import CryptoKit
import Foundation

public struct RDAIIndexOptions: Sendable {
    public var scope: RDAIReadScope
    public var priorityResource: RDAIResourceIdentifier?

    public init(scope: RDAIReadScope, priorityResource: RDAIResourceIdentifier? = nil) {
        self.scope = scope
        self.priorityResource = priorityResource
    }
}

public enum RDAIIndexState: Equatable, Sendable {
    case notStarted
    case indexing(completedResources: Int, totalResources: Int)
    case paused(completedResources: Int, totalResources: Int)
    case ready
    case failed(RDAIError)
}

public struct RDAIRetrievalOptions: Sendable {
    public var maximumResults: Int
    public var scope: RDAIReadScope
    public var minimumScore: Double

    public init(maximumResults: Int = 4, scope: RDAIReadScope, minimumScore: Double = 0.01) {
        self.maximumResults = max(1, maximumResults)
        self.scope = scope
        self.minimumScore = min(max(minimumScore, 0), 1)
    }
}

public struct RDAIRetrievalMatch: Sendable, Identifiable {
    public let id: String
    public let passage: RDAIPassage
    public let score: Double
    public let lexicalScore: Double
    public let semanticScore: Double?

    public init(passage: RDAIPassage, score: Double, lexicalScore: Double, semanticScore: Double? = nil) {
        id = passage.id
        self.passage = passage
        self.score = score
        self.lexicalScore = lexicalScore
        self.semanticScore = semanticScore
    }
}

public enum RDAIContentHasher {
    public static func hash(_ text: String) -> String {
        SHA256.hash(data: Data(text.utf8)).map { String(format: "%02x", $0) }.joined()
    }
}

public actor RDAIInMemoryIndexStore {
    private var resources: [RDAIDocumentIdentifier: [RDAIResourceDescriptor]] = [:]
    private var passages: [RDAIDocumentIdentifier: [RDAIPassage]] = [:]
    private var entities: [RDAIDocumentIdentifier: [RDAIEntityMention]] = [:]

    public init() {}

    public func replace(
        document: RDAIDocumentDescriptor,
        resource: RDAIResourceDescriptor,
        analysis: RDAIAnalysisResult
    ) {
        var documentResources = resources[document.identifier] ?? []
        documentResources.removeAll { $0.identifier == resource.identifier }
        documentResources.append(resource)
        resources[document.identifier] = documentResources.sorted { $0.order < $1.order }

        var documentPassages = passages[document.identifier] ?? []
        documentPassages.removeAll { $0.resourceIdentifier == resource.identifier }
        documentPassages.append(contentsOf: analysis.passages)
        passages[document.identifier] = documentPassages

        var documentEntities = entities[document.identifier] ?? []
        documentEntities.removeAll { $0.locator.resourceIdentifier == resource.identifier }
        documentEntities.append(contentsOf: analysis.entityMentions)
        entities[document.identifier] = documentEntities
    }

    public func passages(for documentIdentifier: RDAIDocumentIdentifier) -> [RDAIPassage] {
        passages[documentIdentifier] ?? []
    }

    public func entities(for documentIdentifier: RDAIDocumentIdentifier) -> [RDAIEntityMention] {
        entities[documentIdentifier] ?? []
    }

    public func resourceOrder(
        for identifier: RDAIResourceIdentifier,
        documentIdentifier: RDAIDocumentIdentifier
    ) -> Int? {
        resources[documentIdentifier]?.first { $0.identifier == identifier }?.order
    }

    public func remove(documentIdentifier: RDAIDocumentIdentifier) {
        resources.removeValue(forKey: documentIdentifier)
        passages.removeValue(forKey: documentIdentifier)
        entities.removeValue(forKey: documentIdentifier)
    }
}

/// First implementation of the local indexing pipeline. Storage is deliberately
/// injectable so a SQLite-backed store can replace it without changing adapters.
@MainActor
public final class RDAIReaderService {
    public private(set) var state: RDAIIndexState = .notStarted {
        didSet { stateContinuations.values.forEach { $0.yield(state) } }
    }

    private let contentProvider: RDAIContentProvider
    private let analyzer: any RDAIAnalyzing
    private let store: RDAIInMemoryIndexStore
    private let persistentStore: RDAISQLiteIndexStore?
    private let generativeProvider: (any RDAIGenerativeProvider)?
    private let semanticScorer: (any RDAISemanticScoring)?
    private let configuration: RDAIReaderConfiguration
    private let diagnostics: (any RDAIDiagnosticsRecording)?
    private var stateContinuations: [UUID: AsyncStream<RDAIIndexState>.Continuation] = [:]
    private var pauseRequested = false
    private var resumeContinuation: CheckedContinuation<Void, Never>?

