mod capture;
mod fieldlens;
mod model;
mod pallet;
mod printers;
mod state;
mod updates;
mod zpl;

use base64::{engine::general_purpose::STANDARD as BASE64_STANDARD, Engine as _};
use parking_lot::Mutex;
use serde_json::Value;
use std::{fs, path::{Path, PathBuf}, time::SystemTime};
#[cfg(target_os = "windows")]
use std::os::windows::process::CommandExt;
use tauri::{AppHandle, Manager, State};

use capture::CaptureRuntime;
use model::{AppConfig, AuthStatus, CaptureStatus, DebugCheck, DebugSnapshot, JobSummary, LoginPoll, LoginStart, RecentCapture, SyncResult};
use printers::{SystemPrinter, VirtualPrinterStatus};
use state::SharedState;

struct AppState {
    shared: SharedState,
    runtime: Mutex<Option<CaptureRuntime>>,
}

#[tauri::command]
fn get_config(state: State<'_, AppState>) -> AppConfig {
    state.shared.config.lock().clone()
}

#[tauri::command]
fn save_config(config: AppConfig, state: State<'_, AppState>) -> Result<AppConfig, String> {
    state
        .shared
        .replace_config(config)
        .map_err(|error| error.to_string())
}

#[tauri::command]
fn get_status(state: State<'_, AppState>) -> CaptureStatus {
    CaptureStatus {
        running: state.runtime.lock().is_some(),
        mode: state.shared.config.lock().mode.clone(),
        pending: state.shared.pending_count(),
        jobs: state.shared.jobs.lock().len(),
    }
}

#[tauri::command]
fn recent_jobs(state: State<'_, AppState>) -> Vec<JobSummary> {
    state.shared.jobs.lock().iter().cloned().collect()
}

#[tauri::command]
fn start_capture(app: AppHandle, state: State<'_, AppState>) -> Result<(), String> {
    let mut runtime = state.runtime.lock();
    if runtime.is_some() {
        return Ok(());
    }

    let config = state.shared.config.lock().clone();
    let next = capture::start(config, state.shared.clone(), app).map_err(|error| error.to_string())?;
    *runtime = Some(next);
    Ok(())
}

#[tauri::command]
fn stop_capture(state: State<'_, AppState>) {
    if let Some(runtime) = state.runtime.lock().take() {
        runtime.stop();
    }
}

#[tauri::command]
fn list_system_printers() -> Result<Vec<SystemPrinter>, String> {
    printers::list_system_printers().map_err(|error| error.to_string())
}

#[tauri::command]
fn get_virtual_printer_status() -> Result<VirtualPrinterStatus, String> {
    printers::virtual_printer_status().map_err(|error| error.to_string())
}

#[tauri::command]
fn install_virtual_printer(target_printer: String) -> Result<VirtualPrinterStatus, String> {
    printers::install_virtual_printer(&target_printer).map_err(|error| error.to_string())
}

#[tauri::command]
fn remove_virtual_printer() -> Result<VirtualPrinterStatus, String> {
    printers::remove_virtual_printer().map_err(|error| error.to_string())
}

#[tauri::command]
fn begin_login(state: State<'_, AppState>) -> Result<LoginStart, String> {
    fieldlens::begin_login(&state.shared).map_err(|error| error.to_string())
}

#[tauri::command]
fn poll_login(state: State<'_, AppState>) -> Result<LoginPoll, String> {
    fieldlens::poll_login(&state.shared).map_err(|error| error.to_string())
}

#[tauri::command]
fn get_auth_status(state: State<'_, AppState>) -> Result<AuthStatus, String> {
    fieldlens::auth_status(&state.shared).map_err(|error| error.to_string())
}

#[tauri::command]
fn logout(state: State<'_, AppState>) -> Result<(), String> {
    fieldlens::logout(&state.shared).map_err(|error| error.to_string())
}

#[tauri::command]
async fn install_linux_update() -> Result<updates::UpdateInstallResult, String> {
    tauri::async_runtime::spawn_blocking(updates::install_linux_update)
        .await
        .map_err(|error| error.to_string())?
        .map_err(|error| error.to_string())
}

#[cfg(target_os = "linux")]
fn build_self_test_pdf() -> Vec<u8> {
    let objects = [
        "1 0 obj\n<< /Type /Catalog /Pages 2 0 R >>\nendobj\n".to_string(),
        "2 0 obj\n<< /Type /Pages /Kids [3 0 R] /Count 1 >>\nendobj\n".to_string(),
        "3 0 obj\n<< /Type /Page /Parent 2 0 R /MediaBox [0 0 612 792] /Resources << /Font << /F1 5 0 R >> >> /Contents 4 0 R >>\nendobj\n".to_string(),
        {
            let stream = "BT /F1 18 Tf 72 720 Td (FieldLens capture self-test) Tj ET\n";
            format!("4 0 obj\n<< /Length {} >>\nstream\n{}endstream\nendobj\n", stream.len(), stream)
        },
        "5 0 obj\n<< /Type /Font /Subtype /Type1 /BaseFont /Helvetica >>\nendobj\n".to_string(),
    ];

