//
//  ProfileViewModel.swift
//  suixinkan
//

import Foundation

/// 个人信息页 ViewModel，负责资料加载、编辑状态和提交更新。
final class ProfileViewModel {

    private(set) var userInfo: UserInfoResponse?
    private(set) var realNameInfo: RealNameInfo?
    private(set) var bankCardInfo: BankCardInfo?
    private(set) var isLoading = false
    private(set) var isSaving = false
    private(set) var isEditingProfile = false
    private(set) var editingNickname = ""
    private(set) var pendingAvatarData: Data?
    private(set) var pendingAvatarFileName: String?
    private(set) var avatarUploadProgress: Int?

    var onStateChange: (() -> Void)?

    var displayNickname: String {
        nonEmpty(userInfo?.nickname) ?? "未设置昵称"
    }

    var displayRealName: String {
        nonEmpty(userInfo?.realName) ?? "--"
    }

    var displayPhone: String {
        nonEmpty(userInfo?.phone) ?? AppStore.shared.phone.nonEmpty ?? "--"
    }

    var displayAvatarURL: String {
        nonEmpty(userInfo?.avatar) ?? AppStore.shared.avatar.nonEmpty ?? ""
    }

    var displayUID: String {
        let uid = AppStore.shared.userId.trimmingCharacters(in: .whitespacesAndNewlines)
        return uid.isEmpty ? "--" : uid
    }

    var accountDisplayName: String {
        let name = AppStore.shared.accountDisplayName.trimmingCharacters(in: .whitespacesAndNewlines)
        return name.isEmpty ? "--" : name
    }

    var currentScenicName: String {
        let name = AppStore.shared.currentScenicName.trimmingCharacters(in: .whitespacesAndNewlines)
        return name.isEmpty ? "--" : name
    }

    var accountStatusText: String {
        nonEmpty(userInfo?.statusName) ?? "--"
    }

    var showPhotographerFields: Bool {
        if AppStore.shared.isPhotographerRole {
            return true
        }
        if let roleName = nonEmpty(userInfo?.roleName) {
            return AppRoleCode.fromRoleName(roleName)?.isPhotographer == true || roleName == "摄影师"
        }
        return false
    }

    var realNameStatusText: String {
        guard let realNameInfo else { return "点击去实名认证" }
        switch realNameInfo.auditStatus {
        case 2: return "已实名认证"
        case 3: return "审核不通过"
        default: return "审核中"
        }
    }

    var bankCardDisplayText: String {
        guard let bankCardInfo else { return "点击绑定银行卡" }
        if bankCardInfo.auditStatus == 2 {
            let masked = Self.maskCardNumber(bankCardInfo.cardNumber)
            return "\(bankCardInfo.bankName) \(masked)"
        }
        let label = bankCardInfo.auditStatusLabel.trimmingCharacters(in: .whitespacesAndNewlines)
        return label.isEmpty ? "审核中" : label
    }

    func updateEditingNickname(_ value: String) {
        editingNickname = value
        notifyStateChange()
    }

    /// 重新加载用户资料，摄影师额外拉取实名与银行卡信息。
    func reload(api: ProfileAPI) async throws {
        guard !isLoading else { return }
        isLoading = true
        notifyStateChange()
        defer {
            isLoading = false
            notifyStateChange()
        }

        let info = try await api.userInfo()
        userInfo = info
        AppStore.shared.applyUserInfo(info)
        if !info.roleName.isEmpty {
            AppStore.shared.roleName = info.roleName
        }

        if showPhotographerFields {
            async let realName = api.realNameInfo()
            async let bankCard = api.bankCardInfo()
            let extra = try await (realName, bankCard)
            realNameInfo = extra.0.realNameInfo
            bankCardInfo = extra.1.bankCard
        } else {
            realNameInfo = nil
            bankCardInfo = nil
        }
    }

    func beginEditing() {
        editingNickname = displayNickname == "未设置昵称" ? "" : displayNickname
        isEditingProfile = true
        notifyStateChange()
    }

