#include "ascii.h"
#include <stdio.h>
#include <string>
#include <list>

std::list<std::string> code;

int current_editor = 0;

void init_terminal();
void do_terminal();

void init_code_editor();
void do_code_editor();
void save_code();

void loop() {
    if (btnp(KEY_TAB)) {
        current_editor = (++current_editor)%2;
        switch(current_editor) {
            case 0:
                init_terminal();
                break;
            case 1:
                init_code_editor();
                break;
        }
    }
    switch(current_editor) {
        case 0:
            do_terminal();
            break;
        case 1:
            do_code_editor();
            break;
    }
}

void execute_run() {
    if (current_editor == 1) save_code();
}

uint8_t get_char(uint8_t key) {
    SDL_Keymod mods = SDL_GetModState();
    if (key != KEY_UNKNOWN) {
        if (key < 30) {
            if ((mods & KMOD_SHIFT) || (mods & KMOD_CAPS)) {
                return key+61;
            } else {
                return key+93;
            }
        }
        else if (key == KEY_0) { if (mods & KMOD_SHIFT) { return '='; } else { return '0'; } }
        else if (key == KEY_1) { if (mods & KMOD_SHIFT) { return '!'; } else if (mods & KMOD_RALT) { return '|'; } else { return '1'; } }
        else if (key == KEY_2) { if (mods & KMOD_SHIFT) { return '"'; } else if (mods & KMOD_RALT) { return '@'; } else { return '2'; } }
        else if (key == KEY_3) { if (mods & KMOD_SHIFT) { return 144; } else if (mods & KMOD_RALT) { return '#'; } else { return '3'; } }
        else if (key == KEY_4) { if (mods & KMOD_SHIFT) { return '$'; } else if (mods & KMOD_RALT) { return '~'; } else { return '4'; } }
        else if (key == KEY_5) { if (mods & KMOD_SHIFT) { return '%'; } else if (mods & KMOD_RALT) { return 180; } else { return '5'; } }
        else if (key == KEY_6) { if (mods & KMOD_SHIFT) { return '&'; } else if (mods & KMOD_RALT) { return 173; } else { return '6'; } }
        else if (key == KEY_7) { if (mods & KMOD_SHIFT) { return '/'; } else { return '7'; } }
        else if (key == KEY_8) { if (mods & KMOD_SHIFT) { return '('; } else { return '8'; } }
        else if (key == KEY_9) { if (mods & KMOD_SHIFT) { return ')'; } else { return '9'; } }
        else if (key == KEY_SPACE) return 32;
        else if (key == KEY_MINUS) { if (mods & KMOD_SHIFT) { return '?'; } else { return '\''; } }
        else if (key == KEY_EQUALS) { if (mods & KMOD_SHIFT) { return 174; } else { return 175; } }
        else if (key == KEY_COMMA) { if (mods & KMOD_SHIFT) { return ';'; } else { return ','; } }
        else if (key == KEY_PERIOD) { if (mods & KMOD_SHIFT) { return ':'; } else { return '.'; } }
        else if (key == KEY_SLASH) { if (mods & KMOD_SHIFT) { return '_'; } else { return '-'; } }
        else if (key == KEY_LEFTBRACKET) { if (mods & KMOD_SHIFT) { return 160; } else if (mods & KMOD_RALT) { return '['; } else { return 96; } }
        else if (key == KEY_RIGHTBRACKET) { if (mods & KMOD_SHIFT) { return '*'; } else if (mods & KMOD_RALT) { return ']'; } else { return '+'; } }
        else if (key == KEY_APOSTROPHE) { if (mods & KMOD_SHIFT) { return 162; } else if (mods & KMOD_RALT) { return '{'; } else { return 161; } }
        else if (key == KEY_BACKSLASH) { if (mods & KMOD_SHIFT) { return 'C'; } else if (mods & KMOD_RALT) { return '}'; } else { return 'c'; } }
        else if (key == KEY_GRAVE) { if (mods & KMOD_SHIFT) { return '>'; } else  { return '<'; } }
        else if (key == KEY_NONUSBACKSLASH) { if (mods & KMOD_SHIFT) { return 164; } else if (mods & KMOD_RALT) { return '\\'; } else { return 163; } }
        else return 0;
    } else {
        return 0;
    }
}

void init_terminal() {
    setmode(0);
    cls();
}

void do_terminal() {
    //SDL_Keymod mods = SDL_GetModState();
    const uint8_t key = whichbtn();
    if (key != KEY_UNKNOWN) {
        if (key == KEY_RETURN or key == KEY_KP_ENTER) debug_get_cmd();
        else if (key == KEY_UP) next_cmd();
        else if (key == KEY_DOWN) prev_cmd();
        else if (key == KEY_BACKSPACE) debugchr(8);
        else {
            uint8_t chr = get_char(key);
            if (chr != 0) debugchr(chr);
        }
    }
}

void save_code() {
    const char* file = get_filename();
    FILE *f = fopen(file, "w");
    for (std::list<std::string>::iterator it = code.begin(); it != code.end(); it++) {
        fprintf(f, "%s\n", (*it).c_str());
    }
    fclose(f);
}

