#ifndef TASK_H
#define TASK_H

#include <efi.h>
#include "boot_info.h"

/* Maximum number of concurrent tasks */
#define TASK_MAX         32

/* Stack size per task: 32 KB (8 pages) */
#define TASK_STACK_PAGES 8
#define TASK_STACK_SIZE  (TASK_STACK_PAGES * 4096)

/* Maximum task name length */
#define TASK_NAME_LEN    32

/* Task states */
typedef enum {
    TASK_STATE_FREE = 0,       /* PCB slot is unused */
    TASK_STATE_READY,          /* Runnable, waiting for CPU */
    TASK_STATE_RUNNING,        /* Currently executing on CPU */
    TASK_STATE_TERMINATED      /* Finished execution */
} TaskState;

/* Task entry function signature */
typedef void (*TaskEntryFn)(void *arg);

/* ================================================================
 *  Process Control Block (PCB)
 * ================================================================ */
typedef struct Task {
    UINT32      pid;                    /* Process ID */
    TaskState   state;                  /* Current state */
    CHAR16      name[TASK_NAME_LEN];    /* Human-readable name */
    UINT64      saved_rsp;              /* Saved stack pointer (context switch) */
    UINT64      stack_base;             /* Base address of allocated stack */
    UINTN       stack_pages;            /* Stack size in pages */
    TaskEntryFn entry;                  /* Entry function pointer */
    void       *arg;                    /* Argument passed to entry */
    UINTN       switches;               /* Number of times scheduled */
} Task;

/* -------- Task API -------- */

void   task_init(BootInfo *Boot);
Task  *task_create(const CHAR16 *name, TaskEntryFn entry, void *arg);
void   task_yield(void);
void   task_exit(void);
Task  *task_current(void);
UINTN  task_count(void);
void   task_print_list(BootInfo *Boot);

/* Assembly context switch (defined in context_switch.S) */
extern void context_switch(UINT64 *old_rsp, UINT64 new_rsp);

#endif