use std::collections::HashMap;
use std::sync::Mutex;

use anyhow::Result;

use super::models::{DailyStats, DownloadRecord, ForceChannel, User};

pub struct Database {
    config: Mutex<HashMap<String, String>>,
    users: Mutex<HashMap<i64, User>>,
    daily_counts: Mutex<HashMap<String, i64>>,
    records: Mutex<Vec<DownloadRecord>>,
    channels: Mutex<Vec<ForceChannel>>,
    next_record_id: Mutex<i64>,
    admin_actions: Mutex<HashMap<i64, String>>,
}

impl Database {
    pub fn open(_db_path: &std::path::Path) -> Result<Self> {
        let mut config = HashMap::new();
        config.insert("default_daily_limit".into(), "3".into());
        config.insert("welcome_message".into(), "".into());
        config.insert("global_mute".into(), "false".into());
        Ok(Self {
            config: Mutex::new(config),
            users: Mutex::new(HashMap::new()),
            daily_counts: Mutex::new(HashMap::new()),
            records: Mutex::new(Vec::new()),
            channels: Mutex::new(Vec::new()),
            next_record_id: Mutex::new(1),
            admin_actions: Mutex::new(HashMap::new()),
        })
    }

    pub fn run_migrations(&self) -> Result<()> {
        Ok(())
    }

    pub fn get_config(&self, key: &str) -> Option<String> {
        self.config.lock().unwrap().get(key).cloned()
    }

    pub fn set_config(&self, key: &str, value: &str) -> Result<()> {
        self.config.lock().unwrap().insert(key.to_string(), value.to_string());
        Ok(())
    }

    pub fn register_user(&self, user_id: i64, username: Option<&str>, first_name: Option<&str>, last_name: Option<&str>) -> Result<User> {
        let mut users = self.users.lock().unwrap();
        if users.contains_key(&user_id) {
            return Ok(users[&user_id].clone());
        }
        let default_limit: i64 = self.get_config("default_daily_limit").and_then(|v| v.parse().ok()).unwrap_or(3);
        let now = chrono::Utc::now().to_rfc3339();
        let user = User {
            user_id,
            username: username.map(|s| s.to_string()),
            first_name: first_name.map(|s| s.to_string()),
            last_name: last_name.map(|s| s.to_string()),
            role: "user".to_string(),
            daily_limit: default_limit,
            format_preference: "epub".to_string(),
            created_at: now.clone(),
            last_active_at: now,
        };
        users.insert(user_id, user.clone());
        Ok(user)
    }

    pub fn get_user(&self, user_id: i64) -> Option<User> {
        self.users.lock().unwrap().get(&user_id).cloned()
    }

    pub fn update_last_active(&self, user_id: i64) {
        if let Ok(mut users) = self.users.lock() {
            if let Some(u) = users.get_mut(&user_id) {
                u.last_active_at = chrono::Utc::now().to_rfc3339();
            }
        }
    }

    pub fn update_username(&self, user_id: i64, username: Option<&str>) {
        if let Ok(mut users) = self.users.lock() {
            if let Some(u) = users.get_mut(&user_id) {
                u.username = username.map(|s| s.to_string());
            }
        }
    }

    pub fn set_user_role(&self, user_id: i64, role: &str) -> Result<()> {
        if let Ok(mut users) = self.users.lock() {
            if let Some(u) = users.get_mut(&user_id) {
                u.role = role.to_string();
            }
        }
        Ok(())
    }

    pub fn set_user_daily_limit(&self, user_id: i64, limit: i64) -> Result<()> {
        if let Ok(mut users) = self.users.lock() {
            if let Some(u) = users.get_mut(&user_id) {
                u.daily_limit = limit;
            }
        }
        Ok(())
    }

    pub fn set_user_format(&self, user_id: i64, format: &str) -> Result<()> {
        if let Ok(mut users) = self.users.lock() {
            if let Some(u) = users.get_mut(&user_id) {
                u.format_preference = format.to_string();
            }
        }
        Ok(())
    }

    pub fn count_users(&self) -> i64 {
        self.users.lock().unwrap().len() as i64
    }

    pub fn get_today_download_count(&self, user_id: i64, date: &str) -> i64 {
        let key = format!("{}:{}", user_id, date);
        *self.daily_counts.lock().unwrap().get(&key).unwrap_or(&0)
    }

    pub fn increment_today_download(&self, user_id: i64, date: &str) -> Result<()> {
        let key = format!("{}:{}", user_id, date);
        *self.daily_counts.lock().unwrap().entry(key).or_insert(0) += 1;
        Ok(())
    }

