use clap::Parser;
use miette::{IntoDiagnostic as _, Result};
use serde::Deserialize;
use std::process::Stdio;
use std::collections::VecDeque;
use std::sync::{Arc, Mutex};
use tokio::{
    fs,
    io::{AsyncBufReadExt, BufReader},
    process::Command,
};
use tracing::{error, info, warn};

fn ndjson_line(category: &str, level: &str, msg: &str, extra: Option<serde_json::Value>) -> String {
    let mut obj = serde_json::json!({
        "category": category,
        "level": level,
        "msg": msg,
    });
    if let Some(ext) = extra {
        if let Some(map) = obj.as_object_mut() {
            if let Some(eo) = ext.as_object() {
                for (k, v) in eo.iter() {
                    map.insert(k.clone(), v.clone());
                }
            }
        }
    }
    obj.to_string()
}

#[derive(Parser, Debug)]
#[command(
    name = "solstice-runner",
    version,
    about = "Solstice CI Workflow Runner (VM agent)"
)]
struct Opts {
    /// Optional path to workflow KDL file (for local testing only)
    #[arg(long, env = "SOL_WORKFLOW_PATH")]
    workflow: Option<String>,
}

#[derive(Debug, Deserialize)]
struct JobFile {
    repo_url: String,
    commit_sha: String,
    #[serde(default)]
    workflow_job_id: Option<String>,
    #[serde(default)]
    script_path: Option<String>,
    #[serde(default)]
    group_id: Option<String>,
}

async fn read_job_file() -> Result<JobFile> {
    let path =
        std::env::var("SOLSTICE_JOB_FILE").unwrap_or_else(|_| "/etc/solstice/job.yaml".into());
    let bytes = fs::read(&path).await.into_diagnostic()?;
    let jf: JobFile = serde_yaml::from_slice(&bytes).into_diagnostic()?;
    Ok(jf)
}

async fn run_shell(cmd: &str) -> Result<i32> {
    info!(%cmd, "exec");
    let status = Command::new("/bin/sh")
        .arg("-lc")
        .arg(cmd)
        .status()
        .await
        .into_diagnostic()?;
    let code = status.code().unwrap_or(1);
    if code != 0 {
        return Err(miette::miette!("command failed ({code}): {cmd}"));
    }
    Ok(code)
}

fn to_https_if_codeberg(repo: &str) -> String {
    // Convert SSH Codeberg URL to HTTPS for anonymous fetches
    if let Some(rest) = repo.strip_prefix("ssh://git@codeberg.org/") {
        return format!("https://codeberg.org/{rest}");
    }
    repo.to_string()
}

async fn has_cmd(name: &str) -> bool {
    tokio::process::Command::new("/bin/sh")
        .arg("-lc")
        .arg(format!("command -v {} >/dev/null 2>&1", name))
        .status()
        .await
        .ok()
        .and_then(|s| s.code())
        .map(|c| c == 0)
        .unwrap_or(false)
}

async fn check_writable(dir: &str) -> bool {
    if fs::create_dir_all(dir).await.is_err() { return false; }
    let test_path = format!("{}/.solstice-writecheck", dir.trim_end_matches('/'));
    match fs::write(&test_path, b"ok").await {
        Ok(_) => {
            let _ = fs::remove_file(&test_path).await; true
        }
        Err(_) => false,
    }
}

fn parse_repo_host_port(repo: &str) -> Option<(String, u16)> {
    let r = repo.trim();
    if let Some(rest) = r.strip_prefix("https://") {
        let host = rest.split('/').next()?.split('@').last()?.split(':').next()?; // ignore embedded user
        return Some((host.to_string(), 443));
    }
    if let Some(rest) = r.strip_prefix("http://") {
        let host = rest.split('/').next()?.split('@').last()?.split(':').next()?;
        return Some((host.to_string(), 80));
    }
    if let Some(rest) = r.strip_prefix("ssh://") {
        // ssh://[user@]host/owner/repo
        let first = rest.split('/').next()?;
        let host = first.split('@').last()?.split(':').next()?;
        return Some((host.to_string(), 22));
    }
    // scp-like: user@host:owner/repo.git
    if let Some(at) = r.find('@') {
        if let Some(colon) = r[at+1..].find(':') { // ensure host:
            let host = &r[at+1..at+1+colon];
            if !host.is_empty() { return Some((host.to_string(), 22)); }
        }
    }
    None
}

async fn check_network_connect(host: &str, port: u16, timeout_ms: u64) -> bool {
    use tokio::time::{timeout, Duration};
    match timeout(Duration::from_millis(timeout_ms), tokio::net::TcpStream::connect((host, port))).await {
        Ok(Ok(_stream)) => { true }
        _ => false,
    }
}

