#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "include/raylib.h"
#include "raymath.h"

#define SCREEN_WIDTH 1000
#define SCREEN_HEIGHT 800
#define IMG_W SCREEN_WIDTH
#define IMG_H SCREEN_HEIGHT
#define IMG_SIZE SCREEN_WIDTH * SCREEN_HEIGHT
#define TARGET_FPS 120

const int maxRadius = 25;
const int paintTankMax = 250;
const Color playerColor = { 0, 121, 241, 255 };

typedef struct Pixel {
    int x;
    int y;
} Pixel;

typedef struct GameState {
    float dt;
    float time_elapsed;
    int frame_count;
    Texture displayTexture;
    Image imageBuffer;
    int paintTank;
    bool joystickActive;
    Vector2 joystickStartPos;
    Vector2 playerPos;
    Vector2 playerDir;
    Color colorUnderPlayer;
    int *bfsBuffer;
    Pixel *queue;
    int q_head;
    int q_tail;
    Pixel *fill;
    int fillCount;
} GameState;

int   PixelToIndex(Pixel p) {return p.y * SCREEN_WIDTH + p.x;}
Pixel IndexToPixel(int idx) {return (Pixel) {idx % SCREEN_WIDTH, (int)(idx / SCREEN_WIDTH) }; }

GameState *Init() {
    InitWindow(SCREEN_WIDTH, SCREEN_HEIGHT, "Flood Fill");
    SetTargetFPS(TARGET_FPS);

    Image imageBuffer = GenImageColor(IMG_W, IMG_H, WHITE);
    GameState state = {
        .imageBuffer      = imageBuffer,
        .displayTexture   = LoadTextureFromImage(imageBuffer),
        .playerPos        = (Vector2){40, 40},
        .paintTank        = paintTankMax,
        .colorUnderPlayer = BLUE,
        .bfsBuffer        = RL_CALLOC(IMG_SIZE, sizeof(int)),
        .queue            = RL_CALLOC(IMG_SIZE, sizeof(Pixel)),
        .fill             = RL_CALLOC(IMG_SIZE, sizeof(Pixel)),
    };

    int r = 150;
    ImageDrawCircle(&state.imageBuffer, 0,         0, r, playerColor);
    ImageDrawCircle(&state.imageBuffer, IMG_W,     0, r, GREEN);
    ImageDrawCircle(&state.imageBuffer, 0,     IMG_H, r, VIOLET);
    ImageDrawCircle(&state.imageBuffer, IMG_W, IMG_H, r, ORANGE);
    UpdateTexture(state.displayTexture, state.imageBuffer.data);

    GameState *state_ptr = RL_MALLOC(sizeof(GameState));
    memcpy(state_ptr, &state, sizeof(GameState));
    return state_ptr;
}

void Input(GameState *S) {
    if (IsMouseButtonPressed(0)) {
        S->joystickStartPos = GetMousePosition();
        S->joystickActive = true;
    }
    if (IsMouseButtonReleased(0)) {
        S->joystickActive = false;
    }
}

void Update(GameState *S) {
    bool dirty = false;
    if (S->joystickActive) {
        Vector2 dist = Vector2Subtract(GetMousePosition(), S->joystickStartPos);
        Vector2 joystickDelta = Vector2Normalize(dist);
        Vector2 dir = Vector2Normalize(joystickDelta);
        S->playerDir = Vector2Lerp(S->playerDir, dir, S->dt * 5.0f);
        S->playerPos = Vector2Add(S->playerPos, Vector2Scale(S->playerDir, 180.0f * S->dt));
        Vector2 minBounds = (Vector2){25.0f, 25.0f};
        Vector2 maxBounds = (Vector2){SCREEN_WIDTH - 25.0f, SCREEN_HEIGHT - 25.0f};
        S->playerPos = Vector2Clamp(S->playerPos, minBounds, maxBounds);

        float r = (float)S->paintTank / 10.0f;

        dist = Vector2Scale(S->playerDir, r + 1);
        Vector2 offset = Vector2Add(S->playerPos, dist);
        S->colorUnderPlayer = GetImageColor(S->imageBuffer, offset.x, offset.y);

        float mag = Vector2Length(joystickDelta);
        if (mag > 0.0f) {
            bool sameColor = ColorIsEqual(S->colorUnderPlayer, playerColor);
            if (sameColor && S->paintTank < paintTankMax) {
                S->paintTank += 4;
                S->paintTank = S->paintTank > paintTankMax ? paintTankMax : S->paintTank;
            } else {
                S->paintTank -= 4;
                S->paintTank = S->paintTank < 0 ? 0 : S->paintTank;
            }
            if (S->paintTank > 0 && !sameColor) {
                ImageDrawCircleV(&S->imageBuffer, S->playerPos, r, BLUE);
                UpdateTexture(S->displayTexture, S->imageBuffer.data);
                dirty = true;
            }
        }
    }

