#include <stdint.h>

#include "alloc.h"
#include "commands.h"
#include "font.h"
#include "kprintf.h"
#include "shell.h"
#include "string.h"
#include "terminal.h"
#include "utils.h"
#include "vbe.h"

#define BORDER "==========================================================="
#define HEADER "Welcome to bozOShell - Available Commands"

struct shell_command {
	char name[16];
	char description[256];
	void (*fn)(char *arg);
};

const struct shell_command cmds[] = {
    {"help", "Print this help menu", help_cmd},
    {"reboot", "Reboot the system", reboot_cmd},
    {"poweroff", "Shut down the system", poweroff_cmd},
    {"halt", "Stop all CPU functions", halt_cmd},
    {"stack", "Print the stack trace", stack_cmd},
    {"heap", "Print the heaps", heap_cmd},
    {"clear", "Clear the current terminal", clear_cmd},
    {"date", "Display the current time and date", date_cmd},
    {"merdella", "Surprise", merdella_cmd},
    {"color", "Change the screen color", color_cmd},
};

#define NB_CMDS ARRAY_SIZE(cmds)

extern struct screen *screen;
extern struct icon *terminal_bg;
extern int line_status;

void help_cmd(char *arg)
{
	const size_t padding = 15;

	(void)arg;
	kprintf("%s\n", BORDER);
	kprintf(" %s\n", HEADER);
	kprintf("%s\n", BORDER);

	for (size_t i = 0; i < NB_CMDS; i++) {
		kprintf(" %s", cmds[i].name);
		for (size_t j = 0; j < (padding - strlen(cmds[i].name)); j++)
			kprintf(" ");
		kprintf(": %s\n", cmds[i].description);
	}

	kprintf("%s\n", BORDER);
}

static void auto_complete(void)
{
	const size_t len = strlen(screen->line);
	int nb_matches = 0;
	const char *last_match;

	for (size_t i = 0; i < NB_CMDS; i++) {
		if (!strncmp(screen->line, cmds[i].name, len)) {
			nb_matches++;
			last_match = cmds[i].name;
		}
	}
	if (nb_matches != 1)
		return;
	for (size_t i = len; last_match[i]; i++) {
		screen->line[i] = last_match[i];
		kprintf("%c", screen->line[i]);
	}
}

static char *get_line(void)
{
	size_t i = 0;
	struct key_event ev;

	while (1) {
		ev = get_key();
		if (ev.c == '\n')
			break;
		char *buf = screen->line;
		i = strlen(screen->line);
		const size_t size = sizeof(screen->line);
		if (ev.scan_code) {
			if (ev.scan_code == KEY_BACKSPACE) {
				if (!i)
					continue;
				buf[--i] = '\0';
				terminal_remove_last_char();
			} else if (ev.scan_code == KEY_TAB && i) {
				auto_complete();
			} else if (ev.c && i < size - 1) {
				kprintf("%c", ev.c);
				buf[i++] = ev.c;
			}
			if (i >= size)
				break;
		}
	}
	kprintf("\n");
	screen->line[i] = '\0';
	return screen->line;
}

void shell_init(void)
{
	while (1) {
		kprintf(PROMPT);
		get_line();
		bool invalid = true;
		for (unsigned i = 0; i < NB_CMDS; i++) {
			if (!strncmp(cmds[i].name, screen->line,
			             strlen(cmds[i].name))) {
				char *args = strchr(screen->line, ' ');
				if (args)
					args++; // skip the space
				cmds[i].fn(args);
				invalid = false;
				break;
			}
		}
		if (invalid && screen->line[0])
			kprintf(KERN_WARNING "invalid command: %s\n",
			        screen->line);
		memset(screen->line, '\0', sizeof(screen->line));
	}
}