use std::env;
use std::fs;
use std::process::Command;

use crate::config::{GameConfig, VsyncMode};
use crate::constants::SEED;

pub fn print_system_info(config: &GameConfig) {
    let os = format!("{} {}", env::consts::OS, env::consts::ARCH);
    let distro = distro_info();
    let kernel = kernel_info();
    let cpu = cpu_info();
    let gpu = gpu_info();
    let (ram_total, ram_free) = mem_info();
    let (res, hz) = display_info();
    let display = vsync_label(&config.display.vsync);
    let radius = config.initial_chunk_radius;
    let seed = SEED;

    let line_width = 34;
    let hline = format!("{:─<width$}", "", width = line_width);

    println!();
    println!("╔═{hline}═╗");
    println!("║{:^width$}║", "DORF SYSTEM", width = line_width + 2);
    println!("╠═{hline}═╣");
    println!("║  OS:      {:<width$}║", os, width = line_width);
    println!("║  Distro:  {:<width$}║", distro, width = line_width);
    println!("║  Kernel:  {:<width$}║", kernel, width = line_width);
    println!("║  CPU:     {:<width$}║", cpu, width = line_width);
    println!("║  GPU:     {:<width$}║", gpu, width = line_width);
    println!(
        "║  RAM:     {:<width$}║",
        format!("{} GB ({} GB free)", ram_total, ram_free),
        width = line_width
    );
    println!(
        "║  Display: {:<width$}║",
        format!("{} @ {}Hz {}", res, hz, display),
        width = line_width
    );
    println!(
        "║  Radius:  {:<width$}║",
        format!("{} chunks", radius),
        width = line_width
    );
    println!("║  Seed:    {:<width$}║", seed, width = line_width);
    println!("╚═{hline}═╝");
    println!();
}

fn cpu_info() -> String {
    #[cfg(target_os = "linux")]
    {
        let Ok(content) = fs::read_to_string("/proc/cpuinfo") else {
            return String::from("Unknown CPU");
        };

        let model_name = content
            .lines()
            .find(|l| l.starts_with("model name"))
            .and_then(|l| l.split(':').nth(1))
            .map(|s| s.trim().to_string())
            .unwrap_or_else(|| String::from("Unknown CPU"));

        let core_count = content
            .lines()
            .filter(|l| l.starts_with("processor"))
            .count()
            .max(1);

        format!("{} ({} cores)", model_name, core_count)
    }

    #[cfg(not(target_os = "linux"))]
    {
        let cores = env::var("NUMBER_OF_PROCESSORS")
            .ok()
            .and_then(|s| s.parse::<usize>().ok())
            .unwrap_or(1);

        format!("Unknown CPU ({} cores)", cores)
    }
}

fn gpu_info() -> String {
    env::var("WEBGPU_ADAPTER_NAME").unwrap_or_else(|_| String::from("Unknown GPU"))
}

fn mem_info() -> (u64, u64) {
    #[cfg(target_os = "linux")]
    {
        let Ok(content) = fs::read_to_string("/proc/meminfo") else {
            return (0, 0);
        };

        let parse_kb = |key: &str| -> u64 {
            content
                .lines()
                .find(|l| l.starts_with(key))
                .and_then(|l| {
                    l.split_whitespace()
                        .nth(1)
                        .and_then(|s| s.parse::<u64>().ok())
                })
                .unwrap_or(0)
        };

        let total_kb = parse_kb("MemTotal:");
        let available_kb = parse_kb("MemAvailable:");
        let total_gb = total_kb / 1024 / 1024;
        let available_gb = available_kb / 1024 / 1024;
        (total_gb, available_gb)
    }

    #[cfg(not(target_os = "linux"))]
    {
        (0, 0)
    }
}

fn vsync_label(mode: &VsyncMode) -> &'static str {
    match mode {
        VsyncMode::Vsync => "vsync",
        VsyncMode::Mailbox => "mailbox",
        VsyncMode::Uncapped => "uncapped",
    }
}

fn distro_info() -> String {
    #[cfg(target_os = "linux")]
    {
        if let Ok(content) = fs::read_to_string("/etc/os-release") {
            let pretty_name = content
                .lines()
                .find(|l| l.starts_with("PRETTY_NAME="))
                .and_then(|l| l.split('=').nth(1))
                .map(|s| s.trim_matches('"').to_string());
            if let Some(name) = pretty_name {
                return name;
            }
        }
        String::from("Unknown distro")
    }
    #[cfg(not(target_os = "linux"))]
    {
        String::from("N/A")
    }
}

fn kernel_info() -> String {
    #[cfg(target_os = "linux")]
    {
        if let Ok(output) = Command::new("uname").arg("-r").output() {
            if let Ok(kernel) = String::from_utf8(output.stdout) {
                return kernel.trim().to_string();
            }
        }
        String::from("Unknown kernel")
    }
    #[cfg(not(target_os = "linux"))]
    {
        String::from("N/A")
    }
}

fn display_info() -> (String, String) {
    #[cfg(target_os = "linux")]
    {
        if let Ok(output) = Command::new("xrandr").output() {
            if let Ok(xr) = String::from_utf8(output.stdout) {
                let lines: Vec<&str> = xr.lines().collect();
                if let Some(current) = lines.iter().find(|l| l.contains("+*")) {
                    let parts: Vec<&str> = current.split_whitespace().collect();
                    let res = parts.get(0).unwrap_or(&"unknown");
                    let mut hz = String::from("60");
                    for part in &parts[1..] {
                        if part.ends_with("Hz") || part.parse::<f32>().is_ok() {
                            hz = part
                                .trim_end_matches("Hz*")
                                .trim_end_matches("Hz")
                                .to_string();
                            break;
                        }
                    }
                    return (res.to_string(), hz);
                }
            }
        }
    }
    #[cfg(not(target_os = "linux"))]
    return (String::from("N/A"), String::from("N/A"));
    (String::from("unknown"), String::from("?"))
}