// slang-json-value.h
#ifndef SLANG_JSON_VALUE_H
#define SLANG_JSON_VALUE_H

#include "../core/slang-basic.h"

#include "slang-source-loc.h"
#include "slang-diagnostic-sink.h"

#include "slang-json-parser.h"

namespace Slang {

typedef uint32_t JSONKey;

struct JSONValue
{
    enum class Kind
    {
        Invalid,

        Null,

        Bool,
        String,
        Integer,
        Float,

        Array,
        Object,

        CountOf, 
    };

    enum class Type
    {
        Invalid,

        True,
        False,
        Null,

        StringLexeme,
        IntegerLexeme,
        FloatLexeme,

        IntegerValue,
        FloatValue,
        StringValue,

        Array,
        Object,

        CountOf,
    };

    static bool isLexeme(Type type) { return Index(type) >= Index(Type::StringLexeme) && Index(type) <= Index(Type::FloatLexeme); }

    static JSONValue makeInt(int64_t inValue, SourceLoc loc = SourceLoc()) { JSONValue value; value.type = Type::IntegerValue; value.loc = loc; value.intValue = inValue; return value; }
    static JSONValue makeFloat(double inValue, SourceLoc loc = SourceLoc()) { JSONValue value; value.type = Type::FloatValue; value.loc = loc; value.floatValue = inValue; return value; }
    static JSONValue makeNull(SourceLoc loc = SourceLoc()) { JSONValue value; value.type = Type::Null; value.loc = loc; return value; }
    static JSONValue makeBool(bool inValue, SourceLoc loc = SourceLoc()) { JSONValue value; value.type = (inValue ? Type::True : Type::False); value.loc = loc; return value; }

    static JSONValue makeLexeme(Type type, SourceLoc loc,  Index length) { SLANG_ASSERT(isLexeme(type)); JSONValue value; value.type = type; value.loc = loc; value.length = length; return value; }

    static JSONValue makeEmptyArray(SourceLoc loc = SourceLoc()) { JSONValue value; value.type = Type::Array; value.loc = loc; value.rangeIndex = 0; return value; }
    static JSONValue makeEmptyObject(SourceLoc loc = SourceLoc()) { JSONValue value; value.type = Type::Object; value.loc = loc; value.rangeIndex = 0; return value; }

    // The following functions only work if the value is stored directly NOT as a lexeme. Use the methods on the container
    // to access values if it is potentially stored as a lexeme

        /// As a boolean value 
    bool asBool() const;
        /// As an integer value
    int64_t asInteger() const;
        /// As a float value
    double asFloat() const;

        /// True if this is a object like
    bool isObjectLike() const { return Index(type) >= Index(Type::Array); }

        /// True if this appears to be a valid value
    bool isValid() const { return type != JSONValue::Type::Invalid; }

        /// True if needs destroy
    bool needsDestroy() const { return isObjectLike() && rangeIndex != 0; }

        /// Get the kind
    SLANG_FORCE_INLINE Kind getKind() const { return getKindForType(type); }

    void reset()
    {
        type = Type::Invalid;
        loc = SourceLoc();
    }

        /// Given a type return the associated kind
    static Kind getKindForType(Type type) { return g_typeToKind[Index(type)]; }

    Type type;                  ///< The type of value
    SourceLoc loc;              ///< The (optional) location in source of this value.

    union 
    {
        Index rangeIndex;           ///< Used for Array/Object
        Index length;               ///< Length in bytes if it is a 'Lexeme'
        double floatValue;          ///< Float value
        int64_t intValue;           ///< Integer value
        JSONKey stringKey;          ///< The pool key if it's a string
    };

    static const Kind g_typeToKind[Index(Type::CountOf)];
};

struct JSONKeyValue
{
        /// True if it's valid
    bool isValid() const { return value.type != JSONValue::Type::Invalid; }

    void reset()
    {
        key = JSONKey(0);
        keyLoc = SourceLoc();
        value.reset();
    }

    JSONKey key;
    SourceLoc keyLoc;
    JSONValue value;

    static JSONKeyValue g_invalid;
};

class JSONContainer : public RefObject
{
public:

        /// Make a new array
    JSONValue createArray(const JSONValue* values, Index valuesCount, SourceLoc loc = SourceLoc());
        /// Make a new object
    JSONValue createObject(const JSONKeyValue* keyValues, Index keyValueCount, SourceLoc loc = SourceLoc());
        /// Make a string
    JSONValue createString(const UnownedStringSlice& slice, SourceLoc loc = SourceLoc()); 

    ConstArrayView<JSONValue> getArray(const JSONValue& in) const;
    ConstArrayView<JSONKeyValue> getObject(const JSONValue& in) const;

    ArrayView<JSONValue> getArray(const JSONValue& in);
    ArrayView<JSONKeyValue> getObject(const JSONValue& in);

        /// Add value to array.
    void addToArray(JSONValue& array, const JSONValue& value);

        /// Get the value at the index in the array
    JSONValue& getAt(const JSONValue& array, Index index);

        /// Returns the index 
    Index findKeyGlobalIndex(const JSONValue& obj, JSONKey key);
    Index findKeyGlobalIndex(const JSONValue& obj, const UnownedStringSlice& slice);

        /// Set a key value for the obj
    void setKeyValue(JSONValue& obj, JSONKey key, const JSONValue& value, SourceLoc loc = SourceLoc());

        /// Returns true if found
    bool removeKey(JSONValue& obj, JSONKey key);
    bool removeKey(JSONValue& obj, const UnownedStringSlice& slice);

