// Utils/PhotoStore.swift
// ----------------------
// Resolves a stored photo path against the CURRENT app container.
//
// ── The bug this exists to fix ───────────────────────────────────────────────
// Every photo path in the database is ABSOLUTE and embeds the app-container
// UUID:
//
//   /var/mobile/Containers/Data/Application/<CONTAINER-UUID>/Documents/JQC/Photos/<file>.jpg
//
// iOS assigns a NEW container UUID on every app update, reinstall and restore.
// The Documents directory survives — the files are all still there — but every
// stored path is instantly dead.
//
// Nothing accounted for that. `uploadPhoto` does
// `FileManager.default.contents(atPath:)`, which returns nil, so the upload
// throws "Could not read photo" and can NEVER succeed no matter how often it is
// retried: the path names a container that no longer exists. Any photo still
// awaiting upload when the app updates is therefore stranded permanently, and
// its inspection is submitted with the field blank.
//
// That is what happened to inspection #887 (9 photos, Aug 2026): the diagnostic
// reported all nine as `upload: pending` with 0 failed rows and
// "Stored path stale (container changed) — file found by name, recoverable".
//
// ── Why basename lookup is safe ──────────────────────────────────────────────
// Filenames are `UUID().uuidString + ".jpg"`, generated per save at every call
// site, so a basename identifies a file unambiguously. This is the same
// resolution PhotoDiagnosticView already performs to report recoverability —
// it just was not wired into the code paths that actually read the files.

import Foundation

nonisolated enum PhotoStore {

    /// Sub-directories of Documents/ the app has ever written photos to.
    /// `JQCPhotos` is not written by any current code path but is checked so a
    /// file left by an older build is still found.
    private static let subdirectories = ["JQC/Photos", "JQC/ResultPhotos", "JQCPhotos"]

    /// Documents/ in the CURRENT container. Recomputed per call — caching it
    /// across an app update would reintroduce the very staleness this fixes.
    private static var documentsDirectory: URL? {
        FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first
    }

    /// Absolute URL for a photo directory in the current container.
    static func directory(_ subdirectory: String = "JQC/Photos") -> URL? {
        documentsDirectory?.appendingPathComponent(subdirectory, isDirectory: true)
    }

    /// The live absolute path for a stored photo path, or nil if the file is
    /// genuinely gone.
    ///
    /// Returns `storedPath` unchanged when it still resolves (the common case,
    /// costing one `fileExists` check). Otherwise re-resolves by filename under
    /// the current container.
    static func resolve(_ storedPath: String) -> String? {
        guard !storedPath.isEmpty else { return nil }
        let fm = FileManager.default
        if fm.fileExists(atPath: storedPath) { return storedPath }

        let name = URL(fileURLWithPath: storedPath).lastPathComponent
        guard !name.isEmpty else { return nil }
        for sub in subdirectories {
            guard let candidate = directory(sub)?.appendingPathComponent(name) else { continue }
            if fm.fileExists(atPath: candidate.path) { return candidate.path }
        }
        return nil
    }

    /// Read a photo's bytes, healing a stale container path first.
    static func contents(at storedPath: String) -> Data? {
        guard let live = resolve(storedPath) else { return nil }
        return FileManager.default.contents(atPath: live)
    }

    /// Delete a photo, whichever container its path was written in.
    @discardableResult
    static func remove(at storedPath: String) -> Bool {
        guard let live = resolve(storedPath) else { return false }
        return (try? FileManager.default.removeItem(atPath: live)) != nil
    }

    /// Filename component, which is the only stable part of a stored path.
    /// Use this — never the full path — to compare a database reference against
    /// a file on disk (see `SyncManager.cleanupOrphanedPhotos`).
    static func filename(of storedPath: String) -> String {
        URL(fileURLWithPath: storedPath).lastPathComponent
    }
}