async fn preflight(repo: &str, workdir: &str) -> Result<()> {
    // Tool availability
    let has_git = has_cmd("git").await;
    let has_curl = has_cmd("curl").await;
    let has_wget = has_cmd("wget").await;
    let has_tar = has_cmd("tar").await;
    for (tool, ok) in [("git", has_git), ("curl", has_curl), ("wget", has_wget), ("tar", has_tar)] {
        let lvl = if ok { "info" } else { "warn" };
        let msg = if ok {
            format!("tool {tool}: available")
        } else {
            format!("tool {tool}: missing")
        };
        println!("{}", ndjson_line("tool_check", lvl, &msg, Some(serde_json::json!({"available": ok, "tool": tool}))));
    }
    let can_clone = has_git || (has_tar && (has_curl || has_wget));
    let lvl = if can_clone { "info" } else { "error" };
    println!(
        "{}",
        ndjson_line(
            "env_setup",
            lvl,
            "clone capability",
            Some(serde_json::json!({
                "git": has_git,
                "tar": has_tar,
                "curl": has_curl,
                "wget": has_wget,
                "can_clone": can_clone
            }))
        )
    );
    if !can_clone {
        return Err(miette::miette!("no available method to fetch repository: need git or (tar and (curl|wget))"));
    }

    // Workdir writability
    let writable = check_writable(workdir).await;
    let lvl = if writable { "info" } else { "error" };
    println!("{}", ndjson_line("env_setup", lvl, "workdir writable", Some(serde_json::json!({"path": workdir, "writable": writable}))));
    if !writable { return Err(miette::miette!("workdir is not writable: {}", workdir)); }

    // Network reachability (best-effort)
    if let Some((host, port)) = parse_repo_host_port(repo) {
        let ok = check_network_connect(&host, port, 2000).await;
        let lvl = if ok { "info" } else { "warn" };
        let status_msg = if ok { "reachable" } else { "unreachable" };
        println!(
            "{}",
            ndjson_line(
                "env",
                lvl,
                &format!("network: {}:{} {}", host, port, status_msg),
                Some(serde_json::json!({"host": host, "port": port, "reachable": ok}))
            )
        );
    }

    Ok(())
}

async fn fetch_repo_via_archive(repo_https: &str, sha: &str, workdir: &str) -> Result<()> {
    // Announce chosen method
    println!("{}", ndjson_line("env_setup", "info", "fetch via http archive", Some(serde_json::json!({
        "url": format!("{}/archive/{}.tar.gz", repo_https.trim_end_matches('.').trim_end_matches(".git"), sha)
    }))));
    // Gitea/Codeberg archive URL pattern: https://codeberg.org/<owner>/<repo>/archive/<sha>.tar.gz
    let base = repo_https.trim_end_matches('.').trim_end_matches(".git");
    let url = format!("{}/archive/{}.tar.gz", base, sha);

    // Check if we should allow insecure TLS (last resort)
    let insecure = std::env::var("SOLSTICE_ALLOW_INSECURE").ok().map(|v| v == "1" || v.eq_ignore_ascii_case("true")).unwrap_or(false);
    let curl_flags = if insecure { "-fSLk" } else { "-fSL" };

    // Try curl | tar, then wget | tar
    let cmd_curl = format!(
        "mkdir -p {workdir} && curl {curl_flags} {url} | tar -xz -C {workdir} --strip-components=1"
    );
    if run_shell(&cmd_curl).await.is_ok() {
        return Ok(());
    }
    let cmd_wget = format!(
        "mkdir -p {workdir} && wget -qO- {url} | tar -xz -C {workdir} --strip-components=1"
    );
    if run_shell(&cmd_wget).await.is_ok() {
        return Ok(());
    }

    // On illumos/SunOS images, curl/wget may be missing or CA bundle absent. Try to install tools and CA certs, then retry.
    let os = std::env::var("SOLSTICE_OS_OVERRIDE").ok().unwrap_or_else(|| {
        // Best-effort OS detection
        std::env::consts::OS.to_string()
    });
    // Prefer uname if available
    let uname = Command::new("/bin/sh").arg("-lc").arg("uname -s 2>/dev/null || echo unknown").output().await.ok()
        .and_then(|o| String::from_utf8(o.stdout).ok()).unwrap_or_default();
    let is_sunos = uname.trim() == "SunOS" || os == "solaris";
    if is_sunos {
        // Try IPS (pkg) first, then pkgin
        let _ = run_shell("sudo pkg refresh || true").await;
        // curl
        if run_shell("sudo pkg install -v web/curl").await.is_err() {
            let _ = run_shell("sudo pkgin -y install curl").await;
        }
        // CA certificates (package name may differ per distro)
        let _ = run_shell("sudo pkg install -v web/ca-certificates || sudo pkg install -v library/security/ca-certificates || true").await;
        let _ = run_shell("sudo pkgin -y install mozilla-rootcerts || true").await;
        let _ = run_shell("sudo mozilla-rootcerts install || true").await;

