use std::fs;
use std::path::Path;
use std::process::Command;
use std::io::{self, Write};
use std::cell::RefCell;

use super::get_aeropkg_base;
use crate::utils::parser::{self, env::get_install_env, repoinfo, pkginfo, env::get_custom_env};
use crate::utils::shell;
use crate::commands::link::link;
use crate::commands::run::config::config;

#[derive(Default)]
struct DownloadSummary {
    no_changes: Vec<String>,
    updated: Vec<(String, u64)>,
    errors: Vec<(String, String)>,
}

thread_local! {
    static SUMMARY: RefCell<DownloadSummary> = RefCell::new(DownloadSummary::default());
}

pub fn print_download_summary() {
    print!("\r\x1B[K");
    io::stdout().flush().unwrap();

    SUMMARY.with(|s| {
        let summary = s.borrow();
        
        if !summary.no_changes.is_empty() {
            println!("No changes: {}", summary.no_changes.join(", "));
        }
        
        if !summary.updated.is_empty() {
            println!("Updated:");
            for (pkg, count) in &summary.updated {
                println!("  {}: {} files", pkg, count);
            }
        }
        
        if !summary.errors.is_empty() {
            eprintln!("Errors:");
            for (pkg, err) in &summary.errors {
                eprintln!("  {}: {}", pkg, err);
            }
        }
        
        drop(summary);
        s.replace(DownloadSummary::default());
    });
}

pub fn download_packages(
    repo: Option<&str>,
    packages: &[String],
    force: bool,
    recursive: bool,
) {
    for pkgname in packages {
        let effective_repo = match repo {
            Some(r) => &r.to_string(),
            None => &pkginfo::get_priority_repo(pkgname),
        };
        
        download(effective_repo, pkgname, force, recursive);
        let pkg_md_path = &crate::commands::get_aeropkg_var().join(format!("{}/{}.md", effective_repo, pkgname));
        let full_env = &get_custom_env(effective_repo, pkgname, pkg_md_path);
        shell::run_install_repo_hook_script(effective_repo, full_env);
        shell::run_install_hook_script(full_env);
    }
}

pub fn download(repo: &String, pkgname: &String, force: bool, recursive: bool) {
    let pkg_md_path = &crate::commands::get_aeropkg_var().join(format!("{}/{}.md", repo, pkgname));

    check_build_dependency(repo, pkg_md_path, force, recursive);
    check_run_dependency(pkg_md_path, force, recursive);

    let source = repoinfo::get_download_source(repo);
    
    if source.is_empty() {
        let msg = format!("Download source not found for repo '{}'", repo);
        SUMMARY.with(|s| s.borrow_mut().errors.push((pkgname.clone(), msg)));
        return;
    }

    let remote_path = format!("{}/{}/", source.trim_end_matches('/'), pkgname);
    let local_path = format!("/pkg/{}/{}", repo, pkgname);
    
    if let Err(e) = std::fs::create_dir_all(&local_path) {
        let msg = format!("Failed to create directory {}: {}", local_path, e);
        SUMMARY.with(|s| s.borrow_mut().errors.push((pkgname.clone(), msg)));
        return;
    }
    let local_path_sync = format!("{}/", local_path);

    print!("\r\x1B[KDownloading {}", pkgname);
    io::stdout().flush().unwrap();

    let mut cmd = Command::new("rsync");
    cmd.arg("-azHX").arg("--stats"); 
    if force { cmd.arg("--delete"); }
    cmd.arg(&remote_path);
    cmd.arg(&local_path_sync);
    
    let result = cmd.output();
    
    match result {
        Ok(output) => {
            let stdout = String::from_utf8_lossy(&output.stdout);
            
            let transferred = stdout
                .lines()
                .find(|line| line.contains("Number of regular files transferred:"))
                .and_then(|line| line.split(':').nth(1))
                .map(|s| s.trim().parse::<u64>().unwrap_or(0))
                .unwrap_or(0);

            if transferred == 0 && output.status.success() {
                SUMMARY.with(|s| s.borrow_mut().no_changes.push(pkgname.clone()));
            } else if !output.status.success() {
                let stderr = String::from_utf8_lossy(&output.stderr);
                let err_msg = stderr.lines().rev().find(|l| !l.trim().is_empty()).unwrap_or("unknown error").to_string();
                SUMMARY.with(|s| s.borrow_mut().errors.push((pkgname.clone(), err_msg)));
            } else {
                SUMMARY.with(|s| s.borrow_mut().updated.push((pkgname.clone(), transferred)));
            }
        }
        Err(e) => {
            SUMMARY.with(|s| s.borrow_mut().errors.push((pkgname.clone(), e.to_string())));
        }
    }
    
    config(repo, pkgname);
    let full_env = get_install_env(repo, pkgname, pkg_md_path, "build");
    if full_env.get("disable").is_some() { 
        let _ = fs::File::create(crate::commands::get_aeropkg_base().join(repo).join(pkgname).join("disabled"));
    } else {
        link(repo, pkgname)
    }
}

fn check_build_dependency(repo: &String, pkg_md_path: &Path, force: bool, recursive: bool) {
    let deps = match parser::get_build_deps(pkg_md_path) {
        Ok(deps) => deps,
        Err(_) => return,
    };

    for dep in deps.split_whitespace() {
        let dep = dep.trim();
        if dep.is_empty() { continue }

        if !get_aeropkg_base().join(repo).join(dep).exists() || recursive {
            download(repo, &dep.to_string(), force, recursive);
        }
    }
}

fn check_run_dependency(pkg_md_path: &Path, force: bool, recursive: bool) {
    let deps = match parser::get_run_deps(pkg_md_path) {
        Ok(deps) => deps,
        Err(_) => return,
    };
    let repo_list = parser::repoinfo::get_repo_list();

    for dep in deps.split_whitespace() {
        let dep = dep.trim();
        if dep.is_empty() { continue }

        let found_repo = repo_list.iter().find(|repo_name| {
            get_aeropkg_base().join(repo_name).join(dep).exists()
        });

        match found_repo {
            Some(found) if recursive => {
                download(found, &dep.to_string(), force, recursive);
            }
            None => {
                download(&pkginfo::get_priority_repo(&dep.to_string()), &dep.to_string(), force, recursive);
            }
            _ => {}
        }
    }
}