// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0+ OR GPL-3.0 WITH Qt-GPL-exception-1.0

#pragma once

#include "qmljs_global.h"

#include "qmljsscanner.h"

#include <QStack>
#include <QList>
#include <QVector>
#include <QMetaObject>

QT_BEGIN_NAMESPACE
class QTextDocument;
class QTextBlock;
QT_END_NAMESPACE

namespace QmlJS {

class QMLJS_EXPORT CodeFormatter
{
    Q_GADGET
public:
    CodeFormatter();
    virtual ~CodeFormatter();

    // updates all states up until block if necessary
    // it is safe to call indentFor on block afterwards
    void updateStateUntil(const QTextBlock &block);

    // calculates the state change introduced by changing a single line
    void updateLineStateChange(const QTextBlock &block);

    int indentFor(const QTextBlock &block);
    int indentForNewLineAfter(const QTextBlock &block);

    void setTabSize(int tabSize);

    void invalidateCache(QTextDocument *document);

protected:
    virtual void onEnter(int newState, int *indentDepth, int *savedIndentDepth) const = 0;
    virtual void adjustIndent(const QList<Token> &tokens, int startLexerState, int *indentDepth) const = 0;

    struct State;
    class QMLJS_EXPORT BlockData
    {
    public:
        BlockData();

        QStack<State> m_beginState;
        QStack<State> m_endState;
        int m_indentDepth;
        int m_blockRevision;
    };

    virtual void saveBlockData(QTextBlock *block, const BlockData &data) const = 0;
    virtual bool loadBlockData(const QTextBlock &block, BlockData *data) const = 0;

    virtual void saveLexerState(QTextBlock *block, int state) const = 0;
    virtual int loadLexerState(const QTextBlock &block) const = 0;

public: // must be public to make Q_GADGET introspection work
    enum StateType {
        invalid = 0,

        topmost_intro, // The first line in a "topmost" definition.

        top_qml, // root state for qml
        top_js, // root for js
        objectdefinition_or_js, // file starts with identifier

        multiline_comment_start,
        multiline_comment_cont,

        import_start, // after 'import'
        import_maybe_dot_or_version_or_as, // after string or identifier
        import_dot, // after .
        import_maybe_as, // after version
        import_as,

        property_start, // after 'property'
        property_modifiers, // after 'default' or readonly
        required_property, // after required
        property_list_open, // after 'list' as a type
        property_name, // after the type
        property_maybe_initializer, // after the identifier
        component_start, // after component
        component_name, // after component Name

        enum_start, // after 'enum'

        signal_start, // after 'signal'
        signal_maybe_arglist, // after identifier
        signal_arglist_open, // after '('

        function_start, // after 'function'
        function_arglist_open, // after '(' starting function argument list
        function_arglist_closed, // after ')' in argument list, expecting '{'

        binding_or_objectdefinition, // after an identifier

        binding_assignment, // after : in a binding
        objectdefinition_open, // after {

        expression,
        expression_continuation, // at the end of the line, when the next line definitely is a continuation
        expression_maybe_continuation, // at the end of the line, when the next line may be an expression
        expression_or_objectdefinition, // after a binding starting with an identifier ("x: foo")
        expression_or_label, // when expecting a statement and getting an identifier

        paren_open, // opening ( in expression
        bracket_open, // opening [ in expression
        objectliteral_open, // opening { in expression

        objectliteral_assignment, // after : in object literal

        bracket_element_start, // after starting bracket_open or after ',' in bracket_open
        bracket_element_maybe_objectdefinition, // after an identifier in bracket_element_start

        ternary_op, // The ? : operator
        ternary_op_after_colon, // after the : in a ternary

        jsblock_open,

        empty_statement, // for a ';', will be popped directly
        breakcontinue_statement, // for continue/break, may be followed by identifier

        if_statement, // After 'if'
        maybe_else, // after the first substatement in an if
        else_clause, // The else line of an if-else construct.

        condition_open, // Start of a condition in 'if', 'while', entered after opening paren

        substatement, // The first line after a conditional or loop construct.
        substatement_open, // The brace that opens a substatement block.