        // Retry with curl and wget
        if run_shell(&cmd_curl).await.is_ok() {
            return Ok(());
        }
        if run_shell(&cmd_wget).await.is_ok() {
            return Ok(());
        }

        // As a last resort with explicit opt-in, try curl --insecure
        if insecure {
            let cmd_curl_insecure = format!(
                "mkdir -p {workdir} && curl -fSLk {url} | tar -xz -C {workdir} --strip-components=1"
            );
            if run_shell(&cmd_curl_insecure).await.is_ok() {
                warn!("used curl --insecure to fetch repo archive on SunOS");
                return Ok(());
            }
        }
    }

    Err(miette::miette!("failed to fetch repo archive via HTTP for {url}"))
}

fn is_hex(s: &str) -> bool { s.chars().all(|c| c.is_ascii_hexdigit()) }

async fn ensure_repo(repo: &str, sha: &str, workdir: &str) -> Result<()> {
    fs::create_dir_all(workdir).await.into_diagnostic()?;
    let repo_eff = to_https_if_codeberg(repo);

    // Prefer git when available; fall back to archive download when git is missing or fetch fails.
    if has_cmd("git").await {
        // Determine object format: if SHA looks like 64-hex, assume sha256 object format
        let sha_len = sha.len();
        let is_sha256 = sha_len == 64 && is_hex(sha);
        let obj_fmt = if is_sha256 { Some("sha256") } else { None };
        // Emit NDJSON about chosen method
        println!(
            "{}",
            ndjson_line(
                "env_setup",
                "info",
                &format!(
                    "fetch via git (object-format={})",
                    obj_fmt.unwrap_or("sha1")
                ),
                Some(serde_json::json!({
                    "method": "git",
                    "object_format": obj_fmt.unwrap_or("sha1"),
                    "sha_len": sha_len,
                    "detached": true
                }))
            )
        );

        let cmds = vec![
            // Re-initialize repository to ensure correct object format
            format!("cd {workdir} && rm -rf .git || true"),
            if let Some(fmt) = obj_fmt { format!("cd {workdir} && git init --object-format={fmt}") } else { format!("cd {workdir} && git init") },
            format!(
                "cd {workdir} && git remote remove origin >/dev/null 2>&1 || true && git remote add origin {repo_eff}"
            ),
            // Use protocol v2 features when available and keep it light
            format!("cd {workdir} && git -c protocol.version=2 fetch --filter=blob:none --depth=1 --no-tags origin {sha}"),
            // Checkout the requested commit in detached HEAD
            format!("cd {workdir} && git checkout -q --detach {sha}"),
        ];
        for c in cmds {
            match run_shell(&c).await {
                Ok(_) => {}
                Err(e) => {
                    // Try archive fallback once on any git failure
                    warn!(error = %e, "git path failed; attempting archive fallback");
                    return fetch_repo_via_archive(&repo_eff, sha, workdir).await;
                }
            }
        }
        Ok(())
    } else {
        fetch_repo_via_archive(&repo_eff, sha, workdir).await
    }
}

async fn run_job_script(workdir: &str, script_override: Option<&str>) -> Result<i32> {
    // Determine the script to execute: prefer override from job.yaml, else default .solstice/job.sh
    let script = if let Some(path) = script_override {
        if path.starts_with('/') { path.to_string() } else { format!("{}/{}", workdir, path.trim_start_matches("./")) }
    } else {
        format!("{}/.solstice/job.sh", workdir)
    };
    if !fs::try_exists(&script).await.into_diagnostic()? {
        warn!(path = %script, "job script not found");
        eprintln!("{}", ndjson_line("job_run", "error", &format!("job script not found at {}", script), None));
        return Ok(1);
    }
    // Emit explicit pre-exec line to aid diagnostics
    println!("{}", ndjson_line("job_run", "info", &format!("executing {}", script), None));
    let _ = run_shell(&format!("chmod +x {} || true", script)).await?;

    let mut cmd = Command::new("/bin/sh");
    cmd.arg("-lc")
        .arg(format!("set -ex; cd {workdir}; {}", script))
        .stdout(Stdio::piped())
        .stderr(Stdio::piped());
    let mut child = cmd.spawn().into_diagnostic()?;

    // Buffer the last N stderr lines for failure summary
    let last_err: Arc<Mutex<VecDeque<String>>> = Arc::new(Mutex::new(VecDeque::with_capacity(20)));

