#pragma once

#include <stdint.h>

#ifndef ACPI_INTERNAL
	#error "Do not include <sys/acpi.h>, only use <acpi.h>"
#endif

struct acpi_header {
	uint32_t signature;
	uint32_t length;
	uint8_t revision;
	uint8_t checksum;
	uint8_t oem_id[6];
	uint8_t oem_table_id[8];
	uint32_t oem_revision;
	uint32_t creator_id;
	uint32_t creator_revision;
} __attribute__((packed));

// root system descriptor pointer
// ACPI 1.0
struct rsdp {
	uint8_t signature[8];
	uint8_t checksum;
	uint8_t oemid[6];
	uint8_t revision;
	uint32_t rsdt_addr;
} __attribute__((packed));

// eXtended system descriptor pointer
// ACPI 2.0
struct xsdp {
	char signature[8];
	uint8_t checksum;
	char oemid[6];
	uint8_t revision;
	uint32_t rsdt_addr;
	uint32_t length;
	uint64_t xsdt_addr;
	uint8_t extendeid_checksum;
	uint8_t reserved[3];
} __attribute__((packed));

// root system descriptor table
// ACPI 1.0
struct rsdt {
	struct acpi_header h;
	uint32_t sdt_pointers[];
} __attribute__((packed));

// eXtended system descriptor table
// ACPI 2.0
struct xsdt {
	struct acpi_header h;
	uint64_t sdt_pointers[];
} __attribute__((packed));


// generic address structure
struct gas {
	uint8_t address_space;
	uint8_t bit_width;
	uint8_t bit_offset;
	uint8_t access_size;
	uint64_t address;
};

// differentiated system description table
struct dsdt {
	struct acpi_header h;
	char s5_addr[];
} __attribute__((packed));

struct apic {
	struct acpi_header h;
	// todo
} __attribute__((packed));

struct hept {
	struct acpi_header h;
	// todo
} __attribute__((packed));

struct waet {
	struct acpi_header h;
	// todo
} __attribute__((packed));

// fixed acpi description table
struct fadt {
	struct acpi_header h;
	uint32_t firmware_ctrl;
	uint32_t dsdt;

	// field used in ACPI 1.0; no longer in use, for compatibility only
	uint8_t  reserved;

	uint8_t  preferred_power_management_profile;
	uint16_t sci_interrupt;
	uint32_t smi_command_port;
	uint8_t  acpi_enable;
	uint8_t  acpi_disable;
	uint8_t  s4bios_req;
	uint8_t  pstate_control;
	uint32_t pm1_a_event_block;
	uint32_t pm1_b_event_block;
	uint32_t pm1_a_control_block;
	uint32_t pm1_b_control_block;
	uint32_t pm2_control_block;
	uint32_t pm_timer_block;
	uint32_t gpe0_block;
	uint32_t gpe1_block;
	uint8_t  pm1_event_length;
	uint8_t  pm1_control_length;
	uint8_t  pm2_control_length;
	uint8_t  pm_timer_length;
	uint8_t  gpe0_length;
	uint8_t  gpe1_length;
	uint8_t  gpe1_base;
	uint8_t  cstate_control;
	uint16_t worst_c2_latency;
	uint16_t worst_c3_latency;
	uint16_t flush_size;
	uint16_t flush_stride;
	uint8_t  duty_offset;
	uint8_t  duty_width;
	uint8_t  day_alarm;
	uint8_t  month_alarm;
	uint8_t  century;

	// reserved in ACPI 1.0; used since ACPI 2.0+
	uint16_t boot_architecture_flags;

	uint8_t  reserved_2;
	uint32_t flags;

	// 12 byte structure; see below for details
	struct gas reset_reg;

	uint8_t  reset_value;
	uint8_t  reserved_3[3];

	// 64bit pointers - Available on ACPI 2.0+
	uint64_t x_firmware_control;
	uint64_t x_dsdt;

	struct gas x_pm1_a_event_block;
	struct gas x_pm1_b_event_block;
	struct gas x_pm1_a_control_block;
	struct gas x_pm1_b_control_block;
	struct gas x_pm2_control_block;
	struct gas x_pm_timer_block;
	struct gas x_gpe0_block;
	struct gas x_gpe1_block;
} __attribute__((packed));

struct acpi_state {
	union {
		struct xsdt *xsdt;
		struct rsdt *rsdt;
	} sdt;
	struct fadt *fadt;
	struct dsdt *dsdt;
	struct apic *apic;
	struct hept *hept;
	struct waet *waet;
	uint8_t version;

	uint16_t SLP_TYPa;
	uint16_t SLP_TYPb;
	uint16_t SLP_EN;
	uint16_t SCI_EN;
};

void acpi_sys_enable(struct acpi_state *state);
int acpi_sys_shutdown(struct acpi_state *state);