import Testing
import Foundation
import GRDB
@testable import Music

@MainActor
struct DBBackupFTS5Tests {

    // Pins down the root cause: does DatabaseService.backup() produce a copy whose
    // FTS5 `tracks_ft` table is functional? GRDB's ValueObservation introspects the
    // whole schema on start, and that introspection throws "no such table: tracks_ft"
    // if the FTS5 shadow tables didn't survive the copy.
    @Test
    func backupCopyHasFunctionalFTS5Table() throws {
        // 1. Build a source DB (DatabasePool/WAL, like the running app) with 3 tracks.
        let tempDir = FileManager.default.temporaryDirectory.appendingPathComponent(UUID().uuidString)
        try FileManager.default.createDirectory(at: tempDir, withIntermediateDirectories: true)
        defer { try? FileManager.default.removeItem(at: tempDir) }
        let srcPath = tempDir.appendingPathComponent("src.sqlite").path
        let src = try DatabaseService(path: srcPath)
        for i in 1...3 {
            var t = Track.fixture(fileURL: "/s\(i).mp3", title: "Song \(i)")
            try src.insert(&t)
        }

        // 2. Copy the DB exactly as the host serves it today.
        let copyPath = tempDir.appendingPathComponent("copy.sqlite").path
        try src.backup(to: copyPath)

        // 3. Open the copy and run the same schema-introspection query GRDB runs when
        //    a ValueObservation starts. If FTS5 didn't transfer, this throws.
        let copy = try DatabaseService(path: copyPath)
        try copy.dbPool.read { db in
            _ = try Row.fetchAll(
                db,
                sql: "SELECT rootpage, sql FROM sqlite_master WHERE (type = 'table' OR type = 'view')"
            )
            // And an actual FTS5 query must work.
            _ = try Row.fetchAll(db, sql: "SELECT * FROM tracks_ft LIMIT 1")
        }
    }
}