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package com.oracle.js.parser.ir;

import java.util.Arrays;
import java.util.Collections;
import java.util.List;

import com.oracle.js.parser.ir.visitor.NodeVisitor;
import com.oracle.js.parser.ir.visitor.TranslatorNodeVisitor;

IR representation for a list of statements.
/**
 * IR representation for a list of statements.
 */
public class Block extends Node implements BreakableNode, Terminal, Flags<Block>, LexicalContextScope {
    
List of statements /** List of statements */
    protected final List<Statement> statements;

    protected final Scope scope;

    
Does the block/function need a new scope? Is this synthetic? /** Does the block/function need a new scope? Is this synthetic? */
    protected final int flags;

    
Flag indicating that this block needs scope /** Flag indicating that this block needs scope */
    public static final int NEEDS_SCOPE = 1 << 0;

    
Is this block tagged as terminal based on its contents (usually the last statement)
/**
     * Is this block tagged as terminal based on its contents (usually the last statement)
     */
    public static final int IS_TERMINAL = 1 << 2;

    
Is this block the eager global scope - i.e. the original program. This isn't true for the
outermost level of recompiles
/**
     * Is this block the eager global scope - i.e. the original program. This isn't true for the
     * outermost level of recompiles
     */
    public static final int IS_GLOBAL_SCOPE = 1 << 3;

    
Is this block a synthetic one introduced by Parser?
/**
     * Is this block a synthetic one introduced by Parser?
     */
    public static final int IS_SYNTHETIC = 1 << 4;

    
Is this the function body block? May not be the first, if parameter list contains
expressions.
/**
     * Is this the function body block? May not be the first, if parameter list contains
     * expressions.
     */
    public static final int IS_BODY = 1 << 5;

    
Is this the parameter initialization block? If present, must be the first block, immediately
wrapping the function body block.
/**
     * Is this the parameter initialization block? If present, must be the first block, immediately
     * wrapping the function body block.
     */
    public static final int IS_PARAMETER_BLOCK = 1 << 6;

    
Marks the variable declaration block for case clauses of a switch statement.
/**
     * Marks the variable declaration block for case clauses of a switch statement.
     */
    public static final int IS_SWITCH_BLOCK = 1 << 7;

    
Is this an expression block (class or do expression) that should return its completion value.
/**
     * Is this an expression block (class or do expression) that should return its completion value.
     */
    public static final int IS_EXPRESSION_BLOCK = 1 << 8;

    
Marks the module body block.
/**
     * Marks the module body block.
     */
    public static final int IS_MODULE_BODY = 1 << 9;

    
Constructor
Params:
token – The first token of the block
finish – The index of the last character
flags – The flags of the block
statements – All statements in the block/**
     * Constructor
     *
     * @param token The first token of the block
     * @param finish The index of the last character
     * @param flags The flags of the block
     * @param statements All statements in the block
     */
    public Block(final long token, final int finish, final int flags, final Scope scope, final Statement... statements) {
        super(token, finish);
        assert start <= finish;

        this.statements = statements.length == 0 ? Collections.emptyList() : Arrays.asList(statements);
        this.scope = scope;
        final int len = statements.length;
        final int terminalFlags = len > 0 && statements[len - 1].hasTerminalFlags() ? IS_TERMINAL : 0;
        this.flags = terminalFlags | flags;
    }

    
Constructor
Params:
token – The first token of the block
finish – The index of the last character
flags – The flags of the block
statements – All statements in the block/**
     * Constructor
     *
     * @param token The first token of the block
     * @param finish The index of the last character
     * @param flags The flags of the block
     * @param statements All statements in the block
     */
    public Block(final long token, final int finish, final int flags, final Scope scope, final List<Statement> statements) {
        this(token, finish, flags, scope, statements.toArray(new Statement[statements.size()]));
    }

    private Block(final Block block, final int finish, final List<Statement> statements, final int flags) {
        super(block, finish);
        this.statements = statements;
        this.flags = flags;
        this.scope = block.scope;
    }