        labelled_statement, // after a label

        return_statement, // After 'return'
        throw_statement, // After 'throw'

        statement_with_condition, // After the 'for', 'while', ... token
        statement_with_condition_paren_open, // While inside the (...)

        try_statement, // after 'try'
        catch_statement, // after 'catch', nested in try_statement
        finally_statement, // after 'finally', nested in try_statement
        maybe_catch_or_finally, // after ther closing '}' of try_statement and catch_statement, nested in try_statement

        do_statement, // after 'do'
        do_statement_while_paren_open, // after '(' in while clause

        switch_statement, // After 'switch' token
        case_start, // after a 'case' or 'default' token
        case_cont // after the colon in a case/default
    };
    Q_ENUM(StateType)

protected:
    // extends Token::Kind from qmljsscanner.h
    // the entries until EndOfExistingTokenKinds must match
    enum TokenKind {
        EndOfFile,
        Keyword,
        Identifier,
        String,
        Comment,
        Number,
        LeftParenthesis,
        RightParenthesis,
        LeftBrace,
        RightBrace,
        LeftBracket,
        RightBracket,
        Semicolon,
        Colon,
        Comma,
        Dot,
        Delimiter,
        RegExp,

        EndOfExistingTokenKinds,

        Break,
        Case,
        Catch,
        Continue,
        Debugger,
        Default,
        Delete,
        Do,
        Else,
        Enum,
        Finally,
        For,
        Function,
        If,
        In,
        Instanceof,
        New,
        Return,
        Switch,
        This,
        Throw,
        Try,
        Typeof,
        Var,
        Void,
        While,
        With,

        Import,
        Signal,
        On,
        As,
        List,
        Property,
        Required,
        Component,
        Readonly,

        Question,
        PlusPlus,
        MinusMinus
    };

    TokenKind extendedTokenKind(const QmlJS::Token &token) const;

    struct State {
        State()
            : savedIndentDepth(0)
            , type(0)
        {}

        State(quint8 ty, quint16 savedDepth)
            : savedIndentDepth(savedDepth)
            , type(ty)
        {}

        quint16 savedIndentDepth;
        quint8 type;

        bool operator==(const State &other) const {
            return type == other.type
                && savedIndentDepth == other.savedIndentDepth;
        }
    };

    State state(int belowTop = 0) const;
    const QVector<State> &newStatesThisLine() const;
    int tokenIndex() const;
    int tokenCount() const;
    const Token &currentToken() const;
    const Token &tokenAt(int idx) const;
    int column(int position) const;

    bool isBracelessState(int type) const;
    bool isExpressionEndState(int type) const;

    void dump() const;
    QString stateToString(int type) const;

private:
    void recalculateStateAfter(const QTextBlock &block);
    void saveCurrentState(const QTextBlock &block);
    void restoreCurrentState(const QTextBlock &block);

    QStringView currentTokenText() const;

    int tokenizeBlock(const QTextBlock &block);

    void turnInto(int newState);

    bool tryInsideExpression(bool alsoExpression = false);
    bool tryStatement();

    void enter(int newState);
    void leave(bool statementDone = false);
    void correctIndentation(const QTextBlock &block);

private:
    static QStack<State> initialState();

    QStack<State> m_beginState;
    QStack<State> m_currentState;
    QStack<State> m_newStates;

    QList<Token> m_tokens;
    QString m_currentLine;
    Token m_currentToken;
    int m_tokenIndex;

    // should store indent level and padding instead
    int m_indentDepth;

    int m_tabSize;
};

class QMLJS_EXPORT QtStyleCodeFormatter : public CodeFormatter
{
public:
    QtStyleCodeFormatter();

    void setIndentSize(int size);

protected:
    void onEnter(int newState, int *indentDepth, int *savedIndentDepth) const override;
    void adjustIndent(const QList<QmlJS::Token> &tokens, int lexerState, int *indentDepth) const override;

private:
    int m_indentSize;
};

} // namespace QmlJS
