#include <iostream>

#include "Game.h"
#include "Types.h"

Game::Game() : activeX(-1), activeY(-1), directionX(0), directionY(0), state(SELECTION), lastLocation(0) {
    reset();
}

void Game::reset() {
    activeX = -1;
    activeY = -1;
    for(uint x = 0; x < 9; x++) {
        for(uint y = 0; y < 5; y++) {
            fields[x][y] = (y > 2 ? WHITE : BLACK);
        }
    }
    fields[0][2] = WHITE;
    fields[2][2] = WHITE;
    fields[4][2] = EMPTY;
    fields[5][2] = WHITE;
    fields[7][2] = WHITE;
}

void Game::reset(String& output) {
    reset();
    output.append("Fanorona Game\n\r");
    print(output);
    output.append("Human Color: White(O)\n\rAIColor: Black(#)\n\rHuman turn\n\rselect stone: ");
}

void Game::print(String& s) const {
    s.append("\n\r  0 1 2 3 4 5 6 7 8\n\r");
    printLine(s, 0);
    s.append("  |\\|/|\\|/|\\|/|\\|/|\n\r");
    printLine(s, 1);
    s.append("  |/|\\|/|\\|/|\\|/|\\|\n\r");
    printLine(s, 2);
    s.append("  |\\|/|\\|/|\\|/|\\|/|\n\r");
    printLine(s, 3);
    s.append("  |/|\\|/|\\|/|\\|/|\\|\n\r");
    printLine(s, 4);
    s.append("\n\r");
}

void Game::printLine(String& s, int index) const {
    static const char map[] = {
        '#', 'O', '.'
    };
    s.append(index + '0').append(' ');
    for(int x = 0; x < 8; x++) {
        if(x == activeX && index == activeY) {
            s.append("*-");
            continue;
        }
        s.append(map[fields[x][index]]).append('-');
    }
    if(8 == activeX && index == activeY) {
        s.append('*');
    } else {
        s.append(map[fields[8][index]]);
    }
    s.append("\n\r");
}

bool Game::parseLocation(const String& input, int& x, int& y) {
    if(input.getLength() <= 2 || !isDigit(input[0]) || input[1] != ' ' || !isDigit(input[2])) {
        return true;
    }
    x = input[0] - '0';
    y = input[2] - '0';
    return x >= 9 || y >= 6;
}

void Game::parse(const String& input, String& output) {
    switch(state) {
        case SELECTION:
            parseSelection(input, output);
            break;
        case MOVE:
            parseMove(input, output);
            break;
        case ANOTHER_MOVE:
            parseAnotherMove(input, output);
            break;
    }
}

void Game::parseSelection(const String& input, String& output) {
    int x;
    int y;
    if(parseLocation(input, x, y) || fields[x][y] != WHITE) {
        output.append("please choose white stone.\n\r");
        print(output);
        output.append("Human Color: White(O)\n\rAIColor: Black(#)\n\rHuman turn\n\rselect stone: ");
        return;
    }
    state = MOVE;
    activeX = x;
    activeY = y;
    print(output);
    output.append("Human Color: White(O)\n\rAIColor: Black(#)\n\rselect location to move: ");
}

void Game::parseMove(const String& input, String& output) {
    int x;
    int y;
    if(parseLocation(input, x, y)) {
        output.append("invalid move location.\n\r");
        print(output);
        output.append("Human Color: White(O)\n\rAIColor: Black(#)\n\rselect location to move: ");
        return;
    }
    if(fields[x][y] == WHITE) {
        activeX = x;
        activeY = y;
        print(output);
        output.append("Human Color: White(O)\n\rAIColor: Black(#)\n\rselect location to move: ");
        return;
    }
    if(fields[x][y] != EMPTY || !areNeighbours(activeX, activeY, x, y)) {
        output.append("invalid move location.\n\r");
        print(output);
        output.append("Human Color: White(O)\n\rAIColor: Black(#)\n\rselect location to move: ");
        return;
    }
    lastLocation = 0;
    move(activeX, activeY, x, y);

    bool removed = false;
    removed = removeLine(x, y, activeX, activeY, BLACK) || removed;
    removed = removeLine(activeX, activeY, x, y, BLACK) || removed;

    activeX = x;
    activeY = y;
    print(output);
    output.append("Human Color: White(O)\n\rAIColor: Black(#)\n\r");
    print(output);
    if(removed && isAnotherTurnPossible()) {
        state = ANOTHER_MOVE;
        output.append("Human Color: White(O)\n\rAIColor: Black(#)\n\rselect location to move: ");
        return;
    }
    state = SELECTION;
    output.append("Human Color: White(O)\n\rAIColor: Black(#)\n\rAI turn\n\r");
    activeX = -1;
    activeY = -1;
    botMove(output);
}

