use std::path::Path;

use anyhow::Result;
use tokio::time;
use tracing::{info, warn};

use crate::core::db::{PostgresDb, VideoRecord, VideoStatus};

pub struct WatcherConfig {
    pub directories: Vec<String>,
    pub poll_interval_ms: u64,
}

impl Default for WatcherConfig {
    fn default() -> Self {
        let default_dir = std::env::var("MOMENTRY_SFTP_ROOT")
            .unwrap_or_else(|_| "/Users/accusys/momentry/var/sftpgo/data/demo/".to_string());
        Self {
            directories: vec![default_dir],
            poll_interval_ms: 60000,
        }
    }
}

/// Starts the file watcher in the background.
/// Detects new files and logs them.
pub async fn run_watcher() -> Result<()> {
    let config = WatcherConfig::default();
    let dirs = config.directories.clone();

    if dirs.is_empty() {
        warn!("No directories configured for watching.");
        return Err(anyhow::anyhow!("No watch directories"));
    }

    info!("Starting File Watcher (detection only, no auto-modification)...");
    info!("Watch directories: {:?}", dirs);

    tokio::spawn(async move {
        let mut interval =
            time::interval(std::time::Duration::from_millis(config.poll_interval_ms));
        let mut known = std::collections::HashSet::new();
        loop {
            interval.tick().await;
            report_new_files(&dirs, &mut known).await;
        }
    });

    Ok(())
}

async fn report_new_files(directories: &[String], known: &mut std::collections::HashSet<String>) {
    for dir in directories {
        let dir_path = Path::new(dir);
        if !dir_path.is_dir() {
            continue;
        }
        let entries = match std::fs::read_dir(dir_path) {
            Ok(e) => e,
            _ => continue,
        };

        let mut current_files = std::collections::HashSet::new();
        for entry in entries.flatten() {
            let file_path = entry.path();
            if !file_path.is_file() {
                continue;
            }
            let fname = match file_path.file_name().and_then(|n| n.to_str()) {
                Some(n) if !n.starts_with('.') && !n.ends_with(".pre.json") => n.to_string(),
                _ => continue,
            };
            current_files.insert(fname.clone());
            if !known.contains(&fname) {
                info!("[WATCHER] New file detected: {} in {}", fname, dir);
                if crate::core::config::get_watcher_auto_register() {
                    let fpath = file_path.to_string_lossy().to_string();
                    tokio::spawn(async move {
                        auto_register_file(&fpath).await;
                    });
                }
                known.insert(fname);
            }
        }
        known.retain(|k| current_files.contains(k));
    }
}

async fn auto_register_file(file_path: &str) {
    let file_uuid = match pre_process_file(file_path).await {
        Some(u) => u,
        None => return,
    };

    let output_dir = std::env::var("MOMENTRY_OUTPUT_DIR")
        .unwrap_or_else(|_| "/Users/accusys/momentry/output_dev".to_string());
    let pre_path = std::path::PathBuf::from(&output_dir).join(format!("{}.pre.json", file_uuid));
    let pre_content = match std::fs::read_to_string(&pre_path) {
        Ok(c) => c,
        Err(e) => {
            warn!("[WATCHER] Failed to read pre.json: {}", e);
            return;
        }
    };
    let pre: serde_json::Value = match serde_json::from_str(&pre_content) {
        Ok(v) => v,
        Err(e) => {
            warn!("[WATCHER] Failed to parse pre.json: {}", e);
            return;
        }
    };

    let file_name = pre
        .get("file_name")
        .and_then(|v| v.as_str())
        .unwrap_or("unknown")
        .to_string();
    let probe = pre.get("probe_json").cloned().unwrap_or_default();
    let file_type = pre
        .get("file_type")
        .and_then(|v| v.as_str())
        .unwrap_or("unknown")
        .to_string();
    let canonical_path = pre
        .get("file_path")
        .and_then(|v| v.as_str())
        .unwrap_or(file_path)
        .to_string();

    let duration = probe
        .get("format")
        .and_then(|f| f.get("duration"))
        .and_then(|v| v.as_f64())
        .unwrap_or(0.0);
    let width = probe
        .get("format")
        .and_then(|f| f.get("width"))
        .and_then(|v| v.as_u64())
        .unwrap_or(0) as u32;
    let height = probe
        .get("format")
        .and_then(|f| f.get("height"))
        .and_then(|v| v.as_u64())
        .unwrap_or(0) as u32;
    let fps_val = probe
        .get("format")
        .and_then(|f| f.get("fps"))
        .and_then(|v| v.as_f64())
        .unwrap_or(0.0);

