#include "raylib.h"
#include <math.h>
#include <stdio.h>

#define RAYGUI_IMPLEMENTATION
#include "raygui.h"

#define UI_WIDTH 400

typedef struct {
    float d1;
    float d2;
    float lambda;
    float angleM1;
    Vector2 center;
} Michelson;

Color WavelengthToColor(float lambda) {
    float r = 0.0f, g = 0.0f, b = 0.0f;
    if (lambda >= 380 && lambda < 440) { r = -(lambda - 440) / (440 - 380); b = 1.0f; }
    else if (lambda >= 440 && lambda < 490) { g = (lambda - 440) / (490 - 440); b = 1.0f; }
    else if (lambda >= 490 && lambda < 510) { g = 1.0f; b = -(lambda - 510) / (510 - 490); }
    else if (lambda >= 510 && lambda < 580) { r = (lambda - 510) / (580 - 510); g = 1.0f; }
    else if (lambda >= 580 && lambda < 645) { r = 1.0f; g = -(lambda - 645) / (645 - 580); }
    else if (lambda >= 645 && lambda <= 780) { r = 1.0f; }

    float factor = 1.0f;
    if (lambda >= 380 && lambda < 420) factor = 0.3f + 0.7f * (lambda - 380) / (420 - 380);
    else if (lambda >= 380 && lambda <= 645) factor = 1.0f;
    else if (lambda > 700 && lambda <= 780) factor = 0.3f + 0.7f * (780 - lambda) / (780 - 700);

    return (Color){(unsigned char)(r * factor * 255), (unsigned char)(g * factor * 255), (unsigned char)(b * factor * 255), 255};
}

void DrawInterferenceView(Michelson *mic, Rectangle rec) {
    DrawText("ECRAN", rec.x, rec.y - 30, 20, WHITE);

    DrawRectangleRec(rec, BLACK);
    DrawRectangleLinesEx(rec, 2, DARKGRAY);
    
    Color baseColor = WavelengthToColor(mic->lambda);
   
    // Diff de marche du à l'axe (2 * e) + micro -> nano
    float deltaLnm = 2.0f * (mic->d1 - mic->d2) * 1000.0f; 
    
    int cx = rec.x + rec.width / 2;
    int cy = rec.y + rec.height / 2;
   
    // Dessin pixel par pixel lent... => faire avec gpu 
    for (int y = rec.y; y < rec.y + rec.height; y++) {
        for (int x = rec.x; x < rec.x + rec.width; x++) {
            float relX = (float)(x - cx);
            float relY = (float)(y - cy);
            float radiusSq = relX * relX + relY * relY;

            // Diff de marche lamme d'air 2 * e cos(i) mais petits angles => cos(i) ~ 1 - i^2/2 mais i ~ r/f et r^2 = x^2 + y^2
            float ringFactor = radiusSq * 0.065f;
            // Diff de marche dut au coin d'air
            float wDelta = relX * mic->angleM1 * 200.0f; 

            float currDelta = deltaLnm - ringFactor + wDelta;

            // Formule de Fresnel : I = I_0 * cos^2(phi)
            float phase = (PI * currDelta) / mic->lambda;
            float intensity = cosf(phase);
            intensity = intensity * intensity;

            Color pixColor = {(unsigned char)(baseColor.r * intensity), (unsigned char)(baseColor.g * intensity), (unsigned char)(baseColor.b * intensity), 255 };
            
            DrawPixel(x, y, pixColor);
        }
    }
   
    // croix centre
    DrawLine(cx - 10, cy, cx + 10, cy, Fade(WHITE, 0.5f));
    DrawLine(cx, cy - 10, cx, cy + 10, Fade(WHITE, 0.5f));
}

void DrawMichelsonSchema (Michelson *mic) {
    Vector2 c = mic->center;
    Color laserColor = WavelengthToColor(mic->lambda);
    
    float thickness = 4.0f;
    float sourceLen = 450.0f;
    float screenLen = 450.0f;
    float mirrorSize = 140.0f;

    // Source
    Vector2 startSource = {c.x - sourceLen, c.y};
    DrawLineEx(startSource, c, thickness, laserColor);
    DrawRectangle(startSource.x - 20, startSource.y - 15, 20, 30, DARKGRAY); 
    DrawText("Source", startSource.x - 30, startSource.y - 40, 20, LIGHTGRAY);

    // Miroir M2 (fixe)
    Vector2 posM2 = {c.x + mic->d2, c.y};
    DrawLineEx(c, posM2, thickness, laserColor);
    DrawLineEx(c, (Vector2){c.x, c.y + screenLen}, thickness, Fade(laserColor, 0.6f));
    DrawRectangle(posM2.x, posM2.y - (mirrorSize / 2), 12, mirrorSize, LIGHTGRAY);
    DrawRectangle(posM2.x, posM2.y - (mirrorSize / 2) + 2, 4, mirrorSize - 4, WHITE);
    DrawText("M2", posM2.x + 20, posM2.y - 10, 20, GRAY);

    // Miroir M1 (mobile)
    Vector2 posM1 = {c.x, c.y - mic->d1};
    DrawLineEx(c, posM1, thickness, laserColor);
    
    // Projection rayon sur écran (corection tangente)
    float angleRad = -(mic->angleM1 * 2.0f) * (PI / 180.0f);
    float yScreen = c.y + screenLen;
    float vertDist = yScreen - posM1.y;
    float xOff = vertDist * tanf(angleRad);
    Vector2 endPointRetour = { posM1.x + xOff, yScreen };
    DrawLineEx(posM1, endPointRetour, thickness, Fade(laserColor, 0.6f));

