// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
// SPDX-License-Identifier: GPL-3.0-or-later

// SPDX-FileCopyrightText: Copyright 2022 yuzu Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later

#pragma once

#include <array>
#include <span>

#include "audio_core/common/common.h"
#include "common/common_types.h"

namespace AudioCore::Renderer {
/**
 * Represents a mixing node, can be connected to a previous and next destination forming a chain
 * that a certain mix buffer will pass through to output.
 */
class SplitterDestinationData {
public:
    /**
     * Biquad filter parameter with float coefficients (SDK REV15+).
     * Defined here to avoid circular dependency with VoiceInfo.
     */
    struct BiquadFilterParameter2 {
        /* 0x00 */ bool enabled;
        /* 0x01 */ u8 reserved1;
        /* 0x02 */ u8 reserved2;
        /* 0x03 */ u8 reserved3;
        /* 0x04 */ std::array<f32, 3> numerator;   // b0, b1, b2
        /* 0x10 */ std::array<f32, 2> denominator; // a1, a2 (a0 = 1)
    };
    static_assert(sizeof(BiquadFilterParameter2) == 0x18,
                  "BiquadFilterParameter2 has the wrong size!");

    /**
     * Legacy biquad filter parameter with fixed-point coefficients (SDK REV12+ for splitters).
     * Matches the old voice biquad format.
     */
    struct BiquadFilterParameterLegacy {
        /* 0x00 */ bool enabled;
        /* 0x02 */ std::array<s16, 3> b; // numerator
        /* 0x08 */ std::array<s16, 2> a; // denominator (a0 = 1)
    };
    static_assert(sizeof(BiquadFilterParameterLegacy) == 0xC,
                  "BiquadFilterParameterLegacy has the wrong size!");

    struct InParameter {
        /* 0x00 */ u32 magic; // 'SNDD'
        /* 0x04 */ s32 id;
        /* 0x08 */ std::array<f32, MaxMixBuffers> mix_volumes;
        /* 0x68 */ u32 mix_id;
        /* 0x6C */ bool in_use;
        /* 0x6D */ bool reset_prev_volume;
    };
    static_assert(sizeof(InParameter) == 0x70,
                  "SplitterDestinationData::InParameter has the wrong size!");

    struct InParameterVersion2a {
        /* 0x00 */ u32 magic; // 'SNDD'
        /* 0x04 */ s32 id;
        /* 0x08 */ std::array<f32, MaxMixBuffers> mix_volumes;
        /* 0x68 */ u32 mix_id;
        /* 0x6C */ std::array<SplitterDestinationData::BiquadFilterParameterLegacy, MaxBiquadFilters>
            biquad_filters;
        /* 0x84 */ bool in_use;
        /* 0x85 */ bool reset_prev_volume; // only effective if supported
        /* 0x86 */ u8 reserved[10];
    };
    static_assert(sizeof(InParameterVersion2a) == 0x90,
                  "SplitterDestinationData::InParameterVersion2a has the wrong size!");

    struct InParameterVersion2b {
        /* 0x00 */ u32 magic; // 'SNDD'
        /* 0x04 */ s32 id;
        /* 0x08 */ std::array<f32, MaxMixBuffers> mix_volumes;
        /* 0x68 */ u32 mix_id;
        /* 0x6C */ std::array<SplitterDestinationData::BiquadFilterParameter2, MaxBiquadFilters>
            biquad_filters;
        /* 0x9C */ bool in_use;
        /* 0x9D */ bool reset_prev_volume;
        /* 0x9E */ u8 reserved[10];
    };
    static_assert(sizeof(InParameterVersion2b) == 0xA8,
                  "SplitterDestinationData::InParameterVersion2b has the wrong size!");

    SplitterDestinationData(s32 id);

    /**
     * Reset the mix volumes for this destination.
     */
    void ClearMixVolume();

    /**
     * Get the id of this destination.
     *
     * @return Id for this destination.
     */
    s32 GetId() const;

    /**
     * Check if this destination is correctly configured.
     *
     * @return True if configured, otherwise false.
     */
    bool IsConfigured() const;

    /**
     * Get the mix id for this destination.
     *
     * @return Mix id for this destination.
     */
    s32 GetMixId() const;

    /**
     * Get the current mix volume of a given index in this destination.
     *
     * @param index - Mix buffer index to get the volume for.
     * @return Current volume of the specified mix.
     */
    f32 GetMixVolume(u32 index) const;

    /**
     * Get the current mix volumes for all mix buffers in this destination.
     *
     * @return Span of current mix buffer volumes.
     */
    std::span<f32> GetMixVolume();

    /**
     * Get the previous mix volume of a given index in this destination.
     *
     * @param index - Mix buffer index to get the volume for.
     * @return Previous volume of the specified mix.
     */
    f32 GetMixVolumePrev(u32 index) const;

    /**
     * Get the previous mix volumes for all mix buffers.
     *
     * @return Span of previous mix buffer volumes.
     */
    std::span<f32> GetMixVolumePrev();

    /**
     * Update this destination.
     *
     * @param params - Input parameters to update the destination.
     */
    void Update(const InParameter& params);

    /**
     * Mark this destination as needing its volumes updated.
     */
    void MarkAsNeedToUpdateInternalState();

    /**
     * Copy current volumes to previous if an update is required.
     */
    void UpdateInternalState();

    /**
     * Get the next destination in the mix chain.
     *
     * @return The next splitter destination, may be nullptr if this is the last in the chain.
     */
    SplitterDestinationData* GetNext() const;

    /**
     * Set the next destination in the mix chain.
     *
     * @param next - Destination this one is to be connected to.
     */
    void SetNext(SplitterDestinationData* next);

    /**
     * Get biquad filter parameters for this destination (REV15+ or mapped from REV12).
     *
     * @return Span of biquad filter parameters.
     */
    std::span<BiquadFilterParameter2> GetBiquadFilters();

    /**
     * Get const biquad filter parameters for this destination (REV15+ or mapped from REV12).
     *
     * @return Const span of biquad filter parameters.
     */
    std::span<const BiquadFilterParameter2> GetBiquadFilters() const;

private:
    /// Id of this destination
    const s32 id;
    /// Mix id this destination represents
    s32 destination_id{UnusedMixId};
    /// Current mix volumes
    std::array<f32, MaxMixBuffers> mix_volumes{0.0f};
    /// Previous mix volumes
    std::array<f32, MaxMixBuffers> prev_mix_volumes{0.0f};
    /// Biquad filter parameters (REV15+ or mapped from REV12)
    std::array<BiquadFilterParameter2, MaxBiquadFilters> biquad_filters{};
    /// Next destination in the mix chain
    SplitterDestinationData* next{};
    /// Is this destination in use?
    bool in_use{};
    /// Does this destination need its volumes updated?
    bool need_update{};
};

} // namespace AudioCore::Renderer