    public init(
        contentProvider: RDAIContentProvider,
        analyzer: some RDAIAnalyzing,
        semanticScorer: (any RDAISemanticScoring)? = nil,
        store: RDAIInMemoryIndexStore = .init(),
        persistentStore: RDAISQLiteIndexStore? = nil,
        generativeProvider: (any RDAIGenerativeProvider)? = nil,
        configuration: RDAIReaderConfiguration = .default,
        diagnostics: (any RDAIDiagnosticsRecording)? = nil
    ) {
        self.contentProvider = contentProvider
        self.analyzer = analyzer
        self.semanticScorer = semanticScorer
        self.store = store
        self.persistentStore = persistentStore
        self.generativeProvider = generativeProvider
        self.configuration = configuration
        self.diagnostics = diagnostics
    }

    public func stateUpdates() -> AsyncStream<RDAIIndexState> {
        let identifier = UUID()
        return AsyncStream { [weak self] continuation in
            guard let self else {
                continuation.finish()
                return
            }
            continuation.yield(self.state)
            self.stateContinuations[identifier] = continuation
            continuation.onTermination = { [weak self] _ in
                Task { @MainActor in self?.stateContinuations.removeValue(forKey: identifier) }
            }
        }
    }

    public func prepareIndex(options: RDAIIndexOptions) async throws {
        guard configuration.isAIEnabled else { throw RDAIError.disabled }
        let startedAt = Date()
        let document = contentProvider.aiDocumentDescriptor()
        var resources = try await contentProvider.aiResources().sorted { $0.order < $1.order }
        resources = prioritized(resources, preferred: options.priorityResource)
        let scopedResources = try await resourcesAllowed(by: options.scope, document: document, resources: resources)
        state = .indexing(completedResources: 0, totalResources: scopedResources.count)

        do {
            for (index, resource) in scopedResources.enumerated() {
                try Task.checkCancellation()
                await waitIfPaused(completed: index, total: scopedResources.count)
                try Task.checkCancellation()
                let sourceSnapshot = try await contentProvider.aiResourceSnapshot(for: resource.identifier)
                let snapshot = limited(sourceSnapshot, by: options.scope)
                guard !snapshot.sourceText.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty else {
                    state = .indexing(completedResources: index + 1, totalResources: scopedResources.count)
                    continue
                }
                if let persistentStore,
                   try await persistentStore.resourceHash(documentID: document.identifier, resourceID: resource.identifier) == snapshot.sourceHash {
                    try await persistentStore.saveCheckpoint(documentID: document.identifier, resourceOrder: resource.order)
                    state = .indexing(completedResources: index + 1, totalResources: scopedResources.count)
                    continue
                }
                let analysis = await analyzer.analyze(document: document, snapshot: snapshot)
                if let persistentStore {
                    try await persistentStore.replace(document: document, resource: resource, analysis: analysis, sourceHash: snapshot.sourceHash)
                    try await persistentStore.saveCheckpoint(documentID: document.identifier, resourceOrder: resource.order)
                } else {
                    await store.replace(document: document, resource: resource, analysis: analysis)
                }
                state = .indexing(completedResources: index + 1, totalResources: scopedResources.count)
            }
            state = .ready
            await record(stage: .indexing, startedAt: startedAt, count: scopedResources.count)
        } catch is CancellationError {
            state = .notStarted
            throw RDAIError.cancelled
        } catch let error as RDAIError {
            state = .failed(error)
            await record(stage: .indexing, startedAt: startedAt, errorCode: "rdai-error")
            throw error
        } catch {
            // Public errors must not expose paths, OCR text or SQLite details.
            let wrapped = RDAIError.indexingFailed("unexpected")
            state = .failed(wrapped)
            await record(stage: .indexing, startedAt: startedAt, errorCode: "indexing-failed")
            throw wrapped
        }
    }