    func cancelEditing() {
        editingNickname = ""
        isEditingProfile = false
        clearPendingAvatar()
        notifyStateChange()
    }

    func prepareAvatarImage(data: Data, timestamp: TimeInterval = Date().timeIntervalSince1970) throws {
        let processed = try AvatarImageProcessor.process(data: data, timestamp: timestamp)
        pendingAvatarData = processed.data
        pendingAvatarFileName = processed.fileName
        if !isEditingProfile {
            beginEditing()
        } else {
            notifyStateChange()
        }
    }

    func saveProfile(api: ProfileAPI, uploader: any OSSUploadServing, scenicId: Int) async throws {
        let nextNickname = editingNickname.trimmingCharacters(in: .whitespacesAndNewlines)
        guard !nextNickname.isEmpty else {
            throw ProfileValidationError.emptyNickname
        }

        let nicknameChanged = nextNickname != displayNickname
        let avatarChanged = pendingAvatarData != nil
        guard nicknameChanged || avatarChanged else {
            cancelEditing()
            return
        }

        guard !isSaving else { return }
        isSaving = true
        avatarUploadProgress = avatarChanged ? 1 : nil
        notifyStateChange()
        defer {
            isSaving = false
            avatarUploadProgress = nil
            notifyStateChange()
        }

        let uploadedAvatarURL = try await uploadPendingAvatarIfNeeded(uploader: uploader, scenicId: scenicId)
        if let uploadedAvatarURL {
            try await api.updateUserAvatarURL(uploadedAvatarURL)
        }
        if nicknameChanged {
            try await api.updateUserInfo(nickname: nextNickname)
        }

        let previous = userInfo ?? UserInfoResponse()
        userInfo = UserInfoResponse(
            avatar: uploadedAvatarURL ?? previous.avatar,
            realName: previous.realName,
            phone: previous.phone,
            nickname: nextNickname,
            roleName: previous.roleName,
            status: previous.status,
            statusName: previous.statusName
        )
        AppStore.shared.userName = nextNickname
        if let uploadedAvatarURL {
            AppStore.shared.avatar = uploadedAvatarURL
        }
        clearPendingAvatar()
        cancelEditing()
    }

    func updatePassword(_ password: String, api: ProfileAPI) async throws {
        let nextPassword = password.trimmingCharacters(in: .whitespacesAndNewlines)
        guard nextPassword.count >= 6 else {
            throw ProfileValidationError.shortPassword
        }

        guard !isSaving else { return }
        isSaving = true
        notifyStateChange()
        defer {
            isSaving = false
            notifyStateChange()
        }

        try await api.updateUserInfo(password: nextPassword)
    }

    static func maskCardNumber(_ cardNumber: String) -> String {
        let digits = cardNumber.filter(\.isNumber)
        guard digits.count >= 4 else { return cardNumber }
        return "**** **** **** \(digits.suffix(4))"
    }

    private func uploadPendingAvatarIfNeeded(uploader: any OSSUploadServing, scenicId: Int) async throws -> String? {
        guard let pendingAvatarData else { return nil }
        let fileName = pendingAvatarFileName ?? "avatar_\(Int(Date().timeIntervalSince1970)).jpg"
        return try await uploader.uploadUserAvatar(data: pendingAvatarData, fileName: fileName, scenicId: scenicId) { [weak self] progress in
            self?.avatarUploadProgress = progress
            self?.notifyStateChange()
        }
    }

    private func clearPendingAvatar() {
        pendingAvatarData = nil
        pendingAvatarFileName = nil
        avatarUploadProgress = nil
    }

    private func nonEmpty(_ value: String?) -> String? {
        let text = value?.trimmingCharacters(in: .whitespacesAndNewlines) ?? ""
        return text.isEmpty ? nil : text
    }

    private func notifyStateChange() {
        onStateChange?()
    }
}

private extension String {
    var nonEmpty: String? {
        let text = trimmingCharacters(in: .whitespacesAndNewlines)
        return text.isEmpty ? nil : text
    }
}