    
Is this block the outermost eager global scope - i.e. the primordial program? Used for global
anchor point for scope depth computation for recompilation code
Returns:
true if outermost eager global scope/**
     * Is this block the outermost eager global scope - i.e. the primordial program? Used for global
     * anchor point for scope depth computation for recompilation code
     *
     * @return true if outermost eager global scope
     */
    public boolean isGlobalScope() {
        return getFlag(IS_GLOBAL_SCOPE);
    }

    
Assist in IR navigation.
Params:
visitor – IR navigating visitor.
Returns:
new or same node/**
     * Assist in IR navigation.
     *
     * @param visitor IR navigating visitor.
     * @return new or same node
     */
    @Override
    public Node accept(final LexicalContext lc, final NodeVisitor<? extends LexicalContext> visitor) {
        if (visitor.enterBlock(this)) {
            return visitor.leaveBlock(setStatements(lc, Node.accept(visitor, statements)));
        }

        return this;
    }

    @Override
    public <R> R accept(LexicalContext lc, TranslatorNodeVisitor<? extends LexicalContext, R> visitor) {
        return visitor.enterBlock(this);
    }

    
Get all the symbols defined in this block, in definition order.
Returns:
symbol iterator/**
     * Get all the symbols defined in this block, in definition order.
     *
     * @return symbol iterator
     */
    public Iterable<Symbol> getSymbols() {
        return scope.getSymbols();
    }

    
Retrieves an existing symbol defined in the current block.
Params:
name – the name of the symbol
Returns:
an existing symbol with the specified name defined in the current block, or null if
        this block doesn't define a symbol with this name./**
     * Retrieves an existing symbol defined in the current block.
     *
     * @param name the name of the symbol
     * @return an existing symbol with the specified name defined in the current block, or null if
     *         this block doesn't define a symbol with this name.
     */
    public Symbol getExistingSymbol(final String name) {
        return scope.getExistingSymbol(name);
    }

    
Test if a symbol with this name is defined in the current block.
Params:
name – the name of the symbol/**
     * Test if a symbol with this name is defined in the current block.
     *
     * @param name the name of the symbol
     */
    public boolean hasSymbol(final String name) {
        return scope.hasSymbol(name);
    }

    
Get the number of symbols defined in this block.
/**
     * Get the number of symbols defined in this block.
     */
    public int getSymbolCount() {
        return scope.getSymbolCount();
    }

    
Test if this block represents a catch block in a try statement.
Returns:
true if this block represents a catch block in a try statement./**
     * Test if this block represents a <tt>catch</tt> block in a <tt>try</tt> statement.
     *
     * @return true if this block represents a catch block in a try statement.
     */
    public boolean isCatchBlock() {
        return getLastStatement() instanceof CatchNode;
    }

    @Override
    public void toString(final StringBuilder sb, final boolean printType) {
        for (final Node statement : statements) {
            statement.toString(sb, printType);
            sb.append(';');
        }
    }

    @Override
    public int getFlags() {
        return flags;
    }

    
Is this a terminal block, i.e. does it end control flow like ending with a throw or return?
Returns:
true if this node statement is terminal/**
     * Is this a terminal block, i.e. does it end control flow like ending with a throw or return?
     *
     * @return true if this node statement is terminal
     */
    @Override
    public boolean isTerminal() {
        return getFlag(IS_TERMINAL);
    }

    
Get the list of statements in this block
Returns:
a list of statements/**
     * Get the list of statements in this block
     *
     * @return a list of statements
     */
    public List<Statement> getStatements() {
        return Collections.unmodifiableList(statements);
    }

    
Returns the number of statements in the block.
Returns:
the number of statements in the block./**
     * Returns the number of statements in the block.
     *
     * @return the number of statements in the block.
     */
    public int getStatementCount() {
        return statements.size();
    }