    public func retrieve(query: String, options: RDAIRetrievalOptions) async -> [RDAIRetrievalMatch] {
        let document = contentProvider.aiDocumentDescriptor()
        let allPassages = await storedPassages(for: document.identifier)
        let filtered = await filter(allPassages, scope: options.scope, documentIdentifier: document.identifier)
        var matches: [RDAIRetrievalMatch] = []
        for passage in filtered {
            let score = lexicalScore(query: query, text: passage.text)
            let semantic = await semanticScorer?.score(query: query, text: passage.text, languageCode: passage.languageCode)
            let finalScore = semantic.map { 0.6 * score + 0.4 * $0 } ?? score
            guard finalScore >= options.minimumScore else { continue }
            matches.append(RDAIRetrievalMatch(passage: passage, score: finalScore, lexicalScore: score, semanticScore: semantic))
        }
        return matches.sorted {
            if $0.score == $1.score { return $0.passage.order < $1.passage.order }
            return $0.score > $1.score
        }
        .prefix(options.maximumResults)
        .map { $0 }
    }

    public func removeIndex() async {
        if let persistentStore { try? await persistentStore.remove(documentID: contentProvider.aiDocumentDescriptor().identifier) }
        else { await store.remove(documentIdentifier: contentProvider.aiDocumentDescriptor().identifier) }
        state = .notStarted
    }

    public func pauseIndexing() {
        pauseRequested = true
    }

    public func resumeIndexing() {
        pauseRequested = false
        resumeContinuation?.resume()
        resumeContinuation = nil
    }

    public func removeAllAIData() async {
        if let persistentStore { try? await persistentStore.removeAll() }
        else { await store.remove(documentIdentifier: contentProvider.aiDocumentDescriptor().identifier) }
        state = .notStarted
    }

    public func storageBytes() async -> Int64 {
        await persistentStore?.storageBytes() ?? 0
    }

    public func showCitation(_ citation: RDAICitation) async throws {
        try await contentProvider.aiShowCitationHighlight(citation)
    }

    public func clearCitationHighlight() {
        contentProvider.aiClearCitationHighlight()
    }

    public func availability(for capability: RDAICapability, locale: Locale = .current) async -> RDAICapabilityAvailability {
        guard configuration.isAIEnabled else { return .unavailable(reason: .providerNotInstalled) }
        switch capability {
        case .languageAnalysis, .entityExtraction, .lexicalSearch: return .available
        case .semanticSearch:
            return semanticScorer == nil ? .degraded(reason: .embeddingAssetsUnavailable) : .available
        case .summarization, .questionAnswering, .characterRelationships:
            guard let generativeProvider else { return .degraded(reason: .providerNotInstalled) }
            return await generativeProvider.availability(for: capability, locale: locale)
        }
    }

    public func summarize(scope: RDAIReadScope, length: RDAISummaryLength) async throws -> RDAISummary {
        guard configuration.isAIEnabled else { throw RDAIError.disabled }
        let document = contentProvider.aiDocumentDescriptor()
        let cacheKey = artifactKey(document: document, scope: scope, suffix: "summary|\(length.rawValue)")
        if configuration.storesGeneratedArtifacts,
           let persistentStore,
           let data = try? await persistentStore.artifact(documentID: document.identifier, key: cacheKey),
           let cached = try? JSONDecoder().decode(RDAISummary.self, from: data) { return cached }
        let passages = try await passages(for: scope, limit: length == .brief ? 2 : (length == .standard ? 4 : 6))
        let metadata = generationMetadata(provider: generativeProvider?.identifier ?? "extractive")
        if let generativeProvider,
           case .available = await generativeProvider.availability(for: .summarization, locale: .current),
           case let .summary(overview, statements) = try await generativeProvider.generate(.init(task: .summary(length), passages: passages, scope: scope)) {
            let validated = validatedStatements(statements, passages: passages)
            guard !validated.isEmpty else { throw RDAIError.insufficientEvidence }
            let result = RDAISummary(title: document.title, overview: overview, keyPoints: validated, citations: citations(for: passages), metadata: metadata)
            try? await saveArtifact(result, document: document, key: cacheKey)
            return result
        }
        let statements = passages.map { RDAISourcedStatement(text: $0.text, citationIdentifiers: [$0.id]) }
        let result = RDAISummary(title: document.title, overview: passages.first?.text ?? "暂无可总结的已读内容。", keyPoints: statements, citations: citations(for: passages), metadata: metadata)
        try? await saveArtifact(result, document: document, key: cacheKey)
        return result
    }

