#![allow(dead_code, unused_imports, unused_variables, unused_macros, unreachable_patterns)]
/// Grid-search outer glow MAE tuning against Krita ground-truth PNGs.
///
/// Expects `_tmp/outer_glow_png_kra_set/` with transparent PNGs exported
/// from `_tmp/outer_glow_kra_set/`.

use std::io::Write;

const GT_DIR: &str = "_tmp/outer_glow_png_kra_set";
static mut CANVAS: u32 = 800;
const RESULTS_FILE: &str = "outer_glow_kra_grid_results.txt";

struct Sample {
    name: String,
    spread: f32,
    size: f32,
    opacity: f32,
    noise: f32,
    color: [u8; 4],
    blend_mode: String,
    ref_pixels: Vec<u8>,
    content_mask: Vec<bool>,
}

fn main() {
    let entries: Vec<_> = std::fs::read_dir(GT_DIR)
        .unwrap_or_else(|e| panic!("cannot read {}: {}", GT_DIR, e))
        .filter_map(|e| e.ok())
        .filter(|e| {
            let s = e.file_name();
            let s = s.to_string_lossy();
            s.starts_with("og_sp") && s.ends_with(".png")
        })
        .collect();

    println!("Found {} PNGs in {}", entries.len(), GT_DIR);

    let mut samples: Vec<Sample> = Vec::new();
    let mut skipped_noise = 0;

    for entry in &entries {
        let path = entry.path();
        let stem = path.file_stem().unwrap().to_string_lossy().to_string();

        let params = match parse_filename(&stem) {
            Some(p) => p,
            None => { eprintln!("  SKIP: {}", stem); continue; }
        };

        let (spread, size, opacity, noise, blend, color) = params;

        if noise > 0.0 {
            skipped_noise += 1;
            continue;
        }

        let img = match image::open(&path) {
            Ok(i) => i,
            Err(e) => { eprintln!("  SKIP {}: {}", stem, e); continue; }
        };

        let rgba = img.to_rgba8();
        let (src_w, src_h) = rgba.dimensions();
        if src_w != src_h {
            eprintln!("  SKIP {}: non-square dimensions {}x{}", stem, src_w, src_h);
            continue;
        }
        unsafe {
            CANVAS = src_w;
        }
        let src_raw = rgba.as_raw();
        let mut cropped_raw = vec![0u8; unsafe { (CANVAS * CANVAS * 4) as usize }];
        cropped_raw.copy_from_slice(src_raw);

        let npix = unsafe { (CANVAS * CANVAS) as usize };
        let mut shape_mask = vec![false; npix];
        for i in 0..npix {
            if cropped_raw[i * 4] == 3 && cropped_raw[i * 4 + 1] == 3 && cropped_raw[i * 4 + 2] == 3 && cropped_raw[i * 4 + 3] == 255 {
                shape_mask[i] = true;
            }
        }
        let mut content_mask = vec![false; npix];
        for i in 0..npix {
            // Glow pixels differ from the 50% gray background [128, 128, 128] and are outside the shape.
            let is_bg = cropped_raw[i * 4] == 128 && cropped_raw[i * 4 + 1] == 128 && cropped_raw[i * 4 + 2] == 128;
            content_mask[i] = !is_bg && !shape_mask[i];
        }

        samples.push(Sample {
            name: stem,
            spread, size, opacity, noise, color, blend_mode: blend,
            ref_pixels: cropped_raw,
            content_mask,
        });
    }

    println!("Loaded {} samples (skipped {} with noise>0)", samples.len(), skipped_noise);
    if samples.is_empty() {
        eprintln!("No valid samples found.");
        std::process::exit(1);
    }

    let content_count = samples[0].content_mask.iter().filter(|&&b| b).count();
    println!("Content pixels per image: {} / {} ({:.1}%)",
        content_count, npix(), content_count as f64 / npix() as f64 * 100.0);

    let rect_alpha: Vec<u8> = {
        let n = npix();
        let mut a = vec![0u8; n];
        for i in 0..n {
            if samples[0].ref_pixels[i * 4] == 3 && samples[0].ref_pixels[i * 4 + 1] == 3 && samples[0].ref_pixels[i * 4 + 2] == 3 && samples[0].ref_pixels[i * 4 + 3] == 255 {
                a[i] = 255;
            }
        }
        a
    };

    let blur_factors: &[f32] = &[1.5, 2.0, 2.5, 3.0, 4.0, 5.0, 6.0, 8.0, 10.0, 12.0];
    let passes_list: &[i32] = &[1, 2, 3, 4, 5];
    let alpha_scales: &[f32] = &[0.0, 0.25, 0.5, 0.75, 1.0];
    let glow_boosts: &[f32] = &[0.5, 0.75, 1.0, 1.25, 1.5, 2.0];
    let spread_positions: &[bool] = &[false, true]; // false = after blur, true = before blur

    let total_combos = blur_factors.len() * passes_list.len() * alpha_scales.len()
        * glow_boosts.len() * spread_positions.len();
    println!("Grid: {} combos x {} samples = {} evals", total_combos, samples.len(), total_combos * samples.len());
    std::io::stdout().flush().ok();

    let mut best_avg_mae = f64::MAX;
    let mut best_params = (0.0f32, 0i32, 0.0f32, 0.0f32, false);
    let mut eval_count = 0usize;

    for &blur_factor in blur_factors {
        for &passes in passes_list {
            for &alpha_scale in alpha_scales {
                for &glow_boost in glow_boosts {
                    for &spread_before_blur in spread_positions {
                        let mut total_mae = 0.0f64;

