// SvelteKit store for Dropbox sync
import { writable, derived } from 'svelte/store'
// For a private module, you would import from your private registry or local path
// import { useSvelteDropboxSync } from '@yourcompany/dropbox-sync';
import { useSvelteDropboxSync } from 'dropbox-sync'
import { browser } from '$app/environment'
import { goto } from '$app/navigation'

// Create a persistent store
export function createDropboxStore() {
    const credentials = {
        clientId: browser
            ? import.meta.env.VITE_DROPBOX_APP_KEY
            : process.env.DROPBOX_APP_KEY,
        // The access token will be added from cookies on the server side
    }

    // Initialize the Dropbox client
    const dropboxSync = useSvelteDropboxSync(credentials)

    // Create stores for state management
    const connected = writable(false)
    const syncing = writable(false)
    const progress = writable(0)
    const message = writable('')
    const error = writable<string | null>(null)
    const syncStats = writable({
        total: 0,
        uploads: 0,
        downloads: 0,
        completed: 0,
    })

    // Check connection status on initialization
    async function checkConnection() {
        if (!browser) return

        try {
            const response = await fetch('/api/dropbox/status')
            const data = await response.json()
            connected.set(data.connected)
        } catch (err) {
            console.error('Error checking Dropbox connection:', err)
            connected.set(false)
        }
    }

    if (browser) {
        checkConnection()

        // Set up socket connection for real-time updates
        dropboxSync.socket.connect()

        // Listen for progress updates
        dropboxSync.socket.on('sync:progress', (data) => {
            progress.set(data.progress)
            message.set(data.message)
        })

        // Listen for queue information
        dropboxSync.socket.on('sync:queue', (data) => {
            syncStats.set({
                total: data.total,
                uploads: data.totalUploads,
                downloads: data.totalDownloads,
                completed: 0,
            })
        })

        // Listen for completion
        dropboxSync.socket.on('sync:complete', (data) => {
            progress.set(100)
            message.set(data.message)
            syncing.set(false)

            if (data.stats) {
                syncStats.update((stats) => ({
                    ...stats,
                    completed: stats.total,
                }))
            }
        })

        // Listen for errors
        dropboxSync.socket.on('sync:error', (data) => {
            error.set(data.message)
            syncing.set(false)
        })
    }

    return {
        connected: { subscribe: connected.subscribe },
        syncing: { subscribe: syncing.subscribe },
        progress: { subscribe: progress.subscribe },
        message: { subscribe: message.subscribe },
        error: { subscribe: error.subscribe },
        syncStats: { subscribe: syncStats.subscribe },

        // Connect to Dropbox
        connect() {
            if (!browser) return
            goto('/api/dropbox/auth/start')
        },

        // Disconnect from Dropbox
        async disconnect() {
            if (!browser) return

            try {
                await fetch('/api/dropbox/logout', { method: 'POST' })
                connected.set(false)
            } catch (err) {
                console.error('Error disconnecting from Dropbox:', err)
            }
        },

        // Start synchronization
        async startSync() {
            if (!browser) return

            try {
                syncing.set(true)
                progress.set(0)
                message.set('Initializing Dropbox sync...')
                error.set(null)

                // Trigger sync via socket
                dropboxSync.socket.emit('dropbox:sync')
            } catch (err: any) {
                console.error('Error starting Dropbox sync:', err)
                error.set(
                    err.message || 'An error occurred while starting sync'
                )
                syncing.set(false)
            }
        },

        // Cancel synchronization
        cancelSync() {
            if (!browser) return

            dropboxSync.sync.cancelSync()
            syncing.set(false)
            message.set('Sync cancelled')
        },

        // Check files that need syncing without starting the sync
        async checkSyncNeeded(options?: {
            localDir?: string
            dropboxDir?: string
        }) {
            if (!browser) return { upload: 0, download: 0 }

            try {
                const { uploadQueue, downloadQueue } =
                    await dropboxSync.sync.createSyncQueue({
                        localDir: options?.localDir,
                        dropboxDir: options?.dropboxDir,
                    })

                return {
                    upload: uploadQueue.length,
                    download: downloadQueue.length,
                }
            } catch (err) {
                console.error('Error checking sync status:', err)
                return { upload: 0, download: 0 }
            }
        },
    }
}

// Export singleton instance
export const dropbox = createDropboxStore()