    public func answer(question: String, scope: RDAIReadScope) async throws -> RDAIAnswer {
        guard configuration.isAIEnabled else { throw RDAIError.disabled }
        let document = contentProvider.aiDocumentDescriptor()
        let cacheKey = artifactKey(document: document, scope: scope, suffix: "answer|\(RDAIContentHasher.hash(question))")
        if configuration.storesGeneratedArtifacts,
           let persistentStore,
           let data = try? await persistentStore.artifact(documentID: document.identifier, key: cacheKey),
           let cached = try? JSONDecoder().decode(RDAIAnswer.self, from: data) { return cached }
        let matches = await retrieve(query: question, options: .init(maximumResults: configuration.maximumRetrievedPassages, scope: scope))
        let passages = matches.map(\.passage)
        let metadata = generationMetadata(provider: generativeProvider?.identifier ?? "extractive")
        guard !passages.isEmpty else { return RDAIAnswer(status: .insufficientEvidence, text: "在当前阅读范围内未找到足够证据。", statements: [], citations: [], metadata: metadata) }
        if let generativeProvider,
           case .available = await generativeProvider.availability(for: .questionAnswering, locale: .current),
           case let .answer(text, statements) = try await generativeProvider.generate(.init(task: .answer, userText: question, passages: passages, scope: scope)) {
            let validated = validatedStatements(statements, passages: passages)
            guard !validated.isEmpty else { return RDAIAnswer(status: .insufficientEvidence, text: "模型结果缺少可验证的原文证据。", statements: [], citations: [], metadata: metadata) }
            let result = RDAIAnswer(status: .answered, text: text, statements: validated, citations: citations(for: passages), metadata: metadata)
            try? await saveArtifact(result, document: document, key: cacheKey)
            return result
        }
        let statements = passages.map { RDAISourcedStatement(text: $0.text, citationIdentifiers: [$0.id]) }
        let result = RDAIAnswer(status: .answered, text: "以下内容与问题最相关：", statements: statements, citations: citations(for: passages), metadata: metadata)
        try? await saveArtifact(result, document: document, key: cacheKey)
        return result
    }

    public func characters(scope: RDAIReadScope) async -> [RDAICharacter] {
        let document = contentProvider.aiDocumentDescriptor()
        let mentions = (await storedEntities(for: document.identifier)).filter { $0.kind == .person }
        let grouped = Dictionary(grouping: mentions, by: { canonicalCharacterName($0.normalizedName) })
        return grouped.compactMap { (name, values) -> RDAICharacter? in
            guard let first = values.first else { return nil }
            let evidence = values.prefix(3).map { mention in
                RDAICitation(passageIdentifier: mention.id, quote: mention.surfaceText, locator: mention.locator)
            }
            return RDAICharacter(id: RDAIContentHasher.hash(name), displayName: first.surfaceText, aliases: Array(Set(values.map(\.surfaceText))).sorted(), description: "在已读内容中出现 \(values.count) 次。", firstAppearance: evidence.first, evidence: evidence)
        }.sorted { $0.displayName < $1.displayName }
    }

    /// Conservative local relationship extraction: entities must co-occur in
    /// one allowed passage. It never promotes co-occurrence to a fact.
    public func relationships(scope: RDAIReadScope) async -> [RDAIRelationship] {
        let document = contentProvider.aiDocumentDescriptor()
        let passages = await filter(await storedPassages(for: document.identifier), scope: scope, documentIdentifier: document.identifier)
        let mentions = (await storedEntities(for: document.identifier)).filter { $0.kind == .person }
        var evidenceByPair: [String: [RDAICitation]] = [:]
        for passage in passages {
            let names = Array(Set(mentions.filter {
                $0.locator.resourceIdentifier == passage.resourceIdentifier && $0.locator.textRange.intersects(passage.locator.textRange)
            }.map { canonicalCharacterName($0.normalizedName) })).sorted()
            guard names.count > 1 else { continue }
            for left in names.indices {
                for right in names.indices where right > left {
                    let key = "\(names[left])|\(names[right])"
                    evidenceByPair[key, default: []].append(citation(for: passage))
                }
            }
        }
        return evidenceByPair.compactMap { key, evidence in
            let names = key.split(separator: "|", maxSplits: 1).map(String.init)
            guard names.count == 2, !evidence.isEmpty else { return nil }
            return RDAIRelationship(id: RDAIContentHasher.hash(key), sourceCharacterIdentifier: RDAIContentHasher.hash(names[0]), targetCharacterIdentifier: RDAIContentHasher.hash(names[1]), label: "共同出现", status: .possible, evidence: Array(evidence.prefix(3)))
        }.sorted { $0.id < $1.id }
    }