void Game::parseAnotherMove(const String& input, String& output) {
    int x;
    int y;
    if(parseLocation(input, x, y) || !canMoveActiveStoneTo(x - activeX, y - activeY)) {
        output.append("invalid move location.\n\r");
        print(output);
        output.append("Human Color: White(O)\n\rAIColor: Black(#)\n\rselect location to move: ");
        return;
    }
    move(activeX, activeY, x, y);

    bool removed = false;
    removed = removeLine(x, y, activeX, activeY, BLACK) || removed;
    removed = removeLine(activeX, activeY, x, y, BLACK) || removed;

    activeX = x;
    activeY = y;
    print(output);
    output.append("Human Color: White(O)\n\rAIColor: Black(#)\n\r");
    print(output);
    if(removed && isAnotherTurnPossible()) {
        output.append("Human Color: White(O)\n\rAIColor: Black(#)\n\rselect location to move: ");
        return;
    }
    state = SELECTION;
    output.append("Human Color: White(O)\n\rAIColor: Black(#)\n\rAI turn\n\r");
    activeX = -1;
    activeY = -1;
    botMove(output);
}

void Game::move(int fromX, int fromY, int toX, int toY) {
    addLocation(fromX, fromY);
    directionX = toX - fromX;
    directionY = toY - fromY;
    fields[fromX][fromY] = EMPTY;
    fields[toX][toY] = WHITE;
}

bool Game::isDigit(char c) const {
    return c >= '0' && c <= '9';
}

bool Game::isInRange(int x, int y) const {
    return x >= 0 && x <= 8 && y >= 0 && y <= 4;
}

bool Game::areNeighbours(int x, int y, int x2, int y2) const {
    if(x == x2 && y == y2) {
        return false;
    }
    int diffX = x - x2;
    int diffY = y - y2;
    if(diffX < -1 || diffX > 1 || diffY < -1 || diffY > 1) {
        return false;
    }
    if(diffX == 0 || diffY == 0) {
        return true;
    }
    return !((x & 1) ^ (y & 1));
}

void Game::revertToSelection(String& output) {
    activeX = -1;
    activeY = -1;
    print(output);
    output.append("Human Color: White(O)\n\rAIColor: Black(#)\n\rHuman turn\n\rselect stone: ");
}

bool Game::removeLine(int x, int y, int x2, int y2, FieldState remove) {
    int diffX = x2 - x;
    int diffY = y2 - y;
    bool removed = false;
    while(true) {
        x2 += diffX;
        y2 += diffY;
        if(!isInRange(x2, y2) || fields[x2][y2] != remove) {
            return removed;
        }
        removed = true;
        fields[x2][y2] = EMPTY;
    }
}

void Game::botMove(String& output) {
    while(true) {
        int x = 0;
        int y = 0;
        while(true) {
            x = rand() % 9;
            y = rand() % 5;
            if(fields[x][y] == EMPTY) {
                break;
            }
        }
        for(uint i = 0; i < 10; i++) {
            int mx = x + (rand() % 3) - 1;
            int my = y + (rand() % 3) - 1;
            if((mx == x && my == y) || !isInRange(mx, my) || fields[mx][my] != BLACK) {
                continue;
            }
            fields[mx][my] = EMPTY;
            fields[x][y] = BLACK;
            removeLine(mx, my, x, y, WHITE);
            removeLine(x, y, mx, my, WHITE);

            activeX = x;
            activeY = y;
            print(output);
            activeX = -1;
            activeY = -1;
            print(output);
            revertToSelection(output);
            return;
        }
    }
}

void Game::addLocation(int x, int y) {
    if(lastLocation >= lastLocations.size()) {
        // safely to ignore, such long turns will never happen
        return;
    }
    lastLocations[lastLocation].x = x;
    lastLocations[lastLocation].y = y;
    lastLocation++;
}

bool Game::isInQueue(int x, int y) const {
    for(uint i = 0; i < lastLocation; i++) {
        if(lastLocations[i].x == x && lastLocations[i].y == y) {
            return true;
        }
    }
    return false;
}

bool Game::canMoveActiveStoneTo(int dirX, int dirY) const {
    if(directionX == dirX && directionY == dirY) {
        return false;
    }
    int newX = activeX + dirX;
    int newY = activeY + dirY;
    return isInRange(newX, newY) && areNeighbours(activeX, activeY, newX, newY) &&
            fields[newX][newY] == EMPTY && !isInQueue(newX, newY);
}

bool Game::isAnotherTurnPossible() const {
    return canMoveActiveStoneTo(-1, -1) || canMoveActiveStoneTo(0, -1) || canMoveActiveStoneTo(1, -1) ||
            canMoveActiveStoneTo(-1, 0) || canMoveActiveStoneTo(1, 0) ||
            canMoveActiveStoneTo(-1, 1) || canMoveActiveStoneTo(0, 1) || canMoveActiveStoneTo(1, 1);
}