    Rectangle recM1 = {posM1.x, posM1.y, mirrorSize, 12.0f}; 
    Vector2 originM1 = {mirrorSize / 2, 6.0f};
    DrawRectanglePro(recM1, originM1, mic->angleM1, LIGHTGRAY);
    Rectangle recM1Face = {posM1.x, posM1.y, mirrorSize - 4, 4.0f}; 
    Vector2 originM1Face = {(mirrorSize - 4) / 2, 6.0f};
    DrawRectanglePro(recM1Face, originM1Face, mic->angleM1, WHITE);
    DrawText("M1", posM1.x - 40, posM1.y - 30, 20, ORANGE);

    // Séparatrice
    float sepLen = 220.0f;
    Rectangle sepRec = {c.x, c.y, 4.0f, sepLen};
    Vector2 sepOrigin = {2.0f, sepLen / 2};
    DrawRectanglePro(sepRec, sepOrigin, -45.0f, Fade(SKYBLUE, 0.4f)); 
    DrawRectanglePro((Rectangle){c.x, c.y, 1.0f, sepLen}, (Vector2){0.5f, sepLen / 2}, -45.0f, Fade(WHITE, 0.5f));

    DrawRectangle(c.x - 300, yScreen, 600, 15, DARKGRAY);
    DrawText("Ecran", c.x - 20, yScreen + 20, 20, GRAY);
}

void DrawControlPanel(Michelson *mic) {
    DrawRectangle(0, 0, UI_WIDTH, GetScreenHeight(), (Color){30, 30, 30, 255});
    DrawLine(UI_WIDTH, 0, UI_WIDTH, GetScreenHeight(), WHITE);
    
    int startX = 30;
    int startY = 30;
    int buttonWidth = 60;
    int spacing = 20; 
    int contentWidth = UI_WIDTH - 60;
    int sliderWidth = contentWidth - buttonWidth - spacing - 15;

    GuiSetStyle(DEFAULT, TEXT_SIZE, 18);
    GuiSetStyle(DEFAULT, BASE_COLOR_NORMAL, 0x404040FF);
    GuiSetStyle(DEFAULT, BORDER_COLOR_NORMAL, 0x808080FF);
    GuiSetStyle(DEFAULT, TEXT_COLOR_NORMAL, 0xFFFFFFFF); 
    
    DrawText("PARAMETRES", startX, startY, 30, WHITE);
    
    // Sliders
    startY += 80;
    DrawText(TextFormat("Longueur d'onde: %.0f nm", mic->lambda), startX, startY, 20, LIGHTGRAY);
    GuiSlider((Rectangle){startX, startY + 30, contentWidth - 45, 30}, NULL, NULL, &mic->lambda, 380, 780);
    DrawRectangle(startX + contentWidth - 35, startY + 30, 35, 30, WavelengthToColor(mic->lambda));

    startY += 100;
    DrawText(TextFormat("Position M1 (d1): %.1f um", mic->d1), startX, startY, 20, ORANGE);
    GuiSlider((Rectangle){startX, startY + 30, sliderWidth, 30}, NULL, NULL, &mic->d1, 100, 600);
    if (GuiButton((Rectangle){startX + sliderWidth + spacing + 15, startY + 30, buttonWidth, 30}, "Egal")) mic->d1 = mic->d2;

    startY += 100;
    DrawText(TextFormat("Inclinaison M1: %.2f deg", mic->angleM1), startX, startY, 20, ORANGE);
    GuiSlider((Rectangle){startX, startY + 30, sliderWidth, 30}, "-1", "+1", &mic->angleM1, -1.0f, 1.0f);
    if (GuiButton((Rectangle){startX + sliderWidth + spacing + 15, startY + 30, buttonWidth, 30}, "0.0")) mic->angleM1 = 0.0f;
    
    const char* modeTxt = (fabs(mic->angleM1) < 0.01f) ? "MODE: LAME D'AIR" : "MODE: COIN D'AIR";
    Color modeColor = (fabs(mic->angleM1) < 0.01f) ? SKYBLUE : GREEN;
    DrawText(modeTxt, startX, startY + 75, 20, modeColor);

    startY += 140;
    DrawRectangleLines(startX - 10, startY - 10, contentWidth + 20, 100, GRAY);
    DrawText("Données", startX, startY, 20, LIGHTGRAY);
    
    float delta = 2 * (mic->d1 - mic->d2);
    DrawText(TextFormat("Delta = %.2f um", delta), startX, startY + 35, 22, WHITE);
    
    float p = (delta * 1000.0f) / mic->lambda; 
    DrawText(TextFormat("Ordre p = %.2f", p), startX, startY + 65, 22, LIGHTGRAY);
}

int main () {
    SetConfigFlags(FLAG_MSAA_4X_HINT);
    InitWindow(1920, 1080, "Interferometre de Michelson");
    SetTargetFPS(60);

    Michelson mic = {0};
    mic.center = (Vector2){ UI_WIDTH + (1920 - UI_WIDTH) / 2.0f - 100, 1080 / 2.0f };
    mic.d1 = 250.0f;
    mic.d2 = 250.0f;
    mic.lambda = 550.0f;
    mic.angleM1 = 0.0f;

    Rectangle screenViewBounds = {1920 - 530, 50, 500, 500};
    //Rectangle screenViewBounds = {400, 0, 1080, 1080};

    while (!WindowShouldClose()) {
        BeginDrawing();
            ClearBackground(BLACK);
            DrawMichelsonSchema(&mic);
            DrawControlPanel(&mic);
            DrawInterferenceView(&mic, screenViewBounds);
        EndDrawing();
    }
    CloseWindow();
    return 0;
}