    private func passages(for scope: RDAIReadScope, limit: Int) async throws -> [RDAIPassage] {
        let document = contentProvider.aiDocumentDescriptor()
        let stored = await storedPassages(for: document.identifier)
        let all = await filter(stored, scope: scope, documentIdentifier: document.identifier)
        guard !all.isEmpty else { throw RDAIError.insufficientEvidence }
        return Array(all.sorted { $0.order < $1.order }.prefix(limit))
    }

    private func citations(for passages: [RDAIPassage]) -> [RDAICitation] { passages.map(citation(for:)) }
    private func citation(for passage: RDAIPassage) -> RDAICitation { RDAICitation(passageIdentifier: passage.id, quote: passage.text, locator: passage.locator) }
    private func validatedStatements(_ statements: [RDAISourcedStatement], passages: [RDAIPassage]) -> [RDAISourcedStatement] {
        let identifiers = Set(passages.map(\.id))
        return statements.compactMap { statement in
            let citations = statement.citationIdentifiers.filter { identifiers.contains($0) }
            guard !citations.isEmpty, !statement.text.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty else { return nil }
            return RDAISourcedStatement(id: statement.id, text: statement.text, citationIdentifiers: citations)
        }
    }
    private func canonicalCharacterName(_ value: String) -> String {
        let compact = value.unicodeScalars.filter { CharacterSet.alphanumerics.contains($0) || (0x4E00...0x9FFF).contains($0.value) }
        var name = String(String.UnicodeScalarView(compact)).lowercased()
        // Only remove explicit honorific suffixes; ambiguous aliases remain
        // distinct so the UI does not silently merge two people.
        for suffix in ["先生", "女士", "小姐", "老师", "教授", "博士", "将军"] where name.hasSuffix(suffix) && name.count > suffix.count {
            name.removeLast(suffix.count)
            break
        }
        return name
    }
    private func generationMetadata(provider: String) -> RDAIGenerationMetadata { .init(providerIdentifier: provider, promptIdentifier: "rdai.evidence.v1", promptVersion: 1, scopeHash: RDAIContentHasher.hash(contentProvider.aiDocumentDescriptor().identifier.rawValue)) }
    private func artifactKey(document: RDAIDocumentDescriptor, scope: RDAIReadScope, suffix: String) -> String {
        let scopeData = (try? JSONEncoder().encode(scope)).map { String(data: $0, encoding: .utf8) } ?? ""
        return RDAIContentHasher.hash("\(document.contentRevision)|\(scopeData)|rdai.evidence.v1|\(generativeProvider?.identifier ?? "extractive")|\(suffix)")
    }
    private func saveArtifact<T: Encodable>(_ value: T, document: RDAIDocumentDescriptor, key: String) async throws {
        guard configuration.storesGeneratedArtifacts, let persistentStore else { return }
        try await persistentStore.saveArtifact(documentID: document.identifier, key: key, payload: JSONEncoder().encode(value))
    }
    private func record(stage: RDAIDiagnosticStage, startedAt: Date, errorCode: String? = nil, count: Int = 0) async {
        guard configuration.diagnosticsLevel != .disabled, let diagnostics else { return }
        await diagnostics.record(.init(documentHash: RDAIContentHasher.hash(contentProvider.aiDocumentDescriptor().identifier.rawValue), stage: stage, durationMilliseconds: Int(Date().timeIntervalSince(startedAt) * 1_000), errorCode: errorCode, count: count))
    }

    private func prioritized(
        _ resources: [RDAIResourceDescriptor],
        preferred: RDAIResourceIdentifier?
    ) -> [RDAIResourceDescriptor] {
        guard let preferred else { return resources }
        return resources.sorted { lhs, rhs in
            if lhs.identifier == preferred { return true }
            if rhs.identifier == preferred { return false }
            return lhs.order < rhs.order
        }
    }

    private func waitIfPaused(completed: Int, total: Int) async {
        guard pauseRequested else { return }
        state = .paused(completedResources: completed, totalResources: total)
        await withTaskCancellationHandler(operation: {
            await withCheckedContinuation { continuation in
                resumeContinuation = continuation
            }
        }, onCancel: { [weak self] in
            Task { @MainActor in self?.resumeIndexing() }
        })
        state = .indexing(completedResources: completed, totalResources: total)
    }

