// Copyright (c) 2023-2026 Chris (boreddevnl)
// This software is released under the GNU General Public License v3.0. See LICENSE file for details.
// This header needs to maintain in any file it is present in, as per the GPL license terms.
#ifndef PROCESS_H
#define PROCESS_H

#include <stdint.h>
#include <stdbool.h>
#include <stddef.h>
#include "gui_ipc.h"

#define MAX_GUI_EVENTS 32
#define MAX_PROCESS_FDS 16
#define MAX_SIGNALS 32

#define PROC_FD_KIND_NONE 0
#define PROC_FD_KIND_FILE 1
#define PROC_FD_KIND_PIPE_READ 2
#define PROC_FD_KIND_PIPE_WRITE 3

typedef struct {
    void *file;
    int refs;
} process_fd_file_ref_t;

typedef struct {
    uint8_t data[4096];
    uint32_t read_pos;
    uint32_t write_pos;
    uint32_t count;
    int readers;
    int writers;
} process_fd_pipe_t;

struct FAT32_FileHandle;

typedef struct registers_t {
    uint8_t fxsave_region[512]; 
    uint64_t r15, r14, r13, r12, r11, r10, r9, r8;
    uint64_t rbp, rdi, rsi, rdx, rcx, rbx, rax;
    uint64_t int_no, err_code;
    uint64_t rip, cs, rflags, rsp, ss;
} __attribute__((packed, aligned(16))) registers_t;

typedef struct process {
    uint32_t pid;
    uint64_t rsp; 
    uint64_t pml4_phys; 
    uint64_t kernel_stack; 
    bool is_user;
    
    gui_event_t gui_events[MAX_GUI_EVENTS];
    int gui_event_head;
    int gui_event_tail;
    void *ui_window; 
    
    uint64_t heap_start;
    uint64_t heap_end;
    
    void *fds[MAX_PROCESS_FDS];
    uint8_t fd_kind[MAX_PROCESS_FDS];
    int fd_flags[MAX_PROCESS_FDS];
    
    void *kernel_stack_alloc; 
    void *user_stack_alloc;  

    bool is_terminal_proc;   
    int tty_id;              
    bool kill_pending;       

    struct process *next;

    bool fpu_initialized; 
    
    char name[64];
    uint64_t ticks;
    uint64_t sleep_until;
    size_t used_memory;
    uint32_t cpu_affinity;    
    bool is_idle;            
    char cwd[1024];          

    uint32_t parent_pid;
    uint32_t pgid;
    bool exited;
    int exit_status;

    uint64_t signal_mask;
    uint64_t signal_pending;
    uint64_t signal_handlers[MAX_SIGNALS];
    uint64_t signal_action_mask[MAX_SIGNALS];
    int signal_action_flags[MAX_SIGNALS];
} __attribute__((aligned(16))) process_t;

typedef struct {
    uint32_t pid;
    char name[64];
    uint64_t ticks;
    size_t used_memory;
    bool is_idle;
} ProcessInfo;

void process_init(void);
process_t* process_create(void (*entry_point)(void), bool is_user);
process_t* process_create_elf(const char* filepath, const char* args_str, bool terminal_proc, int tty_id);
int process_exec_replace_current(registers_t *regs, const char* filepath, const char* args_str);
process_t* process_get_current(void);
uint32_t   process_get_current_pid(void);
void process_set_current_for_cpu(uint32_t cpu_id, process_t* p);
process_t* process_get_current_for_cpu(uint32_t cpu_id);
uint64_t process_schedule(uint64_t current_rsp);
uint64_t process_terminate_current(void);
void process_terminate(process_t *proc);
void process_terminate_with_status(process_t *proc, int status);
process_t* process_get_by_pid(uint32_t pid);
int process_waitpid(uint32_t caller_pid, int target_pid, int options, int *status_out);
int process_reap(uint32_t caller_pid, uint32_t pid, int *status_out);
void process_kill_by_tty(int tty_id);

// SMP: IPI handler for AP scheduling 
uint64_t sched_ipi_handler(registers_t *regs);

void process_push_gui_event(process_t *proc, gui_event_t *ev);
process_t* process_get_by_ui_window(void* win);

#endif