/*
    * SPDX-FileCopyrightText: none
    * SPDX-License-Identifier: CC0-1.0
    */
   
   package dev.metaschema.schemagen;
   
   import org.eclipse.jdt.annotation.NotOwning;
   
  import java.util.ArrayList;
  import java.util.LinkedList;
  import java.util.List;
  
  import dev.metaschema.core.configuration.IConfiguration;
  import dev.metaschema.core.metapath.IMetapathExpression;
  import dev.metaschema.core.model.IDefinition;
  import dev.metaschema.core.model.IModule;
  import dev.metaschema.core.model.INamedInstance;
  import dev.metaschema.core.model.IValuedDefinition;
  import dev.metaschema.core.model.constraint.IAllowedValue;
  import dev.metaschema.core.model.constraint.IAllowedValuesConstraint;
  import dev.metaschema.core.util.CollectionUtil;
  import dev.metaschema.core.util.ObjectUtils;
  import dev.metaschema.schemagen.datatype.IDatatypeManager;
  import edu.umd.cs.findbugs.annotations.NonNull;
  import edu.umd.cs.findbugs.annotations.Nullable;
  
  /**
   * Provides a common base implementation for schema generation state management.
   * <p>
   * This abstract class maintains the context required during schema generation,
   * including the module being processed, the output writer, datatype management,
   * and inlining strategy.
   *
   * @param <WRITER>
   *          the type of writer used for schema output
   * @param <DATATYPE_MANAGER>
   *          the type of datatype manager used for type name resolution
   */
  public abstract class AbstractGenerationState<WRITER, DATATYPE_MANAGER extends IDatatypeManager>
      implements IGenerationState<WRITER> {
    @NonNull
    private final IModule module;
    @NonNull
    private final WRITER writer;
    @NonNull
    private final DATATYPE_MANAGER datatypeManager;
    @NonNull
    private final IInlineStrategy inlineStrategy;
  
    @NonNull
    private final ModuleIndex moduleIndex;
  
    /**
     * Construct a new generation state instance.
     *
     * @param module
     *          the Metaschema module to generate a schema for
     * @param writer
     *          the output writer for the generated schema
     * @param configuration
     *          the configuration controlling schema generation behavior
     * @param datatypeManager
     *          the manager for handling datatype name resolution
     */
    public AbstractGenerationState(
        @NonNull IModule module,
        @NonNull WRITER writer,
        @NonNull IConfiguration<SchemaGenerationFeature<?>> configuration,
        @NonNull DATATYPE_MANAGER datatypeManager) {
      this.module = module;
      this.writer = writer;
      this.datatypeManager = datatypeManager;
      this.inlineStrategy = IInlineStrategy.newInlineStrategy(configuration);
      this.moduleIndex = ModuleIndex.indexDefinitions(module, this.inlineStrategy);
    }
  
    @Override
    public IModule getModule() {
      return module;
    }
  
    @Override
    @NotOwning
    public WRITER getWriter() {
      return writer;
    }
  
    /**
     * Get the datatype manager used for type name resolution.
     *
     * @return the datatype manager
     */
    @NonNull
    protected DATATYPE_MANAGER getDatatypeManager() {
      return datatypeManager;
    }
  
    /**
    * Get the module index containing indexed definitions from the module.
    *
    * @return the module index
    */
   @NonNull
   public ModuleIndex getMetaschemaIndex() {
     return moduleIndex;
   }
 
   @Override
   public boolean isInline(@NonNull IDefinition definition) {
     return inlineStrategy.isInline(definition, getMetaschemaIndex());
   }
 
   /**
    * Retrieve any allowed values that are context independent, meaning they always
    * apply regardless of the location of the node in the larger graph.
    *
    * @param definition
    *          the definition to get allowed values for
    * @return the list of allowed values or an empty list
    */
   @NonNull
   protected static AllowedValueCollection getContextIndependentEnumeratedValues(
       @NonNull IValuedDefinition definition) {
     List<IAllowedValue> values = new LinkedList<>();
     boolean closed = false;
     for (IAllowedValuesConstraint constraint : definition.getAllowedValuesConstraints()) {
       assert constraint != null;
       if (!constraint.isAllowedOther()) {
         closed = true;
       }
 
       // FIXME: Should this compare the actual compiled expression?
       if (!IMetapathExpression.contextNode().getPath().equals(constraint.getTarget().getPath())) {
         values = CollectionUtil.emptyList();
         break;
       }
 
       values.addAll(constraint.getAllowedValues().values());
     }
     return new AllowedValueCollection(closed, values);
   }
 
   /**
    * Get the name of the definition (and any parent instances/definition) to
    * ensure an inline type is unique.
    *
    * @param definition
    *          the definition to generate a type name for
    * @param childModule
    *          the module of the left node
    * @return the unique type name
    */
   private CharSequence getTypeContext(
       @NonNull IDefinition definition,
       @NonNull IModule childModule) {
     StringBuilder builder = new StringBuilder();
     if (definition.isInline()) {
       INamedInstance inlineInstance = definition.getInlineInstance();
       IDefinition parentDefinition = inlineInstance.getContainingDefinition();
 
       builder
           .append(getTypeContext(parentDefinition, childModule))
           .append(IGenerationState.toCamelCase(inlineInstance.getEffectiveName()));
     } else {
       builder.append(IGenerationState.toCamelCase(definition.getName()));
     }
     return builder;
   }
 
   @Override
   @NonNull
   public String getTypeNameForDefinition(@NonNull IDefinition definition, @Nullable String suffix) {
     StringBuilder builder = new StringBuilder()
         .append(IGenerationState.toCamelCase(definition.getModelType().name()))
         .append(IGenerationState.toCamelCase(definition.getContainingModule().getShortName()));
 
     if (isInline(definition)) {
       builder.append(IGenerationState.toCamelCase(definition.getEffectiveName()));
     } else {
       // need to append the parent name(s) to disambiguate this type name
       builder.append(getTypeContext(definition, definition.getContainingModule()));
     }
     if (suffix != null && !suffix.isBlank()) {
       builder.append(suffix);
     }
     builder.append("Type");
 
     return ObjectUtils.notNull(builder.toString());
   }
 
   /**
    * Represents a collection of allowed values with a flag indicating whether the
    * value set is closed (no other values allowed) or open.
    */
   public static class AllowedValueCollection {
     private final boolean closed;
     @NonNull
     private final List<IAllowedValue> values;
 
     /**
      * Construct a new allowed value collection.
      *
      * @param closed
      *          {@code true} if only the specified values are allowed, {@code false}
      *          if other values are also permitted
      * @param values
      *          the list of allowed values
      */
     public AllowedValueCollection(boolean closed, @NonNull List<IAllowedValue> values) {
       this.closed = closed;
       this.values = CollectionUtil.unmodifiableList(new ArrayList<>(values));
     }
 
     /**
      * Determine if the allowed value set is closed.
      *
      * @return {@code true} if only the specified values are allowed, {@code false}
      *         if other values are also permitted
      */
     public boolean isClosed() {
       return closed;
     }
 
     /**
      * Get the list of allowed values.
      *
      * @return an unmodifiable list of allowed values
      */
     @NonNull
     public List<IAllowedValue> getValues() {
       return values;
     }
   }
 }