import Foundation
import Postbox
import TelegramApi
import SwiftSignalKit

func _internal_installInteractiveReadMessagesAction(postbox: Postbox, stateManager: AccountStateManager, peerId: PeerId) -> Disposable {
    return postbox.installStoreMessageAction(peerId: peerId, { messages, transaction in
        var consumeMessageIds: [MessageId] = []
        var readReactionIds: [MessageId] = []
        readReactionIds.removeAll()
        
        var readMessageIndexByNamespace: [MessageId.Namespace: MessageIndex] = [:]
        
        for message in messages {
            if case let .Id(id) = message.id {
                var hasUnconsumedMention = false
                var hasUnconsumedContent = false
                var hasUnseenReactions = false
                
                if message.tags.contains(.unseenPersonalMessage) || message.tags.contains(.unseenReaction) {
                    inner: for attribute in message.attributes {
                        if let attribute = attribute as? ConsumablePersonalMentionMessageAttribute, !attribute.consumed, !attribute.pending {
                            hasUnconsumedMention = true
                        } else if let attribute = attribute as? ConsumableContentMessageAttribute, !attribute.consumed {
                            hasUnconsumedContent = true
                        } else if let attribute = attribute as? ReactionsMessageAttribute, attribute.hasUnseen {
                            hasUnseenReactions = true
                        }
                    }
                }
                
                if hasUnconsumedMention && !hasUnconsumedContent {
                    consumeMessageIds.append(id)
                }
                if hasUnseenReactions {
                    //readReactionIds.append(id)
                }
                
                if !message.flags.intersection(.IsIncomingMask).isEmpty {
                    let index = MessageIndex(id: id, timestamp: message.timestamp)
                    let current = readMessageIndexByNamespace[id.namespace]
                    if current == nil || current! < index {
                        readMessageIndexByNamespace[id.namespace] = index
                    }
                }
            }
        }
        
        for id in Set(consumeMessageIds + readReactionIds) {
            transaction.updateMessage(id, update: { currentMessage in
                var attributes = currentMessage.attributes
                if consumeMessageIds.contains(id) {
                    mentionsLoop: for j in 0 ..< attributes.count {
                        if let attribute = attributes[j] as? ConsumablePersonalMentionMessageAttribute {
                            attributes[j] = ConsumablePersonalMentionMessageAttribute(consumed: attribute.consumed, pending: true)
                            break mentionsLoop
                        }
                    }
                }
                var tags = currentMessage.tags
                if readReactionIds.contains(id) {
                    reactionsLoop: for j in 0 ..< attributes.count {
                        if let attribute = attributes[j] as? ReactionsMessageAttribute {
                            attributes[j] = attribute.withAllSeen()
                            break reactionsLoop
                        }
                    }
                    tags.remove(.unseenReaction)
                }
                return .update(StoreMessage(id: currentMessage.id, globallyUniqueId: currentMessage.globallyUniqueId, groupingKey: currentMessage.groupingKey, threadId: currentMessage.threadId, timestamp: currentMessage.timestamp, flags: StoreMessageFlags(currentMessage.flags), tags: tags, globalTags: currentMessage.globalTags, localTags: currentMessage.localTags, forwardInfo: currentMessage.forwardInfo.flatMap(StoreMessageForwardInfo.init), authorId: currentMessage.author?.id, text: currentMessage.text, attributes: attributes, media: currentMessage.media))
            })
            
            if consumeMessageIds.contains(id) {
                transaction.setPendingMessageAction(type: .consumeUnseenPersonalMessage, id: id, action: ConsumePersonalMessageAction())
            }
            if readReactionIds.contains(id) {
                transaction.setPendingMessageAction(type: .readReaction, id: id, action: ReadReactionAction())
            }
        }
        
        for (_, index) in readMessageIndexByNamespace {
            _internal_applyMaxReadIndexInteractively(transaction: transaction, stateManager: stateManager, index: index)
        }
    })
}

public struct VisibleMessageRange {
    public var lowerBound: MessageIndex
    public var upperBound: MessageIndex?
    
    public init(lowerBound: MessageIndex, upperBound: MessageIndex?) {
        self.lowerBound = lowerBound
        self.upperBound = upperBound
    }
    
    fileprivate func contains(index: MessageIndex) -> Bool {
        if index < lowerBound {
            return false
        }
        if let upperBound = self.upperBound {
            if index > upperBound {
                return false
            }
        }
        return true
    }
}

private final class StoreOrUpdateMessageActionImpl: StoreOrUpdateMessageAction {
    private let getVisibleRange: () -> VisibleMessageRange?
    private let didReadReactionsInMessages: ([MessageId: [ReactionsMessageAttribute.RecentPeer]]) -> Void
    
    init(getVisibleRange: @escaping () -> VisibleMessageRange?, didReadReactionsInMessages: @escaping ([MessageId: [ReactionsMessageAttribute.RecentPeer]]) -> Void) {
        self.getVisibleRange = getVisibleRange
        self.didReadReactionsInMessages = didReadReactionsInMessages
    }
    
    func addOrUpdate(messages: [StoreMessage], transaction: Transaction) {
        var readReactionIds: [MessageId: [ReactionsMessageAttribute.RecentPeer]] = [:]
        
        guard let visibleRange = self.getVisibleRange() else {
            return
        }
        
        for message in messages {
            guard let index = message.index else {
                continue
            }
            if !visibleRange.contains(index: index) {
                continue
            }
            
            if message.tags.contains(.unseenReaction) {
                inner: for attribute in message.attributes {
                    if let attribute = attribute as? ReactionsMessageAttribute, attribute.hasUnseen {
                        readReactionIds[index.id] = attribute.recentPeers
                    }
                }
            }
        }
        
        for id in readReactionIds.keys {
            transaction.updateMessage(id, update: { currentMessage in
                var attributes = currentMessage.attributes
                reactionsLoop: for j in 0 ..< attributes.count {
                    if let attribute = attributes[j] as? ReactionsMessageAttribute {
                        attributes[j] = attribute.withAllSeen()
                        break reactionsLoop
                    }
                }
                var tags = currentMessage.tags
                tags.remove(.unseenReaction)
                return .update(StoreMessage(id: currentMessage.id, globallyUniqueId: currentMessage.globallyUniqueId, groupingKey: currentMessage.groupingKey, threadId: currentMessage.threadId, timestamp: currentMessage.timestamp, flags: StoreMessageFlags(currentMessage.flags), tags: tags, globalTags: currentMessage.globalTags, localTags: currentMessage.localTags, forwardInfo: currentMessage.forwardInfo.flatMap(StoreMessageForwardInfo.init), authorId: currentMessage.author?.id, text: currentMessage.text, attributes: attributes, media: currentMessage.media))
            })
            transaction.setPendingMessageAction(type: .readReaction, id: id, action: ReadReactionAction())
        }
        
        self.didReadReactionsInMessages(readReactionIds)
    }
}

func _internal_installInteractiveReadReactionsAction(postbox: Postbox, stateManager: AccountStateManager, peerId: PeerId, getVisibleRange: @escaping () -> VisibleMessageRange?, didReadReactionsInMessages: @escaping ([MessageId: [ReactionsMessageAttribute.RecentPeer]]) -> Void) -> Disposable {
    return postbox.installStoreOrUpdateMessageAction(peerId: peerId, action: StoreOrUpdateMessageActionImpl(getVisibleRange: getVisibleRange, didReadReactionsInMessages: didReadReactionsInMessages))
}