    let mut pdf = b"%PDF-1.4\n".to_vec();
    let mut offsets = Vec::new();
    for object in &objects {
        offsets.push(pdf.len());
        pdf.extend_from_slice(object.as_bytes());
    }

    let xref = pdf.len();
    pdf.extend_from_slice(format!("xref\n0 {}\n", objects.len() + 1).as_bytes());
    pdf.extend_from_slice(b"0000000000 65535 f \n");
    for offset in offsets {
        pdf.extend_from_slice(format!("{offset:010} 00000 n \n").as_bytes());
    }
    pdf.extend_from_slice(
        format!(
            "trailer\n<< /Size {} /Root 1 0 R >>\nstartxref\n{}\n%%EOF\n",
            objects.len() + 1,
            xref
        )
        .as_bytes(),
    );
    pdf
}

fn debug_command_check(name: &str) -> DebugCheck {
    #[cfg(target_os = "windows")]
    let result = {
        const CREATE_NO_WINDOW: u32 = 0x08000000;
        let mut command = std::process::Command::new("where.exe");
        command.creation_flags(CREATE_NO_WINDOW);
        command.arg(name).output()
    };

    #[cfg(not(target_os = "windows"))]
    let result = std::process::Command::new("sh")
        .args(["-lc", &format!("command -v {name}")])
        .output();

    match result {
        Ok(output) if output.status.success() => DebugCheck {
            name: name.into(),
            ok: true,
            detail: String::from_utf8_lossy(&output.stdout)
                .lines()
                .next()
                .unwrap_or("available")
                .trim()
                .to_string(),
        },
        Ok(_) => DebugCheck {
            name: name.into(),
            ok: false,
            detail: "not found".into(),
        },
        Err(error) => DebugCheck {
            name: name.into(),
            ok: false,
            detail: error.to_string(),
        },
    }
}

#[tauri::command]
fn get_debug_snapshot(state: State<'_, AppState>) -> Result<DebugSnapshot, String> {
    let config = state.shared.config.lock().clone();
    let jobs = state.shared.jobs.lock();
    let installed_printers = printers::list_system_printers()
        .map(|items| items.len())
        .unwrap_or(0);
    let virtual_printer = printers::virtual_printer_status()
        .map(|value| value.detail)
        .unwrap_or_else(|error| format!("status error: {error}"));

    #[cfg(target_os = "linux")]
    let capture_storage = "/var/lib/fieldlens-print/capture".to_string();

    #[cfg(not(target_os = "linux"))]
    let capture_storage = config.spool_dir.clone();

    #[cfg(target_os = "linux")]
    let checks = vec![
        debug_command_check("lp"),
        debug_command_check("pdfinfo"),
        debug_command_check("pdftoppm"),
        debug_command_check("zbarimg"),
        debug_command_check("pkexec"),
    ];

    #[cfg(target_os = "windows")]
    let checks = vec![
        debug_command_check("powershell.exe"),
        debug_command_check("rundll32.exe"),
    ];

    #[cfg(not(any(target_os = "linux", target_os = "windows")))]
    let checks = Vec::new();

    let recent_errors = jobs
        .iter()
        .filter_map(|job| {
            job.error
                .as_ref()
                .map(|error| format!("{}: {}", job.label, error))
        })
        .take(5)
        .collect();

    Ok(DebugSnapshot {
        platform: std::env::consts::OS.into(),
        arch: std::env::consts::ARCH.into(),
        app_version: env!("CARGO_PKG_VERSION").into(),
        data_dir: state.shared.data_dir.to_string_lossy().into_owned(),
        capture_storage,
        capture_running: state.runtime.lock().is_some(),
        capture_mode: config.mode.clone(),
        pending: state.shared.pending_count(),
        jobs: jobs.len(),
        signed_in: state.shared.auth.lock().refresh_token.is_some(),
        forward_printer: config.forward_printer,
        listen_addr: config.listen_addr,
        forward_addr: config.forward_addr,
        client_id: config.client_id,
        virtual_printer,
        installed_printers,
        recent_errors,
        checks,
    })
}

#[tauri::command]
fn run_capture_self_test() -> Result<String, String> {
    #[cfg(target_os = "linux")]
    {
        let path = std::env::temp_dir().join(format!(
            "fieldlens-capture-self-test-{}.pdf",
            uuid::Uuid::new_v4()
        ));
        std::fs::write(&path, build_self_test_pdf()).map_err(|error| error.to_string())?;

        let output = std::process::Command::new("lp")
            .args(["-d", "FieldLens-Test-Capture"])
            .arg(&path)
            .output()
            .map_err(|error| error.to_string());
        let _ = std::fs::remove_file(&path);
        let output = output?;

        if !output.status.success() {
            return Err(format!(
                "CUPS self-test submission failed: {}",
                String::from_utf8_lossy(&output.stderr).trim()
            ));
        }

        let detail = String::from_utf8_lossy(&output.stdout).trim().to_string();
        return Ok(if detail.is_empty() {
            "Self-test submitted to FieldLens Test Capture.".into()
        } else {
            detail
        });
    }

