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#ifdef HAVE_CONFIG_H

#include "config.h"

#endif

#include "main.h"

#include "tuning_parameters.h"

/* Control internal sampling rate */

opus_int silk_control_audio_bandwidth(

    silk_encoder_state          *psEncC,                        /* I/O  Pointer to Silk encoder state               */

    silk_EncControlStruct       *encControl                     /* I    Control structure                           */

)

{

    opus_int   fs_kHz;

    opus_int   orig_kHz;

    opus_int32 fs_Hz;

    orig_kHz = psEncC->fs_kHz;

    /* Handle a bandwidth-switching reset where we need to be aware what the last sampling rate was. */

    if( orig_kHz == 0 ) {

        orig_kHz = psEncC->sLP.saved_fs_kHz;

    }

    fs_kHz = orig_kHz;

    fs_Hz = silk_SMULBB( fs_kHz, 1000 );

    if( fs_Hz == 0 ) {

        /* Encoder has just been initialized */

        fs_Hz  = silk_min( psEncC->desiredInternal_fs_Hz, psEncC->API_fs_Hz );

        fs_kHz = silk_DIV32_16( fs_Hz, 1000 );

    } else if( fs_Hz > psEncC->API_fs_Hz || fs_Hz > psEncC->maxInternal_fs_Hz || fs_Hz < psEncC->minInternal_fs_Hz ) {

        /* Make sure internal rate is not higher than external rate or maximum allowed, or lower than minimum allowed */

        fs_Hz  = psEncC->API_fs_Hz;

        fs_Hz  = silk_min( fs_Hz, psEncC->maxInternal_fs_Hz );

        fs_Hz  = silk_max( fs_Hz, psEncC->minInternal_fs_Hz );

        fs_kHz = silk_DIV32_16( fs_Hz, 1000 );

    } else {

        /* State machine for the internal sampling rate switching */

        if( psEncC->sLP.transition_frame_no >= TRANSITION_FRAMES ) {

            /* Stop transition phase */

            psEncC->sLP.mode = 0;

        }

        if( psEncC->allow_bandwidth_switch || encControl->opusCanSwitch ) {

            /* Check if we should switch down */

            if( silk_SMULBB( orig_kHz, 1000 ) > psEncC->desiredInternal_fs_Hz )

            {

                /* Switch down */

                if( psEncC->sLP.mode == 0 ) {

                    /* New transition */

                    psEncC->sLP.transition_frame_no = TRANSITION_FRAMES;

                    /* Reset transition filter state */

                    silk_memset( psEncC->sLP.In_LP_State, 0, sizeof( psEncC->sLP.In_LP_State ) );

                }

                if( encControl->opusCanSwitch ) {

                    /* Stop transition phase */

                    psEncC->sLP.mode = 0;

                    /* Switch to a lower sample frequency */

                    fs_kHz = orig_kHz == 16 ? 12 : 8;

                } else {

                   if( psEncC->sLP.transition_frame_no <= 0 ) {

                       encControl->switchReady = 1;

                       /* Make room for redundancy */

                       encControl->maxBits -= encControl->maxBits * 5 / ( encControl->payloadSize_ms + 5 );

                   } else {

                       /* Direction: down (at double speed) */

                       psEncC->sLP.mode = -2;

                   }

                }

            }

            else

            /* Check if we should switch up */

            if( silk_SMULBB( orig_kHz, 1000 ) < psEncC->desiredInternal_fs_Hz )

            {

                /* Switch up */

                if( encControl->opusCanSwitch ) {

                    /* Switch to a higher sample frequency */

                    fs_kHz = orig_kHz == 8 ? 12 : 16;

                    /* New transition */

                    psEncC->sLP.transition_frame_no = 0;

                    /* Reset transition filter state */

                    silk_memset( psEncC->sLP.In_LP_State, 0, sizeof( psEncC->sLP.In_LP_State ) );

                    /* Direction: up */

                    psEncC->sLP.mode = 1;

                } else {

                   if( psEncC->sLP.mode == 0 ) {

                       encControl->switchReady = 1;

                       /* Make room for redundancy */

                       encControl->maxBits -= encControl->maxBits * 5 / ( encControl->payloadSize_ms + 5 );

                   } else {

                       /* Direction: up */

                       psEncC->sLP.mode = 1;

                   }

                }

            } else {

               if (psEncC->sLP.mode<0)

                  psEncC->sLP.mode = 1;

            }

        }

    }

    return fs_kHz;

}