/**
 * @file kernel.h
 * @brief Core kernel definitions and types for Automotive RTOS
 * @author Automotive RTOS Team
 * @version 1.0
 */

#ifndef KERNEL_H
#define KERNEL_H

#include <stdint.h>
#include <stdbool.h>

/* Kernel Version */
#define KERNEL_VERSION_MAJOR    1
#define KERNEL_VERSION_MINOR    0
#define KERNEL_VERSION_PATCH    0

/* Configuration Constants */
#define MAX_TASKS               32
#define MAX_PRIORITY_LEVELS     16
#define MAX_TASK_NAME_LENGTH    16
#define IDLE_TASK_PRIORITY      (MAX_PRIORITY_LEVELS - 1)

/* Task States */
typedef enum {
    TASK_SUSPENDED = 0,
    TASK_READY = 1,
    TASK_RUNNING = 2,
    TASK_BLOCKED = 3,
    TASK_TERMINATED = 4
} TaskState_t;

/* Task Priority Type */
typedef uint8_t TaskPriority_t;

/* Task Handle */
typedef struct TaskControlBlock* TaskHandle_t;

/* Task Function */
typedef void (*TaskFunction_t)(void* parameters);

/* Time Types */
typedef uint32_t TickType_t;
typedef uint32_t TimeOut_t;

/* Error Codes */
typedef enum {
    KERNEL_OK = 0,
    KERNEL_ERROR = -1,
    KERNEL_INVALID_PARAMETER = -2,
    KERNEL_OUT_OF_MEMORY = -3,
    KERNEL_TASK_NOT_FOUND = -4,
    KERNEL_PRIORITY_INVALID = -5,
    KERNEL_TIMEOUT = -6,
    KERNEL_RESOURCE_BUSY = -7
} KernelStatus_t;

/* Task Creation Parameters */
typedef struct {
    const char* name;
    TaskFunction_t function;
    void* parameters;
    uint32_t stack_size;
    TaskPriority_t priority;
    TickType_t period_ticks;  /* 0 for aperiodic tasks */
} TaskConfig_t;

/* Task Statistics */
typedef struct {
    uint32_t execution_count;
    TickType_t last_execution_time;
    TickType_t max_execution_time;
    TickType_t total_execution_time;
    uint32_t stack_high_water_mark;
    uint32_t deadline_misses;
} TaskStatistics_t;

/* Kernel Core Functions */
KernelStatus_t kernel_init(void);
KernelStatus_t kernel_start(void);
void kernel_stop(void);
TickType_t kernel_get_tick_count(void);
KernelStatus_t kernel_delay(TickType_t ticks);

/* Task Management Functions */
TaskHandle_t task_create(const TaskConfig_t* config);
KernelStatus_t task_delete(TaskHandle_t task);
KernelStatus_t task_suspend(TaskHandle_t task);
KernelStatus_t task_resume(TaskHandle_t task);
KernelStatus_t task_set_priority(TaskHandle_t task, TaskPriority_t new_priority);
TaskPriority_t task_get_priority(TaskHandle_t task);
TaskState_t task_get_state(TaskHandle_t task);
KernelStatus_t task_get_statistics(TaskHandle_t task, TaskStatistics_t* stats);

/* Scheduler Control */
void scheduler_yield(void);
void scheduler_lock(void);
void scheduler_unlock(void);
TaskHandle_t scheduler_get_current_task(void);

#endif /* KERNEL_H */