    #[cfg(not(target_os = "linux"))]
    {
        Err("Capture self-test is currently available on Linux only.".into())
    }
}

#[tauri::command]
fn sync_pending(state: State<'_, AppState>) -> Result<SyncResult, String> {
    fieldlens::sync_pending(&state.shared).map_err(|error| error.to_string())
}

#[tauri::command]
fn load_ocr_profile(state: State<'_, AppState>) -> Result<Option<Value>, String> {
    let path = state.shared.data_dir.join("ocr-profile.json");
    if !path.is_file() {
        return Ok(None);
    }
    let bytes = fs::read(&path).map_err(|error| error.to_string())?;
    serde_json::from_slice(&bytes)
        .map(Some)
        .map_err(|error| format!("read OCR profile: {error}"))
}

#[tauri::command]
fn save_ocr_profile(profile: Value, state: State<'_, AppState>) -> Result<Value, String> {
    if profile.get("schemaVersion").and_then(Value::as_u64) != Some(1) {
        return Err("unsupported OCR profile schema".into());
    }
    let path = state.shared.data_dir.join("ocr-profile.json");
    let temp = state.shared.data_dir.join("ocr-profile.json.tmp");
    let bytes = serde_json::to_vec_pretty(&profile).map_err(|error| error.to_string())?;
    fs::write(&temp, bytes).map_err(|error| error.to_string())?;
    if path.exists() {
        fs::remove_file(&path).map_err(|error| error.to_string())?;
    }
    fs::rename(&temp, &path).map_err(|error| error.to_string())?;
    Ok(profile)
}

fn newest_supported_capture_in(dir: &Path) -> Option<(PathBuf, SystemTime)> {
    let entries = fs::read_dir(dir).ok()?;
    entries
        .flatten()
        .filter_map(|entry| {
            let path = entry.path();
            if !path.is_file() {
                return None;
            }
            let extension = path.extension()?.to_str()?.to_ascii_lowercase();
            if !matches!(extension.as_str(), "pdf" | "png" | "jpg" | "jpeg" | "webp") {
                return None;
            }
            let modified = entry.metadata().ok()?.modified().ok()?;
            Some((path, modified))
        })
        .max_by_key(|(_, modified)| *modified)
}

#[tauri::command]
fn get_recent_capture(state: State<'_, AppState>) -> Result<RecentCapture, String> {
    let config = state.shared.config.lock().clone();
    let mut directories = Vec::<PathBuf>::new();

    if !config.spool_dir.trim().is_empty() {
        let spool = PathBuf::from(&config.spool_dir);
        directories.push(spool.join("processed"));
        directories.push(spool);
    }
    directories.push(state.shared.data_dir.join("capture").join("processed"));

    #[cfg(target_os = "linux")]
    directories.push(PathBuf::from("/var/lib/fieldlens-print/capture/processed"));

    let latest = directories
        .iter()
        .filter_map(|dir| newest_supported_capture_in(dir))
        .max_by_key(|(_, modified)| *modified)
        .ok_or_else(|| "no recent PDF or image capture was found".to_string())?;

    let metadata = fs::metadata(&latest.0).map_err(|error| error.to_string())?;
    if metadata.len() > 30 * 1024 * 1024 {
        return Err("recent capture is larger than the 30 MB refinement limit".into());
    }

    let bytes = fs::read(&latest.0).map_err(|error| error.to_string())?;
    let extension = latest
        .0
        .extension()
        .and_then(|value| value.to_str())
        .unwrap_or("")
        .to_ascii_lowercase();
    let mime = match extension.as_str() {
        "pdf" => "application/pdf",
        "png" => "image/png",
        "webp" => "image/webp",
        _ => "image/jpeg",
    }
    .to_string();

    Ok(RecentCapture {
        name: latest
            .0
            .file_name()
            .and_then(|value| value.to_str())
            .unwrap_or("recent-capture")
            .to_string(),
        mime,
        data_base64: BASE64_STANDARD.encode(bytes),
    })
}

pub fn run() {
    tauri::Builder::default()
        .plugin(tauri_plugin_opener::init())
        .plugin(tauri_plugin_process::init())
        .plugin(tauri_plugin_updater::Builder::new().build())
        .setup(|app| {
            let data_dir = app.path().app_data_dir()?;
            let shared = SharedState::load(data_dir)
                .map_err(|error| std::io::Error::other(error.to_string()))?;
            app.manage(AppState {
                shared,
                runtime: Mutex::new(None),
            });
            Ok(())
        })
        .invoke_handler(tauri::generate_handler![
            get_config,
            save_config,
            get_status,
            recent_jobs,
            start_capture,
            stop_capture,
            list_system_printers,
            get_virtual_printer_status,
            install_virtual_printer,
            remove_virtual_printer,
            get_debug_snapshot,
            run_capture_self_test,
            begin_login,
            poll_login,
            get_auth_status,
            logout,
            install_linux_update,
            sync_pending,
            load_ocr_profile,
            save_ocr_profile,
            get_recent_capture
        ])
        .run(tauri::generate_context!())
        .expect("error while running FieldLens Print");
}