void load_code() {
    const char* file = get_filename();
    FILE *f = fopen(file, "rb");
    fseek(f, 0, SEEK_END);
    long fsize = ftell(f);
    fseek(f, 0, SEEK_SET);  /* same as rewind(f); */
    char *buffer = (char*)malloc(fsize + 1);
    fread(buffer, 1, fsize, f);
    fclose(f);
    buffer[fsize] = 0;

    int start = 0;
    for (int pos=0;pos<fsize;++pos) {
        if (buffer[pos] == '\n') {
            buffer[pos]='\0';
            code.push_back(&buffer[start]);
            start=pos+1;
        } else if (buffer[pos] == '\r') {
            buffer[pos]='\0';
            code.push_back(&buffer[start]);
            start=pos+1;
            if (buffer[start] == '\n') {pos++; start++;}
        }

    }
    free(buffer);
}

std::list<std::string>::iterator ls[28];
static int col = 0;
static int line = 0;
bool cursor_inverted = false;
int blink_wait = 30;

#define PARSER_NOTHING 0
#define PARSER_NUMBER 1
#define PARSER_IDENTIFIER 2
#define PARSER_STRING 3
#define PARSER_COMMENT 4
#define PARSER_FUNCTION 5

uint16_t parser_offset = 0;
uint8_t parser_pos = 0;
uint8_t parser_start=0;
void parser_setup(uint16_t address) {
    parser_offset = address;
    parser_pos = 0;
    parser_start = 0;
}
const uint8_t parser_get_char(uint8_t offset=0) {
    if ((parser_pos+offset) >= 80) return 0;
    return peek(parser_offset+parser_pos+offset);
}
char alpha[80] = "";
uint8_t alpha_pos = 0;
void parser_next(const bool keep=false) { 
    if (keep) { alpha[alpha_pos++] = parser_get_char(); alpha[alpha_pos]=0; } else { alpha[0]=alpha_pos=0; }
    if (parser_pos < 80) parser_pos++;
}

#define ISZERO (parser_get_char()=='0')
#define ISX (parser_get_char()=='z' || parser_get_char()=='Z')
#define ISDIGIT (parser_get_char()>='0' && parser_get_char() <='9')
#define WILLBEDIGIT (parser_get_char(1)>='0' && parser_get_char(1) <='9')
#define ISPOINT (parser_get_char()=='.')
#define ISALPHA (parser_get_char()>='_' || (parser_get_char()>='a' && parser_get_char()<='z') || (parser_get_char()>='A' && parser_get_char()<='Z'))
#define ISQUOTES (parser_get_char()=='"' || parser_get_char()=='\'')
#define ISMINUS (parser_get_char()=='-')
#define WILLBEMINUS (parser_get_char(1)=='-')
#define ISPAREN (parser_get_char()=='(')
#define ENDED (parser_get_char()==0)

const char* keywords[] = { "and", "break", "do", "else", "elseif", "end", "false", "for", "function", "goto", "if", "in", "local", "nil", "not", "or", "repeat", "return", "then", "true", "until", "while" };

const bool is_keyword() {
    for (int i=0;i<22;++i) if (strcmp(alpha, keywords[i]) == 0) return true;
    return false;
}

void parser_do_color(uint8_t type) {
    uint8_t color = COLOR_WHITE;
    switch (type) {
        case PARSER_NUMBER: color = COLOR_LIGHT_GREEN; break;
        case PARSER_COMMENT: color = COLOR_LIGHT_GRAY; break;
        case PARSER_STRING: color = COLOR_RED; break;
        case PARSER_IDENTIFIER: if (is_keyword()) color = COLOR_MAGENTA; break;
        case PARSER_FUNCTION: color = COLOR_YELLOW; break;
    };
    color = (color&0x0f)+(0x10);
    for (int i=parser_start;i<parser_pos;++i) poke(0x1200+parser_offset+i, color);
    parser_start = parser_pos;
}

void refresh_line_color(uint8_t line) {
    parser_setup(80*(line+1));
    while (!ENDED) {
        uint8_t result = PARSER_NOTHING;
        if (ISZERO) {
            result=PARSER_NUMBER; parser_next();
            if (ISX) {
                if (WILLBEDIGIT) {
                    parser_next();
                    while (ISDIGIT) parser_next();
                }
            } else if (ISDIGIT) {
                while (ISDIGIT) parser_next();
                if (ISPOINT) {
                    parser_next();
                    while (ISDIGIT) parser_next();
                }
            } else if (ISPOINT) {
                    parser_next();
                    while (ISDIGIT) parser_next();
            }
        } else if (ISDIGIT) {
            result = PARSER_NUMBER;
            while (ISDIGIT) parser_next();
            if (ISPOINT) {
                parser_next();
                while (ISDIGIT) parser_next();
            }
        } else if (ISALPHA) {
            result = PARSER_IDENTIFIER;
            while (ISALPHA || ISDIGIT) parser_next(true);
            if (ISPAREN) result = PARSER_FUNCTION;
        } else if (ISQUOTES) {
            result = PARSER_STRING; parser_next();
            while (!ISQUOTES && !ENDED) parser_next();
            parser_next();
        } else if (ISMINUS) {
            if (WILLBEMINUS) {
                result = PARSER_COMMENT;
                while (!ENDED) parser_next();
            }
        }
        if (result == PARSER_NOTHING) parser_next();
        parser_do_color(result);
    }
}

