import SwiftUI

/// 福利:金币余额(只进不出,无提现出口)+ 每日签到 + 任务。未登录拦截。
struct WelfareView: View {
    @Environment(SessionStore.self) private var session
    @State private var vm = WelfareViewModel()

    var body: some View {
        NavigationStack {
            Group {
                if session.isLoggedIn {
                    content
                } else {
                    LoginRequiredView(message: "登录后领取签到与任务奖励,查看省钱战绩")
                }
            }
            .navigationTitle("福利")
        }
        .task(id: session.isLoggedIn) {
            // 登录态变化(含换用户)/ 每次进入都重载;登出清空,防残留上一用户数据
            if session.isLoggedIn {
                await vm.loadAll()
            } else {
                vm.reset()
            }
        }
    }

    @ViewBuilder
    private var content: some View {
        List {
            Section { coinCard }
            Section("每日签到") { signinSection }
            Section("任务") {
                if vm.tasks.isEmpty {
                    Text("暂无任务").font(.subheadline).foregroundStyle(.secondary)
                } else {
                    ForEach(vm.tasks) { taskRow($0) }
                }
            }
        }
        .listStyle(.insetGrouped)
        .refreshable { await vm.loadAll() }
        .overlay(alignment: .bottom) { toastView }
    }

    private var coinCard: some View {
        NavigationLink { CoinHistoryView() } label: {
            HStack(spacing: 12) {
                Image(systemName: "circle.hexagongrid.fill")
                    .font(.title2)
                    .foregroundStyle(AppColors.coin)
                VStack(alignment: .leading, spacing: 2) {
                    Text("我的金币").font(.caption).foregroundStyle(.secondary)
                    Text("\(vm.account?.coinBalance ?? 0)").font(.title3.bold())
                }
                Spacer()
                Text("累计赚 \(vm.account?.totalCoinEarned ?? 0)")
                    .font(.caption).foregroundStyle(.secondary)
            }
        }
    }

    @ViewBuilder
    private var signinSection: some View {
        VStack(spacing: 14) {
            if let steps = vm.signin?.steps, !steps.isEmpty {
                HStack(alignment: .top) {
                    ForEach(steps, id: \.day) { step in
                        VStack(spacing: 4) {
                            ZStack {
                                Circle().fill(circleColor(step.status)).frame(width: 34, height: 34)
                                if step.status == "claimed" {
                                    Image(systemName: "checkmark").font(.caption).foregroundStyle(.white)
                                } else {
                                    Text("\(step.coin)")
                                        .font(.caption2)
                                        .foregroundStyle(step.status == "today" ? .black : AppColors.gray500)
                                }
                            }
                            Text("第\(step.day)天").font(.caption2).foregroundStyle(.secondary)
                        }
                        .frame(maxWidth: .infinity)
                    }
                }
            }
            Button {
                Task { await vm.doSignin() }
            } label: {
                Text(signinButtonText)
                    .font(.subheadline.bold())
                    .frame(maxWidth: .infinity)
                    .padding(.vertical, 12)
                    .background(signinEnabled ? AppColors.primary : AppColors.gray200)
                    .foregroundStyle(signinEnabled ? .black : AppColors.gray500)
                    .clipShape(RoundedRectangle(cornerRadius: 10))
            }
            .disabled(!signinEnabled)
        }
        .padding(.vertical, 4)
    }

    private func taskRow(_ task: TaskDTO) -> some View {
        HStack {
            VStack(alignment: .leading, spacing: 2) {
                Text(WelfareCatalog.taskTitle(task.taskKey)).font(.subheadline)
                let desc = WelfareCatalog.taskDesc(task.taskKey)
                if !desc.isEmpty {
                    Text(desc).font(.caption).foregroundStyle(.secondary)
                }
            }
            Spacer()
            if task.claimed {
                Text("已领取").font(.caption).foregroundStyle(.secondary)
            } else {
                Button {
                    Task { await vm.claimTask(task.taskKey) }
                } label: {
                    Text("领\(task.coin)金币")
                        .font(.caption.bold())
                        .padding(.horizontal, 12)
                        .padding(.vertical, 6)
                        .background(AppColors.primary)
                        .foregroundStyle(.black)
                        .clipShape(Capsule())
                }
                .buttonStyle(.plain)
            }
        }
    }

    @ViewBuilder
    private var toastView: some View {
        if let toast = vm.toast {
            Text(toast)
                .font(.subheadline)
                .padding(.horizontal, 16)
                .padding(.vertical, 10)
                .background(.black.opacity(0.8))
                .foregroundStyle(.white)
                .clipShape(Capsule())
                .padding(.bottom, 30)
                .task(id: toast) {
                    try? await Task.sleep(for: .seconds(2))
                    vm.clearToast()
                }
        }
    }

    private var signinEnabled: Bool {
        vm.signin?.canClaim == true && !vm.signinInProgress
    }

    private var signinButtonText: String {
        if vm.signin?.todaySigned == true { return "今日已签到" }
        if let coin = vm.signin?.todayCoin { return "签到领 \(coin) 金币" }
        return "签到"
    }

    private func circleColor(_ status: String) -> Color {
        switch status {
        case "claimed": return AppColors.success
        case "today": return AppColors.primary
        default: return AppColors.gray200
        }
    }
}