package rendering.source;

import java.util.*;

public class ScopeTracker {

    private final Map<String, Stack<String>> variableToShortTypes = new HashMap<>();

    private final Map<String, Stack<Integer>> variableToLines = new HashMap<>();

    private final Stack<List<String>> scopeToVariableNames = new Stack<>();

    public void startScope() {

        scopeToVariableNames.add(new ArrayList<>());

    }

    public void addVariable(

            String variableName,

            String variableType,

            int lineNumber) {

        if (scopeToVariableNames.isEmpty()) {

            return;

        }

        List<String> variableNames = scopeToVariableNames.peek();

        variableNames.add(variableName);

        Stack<String> types = variableToShortTypes.get(variableName);

        if (types == null) {

            types = new Stack<>();

            variableToShortTypes.put(variableName, types);

        }

        types.add(variableType);

        Stack<Integer> lines = variableToLines.get(variableName);

        if (lines == null) {

            lines = new Stack<>();

            variableToLines.put(variableName, lines);

        }

        lines.add(lineNumber);

    }

    /**

     * @param variableName the name of the variable to search in the scope for.

     * @return the short type that still needs to joined against the imports to figure out the full

     *         class name (fully qualified name).

     */

    public String getVariableShortType(String variableName) {

          Stack<String> types = variableToShortTypes.get(variableName);

          if (types == null) {

              return null;

          }

          if (types.isEmpty()) {

              return null;

          }

          return types.peek();

      }

    public Integer getVariableLine(String variableName) {

        Stack<Integer> lines = variableToLines.get(variableName);

        if (lines == null) {

            return null;

        }

        if (lines.isEmpty()) {

            return null;

        }

        return lines.peek();

    }

    public void endScope() {

        if (scopeToVariableNames.isEmpty()) {

            return;

        }

        List<String> variableNamesToRemove = scopeToVariableNames.pop();

        for (String variableNameToRemove : variableNamesToRemove) {

            Stack<String> types = variableToShortTypes.get(variableNameToRemove);

            if (types != null && !types.isEmpty()) {

                types.pop();

            }

            Stack<Integer> lines = variableToLines.get(variableNameToRemove);

            if (types != null && !types.isEmpty()) {

                types.pop();

            }

        }

    }

}