#include "SDL3/SDL_events.h"
#include "SDL3/SDL_render.h"
#include "SDL3/SDL_video.h"
#include "SDL3/SDL.h"
#include "SDL3/SDL_main.h"

#include "SDL3_ttf/SDL_ttf.h"
#include "Snake.h"
#include "Apple.h"
#include <cstring>

/*
  Compile through this command
g++ main.cpp Snake.cpp Apple.cpp -o Game.exe -I./SDL3-3.3.6/x86_64-w64-mingw32/include -I./SDL3_ttf-3.2.2/x86_64-w64-mingw32/include -L. -lSDL3 -lSDL3_ttf
 */

#define winW 800
#define winH 600
using namespace std;

const Uint64 frameDelay = 1000 / 60; // 60 FPS for Rendering

//For Different States
enum GameState {
    STATE_MENU,
    STATE_PLAYING,
    STATE_GAMEOVER
};

GameState currentState = STATE_MENU;


Uint64 initialInterval = 150;
Uint64 moveInterval = initialInterval;
const Uint64 minInterval = 70; // Hardest speed
int score = 0;

void RenderText(SDL_Renderer* renderer, TTF_Font* font, const char* text, int x, int y, SDL_Color color, bool center = false) {
    if (!font || !text || text[0] == '\0') return;

    SDL_Surface* surface = TTF_RenderText_Blended(font, text, 0, color);
    if (!surface) return;

    SDL_Texture* texture = SDL_CreateTextureFromSurface(renderer, surface);
    if (texture) {
        float w = (float)surface->w;
        float h = (float)surface->h;
        float renderX = (float)x;
        
        if (center) {
            renderX = (float)(x - w / 2);
        }

        SDL_FRect dstRect = { renderX, (float)y, w, h };
        SDL_RenderTexture(renderer, texture, nullptr, &dstRect);
        SDL_DestroyTexture(texture);
    }
    SDL_DestroySurface(surface);
}

// DrawMenu
void DrawMenu(SDL_Renderer* renderer, TTF_Font* font, TTF_Font* smallfont, int _winW, int _winH) {
    SDL_Color white = {255, 255, 255, 255};
    RenderText(renderer, font, "贪吃蛇大作战", _winW / 2, _winH / 2 - 50, white, true);
    SDL_Color gray = {200, 200, 200, 255};
    RenderText(renderer, smallfont, "按任意键开始...", _winW / 2, _winH / 2 + 20, gray, true);
}

void DrawGameOver(SDL_Renderer* renderer, TTF_Font* font, TTF_Font* smallfont, int _winW, int _winH, int _score) {
    SDL_Color red = {255, 50, 50, 255};
    RenderText(renderer, font, "游戏结束", _winW / 2, _winH / 2 - 80, red, true);

    char scoreBuf[64];
    sprintf(scoreBuf, "最终得分: %d", _score);
    SDL_Color white = {255, 255, 255, 255};
    RenderText(renderer, font, scoreBuf, _winW / 2, _winH / 2, white, true);

    SDL_Color gray = {200, 200, 200, 255};
    RenderText(renderer, smallfont, "按R键重新开始...", _winW / 2, _winH / 2 + 120, gray, true);
}

void DrawScore(SDL_Renderer* renderer, TTF_Font* font, int _winW, int _winH, int _score){
    char scoreBuf[64];
    sprintf(scoreBuf, "得分: %d", _score);
    SDL_Color white = {255, 255, 255, 255};
    RenderText(renderer, font, scoreBuf, 60, 0, white, true);
}

int main(int argc, char* argv[]) {
    bool x = SDL_Init(SDL_INIT_VIDEO);
    if(!x){
        SDL_Log("SDL Init Error: %s\n", SDL_GetError());
        return -1;
    }
    if (!TTF_Init()) {
        SDL_Log("TTF Init Error: %s", SDL_GetError());
        return -1;
    }
    TTF_Font* font = TTF_OpenFont("./assets/fonts/NotoSerifCJKsc-Regular.otf", 48);
    TTF_Font* smallFont = TTF_OpenFont("./assets/fonts/NotoSerifCJKsc-Regular.otf", 24);

    if (!font || !smallFont) {
        SDL_Log("Font Load Error: %s", SDL_GetError());
    }

