//
//  AppPaths.swift
//
//  Copyright 2026 Brendan Szymanski <hello@bscubed.dev>
//
//  This program 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.
//
//  This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.
//
//  SPDX-License-Identifier: GPL-3.0-or-later
//

import Foundation

/// Platform-aware locations for Luminate's persistent data.
package enum AppPaths {
    /// Environment variable that overrides the data directory outright; used by tests and CI.
    package static let dataDirectoryOverrideVariable = "LUMINATE_DATA_DIR"

    /// The directory Luminate stores its own data in.
    ///
    /// - Parameters:
    ///   - environment: Environment values used to resolve the location.
    ///   - home: The user's home directory, or `nil` when unavailable.
    ///   - temporaryDirectory: The fallback temporary directory.
    /// - Returns: The resolved application data directory.
    package static func dataDirectory(
        environment: [String: String] = ProcessInfo.processInfo.environment,
        home: URL? = FileManager.default.homeDirectoryForCurrentUser,
        temporaryDirectory: URL = FileManager.default.temporaryDirectory
    ) -> URL {
        if let override = environment[dataDirectoryOverrideVariable], override.hasPrefix("/") {
            return URL(filePath: override)
        }

        #if canImport(Darwin)
            let baseDirectory = home?.appending(
                path: "Library/Application Support",
                directoryHint: .isDirectory
            )
        #else
            let xdgDataHome = environment["XDG_DATA_HOME"]
            let baseDirectory: URL?
            if let xdgDataHome, !xdgDataHome.isEmpty, xdgDataHome.hasPrefix("/") {
                baseDirectory = URL(filePath: xdgDataHome)
            } else if let home, !home.path.isEmpty {
                baseDirectory = home.appending(path: ".local/share", directoryHint: .isDirectory)
            } else {
                baseDirectory = nil
            }
        #endif

        if let baseDirectory {
            return baseDirectory.appending(path: AppInfo.directoryName, directoryHint: .isDirectory)
        }
        return temporaryDirectory.appending(path: AppInfo.directoryName, directoryHint: .isDirectory)
    }

    /// The preferences database inside ``dataDirectory(environment:home:temporaryDirectory:)``.
    ///
    /// - Parameters:
    ///   - environment: Environment values used to resolve the location.
    ///   - home: The user's home directory, or `nil` when unavailable.
    ///   - temporaryDirectory: The fallback temporary directory.
    /// - Returns: The preferences database URL.
    package static func preferencesDatabaseURL(
        environment: [String: String] = ProcessInfo.processInfo.environment,
        home: URL? = FileManager.default.homeDirectoryForCurrentUser,
        temporaryDirectory: URL = FileManager.default.temporaryDirectory
    ) -> URL {
        dataDirectory(
            environment: environment,
            home: home,
            temporaryDirectory: temporaryDirectory
        ).appending(path: "preferences.sqlite", directoryHint: .notDirectory)
    }
}