//
//  AppSettings.swift
//  Zyquo Local
//
//  Author: Simon-Pierre Boucher
//  Mail: contact@spboucher.ai
//

import Foundation
import Observation

/// App-wide settings, persisted as JSON. Appearance lives in ThemeStore.
@MainActor
@Observable
final class AppSettings {
    /// Model loaded automatically on launch (repo ID), nil = none.
    var defaultModelID: String? {
        didSet { persist() }
    }

    /// Keep the model loaded when the window closes / app is in background.
    var keepModelLoaded: Bool {
        didSet { persist() }
    }

    /// Hugging Face token for gated models. Sent only to huggingface.co.
    var hfToken: String {
        didSet { persist() }
    }

    /// Verify file sizes after download completes.
    var autoVerifyDownloads: Bool {
        didSet { persist() }
    }

    /// Default generation parameters for new conversations.
    var defaultParams: GenerationParams {
        didSet { persist() }
    }

    /// MLX GPU buffer-cache limit in MB (0 = MLX default).
    var gpuCacheLimitMB: Int {
        didSet { persist() }
    }

    /// Hard cap applied on top of the model's context window (0 = model max).
    var contextLengthCap: Int {
        didSet { persist() }
    }

    /// Global default system prompt for new conversations.
    var defaultSystemPrompt: String {
        didSet { persist() }
    }

    var menuBarExtraEnabled: Bool {
        didSet { persist() }
    }

    private struct Persisted: Codable {
        var defaultModelID: String?
        var keepModelLoaded: Bool
        var hfToken: String
        var autoVerifyDownloads: Bool
        var defaultParams: GenerationParams
        var gpuCacheLimitMB: Int
        var contextLengthCap: Int
        var defaultSystemPrompt: String
        var menuBarExtraEnabled: Bool
    }

    init() {
        let stored = PersistenceService.loadDocument(Persisted.self, named: "settings")
        defaultModelID = stored?.defaultModelID
        keepModelLoaded = stored?.keepModelLoaded ?? true
        hfToken = stored?.hfToken ?? ""
        autoVerifyDownloads = stored?.autoVerifyDownloads ?? true
        defaultParams = stored?.defaultParams ?? GenerationParams()
        gpuCacheLimitMB = stored?.gpuCacheLimitMB ?? 0
        contextLengthCap = stored?.contextLengthCap ?? 0
        defaultSystemPrompt = stored?.defaultSystemPrompt ?? ""
        menuBarExtraEnabled = stored?.menuBarExtraEnabled ?? true
    }

    private func persist() {
        PersistenceService.saveDocument(
            Persisted(
                defaultModelID: defaultModelID,
                keepModelLoaded: keepModelLoaded,
                hfToken: hfToken,
                autoVerifyDownloads: autoVerifyDownloads,
                defaultParams: defaultParams,
                gpuCacheLimitMB: gpuCacheLimitMB,
                contextLengthCap: contextLengthCap,
                defaultSystemPrompt: defaultSystemPrompt,
                menuBarExtraEnabled: menuBarExtraEnabled
            ),
            named: "settings"
        )
    }
}