// © 2017 and later: Unicode, Inc. and others.

// License & terms of use: http://www.unicode.org/copyright.html

#include "unicode/utypes.h"

#if !UCONFIG_NO_FORMATTING

#ifndef __NUMBER_STRINGBUILDER_H__

#define __NUMBER_STRINGBUILDER_H__

#include <cstdint>

#include "unicode/numfmt.h"

#include "unicode/ustring.h"

#include "cstring.h"

#include "uassert.h"

#include "number_types.h"

#include "fphdlimp.h"

U_NAMESPACE_BEGIN namespace number {

namespace impl {

class U_I18N_API NumberStringBuilder : public UMemory {

  private:

    static const int32_t DEFAULT_CAPACITY = 40;

    template<typename T>

    union ValueOrHeapArray {

        T value[DEFAULT_CAPACITY];

        struct {

            T *ptr;

            int32_t capacity;

        } heap;

    };

  public:

    NumberStringBuilder();

    ~NumberStringBuilder();

    NumberStringBuilder(const NumberStringBuilder &other);

    NumberStringBuilder &operator=(const NumberStringBuilder &other);

    int32_t length() const;

    int32_t codePointCount() const;

    inline char16_t charAt(int32_t index) const {

        U_ASSERT(index >= 0);

        U_ASSERT(index < fLength);

        return getCharPtr()[fZero + index];

    }

    inline Field fieldAt(int32_t index) const {

        U_ASSERT(index >= 0);

        U_ASSERT(index < fLength);

        return getFieldPtr()[fZero + index];

    }

    UChar32 getFirstCodePoint() const;

    UChar32 getLastCodePoint() const;

    UChar32 codePointAt(int32_t index) const;

    UChar32 codePointBefore(int32_t index) const;

    NumberStringBuilder &clear();

    int32_t appendCodePoint(UChar32 codePoint, Field field, UErrorCode &status);

    int32_t insertCodePoint(int32_t index, UChar32 codePoint, Field field, UErrorCode &status);

    int32_t append(const UnicodeString &unistr, Field field, UErrorCode &status);

    int32_t insert(int32_t index, const UnicodeString &unistr, Field field, UErrorCode &status);

    int32_t insert(int32_t index, const UnicodeString &unistr, int32_t start, int32_t end, Field field,

                   UErrorCode &status);

    int32_t splice(int32_t startThis, int32_t endThis,  const UnicodeString &unistr,

                   int32_t startOther, int32_t endOther, Field field, UErrorCode& status);

    int32_t append(const NumberStringBuilder &other, UErrorCode &status);

    int32_t insert(int32_t index, const NumberStringBuilder &other, UErrorCode &status);

    /**

     * Gets a "safe" UnicodeString that can be used even after the NumberStringBuilder is destructed.

     * */

    UnicodeString toUnicodeString() const;

    /**

     * Gets an "unsafe" UnicodeString that is valid only as long as the NumberStringBuilder is alive and

     * unchanged. Slightly faster than toUnicodeString().

     */

    const UnicodeString toTempUnicodeString() const;

    UnicodeString toDebugString() const;

    const char16_t *chars() const;

    bool contentEquals(const NumberStringBuilder &other) const;

    bool nextFieldPosition(FieldPosition& fp, UErrorCode& status) const;

    void getAllFieldPositions(FieldPositionIteratorHandler& fpih, UErrorCode& status) const;

  private:

    bool fUsingHeap = false;

    ValueOrHeapArray<char16_t> fChars;

    ValueOrHeapArray<Field> fFields;

    int32_t fZero = DEFAULT_CAPACITY / 2;

    int32_t fLength = 0;

    inline char16_t *getCharPtr() {

        return fUsingHeap ? fChars.heap.ptr : fChars.value;

    }

    inline const char16_t *getCharPtr() const {

        return fUsingHeap ? fChars.heap.ptr : fChars.value;

    }

    inline Field *getFieldPtr() {

        return fUsingHeap ? fFields.heap.ptr : fFields.value;

    }

    inline const Field *getFieldPtr() const {

        return fUsingHeap ? fFields.heap.ptr : fFields.value;

    }

    inline int32_t getCapacity() const {

        return fUsingHeap ? fChars.heap.capacity : DEFAULT_CAPACITY;

    }

    int32_t prepareForInsert(int32_t index, int32_t count, UErrorCode &status);

    int32_t prepareForInsertHelper(int32_t index, int32_t count, UErrorCode &status);

    int32_t remove(int32_t index, int32_t count);

};

} // namespace impl

} // namespace number

U_NAMESPACE_END

#endif //__NUMBER_STRINGBUILDER_H__

#endif /* #if !UCONFIG_NO_FORMATTING */