void refresh_color_highlight() {
    cursor_inverted = false;
    for (int i=0;i<28;++i) refresh_line_color(i);
}

void refresh_code_editor() {
    color(COLOR_WHITE, COLOR_BLUE);
    cls();
    color(COLOR_BLACK, COLOR_LIGHT_GRAY);
    print("  File  Edit  Run                                                               ",0,0);
    print("                                                                               ",0,29);
    color(COLOR_WHITE, COLOR_BLUE);
    std::list<std::string>::iterator it = code.begin();
    int i=0;
    while (it != code.end() && i<28) {
        ls[i] = it;
        print((*it).c_str(), 0, i+1);
        ++i; ++it;
    }
    refresh_color_highlight();
}

void init_code_editor() {
    setmode(3);
    code.clear();
    load_code();
    refresh_code_editor();
}

std::string get_current_line() {
    return *ls[line];
}

void invert_cursor() {
    cursor_inverted = !cursor_inverted;
    uint16_t pos = 0x1200 + col + (line+1)*80;
    uint8_t col = peek(pos);
    poke(pos, ((col >> 4) & 0x0f) + ((col << 4) & 0xf0) );
}

void move_cursor_up() {
    if (line > 0) {
        if (cursor_inverted) invert_cursor();
        line--;
        if (get_current_line().size() < col) col = get_current_line().size();
        blink_wait=1;
    }
}

void move_cursor_down() {
    if (line < code.size()-1) {
        if (cursor_inverted) invert_cursor();
        line++;
        if (get_current_line().size() < col) col = get_current_line().size();
        blink_wait=1;
    }
}

void move_cursor_right() {
    if ( col < get_current_line().size() ) {
        if (cursor_inverted) invert_cursor();
        col++;
        blink_wait=1;
    } else {
        if (line < code.size()-1) {
            col = 0;
            move_cursor_down();
        }
    }
}

void move_cursor_left() {
    if (col > 0) {
        if (cursor_inverted) invert_cursor();
        col--;
        blink_wait=1;
    } else {
        if (line > 0) {
            move_cursor_up();
            col = get_current_line().size();
        }
    }
}

void move_line_end() {
    if (cursor_inverted) invert_cursor();
    col = get_current_line().size();
    blink_wait=1;
}

void move_line_home() {
    if (cursor_inverted) invert_cursor();
    col = 0;
    blink_wait=1;
}

void split_line() {
    std::string str = get_current_line();
    *ls[line] = str.substr(col);
    std::list<std::string>::iterator newline = ls[line]++;
    code.insert(newline, str.substr(0, col));

    if (cursor_inverted) invert_cursor();
    line++; col=0;
    blink_wait=1;
    refresh_code_editor();
}

void join_lines() {
    if (cursor_inverted) invert_cursor();
    std::string str = get_current_line();
    //std::list<std::string>::iterator prevline = ls[line]--;
    code.erase(ls[line]);
    line--;
    const int line_size = (*ls[line]).size();
    *ls[line] += str;
    col = line_size;
    blink_wait=1;
    refresh_code_editor();
}

void delete_char() {
    if (col == 0) {
        if (line > 0) join_lines();
    } else {
    if (cursor_inverted) invert_cursor();
        std::string str = get_current_line();
        std::string a = str.substr(0,col-1);
        std::string b = str.substr(col);
        *ls[line] = a+b;
        col--;
        blink_wait=1;
        refresh_code_editor();
    }
}

void supr_char() {
    if ((col == (*ls[line]).size()) && (line == code.size()-1)) return;
    move_cursor_right();
    delete_char();
}

void add_char(uint8_t chr) {
    std::string str = get_current_line();
    std::string a = str.substr(0,col);
    std::string b = str.substr(col);
    std::string c = " "; c[0] = chr;
    *ls[line] = a+c+b;
    col++;
    blink_wait=1;
    refresh_code_editor();
}

void do_code_editor() {
    const uint8_t key = whichbtn();
    if (key != KEY_UNKNOWN) {
        if (key == KEY_RETURN or key == KEY_KP_ENTER) {
            split_line();
        }
        else if (key == KEY_UP) move_cursor_up();
        else if (key == KEY_DOWN) move_cursor_down();
        else if (key == KEY_LEFT) move_cursor_left();
        else if (key == KEY_RIGHT) move_cursor_right();
        else if (key == KEY_BACKSPACE) delete_char();
        else if (key == KEY_DELETE) supr_char();
        else if (key == KEY_END) move_line_end();
        else if (key == KEY_HOME) move_line_home();
        else {
            uint8_t chr = get_char(key);
            if (chr != 0) add_char(chr);
        }
    }

    blink_wait--;
    if (blink_wait == 0) {
        blink_wait = 30;
        invert_cursor();
    }
}