    let record = VideoRecord {
        id: 0,
        file_uuid,
        file_path: canonical_path,
        file_name,
        file_type: Some(file_type),
        duration,
        width,
        height,
        fps: fps_val,
        probe_json: Some(probe),
        storage: Default::default(),
        status: VideoStatus::Registered,
        processing_status: None,
        birth_registration: None,
        user_id: None,
        job_id: None,
        created_at: String::new(),
        registration_time: None,
        total_frames: 0,
        parent_uuid: None,
        cut_done: false,
        cut_count: 0,
        cut_max_duration: 0.0,
        scene_done: false,
        audio_tracks: None,
    };

    let database_url = crate::core::config::DATABASE_URL.as_str();
    let db = match PostgresDb::new(database_url).await {
        Ok(d) => d,
        Err(e) => {
            warn!("[WATCHER] Failed to connect DB for auto-register: {}", e);
            return;
        }
    };

    match db.register_video(&record).await {
        Ok(id) => info!("[WATCHER] Auto-registered {} (id={})", record.file_uuid, id),
        Err(e) => warn!(
            "[WATCHER] Auto-register failed for {}: {}",
            record.file_uuid, e
        ),
    }
}

/// Pre-process a single file: compute SHA256 + probe + UUID → .pre.json
pub async fn pre_process_file(file_path: &str) -> Option<String> {
    let path = std::path::Path::new(file_path);
    if !path.is_file() {
        return None;
    }
    let canonical = path.canonicalize().ok()?;
    let canonical_str = canonical.to_string_lossy().to_string();
    let filename = path.file_name()?.to_string_lossy().to_string();

    let output_dir = std::env::var("MOMENTRY_OUTPUT_DIR")
        .unwrap_or_else(|_| "/Users/accusys/momentry/output_dev".to_string());

    let birthday = std::fs::metadata(&path)
        .ok()
        .and_then(|m| m.modified().ok())
        .map(|t| {
            let secs = t
                .duration_since(std::time::UNIX_EPOCH)
                .unwrap_or_default()
                .as_secs();
            chrono::DateTime::from_timestamp(secs as i64, 0)
                .map(|dt| dt.to_rfc3339())
                .unwrap_or_else(|| chrono::Utc::now().to_rfc3339())
        })
        .unwrap_or_else(|| chrono::Utc::now().to_rfc3339());

    let mac = crate::core::storage::uuid::get_mac_address();
    let file_uuid =
        crate::core::storage::uuid::compute_birth_uuid(&mac, &birthday, &canonical_str, &filename);

    let pre_path = std::path::PathBuf::from(&output_dir).join(format!("{}.pre.json", file_uuid));
    if pre_path.exists() {
        info!("[PRE-PROCESS] Already pre-processed: {}", filename);
        return Some(file_uuid);
    }

    info!("[PRE-PROCESS] Pre-processing: {} → {}", filename, file_uuid);

    let content_hash =
        crate::core::storage::content_hash::compute_sha256(&path).unwrap_or_default();

    let scripts_dir = std::env::var("MOMENTRY_SCRIPTS_DIR")
        .unwrap_or_else(|_| "/Users/accusys/momentry_core_0.1/scripts".to_string());
    let python_path = std::env::var("MOMENTRY_PYTHON_PATH")
        .unwrap_or_else(|_| "/opt/homebrew/bin/python3.11".to_string());
    let probe_json =
        crate::core::probe::unified::unified_probe(&path, &scripts_dir, &python_path).await;

    let file_type = probe_json
        .get("format")
        .and_then(|f| f.get("file_type"))
        .and_then(|v| v.as_str())
        .unwrap_or("unknown")
        .to_string();

    let pre_data = serde_json::json!({
        "file_name": filename,
        "file_path": canonical_str,
        "content_hash": content_hash,
        "probe_json": probe_json,
        "birthday": birthday,
        "file_uuid": file_uuid,
        "file_size": std::fs::metadata(&path).ok().map(|m| m.len()).unwrap_or(0),
        "file_type": file_type,
        "pre_processed_at": chrono::Utc::now().to_rfc3339(),
    });

    if let Ok(content) = serde_json::to_string_pretty(&pre_data) {
        if std::fs::write(&pre_path, content).is_ok() {
            info!("[PRE-PROCESS] {} → {}.pre.json", filename, file_uuid);
        }
    }
    Some(file_uuid)
}