/*
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.
*/

#include <string.h>

#include "common.h"
#include "bitmap.h"
#include "filesystem.c"

#include "rom.c"
#include "uxn.c"
#include "ppu.c"
#include "apu.c"
#include "text.h"

//
// Config parameters.
//

#if !defined(TEXT_MODE) || TEXT_MODE == 0
#define TEXT_LAYER ppu.fg
#else
#define TEXT_LAYER ppu.bg
#endif

#ifndef CONTROL_METHODS
#define CONTROL_METHODS CONTROL_CONTROLLER,CONTROL_MOUSE,CONTROL_KEYBOARD
#endif

#ifdef PROF_ENABLE
#if PROF_ENABLE == 0
#define PROF(F,VAR) (profile_start(),(F),(VAR) = profile_stop())
#elif PROF_ENABLE == 1
#define PROF(F,VAR) (profile_start(),(F),(VAR) = MAX(profile_stop(), (VAR)))
#endif
#ifndef PROF_SHOW_X
#define PROF_SHOW_X 0
#endif
#ifndef PROF_SHOW_Y
#define PROF_SHOW_Y 0
#endif
#define PROF_SHOW() \
    do { \
        txt_position((PROF_SHOW_X), (PROF_SHOW_Y));\
        txt_printf("INPUT: %lu    ", input_cycles);\
        txt_position((PROF_SHOW_X), (PROF_SHOW_Y)+1);\
        txt_printf("EVAL:  %lu    ", eval_cycles);\
        txt_position((PROF_SHOW_X), (PROF_SHOW_Y)+2);\
        txt_printf("FLIP:  %lu    ", flip_cycles);\
        txt_position((PROF_SHOW_X), (PROF_SHOW_Y)+3);\
        txt_printf("MIX:   %lu    ", mix_cycles);\
    } while (0)
#define PROF_INIT() \
    u32 flip_cycles = 0;\
    u32 eval_cycles = 0;\
    u32 input_cycles = 0;\
    u32 mix_cycles = 0;
#else
#define PROF(F,VAR) (F)
#define PROF_SHOW()
#define PROF_INIT()
#endif

typedef enum {
    CONTROL_CONTROLLER,
    CONTROL_MOUSE,
    CONTROL_KEYBOARD,
} ControlMethod;

const ControlMethod ctrl_methods[] = {
    CONTROL_METHODS
};
static ControlMethod ctrl_idx = 0;

#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 Device *devaudio;

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;
        u8 color = d->dat[0xf] & 0xf;
        if(!mode) {
            ppu_pixel(layer, x, y, d->dat[0xe] & 0x3);
        } else if(mode-- & 0x1) {
            u8 flipx = mode & 0x2;
            u8 flipy = mode & 0x4;
            ppu_1bpp(layer, x, y, addr, color, flipx, flipy);
        } else {
            u8 flipx = mode & 0x2;
            u8 flipy = mode & 0x4;
            ppu_2bpp(layer, x, y, addr, color, flipx, flipy);
        }
    } else if(w && b0 == 0xf) {
        u16 x = mempeek16(d->dat, 0x8);
        u16 y = mempeek16(d->dat, 0xa);
        u8 *addr = &d->mem[mempeek16(d->dat, 0xc)];
        u8 *layer = d->dat[0xf] >> 6 & 0x1 ? ppu.fg : ppu.bg;
        u8 color = d->dat[0xf] & 0xf;
        u8 flipx = (d->dat[0xf] >> 0x4) & 0x1;
        u8 flipy = (d->dat[0xf] >> 0x5) & 0x1;
        if(d->dat[0xf] >> 0x7 & 0x1) {
            ppu_2bpp(layer, x, y, addr, color, flipx, flipy);
        } else {
            ppu_1bpp(layer, x, y, addr, color, flipx, flipy);
        }
    }
}

static void
audio_talk(Device *d, u8 b0, u8 w) {
    AudioChannel *c = &channels[d - devaudio];
    if(!w) {
        if(b0 == 0x2) {
            mempoke16(d->dat, 0x2, c->pos);
            c->pos <<= 12; // fixed point.
        } else if(b0 == 0x4) {
            // d->dat[0x4] = apu_get_vu(c);
        }
    } else if(b0 == 0xf) {
        u16 length = mempeek16(d->dat, 0xa);
        u8 *data = &d->mem[mempeek16(d->dat, 0xc)];
        u8 pitch = d->dat[0xf] & 0x7f;
        u16 adsr = mempeek16(d->dat, 0x8);
        u32 vol = MAX(d->dat[0xe] >> 4, d->dat[0xe] & 0xf) * 4 / 3;
        bool loop = !(d->dat[0xf] & 0x80);
        update_channel(c, data, length, pitch, adsr, vol, loop);
    }
}

