;
+        while (shouldContinue && context.currentLine < context.lines.length) {
+            String line = context.lines[context.currentLine];
+
+            if (DecodeHelper.isBlankLine(line)) {
+                if (handleBlankLineInListArray(depth, context)) {
+                    shouldContinue = false;
+                }
+            } else {
+                int lineDepth = DecodeHelper.getDepth(line, context);
+                if (shouldTerminateListArray(lineDepth, depth, line, context)) {
+                    shouldContinue = false;
+                } else {
+                    ListItemDecoder.processListArrayItem(line, lineDepth, depth, result, context);
+                }
+            }
+        }
+
+        if (header != null) {
+            ArrayDecoder.validateArrayLength(header, result.size());
+        }
+        return result;
+    }
+
+    /**
+     * Handles blank line processing in list array.
+     * Returns true if array should terminate, false if line should be skipped.
+     */
+    private static boolean handleBlankLineInListArray(int depth, DecodeContext context) {
+        int nextNonBlankLine = DecodeHelper.findNextNonBlankLine(context.currentLine + 1, context);
+
+        if (nextNonBlankLine >= context.lines.length) {
+            return true; // End of file - terminate array
+        }
+
+        int nextDepth = DecodeHelper.getDepth(context.lines[nextNonBlankLine], context);
+        if (nextDepth <= depth) {
+            return true; // Blank line is outside array - terminate
+        }
+
+        // Blank line is inside array
+        if (context.options.strict()) {
+            throw new IllegalArgumentException("Blank line inside list array at line " + (context.currentLine + 1));
+        }
+        // In non-strict mode, skip blank lines
+        context.currentLine++;
+        return false;
+    }
+
+    /**
+     * Determines if list array parsing should terminate based online depth.
+     * Returns true if array should terminate, false otherwise.
+     */
+    private static boolean shouldTerminateListArray(int lineDepth, int depth, String line, DecodeContext context) {
+        if (lineDepth < depth + 1) {
+            return true; // Line depth is less than expected - terminate
+        }
+        // Also terminate if line is at expected depth but doesn't start with "-"
+        if (lineDepth == depth + 1) {
+            String content = line.substring((depth + 1) * context.options.indent());
+            return !content.startsWith("-"); // Not an array item - terminate
+        }
+        return false;
+    }
+}

src/main/java/dev/toonformat/jtoon/decoder/DecodeContext.java

@@ -0,0 +1,16 @@
+package dev.toonformat.jtoon.decoder;
+
+import dev.toonformat.jtoon.DecodeOptions;
+
+/**
+ * Deals with the main attributes used to decode TOON to JSON format
+ */
+public class DecodeContext {
+
+    protected String[] lines;
+    protected DecodeOptions options;
+    protected String delimiter;
+    protected int currentLine = 0;
+
+    public DecodeContext () {}
+}