    SDL_Window* mainWindow = SDL_CreateWindow(
        "Blockade: Snake Game",
        winW, winH,
        SDL_WINDOW_RESIZABLE
        );
    if(!mainWindow){
        SDL_Log("SDL Init Window Error: %s\n", SDL_GetError());
        return -1;
    }
    
    SDL_Renderer* mainRender = SDL_CreateRenderer(mainWindow, nullptr);
    if(!mainRender){
        SDL_Log("SDL Init Renderer Error: %s\n", SDL_GetError());
        return -1;
    }

    Snake snake(winW, winH, 25);
    Apple apple(winW, winH, 25);
    Uint64 lastUpdateTime = SDL_GetTicks();

    SDL_Event event;
    int running = 1;

    while(running){
        Uint64 frameStart = SDL_GetTicks();

        while(SDL_PollEvent(&event)){
            if(event.type == SDL_EVENT_QUIT) running = 0;

            if (event.type == SDL_EVENT_KEY_DOWN) {
                if (event.key.key == SDLK_ESCAPE) running = false;

                if (currentState == STATE_MENU) {
                    currentState = STATE_PLAYING;
                } 
                else if (currentState == STATE_GAMEOVER) {
                    if (event.key.key == SDLK_R) {
                        snake.Reset(winW, winH);
                        apple.Spawn();
                        score = 0;
                        moveInterval = initialInterval;
                        currentState = STATE_PLAYING;
                    }
                } 
                else if (currentState == STATE_PLAYING) {
                    snake.HandleInput(event.key.key);
                }
            }
        }
        if(currentState == STATE_PLAYING){
            Uint64 currentTime = SDL_GetTicks();
            if (currentTime - lastUpdateTime >= moveInterval) {
                snake.Update();

                SDL_Point head = snake.GetHeadPos();
                SDL_Point applePos = apple.GetPos();
            
                if (snake.CheckCollision(winW, winH)) {
                    SDL_Log("Game Over! Restarting...");
                    currentState = STATE_GAMEOVER;
                }
                if(head.x == applePos.x && head.y == applePos.y){
                    snake.Grow();
                    apple.Spawn();
                    score += 10;
                    if(moveInterval > minInterval){
                        moveInterval -= 5; //Everytime add Speeeeeeeeeeeeeed
                    }
                    //Check if Apple is inside the snake
                    bool collision;
                    do {
                        collision = false;
                        apple.Spawn();
                        SDL_Point newApplePos = apple.GetPos();
                        const std::deque<SDL_Point>& segments = snake.GetBody();
                    
                        for (const auto& segment : segments) {
                            if (newApplePos.x == segment.x && newApplePos.y == segment.y) {
                                collision = true;
                                break;
                            }
                        }
                    } while (collision); 
                }
            lastUpdateTime = currentTime;
            }
        }

        // Rendering
        // Clear screen to Black
        SDL_SetRenderDrawColor(mainRender, 0, 0, 0, 255);
        SDL_RenderClear(mainRender);

        if(currentState == STATE_MENU) {
            DrawMenu(mainRender, font, smallFont, winW, winH);
        }
        else if(currentState == STATE_PLAYING) {
            // Draw Snake
            snake.Render(mainRender);
            apple.Render(mainRender);
            DrawScore(mainRender, smallFont, winW, winH, score);
        }
        else if(currentState == STATE_GAMEOVER) {
            DrawGameOver(mainRender, font, smallFont, winW, winH, score);
        }
        

        // Present the backbuffer
        SDL_RenderPresent(mainRender);
        
        // Control FPS (Cap at 60 FPS)
        Uint64 frameTime = SDL_GetTicks() - frameStart;
        if (frameTime < frameDelay) {
            SDL_Delay((Uint32)(frameDelay - frameTime));
        }
    }

    // Cleanup
    SDL_DestroyRenderer(mainRender);
    SDL_DestroyWindow(mainWindow);
    SDL_Quit();

    return 0;
}