    private func resourcesAllowed(
        by scope: RDAIReadScope,
        document: RDAIDocumentDescriptor,
        resources: [RDAIResourceDescriptor]
    ) async throws -> [RDAIResourceDescriptor] {
        guard !scope.includesWholeDocument else { return resources }
        guard let upperBound = scope.upperBound,
              upperBound.documentIdentifier == document.identifier,
              let boundary = resources.first(where: { $0.identifier == upperBound.resourceIdentifier }) else {
            return []
        }
        return resources.filter { $0.order <= boundary.order }
    }

    private func limited(_ snapshot: RDAIResourceSnapshot, by scope: RDAIReadScope) -> RDAIResourceSnapshot {
        guard !scope.includesWholeDocument,
              let upperBound = scope.upperBound,
              upperBound.resourceIdentifier == snapshot.descriptor.identifier else {
            return snapshot
        }
        let length = min(max(upperBound.textRange.upperBound, 0), snapshot.sourceText.utf16.count)
        let source = (snapshot.sourceText as NSString).substring(to: length)
        let availableRange = RDAITextRange(location: 0, length: length)
        let runs = snapshot.locatorRuns.filter { $0.textRange.intersects(availableRange) }
        return RDAIResourceSnapshot(
            descriptor: snapshot.descriptor,
            sourceText: source,
            sourceHash: RDAIContentHasher.hash(source),
            locatorRuns: runs
        )
    }

    private func filter(
        _ passages: [RDAIPassage],
        scope: RDAIReadScope,
        documentIdentifier: RDAIDocumentIdentifier
    ) async -> [RDAIPassage] {
        guard !scope.includesWholeDocument else { return passages }
        guard let upperBound = scope.upperBound,
              upperBound.documentIdentifier == documentIdentifier,
              let boundaryOrder = await resourceOrder(for: upperBound.resourceIdentifier, documentIdentifier: documentIdentifier) else {
            return []
        }
        return await withTaskGroup(of: (RDAIPassage, Int?).self) { group in
            for passage in passages {
                group.addTask { [store] in
                    let order = await self.resourceOrder(for: passage.resourceIdentifier, documentIdentifier: documentIdentifier)
                    return (passage, order)
                }
            }
            var allowed: [RDAIPassage] = []
            for await (passage, order) in group {
                guard let order, order <= boundaryOrder else { continue }
                if passage.resourceIdentifier == upperBound.resourceIdentifier,
                   passage.locator.textRange.location >= upperBound.textRange.upperBound {
                    continue
                }
                allowed.append(passage)
            }
            return allowed
        }
    }

    private func resourceOrder(for identifier: RDAIResourceIdentifier, documentIdentifier: RDAIDocumentIdentifier) async -> Int? {
        if let persistentStore { return try? await persistentStore.resourceOrder(documentID: documentIdentifier, resourceID: identifier) }
        return await store.resourceOrder(for: identifier, documentIdentifier: documentIdentifier)
    }

    private func storedPassages(for identifier: RDAIDocumentIdentifier) async -> [RDAIPassage] {
        if let persistentStore { return (try? await persistentStore.passages(documentID: identifier)) ?? [] }
        return await store.passages(for: identifier)
    }

    private func storedEntities(for identifier: RDAIDocumentIdentifier) async -> [RDAIEntityMention] {
        if let persistentStore { return (try? await persistentStore.entities(documentID: identifier)) ?? [] }
        return await store.entities(for: identifier)
    }

    private func lexicalScore(query: String, text: String) -> Double {
        let trimmed = query.trimmingCharacters(in: .whitespacesAndNewlines)
        guard !trimmed.isEmpty else { return 0 }
        let normalizedText = text.folding(options: [.caseInsensitive, .diacriticInsensitive], locale: .current)
        let normalizedQuery = trimmed.folding(options: [.caseInsensitive, .diacriticInsensitive], locale: .current)
        if normalizedText.localizedCaseInsensitiveContains(normalizedQuery) { return 1 }
        let terms = normalizedQuery.split(whereSeparator: { $0.isWhitespace || $0.isNewline }).map(String.init)
        guard !terms.isEmpty else { return 0 }
        let matches = terms.filter { normalizedText.localizedCaseInsensitiveContains($0) }.count
        return Double(matches) / Double(terms.count)
    }
}