import * as math from "./pytra/std/math.js";
import { perf_counter } from "./pytra/std/time.js";
import { save_gif } from "./pytra/utils/gif.js";

// 06: Sample that sweeps Julia-set parameters and outputs a GIF.

function julia_palette() {
    // Keep index 0 black for points inside the set; build a high-saturation gradient for the rest.
    let palette = (typeof (256 * 3) === "number" ? new Array(Math.max(0, Math.trunc(Number((256 * 3))))).fill(0) : (Array.isArray((256 * 3)) ? (256 * 3).slice() : Array.from((256 * 3))));
    palette[(((0) < 0) ? ((palette).length + (0)) : (0))] = 0;
    palette[(((1) < 0) ? ((palette).length + (1)) : (1))] = 0;
    palette[(((2) < 0) ? ((palette).length + (2)) : (2))] = 0;
    for (let i = 1; i < 256; i += 1) {
        let t = (i - 1) / 254.0;
        let r = Math.trunc(Number(255.0 * 9.0 * (1.0 - t) * t * t * t));
        let g = Math.trunc(Number(255.0 * 15.0 * (1.0 - t) * (1.0 - t) * t * t));
        let b = Math.trunc(Number(255.0 * 8.5 * (1.0 - t) * (1.0 - t) * (1.0 - t) * t));
        palette[(((i * 3 + 0) < 0) ? ((palette).length + (i * 3 + 0)) : (i * 3 + 0))] = r;
        palette[(((i * 3 + 1) < 0) ? ((palette).length + (i * 3 + 1)) : (i * 3 + 1))] = g;
        palette[(((i * 3 + 2) < 0) ? ((palette).length + (i * 3 + 2)) : (i * 3 + 2))] = b;
    }
    return (Array.isArray((palette)) ? (palette).slice() : Array.from((palette)));
}

function render_frame(width, height, cr, ci, max_iter, phase) {
    let frame = (typeof (width * height) === "number" ? new Array(Math.max(0, Math.trunc(Number((width * height))))).fill(0) : (Array.isArray((width * height)) ? (width * height).slice() : Array.from((width * height))));
    let __hoisted_cast_1 = Number(height - 1);
    let __hoisted_cast_2 = Number(width - 1);
    for (let y = 0; y < height; y += 1) {
        let row_base = y * width;
        let zy0 = -1.2 + 2.4 * (y / __hoisted_cast_1);
        for (let x = 0; x < width; x += 1) {
            let zx = -1.8 + 3.6 * (x / __hoisted_cast_2);
            let zy = zy0;
            let i = 0;
            while (i < max_iter) {
                let zx2 = zx * zx;
                let zy2 = zy * zy;
                if (zx2 + zy2 > 4.0) {
                    break;
                }
                zy = 2.0 * zx * zy + ci;
                zx = zx2 - zy2 + cr;
                i += 1;
            }
            if (i >= max_iter) {
                frame[(((row_base + x) < 0) ? ((frame).length + (row_base + x)) : (row_base + x))] = 0;
            } else {
                // Add a small frame phase so colors flow smoothly.
                let color_index = 1 + (Math.floor(i * 224 / max_iter) + phase) % 255;
                frame[(((row_base + x) < 0) ? ((frame).length + (row_base + x)) : (row_base + x))] = color_index;
            }
        }
    }
    return (Array.isArray((frame)) ? (frame).slice() : Array.from((frame)));
}

function run_06_julia_parameter_sweep() {
    let width = 320;
    let height = 240;
    let frames_n = 72;
    let max_iter = 180;
    let out_path = "sample/out/06_julia_parameter_sweep.gif";
    
    let start = perf_counter();
    let frames = [];
    // Orbit an ellipse around a known visually good region to reduce flat blown highlights.
    let center_cr = -0.745;
    let center_ci = 0.186;
    let radius_cr = 0.12;
    let radius_ci = 0.10;
    // Add start and phase offsets so GitHub thumbnails do not appear too dark.
    // Tune it to start in a red-leaning color range.
    let start_offset = 20;
    let phase_offset = 180;
    let __hoisted_cast_3 = Number(frames_n);
    for (let i = 0; i < frames_n; i += 1) {
        let t = (i + start_offset) % frames_n / __hoisted_cast_3;
        let angle = 2.0 * math.pi * t;
        let cr = center_cr + radius_cr * math.cos(angle);
        let ci = center_ci + radius_ci * math.sin(angle);
        let phase = (phase_offset + i * 5) % 255;
        frames.push(render_frame(width, height, cr, ci, max_iter, phase));
    }
    save_gif(out_path, width, height, frames, julia_palette());
    let elapsed = perf_counter() - start;
    console.log("output:", out_path);
    console.log("frames:", frames_n);
    console.log("elapsed_sec:", elapsed);
}

run_06_julia_parameter_sweep();