        /// As a boolean value
    bool asBool(const JSONValue& value);
        /// As an integer value
    int64_t asInteger(const JSONValue& value);
        /// As a float value
    double asFloat(const JSONValue& value);

        /// Returns string as a key
    JSONKey getStringKey(const JSONValue& in);

        /// Get as a string. 
    UnownedStringSlice getString(const JSONValue& in);

        /// Gets the lexeme
    UnownedStringSlice getLexeme(const JSONValue& in);

        /// Get a key for a name
    JSONKey getKey(const UnownedStringSlice& slice);
        /// Get the string from the key
    UnownedStringSlice getStringFromKey(JSONKey key) const { return m_slicePool.getSlice(StringSlicePool::Handle(key)); }

        /// True if they are the same value
        /// If object like type comparison is performed recursively.
        /// NOTE! That Float and Integer values do not compare & source locations are ignored.
    bool areEqual(const JSONValue& a, const JSONValue& b);
    bool areEqual(const JSONValue* a, const JSONValue* b, Index count);
    bool areEqual(const JSONKeyValue* a, const JSONKeyValue* b, Index count);

        /// Destroy value
    void destroy(JSONValue& value);
        /// Destroy recursively from value
    void destroyRecursively(JSONValue& value);

        /// Traverse a JSON hierarchy from value, outputting to the listener
    void traverseRecursively(const JSONValue& value, JSONListener* listener);

        /// Returns the source manager used. 
    SourceManager* getSourceManager() const { return m_sourceManager; } 

        // Ctor
    JSONContainer(SourceManager* sourceManger);

        /// Returns true if all the keys are unique
    static bool areKeysUnique(const JSONKeyValue* keyValues, Index keyValueCount);

protected:
    struct Range
    {
        // We want to record the underlying range, because we don't track JSONValue, and so we need to know what the range
        // applies to if we want to reorder, flatten etc.
        enum class Type
        {
            None,
            Destroyed,
            Object,
            Array,
        };

            /// Is active if it consuming some part of a value list (even if zero count)
        SLANG_FORCE_INLINE bool isActive() const { return Index(type) >= Index(Type::Object); }

        Type type;
        Index startIndex;
        Index count;
        Index capacity;
    };

    template <typename T>
    static void _add(Range& range, List<T>& list, const T& value);

    Index _addRange(Range::Type type, Index startIndex, Index count);
    void _removeKey(JSONValue& obj, Index globalIndex);
        /// Note does not destroy values in range.
    void _destroyRange(Index rangeIndex);

    static bool _sameKeyOrder(const JSONKeyValue* a, const JSONKeyValue* b, Index count);
        /// True if the values are equal
    bool _areEqualValues(const JSONKeyValue* a, const JSONKeyValue* b, Index count);
        /// True if the key and value are equal
    bool _areEqualOrderedKeys(const JSONKeyValue* a, const JSONKeyValue* b, Index count);

    StringBuilder m_buf;                        ///< A temporary buffer used to hold unescaped strings

    SourceView* m_currentView = nullptr;
    SourceManager* m_sourceManager;

    StringSlicePool m_slicePool;
    List<Range> m_ranges;
    List<Index> m_freeRangeIndices;
    List<JSONValue> m_arrayValues;
    List<JSONKeyValue> m_objectValues;
};

class JSONBuilder : public JSONListener
{
public:

    typedef uint32_t Flags;
    struct Flag
    {
        enum Enum : Flags
        {
            ConvertLexemes = 0x01,
        };
    };


    virtual void startObject(SourceLoc loc) SLANG_OVERRIDE;
    virtual void endObject(SourceLoc loc) SLANG_OVERRIDE;
    virtual void startArray(SourceLoc loc) SLANG_OVERRIDE;
    virtual void endArray(SourceLoc loc) SLANG_OVERRIDE;
    virtual void addKey(const UnownedStringSlice& key, SourceLoc loc) SLANG_OVERRIDE;
    virtual void addLexemeValue(JSONTokenType type, const UnownedStringSlice& value, SourceLoc loc) SLANG_OVERRIDE;
    virtual void addIntegerValue(int64_t value, SourceLoc loc) SLANG_OVERRIDE;
    virtual void addFloatValue(double value, SourceLoc loc) SLANG_OVERRIDE;
    virtual void addBoolValue(bool value, SourceLoc loc) SLANG_OVERRIDE;
    virtual void addStringValue(const UnownedStringSlice& string, SourceLoc loc) SLANG_OVERRIDE;
    virtual void addNullValue(SourceLoc loc) SLANG_OVERRIDE;

        /// Reset the state
    void reset();

        /// Get the root value. Will be set after valid construction
    const JSONValue& getRootValue() const { return m_rootValue; }

    JSONBuilder(JSONContainer* container, Flags flags = 0);

protected:

    struct State
    {
        enum class Kind : uint8_t
        {
            Root,
            Object,
            Array,
        };
        Kind m_kind;
        Index m_startIndex;
        SourceLoc m_loc;
    };

    void _popState();
    void _add(const JSONValue& value);

    Index _findKeyIndex(JSONKey key) const;

    Flags m_flags;

    List<JSONKeyValue> m_keyValues;
    List<JSONValue> m_values;
    List<State> m_stateStack;

    State m_state;

    JSONContainer* m_container;

    JSONKeyValue m_keyValue;
    JSONValue m_rootValue;
};

} // namespace Slang

#endif