#pragma once

#include <core_audio_types.h>
#include <defines.h>
#include <identifiers/khandle.h>
#include <math/math_types.h>

struct frame_data;
struct kaudio_backend_state;

/**
 * Represents a Kohi Audio.
 */
typedef u16 kaudio;

// The id representing an invalid kaudio.
#define INVALID_KAUDIO INVALID_ID_U16

typedef struct kaudio_instance {
	kaudio base;
	u16 instance_id;
} kaudio_instance;

/**
 * @brief The configuration for an audio backend.
 */
typedef struct kaudio_backend_config {
	/** @brief The frequency to output audio at (i.e. 44100). */
	u32 frequency;
	/**
	 * @brief The number of audio channels to support (i.e. 2 for stereo, 1 for mono).
	 * not to be confused with audio_channel_count below.
	 */
	u32 channel_count;

	/**
	 * The size to chunk streamed audio data in.
	 */
	u32 chunk_size;

	/**
	 * @brief The number of separately-controlled channels used for mixing purposes. Each channel
	 * can have its volume independently controlled. Not to be confused with channel_count above.
	 */
	u32 audio_channel_count;

	/** @brief The maximum number of kaudios (sounds or music) that can be loaded at once. */
	u16 max_count;
} kaudio_backend_config;

typedef struct kaudio_backend_interface {
	struct kaudio_backend_state *internal_state;

	b8 (*initialize)(struct kaudio_backend_interface *backend, const kaudio_backend_config *config);

	void (*shutdown)(struct kaudio_backend_interface *backend);

	b8 (*update)(struct kaudio_backend_interface *backend, struct frame_data *p_frame_data);

	b8 (*listener_position_set)(struct kaudio_backend_interface *backend, vec3 position);

	b8 (*listener_orientation_set)(struct kaudio_backend_interface *backend, vec3 forward, vec3 up);

	/**
	 * @param backend A pointer to the backend interface.
	 * @param channel_id The identifier of the channel to modify.
	 * @param gain Indicate the gain (volume amplification) applied. Range: [0.0f - ? ]
	 *  A value of 1.0 means un-attenuated/unchanged. Each division by 2 equals an
	 *  attenuation of -6dB. Each multiplicaton with 2 equals an amplification of +6dB.
	 *  A value of 0.0f is meaningless with respect to a logarithmic scale; it is
	 *  interpreted as zero volume - the channel is effectively disabled.
	 * @returns True on success; otherwise false.
	 */
	b8 (*channel_gain_set)(struct kaudio_backend_interface *backend, u8 channel_id, f32 gain);

	/**
	 * @param backend A pointer to the backend interface.
	 * @param channel_id The identifier of the channel to modify.
	 * @param Specify the pitch to be applied at source. Range: [0.5f - 2.0f] Default: 1.0f
	 * @returns True on success; otherwise false.
	 */
	b8 (*channel_pitch_set)(struct kaudio_backend_interface *backend, u8 channel_id, f32 pitch);

	b8 (*channel_position_set)(struct kaudio_backend_interface *backend, u8 channel_id, vec3 position);

	b8 (*channel_looping_set)(struct kaudio_backend_interface *backend, u8 channel_id, b8 looping);

	b8 (*load)(struct kaudio_backend_interface *backend, i32 channels, u32 sample_rate, u32 total_sample_count, u64 pcm_data_size, i16 *pcm_data, b8 is_stream, kaudio audio);
	void (*unload)(struct kaudio_backend_interface *backend, kaudio audio);

	// Play whatever is currently bound to the channel.
	b8 (*channel_play)(struct kaudio_backend_interface *backend, u8 channel_id);
	b8 (*channel_play_resource)(struct kaudio_backend_interface *backend, kaudio audio, u16 instance_id, kaudio_space audio_space, u8 channel_id);

	b8 (*channel_stop)(struct kaudio_backend_interface *backend, u8 channel_id);
	b8 (*channel_pause)(struct kaudio_backend_interface *backend, u8 channel_id);
	b8 (*channel_resume)(struct kaudio_backend_interface *backend, u8 channel_id);

	b8 (*channel_is_playing)(struct kaudio_backend_interface *backend, u8 channel_id);
	b8 (*channel_is_paused)(struct kaudio_backend_interface *backend, u8 channel_id);
	b8 (*channel_is_stopped)(struct kaudio_backend_interface *backend, u8 channel_id);

} kaudio_backend_interface;