    pub fn count_today_downloads_total(&self, date: &str) -> i64 {
        self.daily_counts.lock().unwrap().iter().filter(|(k, _)| k.ends_with(&format!(":{}", date))).map(|(_, v)| *v).sum()
    }

    pub fn add_download_record(&self, user_id: i64, book_id: &str, book_name: Option<&str>, format: Option<&str>, status: &str) -> Result<i64> {
        let id = *self.next_record_id.lock().unwrap();
        *self.next_record_id.lock().unwrap() += 1;
        let record = DownloadRecord {
            id,
            user_id,
            book_id: book_id.to_string(),
            book_name: book_name.map(|s| s.to_string()),
            format: format.map(|s| s.to_string()),
            status: status.to_string(),
            file_size: None,
            started_at: chrono::Utc::now().to_rfc3339(),
            finished_at: None,
        };
        self.records.lock().unwrap().push(record);
        Ok(id)
    }

    pub fn finish_download_record(&self, record_id: i64, status: &str, file_size: Option<i64>) -> Result<()> {
        if let Ok(mut records) = self.records.lock() {
            if let Some(r) = records.iter_mut().find(|r| r.id == record_id) {
                r.status = status.to_string();
                r.file_size = file_size;
                r.finished_at = Some(chrono::Utc::now().to_rfc3339());
            }
        }
        Ok(())
    }

    pub fn count_user_downloads(&self, user_id: i64) -> i64 {
        self.records.lock().unwrap().iter().filter(|r| r.user_id == user_id && r.status == "completed").count() as i64
    }

    pub fn get_force_channels(&self) -> Vec<ForceChannel> {
        self.channels.lock().unwrap().clone()
    }

    pub fn add_force_channel(&self, channel_id: &str, channel_name: Option<&str>, channel_type: &str, invite_link: Option<&str>, added_by: i64) -> Result<()> {
        let id = self.channels.lock().unwrap().len() as i64 + 1;
        self.channels.lock().unwrap().push(ForceChannel {
            id,
            channel_id: channel_id.to_string(),
            channel_name: channel_name.map(|s| s.to_string()),
            channel_type: channel_type.to_string(),
            invite_link: invite_link.map(|s| s.to_string()),
            added_at: chrono::Utc::now().to_rfc3339(),
            added_by,
        });
        Ok(())
    }

    pub fn remove_force_channel(&self, channel_id: &str) -> Result<()> {
        self.channels.lock().unwrap().retain(|c| c.channel_id != channel_id);
        Ok(())
    }

    pub fn is_admin(&self, user_id: i64) -> bool {
        self.get_admin_ids().contains(&user_id)
    }

    pub fn get_admin_ids(&self) -> Vec<i64> {
        self.get_config("admin_ids").and_then(|v| serde_json::from_str(&v).ok()).unwrap_or_default()
    }

    pub fn set_admin_ids(&self, ids: &[i64]) -> Result<()> {
        let json = serde_json::to_string(ids).unwrap();
        self.set_config("admin_ids", &json)
    }

    pub fn is_global_muted(&self) -> bool {
        self.get_config("global_mute").as_deref() == Some("true")
    }

    pub fn toggle_global_mute(&self) -> Result<bool> {
        let current = self.is_global_muted();
        self.set_config("global_mute", if current { "false" } else { "true" })?;
        Ok(!current)
    }

    pub fn get_default_daily_limit(&self) -> i64 {
        self.get_config("default_daily_limit").and_then(|v| v.parse().ok()).unwrap_or(3)
    }

    pub fn set_default_daily_limit(&self, limit: i64) -> Result<()> {
        self.set_config("default_daily_limit", &limit.to_string())
    }

    pub fn clean_old_stats(&self) -> Result<()> {
        Ok(())
    }

    pub fn total_completed_downloads(&self) -> i64 {
        self.records.lock().unwrap().iter().filter(|r| r.status == "completed").count() as i64
    }

    pub fn get_all_admin_users(&self) -> Vec<User> {
        let ids = self.get_admin_ids();
        let users = self.users.lock().unwrap();
        ids.iter().filter_map(|id| users.get(id).cloned()).collect()
    }

    pub fn set_action(&self, user_id: i64, action: &str) {
        self.admin_actions.lock().unwrap().insert(user_id, action.to_string());
    }

    pub fn take_action(&self, user_id: i64) -> Option<String> {
        self.admin_actions.lock().unwrap().remove(&user_id)
    }
}