    // Attach readers to child stdout/stderr so logs stream as NDJSON categorized under job_run
    if let Some(stdout) = child.stdout.take() {
        let mut reader = BufReader::new(stdout);
        tokio::spawn(async move {
            loop {
                let mut buf = Vec::with_capacity(256);
                match reader.read_until(b'\n', &mut buf).await {
                    Ok(0) => break,
                    Ok(_) => {
                        let line = String::from_utf8_lossy(&buf).trim_end_matches(['\n', '\r']).to_string();
                        println!("{}", ndjson_line("job_run", "info", &line, None));
                    }
                    Err(e) => {
                        eprintln!("{}", ndjson_line("job_run", "error", &format!("error reading stdout: {}", e), None));
                        break;
                    }
                }
            }
        });
    }
    if let Some(stderr) = child.stderr.take() {
        let mut reader = BufReader::new(stderr);
        let last_err2 = last_err.clone();
        tokio::spawn(async move {
            loop {
                let mut buf = Vec::with_capacity(256);
                match reader.read_until(b'\n', &mut buf).await {
                    Ok(0) => break,
                    Ok(_) => {
                        let line = String::from_utf8_lossy(&buf).trim_end_matches(['\n', '\r']).to_string();
                        eprintln!("{}", ndjson_line("job_run", "error", &line, None));
                        if let Ok(mut dq) = last_err2.lock() {
                            if dq.len() == 20 { dq.pop_front(); }
                            dq.push_back(line);
                        }
                    }
                    Err(e) => {
                        eprintln!("{}", ndjson_line("job_run", "error", &format!("error reading stderr: {}", e), None));
                        break;
                    }
                }
            }
        });
    }

    let status = child.wait().await.into_diagnostic()?;
    let code = status.code().unwrap_or(1);

    if code != 0 {
        // Emit a concise failure summary (structured)
        eprintln!("{}", ndjson_line("job_run", "error", &format!("job script exited with code {}", code), None));

        // Include recent stderr lines for context (structured)
        let lines: Vec<String> = last_err
            .lock()
            .ok()
            .map(|dq| dq.iter().cloned().collect())
            .unwrap_or_default();
        if lines.is_empty() {
            eprintln!("{}", ndjson_line("job_run", "warn", "no stderr lines were captured from the script", None));
        } else {
            eprintln!("{}", ndjson_line("job_run", "info", "recent stderr lines follow", None));
            for l in lines {
                eprintln!("{}", ndjson_line("job_run", "error", &l, None));
            }
        }
    }

    Ok(code)
}

#[tokio::main(flavor = "multi_thread")]
async fn main() -> Result<()> {
    let _t = common::init_tracing("solstice-workflow-runner")?;
    let _opts = Opts::parse();

    // Try env overrides first for robustness
    let repo = std::env::var("SOLSTICE_REPO_URL").ok();
    let sha = std::env::var("SOLSTICE_COMMIT_SHA").ok();

    let (repo, sha) = match (repo, sha) {
        (Some(r), Some(s)) => (r, s),
        _ => {
            let jf = read_job_file().await?;
            (jf.repo_url, jf.commit_sha)
        }
    };

    info!(%repo, %sha, "runner starting");
    // Workdir selection: prefer explicit SOLSTICE_WORKDIR, otherwise default to "$HOME/work"
    let workdir = std::env::var("SOLSTICE_WORKDIR").ok().or_else(|| {
        std::env::var("HOME").ok().map(|home| format!("{}/work", home))
    }).unwrap_or_else(|| "/root/work".into());

    // Emit startup environment and tool checks
    let uname = Command::new("/bin/sh").arg("-lc").arg("uname -a || echo unknown").output().await.ok()
        .and_then(|o| String::from_utf8(o.stdout).ok()).unwrap_or_else(|| "unknown".into());
    let uname_trim = uname.trim().to_string();
    println!("{}", ndjson_line("env", "info", &format!("system: {}", uname_trim), Some(serde_json::json!({"uname": uname_trim}))));

    // Preflight environment checks (tools, workdir, network)
    if let Err(e) = preflight(&repo, &workdir).await {
        eprintln!("{}", ndjson_line("env_setup", "error", &format!("preflight failed: {}", e), None));
        std::process::exit(1);
    }

    // Announce workspace
    println!("{}", ndjson_line("env_setup", "info", "workdir", Some(serde_json::json!({"path": workdir}))));

    let code = match ensure_repo(&repo, &sha, &workdir).await {
        Ok(_) => {
            // Read job.yaml to get optional script override
            let jf = read_job_file().await.ok();
            let script_override = jf.as_ref().and_then(|j| j.script_path.as_deref());
            // proceed to run job script
            run_job_script(&workdir, script_override).await?
        }
        Err(e) => {
            eprintln!("{}", ndjson_line("env_setup", "error", &format!("failed to prepare repo: {}", e), None));
            1
        }
    };

    if code != 0 {
        error!(exit_code = code, "job script failed");
        std::process::exit(code);
    }

    info!("job complete");
    Ok(())
}