// Copyright 2015, 2016 Ethcore (UK) Ltd.
// This file is part of Parity.

// Parity is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// Parity is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with Parity.  If not, see <http://www.gnu.org/licenses/>.

use std::sync::{RwLock,Arc};
use ipc::IpcConfig;
use std::collections::HashMap;
use nanoipc;

pub type IpcModuleId = u64;

/// Blockhain database module id
pub const CLIENT_MODULE_ID: IpcModuleId = 2000;

/// Sync module id
pub const SYNC_MODULE_ID: IpcModuleId = 2100;

/// IPC service that handles module management
pub struct HypervisorService {
	modules: RwLock<HashMap<IpcModuleId, ModuleState>>,
}

#[derive(Default)]
pub struct ModuleState {
	started: bool,
	control_url: String,
	shutdown: bool,
}


#[derive(Ipc)]
pub trait ControlService {
	fn shutdown(&self) -> bool;
}

#[derive(Ipc)]
impl HypervisorService {
	// return type for making method synchronous
	fn module_ready(&self, module_id: u64, control_url: String) -> bool {
		let mut modules = self.modules.write().unwrap();
		modules.get_mut(&module_id).map(|mut module| {
			module.started = true;
			module.control_url = control_url;
		});
		trace!(target: "hypervisor", "Module ready: {}", module_id);
		true
	}

	// return type for making method synchronous
	fn module_shutdown(&self, module_id: u64) -> bool {
		let mut modules = self.modules.write().unwrap();
		modules.get_mut(&module_id).map(|mut module| {
			module.shutdown = true;
		});
		trace!(target: "hypervisor", "Module shutdown: {}", module_id);
		true
	}
}

impl HypervisorService {
	/// New service with the default list of modules
	pub fn new() -> Arc<HypervisorService> {
		HypervisorService::with_modules(vec![])
	}

	/// New service with list of modules that will report for being ready
	pub fn with_modules(module_ids: Vec<IpcModuleId>) -> Arc<HypervisorService> {
		let mut modules = HashMap::new();
		for module_id in module_ids {
			modules.insert(module_id, ModuleState::default());
		}
		Arc::new(HypervisorService {
			modules: RwLock::new(modules),
		})
	}

	/// Add the module to the check-list
	pub fn add_module(&self, module_id: IpcModuleId) {
		self.modules.write().unwrap().insert(module_id, ModuleState::default());
	}

	/// Number of modules still being waited for check-in
	pub fn unchecked_count(&self) -> usize {
		self.modules.read().unwrap().iter().filter(|&(_, module)| !module.started).count()
	}

	/// List of all modules within this service
	pub fn module_ids(&self) -> Vec<IpcModuleId> {
		self.modules.read().unwrap().iter().map(|(module_id, _)| module_id).cloned().collect()
	}

	/// Number of modules started and running
	pub fn running_count(&self) -> usize {
		self.modules.read().unwrap().iter().filter(|&(_, module)| module.started && !module.shutdown).count()
	}

	pub fn send_shutdown(&self, module_id: IpcModuleId) {
		let modules = self.modules.read().unwrap();
		modules.get(&module_id).map(|module| {
			trace!(target: "hypervisor", "Sending shutdown to {}({})", module_id, &module.control_url);
			let client = nanoipc::fast_client::<ControlServiceClient<_>>(&module.control_url).unwrap();
			client.shutdown();
			trace!(target: "hypervisor", "Sent shutdown to {}", module_id);
		});
	}
}

impl ::ipc::IpcConfig for HypervisorService {}

impl ::ipc::IpcConfig for ControlService {}