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);
        OpenMode mode = FS_OPEN_READ;
        if (!read) {
            mode = offset ? FS_OPEN_APPEND : FS_OPEN_WRITE;
        }
        File file = fs_open_file(name, mode);
        if (file.index != FS_NULL) {
            if(fs_seek(&file, offset, SEEK_SET) != -1) {
                if (read) {
                    result = fs_read(&d->mem[addr], length, &file);
                } else {
                    result = fs_write(&d->mem[addr], length, &file);
                }
            }
        }
        mempoke16(d->dat, 0x2, result);
    }
}

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

    // Enable sound.
    init_sound();

    // 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);
    devaudio = portuxn(u, 0x3, "audio0", audio_talk);
    portuxn(u, 0x4, "audio1", audio_talk);
    portuxn(u, 0x5, "audio2", audio_talk);
    portuxn(u, 0x6, "audio3", audio_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)) {
        // Reset control variables on method switch.
        switch (ctrl_methods[ctrl_idx]) {
            case CONTROL_CONTROLLER: {
                devctrl->dat[2] = 0;
                evaluxn(u, mempeek16(devctrl->dat, 0));
                devctrl->dat[3] = 0;
            } break;
            case CONTROL_MOUSE: {
                devmouse->dat[6] = 0;
                devmouse->dat[7] = 0;
                mempoke16(devmouse->dat, 0x2, -10);
                mempoke16(devmouse->dat, 0x4, -10);
                evaluxn(u, mempeek16(devmouse->dat, 0));
            } break;
            case CONTROL_KEYBOARD: {
                toggle_keyboard();
            } break;
        }

        // Update ctrl_idx.
        ctrl_idx = (ctrl_idx + 1 > (int)LEN(ctrl_methods) - 1) ? 0 : ctrl_idx + 1;

        // Initialize controller variables here.
        if (ctrl_methods[ctrl_idx] == CONTROL_KEYBOARD) {
            toggle_keyboard();
        }
    }

    if (ctrl_methods[ctrl_idx] == 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 (ctrl_methods[ctrl_idx] == 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));
    } else if (ctrl_methods[ctrl_idx] == CONTROL_KEYBOARD) {
        if (key_tap(KEY_LEFT)) {
            update_cursor(cursor_position - 1);
        } else if (key_tap(KEY_RIGHT)) {
            update_cursor(cursor_position + 1);
        }
        if (key_tap(KEY_UP) && cursor_position >= KEYBOARD_ROW_SIZE) {
            update_cursor(cursor_position - KEYBOARD_ROW_SIZE);
        } else if (key_tap(KEY_DOWN)
                && cursor_position < LEN(keyboard) - KEYBOARD_ROW_SIZE) {
            update_cursor(cursor_position + KEYBOARD_ROW_SIZE);
        }
        if (key_tap(KEY_B)) {
            u8 symbol = keyboard[cursor_position].symbol;
            switch (symbol) {
                case 0x7f: {
                    // Backspace.
                    devctrl->dat[3] = 0x08;
                } break;
                case 0x14: {
                    // New line.
                    devctrl->dat[3] = 0x0d;
                } break;
                case 0x18: {
                    // Arrow up.
                    devctrl->dat[2] = 0x10;
                } break;
                case 0x19: {
                    // Arrow down.
                    devctrl->dat[2] = 0x20;
                } break;
                case 0x1b: {
                    // Arrow left.
                    devctrl->dat[2] = 0x40;
                } break;
                case 0x1a: {
                    // Arrow right.
                    devctrl->dat[2] = 0x80;
                } break;
                default: {
                    devctrl->dat[3] = symbol;
                } break;
            }
            evaluxn(u, mempeek16(devctrl->dat, 0));
            devctrl->dat[3] = 0;
        }
    }
}

static Uxn u;
EWRAM_BSS
static u8 umem[KB(65)];

int main(void) {
    // Adjust system wait times.
    SYSTEM_WAIT = SYSTEM_WAIT_CARTRIDGE;

    // Initialize filesystem.
    fs_init();

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

    // Initialize VM.
    dma_fill(&u, 0, sizeof(u), 3);
    u.ram.dat = umem;
    init_uxn(&u);

    // Initialize text engine.
    txt_init(1, TEXT_LAYER);
    txt_position(0,0);

    // Initialize sound mixer.
    init_sound();

    // Main loop.
    evaluxn(&u, 0x0100);
    PROF_INIT();
    while(true) {
        bios_vblank_wait();
        PROF(handle_input(&u), input_cycles);
        PROF(evaluxn(&u, mempeek16(devscreen->dat, 0)), eval_cycles);
        PROF(sound_mix(), mix_cycles);
        PROF_SHOW();
        PROF(flipbuf(&ppu), flip_cycles);
    }

    return 0;
}