    
Returns the line number of the first statement in the block.
Returns:
the line number of the first statement in the block, or -1 if the block has no
        statements./**
     * Returns the line number of the first statement in the block.
     *
     * @return the line number of the first statement in the block, or -1 if the block has no
     *         statements.
     */
    public int getFirstStatementLineNumber() {
        if (statements == null || statements.isEmpty()) {
            return -1;
        }
        return statements.get(0).getLineNumber();
    }

    
Returns the first statement in the block.
Returns:
the first statement in the block, or null if the block has no statements./**
     * Returns the first statement in the block.
     *
     * @return the first statement in the block, or null if the block has no statements.
     */
    public Statement getFirstStatement() {
        return statements.isEmpty() ? null : statements.get(0);
    }

    
Returns the last statement in the block.
Returns:
the last statement in the block, or null if the block has no statements./**
     * Returns the last statement in the block.
     *
     * @return the last statement in the block, or null if the block has no statements.
     */
    public Statement getLastStatement() {
        return statements.isEmpty() ? null : statements.get(statements.size() - 1);
    }

    
Reset the statement list for this block
Params:
lc – lexical context
statements – new statement list
Returns:
new block if statements changed, identity of statements == block.statements/**
     * Reset the statement list for this block
     *
     * @param lc lexical context
     * @param statements new statement list
     * @return new block if statements changed, identity of statements == block.statements
     */
    public Block setStatements(final LexicalContext lc, final List<Statement> statements) {
        if (this.statements == statements) {
            return this;
        }
        int lastFinish = 0;
        if (!statements.isEmpty()) {
            lastFinish = statements.get(statements.size() - 1).getFinish();
        }
        return Node.replaceInLexicalContext(lc, this, new Block(this, Math.max(finish, lastFinish), statements, flags));
    }

    
Check whether scope is necessary for this Block
Returns:
true if this function needs a scope/**
     * Check whether scope is necessary for this Block
     *
     * @return true if this function needs a scope
     */
    public boolean needsScope() {
        return (flags & NEEDS_SCOPE) == NEEDS_SCOPE;
    }

    
Check whether this block is synthetic or not.
Returns:
true if this is a synthetic block/**
     * Check whether this block is synthetic or not.
     *
     * @return true if this is a synthetic block
     */
    public boolean isSynthetic() {
        return (flags & IS_SYNTHETIC) == IS_SYNTHETIC;
    }

    @Override
    public Block setFlags(final LexicalContext lc, final int flags) {
        if (this.flags == flags) {
            return this;
        }
        return Node.replaceInLexicalContext(lc, this, new Block(this, finish, statements, flags));
    }

    @Override
    public Block setFlag(final LexicalContext lc, final int flag) {
        return setFlags(lc, flags | flag);
    }

    @Override
    public boolean getFlag(final int flag) {
        return (flags & flag) == flag;
    }

    @Override
    public boolean isBreakableWithoutLabel() {
        return false;
    }

    @Override
    public Node accept(final NodeVisitor<? extends LexicalContext> visitor) {
        return BreakableNode.super.accept(visitor);
    }

    @Override
    public <R> R accept(TranslatorNodeVisitor<? extends LexicalContext, R> visitor) {
        return BreakableNode.super.accept(visitor);
    }

    @Override
    public Scope getScope() {
        return scope;
    }

    public boolean isFunctionBody() {
        return getFlag(IS_BODY);
    }

    public boolean isParameterBlock() {
        return getFlag(IS_PARAMETER_BLOCK);
    }

    public boolean isSwitchBlock() {
        return getFlag(IS_SWITCH_BLOCK);
    }

    public boolean isExpressionBlock() {
        return getFlag(IS_EXPRESSION_BLOCK);
    }

    public boolean isModuleBody() {
        return getFlag(IS_MODULE_BODY);
    }
}