#include <string.h>

#include "common.h"
#include "bitmap.h"
#include "bd-font.c"
#include "filesystem.c"

#include "rom.c"
#include "uxn/uxn.h"
#include "uxn/uxn.c"
#include "uxn/devices/ppu.h"
#include "uxn/devices/ppu.c"

#include "text.h"

/*
Copyright (c) 2021 Bad Diode

Permission to use, copy, modify, and distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE.
*/

typedef enum {
    CONTROL_CONTROLLER,
    CONTROL_MOUSE,
} ControlMethod;

static ControlMethod control_method = CONTROL_CONTROLLER;

#define MOUSE_DELTA 1
typedef struct Mouse {
    int x;
    int y;
} Mouse;

static Ppu ppu;
static Device *devscreen;
static Device *devctrl;
static Device *devmouse;

static Mouse mouse = {SCREEN_WIDTH / 2, SCREEN_HEIGHT / 2};

void
nil_talk(Device *d, u8 b0, u8 w) {
    (void)d;
    (void)b0;
    (void)w;
}

void
console_talk(Device *d, u8 b0, u8 w) {
    char stmp[2];
    if(!w) {
        return;
    }
    switch(b0) {
        case 0x8: stmp[0] = d->dat[0x8]; stmp[1] = 0; txt_printf(stmp); break;
        case 0x9: txt_printf("0x%02x", d->dat[0x9]); break;
        case 0xb: txt_printf("0x%04x", mempeek16(d->dat, 0xa)); break;
        case 0xd: txt_printf("%s", &d->mem[mempeek16(d->dat, 0xc)]); break;
    }
}

void
system_talk(Device *d, u8 b0, u8 w) {
    if(!w) {
        d->dat[0x2] = d->u->wst.ptr;
        d->dat[0x3] = d->u->rst.ptr;
    } else {
        putcolors(&d->dat[0x8]);
    }
    (void)b0;
}

IWRAM_CODE
void
screen_talk(Device *d, u8 b0, u8 w) {
    if(w && b0 == 0xe) {
        u16 x = mempeek16(d->dat, 0x8);
        u16 y = mempeek16(d->dat, 0xa);
        u8 *addr = &d->mem[mempeek16(d->dat, 0xc)];
        u8 *layer = d->dat[0xe] >> 4 & 0x1 ? ppu.fg : ppu.bg;
        u8 mode = d->dat[0xe] >> 5;
        if(!mode) {
            putpixel(layer, x, y, d->dat[0xe] & 0x3);
        } else if(mode-- & 0x1) {
            puticn(layer, x, y, addr, d->dat[0xe] & 0xf, mode & 0x2, mode & 0x4);
        } else {
            putchr(layer, x, y, addr, d->dat[0xe] & 0xf, mode & 0x2, mode & 0x4);
        }
    }
}

void
datetime_talk(Device *d, u8 b0, u8 w) {
	(void)d;
	(void)b0;
	(void)w;
}

void
file_talk(Device *d, u8 b0, u8 w) {
	u8 read = b0 == 0xd;
	if(w && (read || b0 == 0xf)) {
        char *name = (char *)&d->mem[mempeek16(d->dat, 0x8)];
        u16 result = 0, length = mempeek16(d->dat, 0xa);
        u16 offset = mempeek16(d->dat, 0x4);
        u16 addr = mempeek16(d->dat, b0 - 1);
        int file_idx = fs_open_file(name, read ? OPEN_READ : OPEN_WRITE);
        if (file_idx >= 0) {
            if (read) {
                result = fs_read(&d->mem[addr], length, file_idx, offset);
            } else {
                result = fs_write(&d->mem[addr], length, file_idx, offset, offset > 0);
            }
        }
		mempoke16(d->dat, 0x2, result);
	}
}

void
init_uxn(Uxn *u) {
    // Initialize PPU.
    initppu(&ppu, 30, 20, 0);

    // Copy rom to VM.
    memcpy(u->ram.dat + PAGE_PROGRAM, uxn_rom, sizeof(uxn_rom));

    // Prepare devices.
    portuxn(u, 0x0, "system", system_talk);
    portuxn(u, 0x1, "console", console_talk);
    devscreen = portuxn(u, 0x2, "screen", screen_talk);
    portuxn(u, 0x3, "---", nil_talk);
    portuxn(u, 0x4, "---", nil_talk);
    portuxn(u, 0x5, "---", nil_talk);
    portuxn(u, 0x6, "---", nil_talk);
    portuxn(u, 0x7, "---", nil_talk);
	devctrl = portuxn(u, 0x8, "controller", nil_talk);
	devmouse = portuxn(u, 0x9, "mouse", nil_talk);
	portuxn(u, 0xa, "file", file_talk);
	portuxn(u, 0xb, "datetime", datetime_talk);
    portuxn(u, 0xc, "---", nil_talk);
    portuxn(u, 0xd, "---", nil_talk);
    portuxn(u, 0xe, "---", nil_talk);
    portuxn(u, 0xf, "---", nil_talk);
    mempoke16(devscreen->dat, 2, ppu.hor * 8);
    mempoke16(devscreen->dat, 4, ppu.ver * 8);
}

