//
//  DatabaseFiles.swift
//  secant-testnet
//
//  Created by Lukáš Korba on 05.04.2022.
//

import Foundation
import ZcashLightClientKit

struct DatabaseFiles {
    enum DatabaseFilesError: Error {
        case getFsBlockDbRoot
        case getDocumentsURL
        case getCacheURL
        case getDataURL
        case getOutputParamsURL
        case getPendingURL
        case getSpendParamsURL
        case nukeFiles
        case filesPresentCheck
    }
    
    private let fileManager: FileManagerClient
    
    init(fileManager: FileManagerClient) {
        self.fileManager = fileManager
    }
    
    func documentsDirectory() throws -> URL {
        do {
            return try fileManager.url(.documentDirectory, .userDomainMask, nil, true)
        } catch {
            throw DatabaseFilesError.getDocumentsURL
        }
    }

    func cacheDbURL(for network: ZcashNetwork) throws -> URL {
        do {
            return try documentsDirectory()
                .appendingPathComponent(
                    "\(network.constants.defaultDbNamePrefix)cache.db",
                    isDirectory: false
                )
        } catch {
            throw DatabaseFilesError.getCacheURL
        }
    }

    func dataDbURL(for network: ZcashNetwork) throws -> URL {
        do {
            return try documentsDirectory()
                .appendingPathComponent(
                    "\(network.constants.defaultDbNamePrefix)data.db",
                    isDirectory: false
                )
        } catch {
            throw DatabaseFilesError.getDataURL
        }
    }

    func outputParamsURL(for network: ZcashNetwork) throws -> URL {
        do {
            return try documentsDirectory()
                .appendingPathComponent(
                    "\(network.constants.defaultDbNamePrefix)sapling-output.params",
                    isDirectory: false
                )
        } catch {
            throw DatabaseFilesError.getOutputParamsURL
        }
    }

    func pendingDbURL(for network: ZcashNetwork) throws -> URL {
        do {
            return try documentsDirectory()
                .appendingPathComponent(
                    "\(network.constants.defaultDbNamePrefix)pending.db",
                    isDirectory: false
                )
        } catch {
            throw DatabaseFilesError.getPendingURL
        }
    }

    func spendParamsURL(for network: ZcashNetwork) throws -> URL {
        do {
            return try documentsDirectory()
                .appendingPathComponent(
                    "\(network.constants.defaultDbNamePrefix)sapling-spend.params",
                    isDirectory: false
                )
        } catch {
            throw DatabaseFilesError.getSpendParamsURL
        }
    }

    func areDbFilesPresent(for network: ZcashNetwork) throws -> Bool {
        do {
            let dataDbURL = try dataDbURL(for: network)
            return fileManager.fileExists(dataDbURL.path)
        } catch {
            throw DatabaseFilesError.filesPresentCheck
        }
    }
    
    func nukeDbFiles(for network: ZcashNetwork) throws {
        do {
            let cacheDbURL = try cacheDbURL(for: network)
            let dataDbURL = try dataDbURL(for: network)
            let pendingDbURL = try pendingDbURL(for: network)
            try fileManager.removeItem(cacheDbURL)
            try fileManager.removeItem(dataDbURL)
            try fileManager.removeItem(pendingDbURL)
        } catch {
            throw DatabaseFilesError.nukeFiles
        }
    }
}