    if (!dirty) {
        return;
    }
    for (int i = 0; i < IMG_SIZE; i++) {
        Pixel pixel = IndexToPixel(i);
        Color color = GetImageColor(S->imageBuffer, pixel.x, pixel.y);
        bool sameColor = ColorIsEqual(color, playerColor);
        if (S->bfsBuffer[i] != 0 || sameColor) {
            continue;
        }
        S->queue[0] = pixel;
        S->q_tail++;
        bool edgeDetected = false;
        while (S->q_head != S->q_tail) {
            Pixel pixel = S->queue[S->q_head++];
            int idx = PixelToIndex(pixel);

            int left   = pixel.y * IMG_W - idx - 1 >= 0    ? idx - 1 : -1;
            int right  = pixel.y * IMG_W - idx + 1 < IMG_W ? idx + 1 : IMG_W;
            int top    = idx - IMG_W;
            int bottom = idx + IMG_W;
            int directions[] = { left, right, top, bottom };
            for (int i = 0; i < 4; i++) {
                int j = directions[i];
                if (j >= 0 && j < IMG_W) {
                    Pixel pixel = IndexToPixel(j);
                    Color c = GetImageColor(S->imageBuffer, pixel.x, pixel.y);
                    if (S->bfsBuffer[j] == 0 && !ColorIsEqual(playerColor, c)) {
                        S->queue[S->q_tail++] = pixel;
                    } else if (S->bfsBuffer[j] == 0) {
                        S->bfsBuffer[j] = -1;
                    }
                } else {
                    edgeDetected = true;
                }
            }
            S->bfsBuffer[idx] = 1;
            if (!edgeDetected) {
                S->fill[S->fillCount++] = pixel;
            }
        }
        // Fill that sucker
        if (!edgeDetected) {
            for (int i = 0; i < S->fillCount; i++) {
                Pixel p = S->fill[i];
                ImageDrawPixel(&S->imageBuffer, p.x, p.y, playerColor);
            }
            UpdateTexture(S->displayTexture, S->imageBuffer.data);
        }
        S->fillCount = 0;
        S->q_head = S->q_tail = 0;
    }
    memset(S->bfsBuffer, 0, IMG_SIZE * sizeof(int));
}

void Draw2D(const GameState *S) {
    DrawTexture(S->displayTexture, 0, 0, WHITE);
    DrawCircleV(S->playerPos, 20, BLACK);
    Vector2 lookPos = Vector2Scale(S->playerDir, 50.0f);
    lookPos = Vector2Add(S->playerPos, lookPos);
    DrawLineV(S->playerPos, lookPos, RED);
    int barWidth = 50, barHeight = 12;
    float perc = S->paintTank / (float)paintTankMax;
    float barX = S->playerPos.x - barWidth / 2;
    float barY = S->playerPos.y + 10;
    Rectangle barBGRect = {barX, barY, barWidth,        barHeight};
    Rectangle barFGRect = {barX, barY, barWidth * perc, barHeight};
    DrawRectangleRec(barBGRect, GRAY);
    DrawRectangleRec(barFGRect, RED);

    if (S->joystickActive) {
        Color grayish = {200, 200, 200, 100};
        DrawRing(S->joystickStartPos, 60, 80, 0.0f, 360.0f, 50, grayish);
        Vector2 mousePos = GetMousePosition();
        Vector2 padDir = Vector2Normalize(Vector2Subtract(mousePos, S->joystickStartPos));
        Vector2 offsetPos = Vector2Add(S->joystickStartPos, Vector2Scale(padDir, 30.0f));
        Vector2 clampedPos = Vector2Clamp(mousePos, S->joystickStartPos, offsetPos);
        DrawCircleV(clampedPos, 25, grayish);
    }
}

void Draw2DDebug(GameState *S) {
    Rectangle rect = {SCREEN_WIDTH / 2 - 50, SCREEN_HEIGHT - 100, 110, 50};
    DrawRectangleRec(rect, S->colorUnderPlayer);
    DrawRectangleLinesEx(rect, 2, BLACK);
    DrawFPS(rect.x + 17, SCREEN_HEIGHT - 33);
}

int main(void) {
    GameState *state = Init();
    while (!WindowShouldClose()) {
        state->dt           = GetFrameTime();
        state->time_elapsed = GetTime();

        Input(state);

        Update(state);

        BeginDrawing();
        {
            ClearBackground(RAYWHITE);

            Draw2D(state);
            Draw2DDebug(state);
        }
        EndDrawing();
        state->frame_count++;
    }

    UnloadImage(state->imageBuffer);
    UnloadTexture(state->displayTexture);
    CloseWindow();
    free(state->fill);
    free(state->queue);
    free(state->bfsBuffer);
    free(state);
}