IWRAM_CODE
void
handle_input(Uxn *u) {
    poll_keys();
	if (key_tap(KEY_SELECT)) {
	    switch (control_method) {
	        case CONTROL_CONTROLLER: {
                devctrl->dat[2] = 0;
                evaluxn(u, mempeek16(devctrl->dat, 0));
                devctrl->dat[3] = 0;
                control_method = CONTROL_MOUSE;
            } break;
	        default: {
	            devmouse->dat[6] = 0;
	            devmouse->dat[7] = 0;
                mempoke16(devmouse->dat, 0x2, -10);
                mempoke16(devmouse->dat, 0x4, -10);
                evaluxn(u, mempeek16(devmouse->dat, 0));
                control_method = CONTROL_CONTROLLER;
            } break;
	    }
    }

    if (control_method == CONTROL_CONTROLLER) {
        // TODO: We don't need ifs if we use KEY_INPUTS directly and mayvbe just
        // swap some things if needed.
        u8 *flag = &devctrl->dat[2];
        if (key_pressed(KEY_A)) {
            *flag |= 0x01;
        } else {
            *flag &= ~0x01;
        }
        if (key_pressed(KEY_B)) {
            *flag |= 0x02;
        } else {
            *flag &= ~0x02;
        }
        if (key_pressed(KEY_L)) {
            *flag |= 0x04;
        } else {
            *flag &= ~0x04;
        }
        if (key_pressed(KEY_R)) {
            *flag |= 0x08;
        } else {
            *flag &= ~0x08;
        }
        if (key_pressed(KEY_UP)) {
            *flag |= 0x10;
        } else {
            *flag &= ~0x10;
        }
        if (key_pressed(KEY_DOWN)) {
            *flag |= 0x20;
        } else {
            *flag &= ~0x20;
        }
        if (key_pressed(KEY_LEFT)) {
            *flag |= 0x40;
        } else {
            *flag &= ~0x40;
        }
        if (key_pressed(KEY_RIGHT)) {
            *flag |= 0x80;
        } else {
            *flag &= ~0x80;
        }

        evaluxn(u, mempeek16(devctrl->dat, 0));
        devctrl->dat[3] = 0;
    } else if (control_method == CONTROL_MOUSE) {
        // Detect "mouse key press".
		u8 flag = devmouse->dat[6];
        if (key_tap(KEY_B)) {
            flag |= 0x01;
        } else if (key_released(KEY_B)) {
            flag &= ~0x01;
        }
        if (key_tap(KEY_A)) {
            flag |= 0x10;
        } else if (key_released(KEY_A)) {
            flag &= ~0x10;
        }

        // Handle chording.
        devmouse->dat[6] = flag;
		if(flag == 0x10 && (devmouse->dat[6] & 0x01)) {
			devmouse->dat[7] = 0x01;
        }
		if(flag == 0x01 && (devmouse->dat[6] & 0x10)) {
			devmouse->dat[7] = 0x10;
        }

        // Detect mouse movement.
        if (key_pressed(KEY_UP)) {
            mouse.y = CLAMP(mouse.y - MOUSE_DELTA, 0, SCREEN_HEIGHT - 8);
        } else if (key_pressed(KEY_DOWN)) {
            mouse.y = CLAMP(mouse.y + MOUSE_DELTA, 0, SCREEN_HEIGHT - 8);
        }
        if (key_pressed(KEY_LEFT)) {
            mouse.x = CLAMP(mouse.x - MOUSE_DELTA, 0, SCREEN_WIDTH - 8);
        } else if (key_pressed(KEY_RIGHT)) {
            mouse.x = CLAMP(mouse.x + MOUSE_DELTA, 0, SCREEN_WIDTH - 8);
        }

        // Eval mouse.
        mempoke16(devmouse->dat, 0x2, mouse.x);
        mempoke16(devmouse->dat, 0x4, mouse.y);
	    evaluxn(u, mempeek16(devmouse->dat, 0));
    }
}

static Uxn u;
EWRAM_BSS
static u8 umem[65536];

int main(void) {
    // Initialize filesystem.
    fs_init();

    // Register interrupts.
    irq_init();
    irs_set(IRQ_VBLANK, irs_stub);

    // Initialize VM.
    memset(&u, 0, sizeof(u));
    u.ram.dat = umem;
    init_uxn(&u);

    // Initialize text engine.
    txt_init_hybrid(
            TXT_MODE_HYBRID,
            (Font){
                .data = bd_font,
                .char_height = 8,
                .char_width = 8,
            }, ppu.fg);
    txt_position(0,0);

    // Main loop.
    int frame_counter = 0;
    evaluxn(&u, 0x0100);
    while(true) {
        bios_vblank_wait();
        handle_input(&u);
        evaluxn(&u, mempeek16(devscreen->dat, 0));
        flipbuf(&ppu);
        frame_counter++;
    }

    return 0;
}