#include <ncurses.h>
#include <curses.h>
#include <string>
#include <vector>
#include <fstream>

#include "treap.hpp"

using std::string;
using std::vector;

#define ESC 27
#define ENTER 10
#define BS 127
#define adds(s) addstr(s.c_str())
enum mode_type { insert, normal };


// Global variables
treap file;
int row = 0, col = 0;
int file_offset = 0;

// Accessing the file
string get_line(int r) {
	string line = (*file.find(file_offset+r)).text;
	for(int i = 0; i < line.size(); ++i)
		if(line[i] == '\t')
			line[i] = ' ';
	return line;
}
char get(int r, int s) { return get_line(file_offset+r)[s]; }
void set(int r, int s, char ch) { file.find(file_offset+r)->text[s] = ch; }
void insert_line(int r, string text = "") { file.insert(file_offset+r, text); }
void insert_char(int r, int s, char ch) { file.find(file_offset+r)->text.insert(s, string{ch}); }
void remove_char(int r, int s, int len=1) { file.find(file_offset+r)->text.erase(s,len); }
void remove_line(int r) { file.remove(file_offset+r); }


// Load file to buffer
bool load(string filename) {
	std::ifstream infile(filename);
	if(!infile.good())
		return 1;

	string line;
	while (std::getline(infile, line))
		file.insert(file.size(), line);
	return 0;
}
// Save file from buffer
bool save(string filename) {
	std::ofstream outfile(filename);
	if(!outfile.good())
		return 1;

	for(int i = 0; i < file.size(); ++i)
		outfile << get_line(i-file_offset) << std::endl;
	return 0;
}


// Clear line
void clear_line(int pos) {
	move(pos, 0);
	clrtoeol();
}
// Print line
void print_line(int pos) {
	clear_line(pos);
	move(pos, 0);
	adds(get_line(pos));
}
// Print file content
void print_file(int start = 0) {
	for(int i = start; i < LINES; i++)
		if(file_offset+i < file.size())
			print_line(i);
		else
			clear_line(i);
}
// Splitting lines
string split_line(int r, int s) {
	string line = get_line(r);
	string ret = line.substr(s, line.size());
	remove_char(r, s, line.size()-s);
	return ret;
}


// TODO skoky a přesuny
// TODO kopirování
// TODO hledání a nahrazování
// TODO undo


// Jump to end of line
void jump_line_end() {
	int line_size = get_line(row).size();
	if(col > line_size)
		col = line_size;
}
// Cursor movement
void move_cursor(char ch) {
	switch(ch) {
		case 'h':
			if(col > 0)
				move(row, --col);
			break;

		case 'j':
			if(file_offset + row >= file.size()-1) break;
			if(row < LINES-1) {
				move(++row, col);
				jump_line_end();
			}
			else if(row == LINES-1) {
				file_offset++;
				jump_line_end();
				print_file();
			}
			break;

		case 'k':
			if(row > 0) {
				move(--row, col);
				jump_line_end();
			}
			else if(file_offset > 0) {
				file_offset--;
				jump_line_end();
				print_file();
			}
			break;

		case 'l':
			if(col < get_line(row).size())
				move(row, ++col);
			break;
	}
}


int main(int argc, char* argv[]) {
	
	// Check valid filename and load
	if(argc <= 1)
		return 1;
	string filename = argv[1];
	if(load(filename))
		return 1;

	// Init
	initscr();
	refresh();
	print_file();

	mode_type mode = normal;

	// Main loop
	bool run = true;
	while(run) {
		move(row, col);
		char ch = getch();
		switch(mode) {
			case normal:
				print_line(row);
				switch(ch) {
					case 'h': case 'j': case 'k': case 'l':
						move_cursor(ch);
						break;
					case 'd':
						remove_line(row);
						print_file(row);
						break;
					case 'x':
						remove_char(row, col);
						print_line(row);
						break;
					case 'o':
						insert_line(row);
						print_file(row);
						break;
					case 'q':
						run = false;
						break;
					case 'w':
						save(filename);
						break;
					case 'i':
						mode = insert;
						break;
					default:
						break;
				}
				break;
			case insert:
				switch(ch) {
					case ESC:
						mode = normal;
						print_line(row);
						break;
					case BS:
						if(col>0)
							remove_char(row, --col);
						print_line(row);
						break;
					case ENTER:
						insert_line(row+1, split_line(row, col));
						print_file(row++);
						jump_line_end();
						break;
					default:
						insert_char(row, col++, ch);
						print_line(row);
						break;
				}
		}
		refresh();
	}

	// End
	endwin();
	return 0;
}