import Foundation

#if os(macOS)
import SweetCookieKit

public enum ManusCookieImporter {
    private static let log = CodexBarLog.logger(LogCategories.provider(.manus, scope: "cookie"))
    private static let cookieClient = BrowserCookieClient()
    private static let cookieDomains = ["manus.im", "www.manus.im"]
    private static let cookieImportOrder: BrowserCookieImportOrder =
        ProviderDefaults.metadata[.manus]?.browserCookieOrder ?? Browser.defaultImportOrder
    #if DEBUG
    final class ImportSessionOverrideStore: @unchecked Sendable {
        let importSession: (BrowserDetection, ((String) -> Void)?) throws -> SessionInfo

        init(importSession: @escaping (BrowserDetection, ((String) -> Void)?) throws -> SessionInfo) {
            self.importSession = importSession
        }
    }

    final class ImportSessionsOverrideStore: @unchecked Sendable {
        let importSessions: (BrowserDetection, ((String) -> Void)?) throws -> [SessionInfo]

        init(importSessions: @escaping (BrowserDetection, ((String) -> Void)?) throws -> [SessionInfo]) {
            self.importSessions = importSessions
        }
    }

    @TaskLocal private static var taskImportSessionOverrideStore: ImportSessionOverrideStore?
    @TaskLocal private static var taskImportSessionsOverrideStore: ImportSessionsOverrideStore?

    static func withImportSessionOverrideForTesting<T>(
        _ override: ((BrowserDetection, ((String) -> Void)?) throws -> SessionInfo)?,
        operation: () async throws -> T) async rethrows -> T
    {
        try await self.$taskImportSessionOverrideStore.withValue(override.map(ImportSessionOverrideStore.init)) {
            try await operation()
        }
    }

    static func withImportSessionsOverrideForTesting<T>(
        _ override: ((BrowserDetection, ((String) -> Void)?) throws -> [SessionInfo])?,
        operation: () async throws -> T) async rethrows -> T
    {
        try await self.$taskImportSessionsOverrideStore.withValue(override.map(ImportSessionsOverrideStore.init)) {
            try await operation()
        }
    }
    #endif

    public struct SessionInfo: Sendable {
        public let cookies: [HTTPCookie]
        public let sourceLabel: String

        public init(cookies: [HTTPCookie], sourceLabel: String) {
            self.cookies = cookies
            self.sourceLabel = sourceLabel
        }

        public var sessionToken: String? {
            ManusCookieHeader.sessionToken(from: self.cookies)
        }
    }

    public static func importSessions(
        browserDetection: BrowserDetection = BrowserDetection(),
        logger: ((String) -> Void)? = nil) throws -> [SessionInfo]
    {
        #if DEBUG
        if let override = self.taskImportSessionsOverrideStore?.importSessions {
            return try override(browserDetection, logger)
        }
        if let override = self.taskImportSessionOverrideStore?.importSession {
            return try [override(browserDetection, logger)]
        }
        #endif

        var sessions: [SessionInfo] = []
        let candidates = self.cookieImportOrder.cookieImportCandidates(using: browserDetection)
        for browserSource in candidates {
            do {
                let perSource = try self.importSessions(from: browserSource, logger: logger)
                sessions.append(contentsOf: perSource)
            } catch {
                BrowserCookieAccessGate.recordIfNeeded(error)
                self.emit(
                    "\(browserSource.displayName) cookie import failed: \(error.localizedDescription)",
                    logger: logger)
            }
        }

        guard !sessions.isEmpty else {
            throw ManusCookieImportError.noCookies
        }
        return sessions
    }

    public static func importSessions(
        from browserSource: Browser,
        logger: ((String) -> Void)? = nil) throws -> [SessionInfo]
    {
        let query = BrowserCookieQuery(domains: self.cookieDomains)
        let log: (String) -> Void = { message in self.emit(message, logger: logger) }
        let sources = try Self.cookieClient.codexBarRecords(
            matching: query,
            in: browserSource,
            logger: log)

        var sessions: [SessionInfo] = []
        let grouped = Dictionary(grouping: sources, by: { $0.store.profile.id })
        let sortedGroups = grouped.values.sorted { lhs, rhs in
            self.mergedLabel(for: lhs) < self.mergedLabel(for: rhs)
        }

        for group in sortedGroups where !group.isEmpty {
            let label = self.mergedLabel(for: group)
            let mergedRecords = self.mergeRecords(group)
            guard !mergedRecords.isEmpty else { continue }
            let httpCookies = BrowserCookieClient.makeHTTPCookies(mergedRecords, origin: query.origin)
            guard !httpCookies.isEmpty else { continue }

            let session = SessionInfo(cookies: httpCookies, sourceLabel: label)
            guard let token = session.sessionToken else {
                continue
            }

            log("Found \(ManusCookieHeader.sessionCookieName) cookie in \(label)")
            if !token.isEmpty {
                sessions.append(session)
            }
        }

        return sessions
    }

    public static func importSession(
        browserDetection: BrowserDetection = BrowserDetection(),
        logger: ((String) -> Void)? = nil) throws -> SessionInfo
    {
        let sessions = try self.importSessions(browserDetection: browserDetection, logger: logger)
        guard let first = sessions.first else {
            throw ManusCookieImportError.noCookies
        }
        return first
    }

    public static func hasSession(
        browserDetection: BrowserDetection = BrowserDetection(),
        logger: ((String) -> Void)? = nil) -> Bool
    {
        do {
            _ = try self.importSession(browserDetection: browserDetection, logger: logger)
            return true
        } catch {
            return false
        }
    }

    private static func emit(_ message: String, logger: ((String) -> Void)?) {
        logger?("[manus-cookie] \(message)")
        self.log.debug(message)
    }

    private static func mergedLabel(for sources: [BrowserCookieStoreRecords]) -> String {
        guard let base = sources.map(\.label).min() else { return "Unknown" }
        if base.hasSuffix(" (Network)") {
            return String(base.dropLast(" (Network)".count))
        }
        return base
    }

    private static func mergeRecords(_ sources: [BrowserCookieStoreRecords]) -> [BrowserCookieRecord] {
        let sortedSources = sources.sorted { lhs, rhs in
            self.storePriority(lhs.store.kind) < self.storePriority(rhs.store.kind)
        }
        var mergedByKey: [String: BrowserCookieRecord] = [:]
        for source in sortedSources {
            for record in source.records {
                let key = self.recordKey(record)
                if let existing = mergedByKey[key] {
                    if self.shouldReplace(existing: existing, candidate: record) {
                        mergedByKey[key] = record
                    }
                } else {
                    mergedByKey[key] = record
                }
            }
        }
        return Array(mergedByKey.values)
    }

    private static func storePriority(_ kind: BrowserCookieStoreKind) -> Int {
        switch kind {
        case .network: 0
        case .primary: 1
        case .safari: 2
        }
    }

    private static func recordKey(_ record: BrowserCookieRecord) -> String {
        "\(record.name)|\(record.domain)|\(record.path)"
    }

    private static func shouldReplace(existing: BrowserCookieRecord, candidate: BrowserCookieRecord) -> Bool {
        switch (existing.expires, candidate.expires) {
        case let (lhs?, rhs?): rhs > lhs
        case (nil, .some): true
        case (.some, nil): false
        case (nil, nil): false
        }
    }
}

enum ManusCookieImportError: LocalizedError {
    case noCookies

    var errorDescription: String? {
        switch self {
        case .noCookies:
            "No Manus session cookies found in browsers. Please log into manus.im."
        }
    }
}
#endif
