//! `warpgate status` — show service status, cache stats, write-back queue, bandwidth.
//!
//! Prefers querying the daemon's web API for complete health information.
//! Falls back to direct mount/RC checks when the daemon API is unreachable.

use anyhow::Result;
use serde::Deserialize;

use crate::config::Config;
use crate::daemon::DEFAULT_WEB_PORT;
use crate::rclone::{mount, rc};

/// JSON response from GET /api/status.
#[derive(Deserialize)]
struct ApiStatus {
    shares: Vec<ApiShare>,
}

#[derive(Deserialize)]
struct ApiShare {
    name: String,
    mounted: bool,
    health: String,
    health_message: Option<String>,
    cache_bytes: u64,
    dirty_count: u64,
    errored_files: u64,
    speed: f64,
    transfers: u64,
    errors: u64,
    #[serde(default)]
    warmup_state: Option<String>,
    #[serde(default)]
    warmup_done: Option<usize>,
    #[serde(default)]
    warmup_total: Option<usize>,
    #[serde(default)]
    dir_refresh_active: Option<bool>,
    #[serde(default)]
    last_dir_refresh_ago: Option<String>,
}

pub fn run(config: &Config) -> Result<()> {
    // Try daemon API first for full health information
    if let Some(api) = try_daemon_api() {
        return print_api_status(&api);
    }

    // Fallback: direct mount/RC checks (daemon not running)
    print_direct_status(config)
}

/// Try to reach the daemon's web API.
fn try_daemon_api() -> Option<ApiStatus> {
    let url = format!("http://127.0.0.1:{DEFAULT_WEB_PORT}/api/status");
    let resp = ureq::get(&url).call().ok()?;
    resp.into_body().read_json().ok()
}

/// Print status using daemon API response (includes health info).
fn print_api_status(api: &ApiStatus) -> Result<()> {
    let mut any_active = false;

    for share in &api.shares {
        // Build warmup suffix
        let warmup_suffix = match share.warmup_state.as_deref() {
            Some("running") => {
                let done = share.warmup_done.unwrap_or(0);
                let total = share.warmup_total.unwrap_or(0);
                format!("\tWarmup [{done}/{total}]")
            }
            Some("pending") => "\tWarmup...".to_string(),
            Some("complete") => "\tWarmup done".to_string(),
            Some("failed") => "\tWarmup FAILED".to_string(),
            _ => String::new(),
        };

        // Build dir-refresh suffix
        let dir_refresh_suffix = if share.dir_refresh_active == Some(true) {
            match share.last_dir_refresh_ago.as_deref() {
                Some(ago) => format!("\tDir-Refresh {ago}"),
                None => "\tDir-Refresh pending...".to_string(),
            }
        } else {
            String::new()
        };

        match share.health.as_str() {
            "OK" => {
                if share.mounted {
                    println!("Mount:  OK      {}{}{}", share.name, warmup_suffix, dir_refresh_suffix);
                    any_active = true;
                } else {
                    println!("Mount:  DOWN    {} — mount lost", share.name);
                    any_active = true;
                }
            }
            "FAILED" => {
                let msg = share
                    .health_message
                    .as_deref()
                    .unwrap_or("probe failed");
                println!("Mount:  FAILED  {} — {}", share.name, msg);
            }
            "PROBING" => {
                println!("Mount:  PROBING {}", share.name);
            }
            _ => {
                println!("Mount:  PENDING {}", share.name);
            }
        }
    }

    if !any_active {
        println!("\nNo healthy mounts are active.");
        return Ok(());
    }

    // Aggregate stats from API response
    let mut total_speed = 0.0f64;
    let mut total_cache = 0u64;
    let mut total_dirty = 0u64;
    let mut total_transfers = 0u64;
    let mut total_errors = 0u64;
    let mut total_errored = 0u64;

    for share in &api.shares {
        if share.health == "OK" {
            total_speed += share.speed;
            total_cache += share.cache_bytes;
            total_dirty += share.dirty_count;
            total_transfers += share.transfers;
            total_errors += share.errors;
            total_errored += share.errored_files;
        }
    }

    println!("Speed:  {}/s", format_bytes(total_speed as u64));
    println!("Active: {} transfers", total_transfers);
    println!("Errors: {}", total_errors);
    println!("Cache:  {}", format_bytes(total_cache));
    println!("Dirty:  {}", total_dirty);
    if total_errored > 0 {
        println!("Errored: {} files", total_errored);
    }