                        for s in &samples {
                            let glow = hcie_fx::tuned::generate_glow_tuned(
                                &rect_alpha, unsafe { CANVAS }, unsafe { CANVAS },
                                s.spread, s.size, s.color, false,
                                blur_factor, passes, alpha_scale, glow_boost, spread_before_blur,
                            );

                            let blend = blend_mode_from_name(&s.blend_mode);

                            let px = npix();
                            // Start with 50% gray background
                            let mut out = vec![128u8; px * 4];
                            for i in 0..px {
                                out[i * 4 + 3] = 255;
                            }

                            // 1. Composite outer glow onto the background using actual blend mode
                            for i in 0..px {
                                let sa = glow[i * 4 + 3];
                                if sa == 0 { continue; }
                                let dst = [out[i * 4], out[i * 4 + 1], out[i * 4 + 2], out[i * 4 + 3]];
                                let src = [glow[i * 4], glow[i * 4 + 1], glow[i * 4 + 2], sa];
                                let blended = hcie_blend::blend_pixels(dst, src, blend, s.opacity);
                                out[i * 4..i * 4 + 4].copy_from_slice(&blended);
                            }

                            // 2. Composite black shape on top using Normal blend
                            for i in 0..px {
                                if rect_alpha[i] > 0 {
                                    let dst = [out[i * 4], out[i * 4 + 1], out[i * 4 + 2], out[i * 4 + 3]];
                                    let src = [3, 3, 3, 255];
                                    let blended = hcie_blend::blend_pixels(dst, src, hcie_blend::BlendMode::Normal, 1.0);
                                    out[i * 4..i * 4 + 4].copy_from_slice(&blended);
                                }
                            }

                            let mut diff_sum = 0.0f64;
                            let mut content_pixels = 0u64;
                            for i in 0..px {
                                if !s.content_mask[i] { continue; }
                                content_pixels += 1;
                                for c in 0..4 {
                                    diff_sum += (out[i * 4 + c] as i32 - s.ref_pixels[i * 4 + c] as i32).abs() as f64;
                                }
                            }
                            if content_pixels > 0 {
                                total_mae += diff_sum / content_pixels as f64 / 4.0;
                            }
                        }

                        eval_count += 1;
                        let avg_mae = total_mae / samples.len() as f64;

                        if avg_mae < best_avg_mae {
                            best_avg_mae = avg_mae;
                            best_params = (blur_factor, passes, alpha_scale, glow_boost, spread_before_blur);
                            println!("*** [{}/{}] NEW BEST avg MAE = {:.4} (bf={:.1}, p={}, as={:.2}, gb={:.2}, spb={})",
                                eval_count, total_combos, best_avg_mae, blur_factor, passes, alpha_scale, glow_boost, spread_before_blur);
                            std::io::stdout().flush().ok();
                        } else if eval_count % 500 == 0 {
                            println!("  [{}/{}] avg={:.4}  best={:.4}", eval_count, total_combos, avg_mae, best_avg_mae);
                            std::io::stdout().flush().ok();
                        }
                    }
                }
            }
        }
    }

    let (bbf, bp, bas, bgb, bspb) = best_params;
    println!("\n=== RESULT ===");
    println!("Best avg MAE = {:.4}", best_avg_mae);
    println!("  blur_factor       = {:.1}", bbf);
    println!("  passes            = {}", bp);
    println!("  alpha_scale       = {:.2}", bas);
    println!("  glow_boost        = {:.2}", bgb);
    println!("  spread_before_blur= {}", bspb);

    if let Ok(mut file) = std::fs::OpenOptions::new()
        .create(true).write(true).truncate(true).open(RESULTS_FILE)
    {
        let _ = writeln!(file,
            "blur_factor={:.1}  passes={}  alpha_scale={:.2}  glow_boost={:.2}  spread_before_blur={}\n\
             avg_mae={:.4}  samples={}  combos={}",
            bbf, bp, bas, bgb, bspb, best_avg_mae, samples.len(), total_combos);
    }
}

fn npix() -> usize { unsafe { (CANVAS * CANVAS) as usize } }

fn parse_filename(name: &str) -> Option<(f32, f32, f32, f32, String, [u8; 4])> {
    // og_sp{spread}_s{size}_op{opacity}_n{noise}_{blend}_{color}
    let parts: Vec<&str> = name.split('_').collect();
    if parts.len() < 7 || parts[0] != "og" { return None; }
    let spread  = parts[1].strip_prefix("sp")?.parse::<f32>().ok()?;
    let size    = parts[2].strip_prefix('s')?.parse::<f32>().ok()?;
    let opacity = parts[3].strip_prefix("op")?.parse::<f32>().ok()? / 100.0;
    let noise   = parts[4].strip_prefix('n')?.parse::<f32>().ok()?;
    let blend   = parts[5].to_string();
    let color   = color_from_name(parts[6]);
    Some((spread, size, opacity, noise, blend, color))
}

fn color_from_name(name: &str) -> [u8; 4] {
    match name {
        "red"     => [220, 30, 30, 255],
        "green"   => [30, 180, 30, 255],
        "blue"    => [30, 60, 220, 255],
        "white"   => [220, 220, 220, 255],
        "yellow"  => [255, 220, 30, 255],
        "cyan"    => [30, 220, 220, 255],
        "magenta" => [255, 30, 180, 255],
        _         => [220, 30, 30, 255],
    }
}

fn blend_mode_from_name(name: &str) -> hcie_blend::BlendMode {
    match name {
        "multiply" => hcie_blend::BlendMode::Multiply,
        "screen"   => hcie_blend::BlendMode::Screen,
        "normal"   => hcie_blend::BlendMode::Normal,
        _          => hcie_blend::BlendMode::Normal,
    }
}