package cparser;

import java.util.*;

import cparser.Tokenizer.Token;
import cparser.Log;

public class Parser {
  private Tokenizer.TokenSet tokenSet;
  private List<Variable> variables;
  private List<Function> functions;
  private List<FunctionCall> functionCalls;
  private Log log;

  public Parser(Tokenizer.TokenSet tokenSet, Log log) {
    this.tokenSet = tokenSet;
    this.variables = new ArrayList<>();
    this.functions = new ArrayList<>();
    this.functionCalls = new ArrayList<>();
  }

  void log(String msg) {
    if (log != null) {
      log.log(msg);
    }
  }

  int index = 0;

  public void parse() {
    Tokenizer.Token[] tokens = tokenSet.getTokens();
    for (index = 0; index < tokens.length; index++) {
      Tokenizer.Token token = tokens[index];
      if (token.type == Tokenizer.TokenType.BLOCK_COMMENT || token.type == Tokenizer.TokenType.COMMENT) {
        continue;
      } else if (token.type == Tokenizer.TokenType.HASH) {
        index = parsePreprocessorExpression();
      } else if (tokens[index].type == Tokenizer.TokenType.IDENTIFIER) {
        if (index + 1 < tokens.length && tokens[index + 1].type == Tokenizer.TokenType.L_PAREN) {
          // Function call or declaration/definition
          if (index > 0 && (tokens[index - 1].type == Tokenizer.TokenType.IDENTIFIER ||
              tokens[index - 1].type == Tokenizer.TokenType.OTHER)) {
            // Function declaration or definition
            index = parseFunctionDeclaration();
          } else {
            // Function call
            index = parseFunctionCall();
          }
        } else {
          // Variable reference
          index = parseVariableReference();
        }
      }
    }
  }

  // Try to parse prep expression
  private int parsePreprocessorExpression() {
    int index = this.index;
    if (tokenSet.tokens[index].type == Tokenizer.TokenType.HASH) {
      int startLine = tokenSet.getLine(index);
      while (index < tokenSet.tokens.length) {
        if (tokenSet.getLine(index) > startLine) {
          break;
        }
        index++;
      }
      // Find first next line token
      index--;
    }
    return index;
  }

  // Try to parse function declaration and return the ending token index
  private int parseFunctionDeclaration() {
    Tokenizer.Token[] tokens = tokenSet.getTokens();
    String name = tokenSet.getTextNoNewlines(tokens[index]);
    int endIndex = findClosingParenthesis(index + 1);

    if (endIndex == -1)
      return index;

    boolean isDefinition = false;
    if (endIndex + 1 < tokens.length && tokens[endIndex + 1].type == Tokenizer.TokenType.L_BRACE) {
      isDefinition = true;
      endIndex = findClosingBrace(endIndex + 1);
    }

    if (endIndex == -1)
      return index;

    Function function = new Function(name, tokens[index].ofs, tokens[endIndex].ofs + tokens[endIndex].len,
        isDefinition);
    functions.add(function);
    return endIndex - 1;
  }

  // Try to parse function call and return the ending token index
  private int parseFunctionCall() {
    Tokenizer.Token[] tokens = tokenSet.getTokens();
    String name = tokenSet.getTextNoNewlines(tokens[index]);
    int endIndex = findClosingParenthesis(index + 1);
    if (endIndex == -1)
      return index;

    FunctionCall functionCall = new FunctionCall(name, tokens[index].ofs,
        tokens[endIndex].ofs + tokens[endIndex].len);
    functionCalls.add(functionCall);
    return endIndex - 1;
  }

  // Try to parse variable reference and add it to the list
  private int parseVariableReference() {
    Tokenizer.Token token = tokenSet.getTokens()[index];
    String name = tokenSet.getTextNoNewlines(token);
    Variable variable = new Variable(name, token.ofs, token.ofs + token.len);
    variables.add(variable);
    return index + 1;
  }

  private int findClosingParenthesis(int startIndex) {
    Tokenizer.Token[] tokens = tokenSet.getTokens();
    int parenCount = 1;
    for (int i = startIndex + 1; i < tokens.length; i++) {
      if (tokens[i].type == Tokenizer.TokenType.L_PAREN) {
        parenCount++;
      } else if (tokens[i].type == Tokenizer.TokenType.R_PAREN) {
        parenCount--;
        if (parenCount == 0) {
          return i;
        }
      }
    }
    return -1;
  }

  private int findClosingBrace(int startIndex) {
    Tokenizer.Token[] tokens = tokenSet.getTokens();
    int braceCount = 1;
    for (int i = startIndex + 1; i < tokens.length; i++) {
      if (tokens[i].type == Tokenizer.TokenType.L_BRACE) {
        braceCount++;
      } else if (tokens[i].type == Tokenizer.TokenType.R_BRACE) {
        braceCount--;
        if (braceCount == 0) {
          return i;
        }
      }
    }
    return -1;
  }

  public List<Variable> getVariables() {
    return variables;
  }

  public List<Function> getFunctions() {
    return functions;
  }

  public List<FunctionCall> getFunctionCalls() {
    return functionCalls;
  }

  public static class Variable {
    public final String name;
    public final int startOffset;
    public final int endOffset;

    public Variable(String name, int startOffset, int endOffset) {
      this.name = name;
      this.startOffset = startOffset;
      this.endOffset = endOffset;
    }
  }

  public static class Function {
    public final String name;
    public final int startOffset;
    public final int endOffset;
    public final boolean isDefinition;

    public Function(String name, int startOffset, int endOffset, boolean isDefinition) {
      this.name = name;
      this.startOffset = startOffset;
      this.endOffset = endOffset;
      this.isDefinition = isDefinition;
    }
  }

  public static class FunctionCall {
    public final String name;
    public final int startOffset;
    public final int endOffset;

    public FunctionCall(String name, int startOffset, int endOffset) {
      this.name = name;
      this.startOffset = startOffset;
      this.endOffset = endOffset;
    }
  }
}