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

#include "vga.h"
#include "serial.h"
#include "console.h"
#include "stdlib.h"
#include "string.h"
#include "stdio.h"
#include "interrupts.h"
#include "keyboard.h"
#include "mouse.h"
#include "pci.h"
#include "setjmp.h"

#include "kernel.h"

static jmp_buf panic_jmp_buf;

static void handle_keyboard_event( keyboard_event_t *event, void *context );
static void handle_mouse_event( mouse_event_t *event, void *context );

static bool terminate = false;

// must be first entry in kernel.bin (0x8400) as stage 2 of
// the boot loader expects the entry point to be here!
void entry( void )
{	
	serial_t serial;
	serial_init( &serial );

	vga_t vga;
	vga_init( &vga );
	vga_set_color( &vga, VGA_COLOR_LIGHT_GREY );
	vga_set_background_color( &vga, VGA_COLOR_BLACK );

	console_t console;
	console_init( &console );
	console_add_vga_output( &console, &vga );
// TODO: breaks on real hardware, we need proper interrupt handling
// and driver implementation as for the mouse and the keyboard
	console_add_serial_output( &console, &serial );
	
	// initialize the early console of the kernel
	stdio_set_console( &console );
	puts( "Started early kernel console" );
	printf( "Kernel code and data is at 0x%X, kernel stack at 0x%X\n", 0x8400, 0x90000 );

	puts( "Initializing interrupts" );
	interrupt_t interrupt;
	interrupts_init( &interrupt );
	
	puts( "Initializing PS/2 keyboard" );
	keyboard_t keyboard;
	keyboard_init( &keyboard, &handle_keyboard_event, NULL );
	interrupt_handler_t keyboard_interrupt_handler;
	interrupt_handler_init( &keyboard_interrupt_handler, IRQ_BASE + 0x01, &interrupt, keyboard_handle_interrupt, &keyboard );
	interrupts_register_interrupt_handler( keyboard_interrupt_handler );

	puts( "Initializing PS/2 mouse" );
	mouse_t mouse;
	mouse_init( &mouse, &handle_mouse_event, (void *)&vga, vga.res_x, vga.res_y );
	interrupt_handler_t mouse_interrupt_handler;
	interrupt_handler_init( &mouse_interrupt_handler, IRQ_BASE + 0x0C, &interrupt, mouse_handle_interrupt, &mouse );
	interrupts_register_interrupt_handler( mouse_interrupt_handler );

	// exit point in case of kernel panic, do this as soon as
	// possible
	if( setjmp( panic_jmp_buf ) > 0 ) {
		goto TERMINATE;
	}
	
	puts( "Enabling interrupt handing now.." );
	interrupts_enable( );

	puts( "Detecting devices via PCI.." );
	pci_controller_t pci_controller;
	pci_controller_init( &pci_controller );
	pci_controller_scan( &pci_controller );

	puts( "Running.." );
	
	// endless loop doing nothing, later we have to get events
	// here from queues and for instance print characters received
	// from the keyboard to stdout
	while( !terminate ) {
		// for now we are only interested in interrupts,
		// so we let the main thread sleep instead of
		// burning CPU..
		kernel_halt( );
	}			
	
TERMINATE:
	puts( "Deinitializing PS/2 mouse.." );
	mouse_deinit( &mouse );

	puts( "Deinitializing PS/2 keyboard.." );
	keyboard_deinit( &keyboard );
	
	puts( "Terminating" );
}

void kernel_panic( const char *format, ... )
{
	(void)printf( "\n*** KERNEL PANIC ***\n" );
	
	va_list args;
        va_start( args, format );
        (void)vprintf( format, args );
        va_end( args );

	longjmp( panic_jmp_buf, 47 );
}

static void handle_keyboard_event( keyboard_event_t *event, void *context )
{
	static int pos = 0;
	static char buf[80];

	if( event->type == KEYBOARD_EVENT_TYPE_KEY_PRESSED ) {
		if( event->key == KEYBOARD_KEY_ASCII ) {
			if( event->ascii_key == '\n' ) {
				buf[pos] = '\0';
				pos = 0;
				puts( "" );
				if( strcmp( buf, "help" ) == 0 ) {
					puts( "quit   - terminate os" );
					puts( "mem    - show memory usage" );
					puts( "driver - show status of drivers" );
					puts( "proc   - show process status" );  
				} else if( strcmp( buf, "quit" ) == 0 ) {
					terminate = true;
				} else if( strcmp( buf, "mem" ) == 0 ) {
					// TODO: print memory usage
				} else if( strcmp( buf, "proc" ) == 0 ) {
					// TODO: print scheduler status
				} else if( strcmp( buf, "driver" ) == 0 ) {
					// TODO: print driver information
				} else {
					printf( "ERR: Unknown pre-boot command '%s'\n", buf );
				}
			} else {
				printf( "%c", event->ascii_key );
				buf[pos++] = event->ascii_key;
			}
		}
	}
}

static void handle_mouse_event( mouse_event_t *event, void *context )
{
	vga_t *vga = (vga_t *)context;

	switch( event->type ) {
		case MOUSE_EVENT_TYPE_BUTTON_UP:
			printf( "MOUSE UP %d AT X:%d, Y:%d\n", event->button, event->cursor_x,
				event->cursor_y );
			break;

		case MOUSE_EVENT_TYPE_BUTTON_DOWN:
			printf( "MOUSE DOWN %d AT X:%d, Y:%d\n", event->button, event->cursor_x,
				event->cursor_y );
			break;

		case MOUSE_EVENT_TYPE_MOVE:
			vga_inverse_colors_at( vga, event->old_cursor_x, event->old_cursor_y );
			vga_inverse_colors_at( vga, event->cursor_x, event->cursor_y );
			break;
	}
}