    // "Safe to disconnect" indicator
    if total_dirty == 0 && total_transfers == 0 {
        println!("\n[OK] All synced — safe to disconnect");
    } else {
        println!(
            "\n[!!] {} dirty files, {} active transfers — DO NOT disconnect",
            total_dirty, total_transfers
        );
    }

    Ok(())
}

/// Fallback: check mounts and RC API directly (no daemon API).
fn print_direct_status(config: &Config) -> Result<()> {
    let mut any_mounted = false;
    for share in &config.shares {
        let mounted = match mount::is_mounted(&share.mount_point) {
            Ok(m) => m,
            Err(e) => {
                eprintln!(
                    "Warning: could not check mount for '{}': {}",
                    share.name, e
                );
                false
            }
        };

        let ro_tag = if share.read_only { " (ro)" } else { "" };
        if mounted {
            println!(
                "Mount:  OK      {} → {}{}",
                share.name,
                share.mount_point.display(),
                ro_tag
            );
            any_mounted = true;
        } else {
            println!("Mount:  DOWN    {}{}", share.name, ro_tag);
        }
    }

    if !any_mounted {
        println!("\nNo rclone VFS mounts are active.");
        println!("Start with: systemctl start warpgate");
        return Ok(());
    }

    // Aggregate stats from all share RC ports
    let mut total_bytes = 0u64;
    let mut total_speed = 0.0f64;
    let mut total_transfers = 0u64;
    let mut total_errors = 0u64;
    let mut total_cache_used = 0u64;
    let mut total_uploading = 0u64;
    let mut total_queued = 0u64;
    let mut total_errored = 0u64;
    let mut rc_reachable = false;

    for (i, _share) in config.shares.iter().enumerate() {
        let port = config.rc_port(i);
        if let Ok(stats) = rc::core_stats(port) {
            rc_reachable = true;
            total_bytes += stats.bytes;
            total_speed += stats.speed;
            total_transfers += stats.transfers;
            total_errors += stats.errors;
        }
        if let Ok(vfs) = rc::vfs_stats(port) {
            if let Some(dc) = vfs.disk_cache {
                total_cache_used += dc.bytes_used;
                total_uploading += dc.uploads_in_progress;
                total_queued += dc.uploads_queued;
                total_errored += dc.errored_files;
            }
        }
    }

    if rc_reachable {
        println!("Speed:  {}/s", format_bytes(total_speed as u64));
        println!("Moved:  {}", format_bytes(total_bytes));
        println!("Active: {} transfers", total_transfers);
        println!("Errors: {}", total_errors);
        println!("Cache:  {}", format_bytes(total_cache_used));
        println!(
            "Dirty:  {} uploading, {} queued",
            total_uploading, total_queued
        );
        if total_errored > 0 {
            println!("Errored: {} files", total_errored);
        }
    } else {
        eprintln!("Could not reach any rclone RC API.");
    }

    Ok(())
}

fn format_bytes(bytes: u64) -> String {
    const KIB: f64 = 1024.0;
    const MIB: f64 = KIB * 1024.0;
    const GIB: f64 = MIB * 1024.0;

    let b = bytes as f64;
    if b >= GIB {
        format!("{:.1} GiB", b / GIB)
    } else if b >= MIB {
        format!("{:.1} MiB", b / MIB)
    } else if b >= KIB {
        format!("{:.1} KiB", b / KIB)
    } else {
        format!("{} B", bytes)
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_format_bytes_zero() {
        assert_eq!(format_bytes(0), "0 B");
    }

    #[test]
    fn test_format_bytes_bytes() {
        assert_eq!(format_bytes(512), "512 B");
    }

    #[test]
    fn test_format_bytes_kib() {
        assert_eq!(format_bytes(1024), "1.0 KiB");
        assert_eq!(format_bytes(1536), "1.5 KiB");
    }

    #[test]
    fn test_format_bytes_mib() {
        assert_eq!(format_bytes(1048576), "1.0 MiB");
    }

    #[test]
    fn test_format_bytes_gib() {
        assert_eq!(format_bytes(1073741824), "1.0 GiB");
    }

    #[test]
    fn test_format_bytes_boundary() {
        assert_eq!(format_bytes(1023), "1023 B");
        assert_eq!(format_bytes(1024), "1.0 KiB");
    }
}