using System.IO.Compression;
using System.Security.Claims;
using System.Text;
using System.Text.Json;
using MiaoJiZhang.Api.Contracts;
using MiaoJiZhang.Domain.Entities;
using MiaoJiZhang.Api.Services;
using MiaoJiZhang.Domain.Enums;
using MiaoJiZhang.Infrastructure.Persistence;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;

namespace MiaoJiZhang.Api.Controllers;

[ApiController]
[Authorize]
[Route("api/users/me")]
public class UsersController(
    AppDbContext db,
    JwtService jwt,
    AiPermissionService aiPermissions) : ControllerBase
{
    private long CurrentUserId =>
        long.Parse(User.FindFirstValue(ClaimTypes.NameIdentifier)
                   ?? User.FindFirstValue("sub")!);

    /// <summary>当前用户信息（含 AI 伙伴设置与模式）</summary>
    [HttpGet]
    public async Task<ActionResult<UserProfileResponse>> Me()
    {
        var user = await db.Users
            .Include(u => u.AiCompanion)
            .Include(u => u.FeaturePermissions)
            .FirstOrDefaultAsync(u => u.Id == CurrentUserId);
        if (user is null) return NotFound(new ApiError("USER_NOT_FOUND", "用户不存在"));

        return Ok(ToProfile(user));
    }

    /// <summary>完成首次引导：选模式 + 选 AI 伙伴（形象/性格/昵称）</summary>
    [HttpPost("onboarding")]
    public async Task<ActionResult<UserProfileResponse>> Onboarding(OnboardingRequest req)
    {
        var user = await db.Users
            .Include(u => u.AiCompanion)
            .Include(u => u.FeaturePermissions)
            .FirstOrDefaultAsync(u => u.Id == CurrentUserId);
        if (user is null) return NotFound(new ApiError("USER_NOT_FOUND", "用户不存在"));

        if (!await aiPermissions.IsEnabledAsync(CurrentUserId))
        {
            user.AppMode = AppMode.Normal;
            await db.SaveChangesAsync();
            return Ok(ToProfile(user));
        }

        if (!await db.AiAvatars.AnyAsync(a => a.Key == req.AvatarKey && a.IsEnabled))
            return BadRequest(new ApiError("AVATAR_INVALID", "形象不存在"));
        if (!await db.AiPersonas.AnyAsync(p => p.Key == req.PersonaKey && p.IsEnabled))
            return BadRequest(new ApiError("PERSONA_INVALID", "性格不存在"));

        user.AppMode = req.AppMode == "ai" ? AppMode.AiFirst : AppMode.Normal;
        user.AiCompanion ??= new AiCompanionSetting { UserId = user.Id };
        user.AiCompanion.AvatarKey = req.AvatarKey;
        user.AiCompanion.PersonaKey = req.PersonaKey;
        user.AiCompanion.CustomName = string.IsNullOrWhiteSpace(req.CustomName) ? null : req.CustomName.Trim();

        await db.SaveChangesAsync();
        return Ok(ToProfile(user));
    }

    /// <summary>切换 App 模式（决策：双模式可随时切换）</summary>
    [HttpPut("mode")]
    public async Task<ActionResult<UserProfileResponse>> SwitchMode(SwitchModeRequest req)
    {
        var user = await db.Users
            .Include(u => u.AiCompanion)
            .Include(u => u.FeaturePermissions)
            .FirstOrDefaultAsync(u => u.Id == CurrentUserId);
        if (user is null) return NotFound(new ApiError("USER_NOT_FOUND", "用户不存在"));

        if (req.AppMode == "ai" && !await aiPermissions.IsEnabledAsync(CurrentUserId))
            return StatusCode(403, new ApiError("AI_PERMISSION_DENIED", "当前账号未开通 AI 功能"));
        user.AppMode = req.AppMode == "ai" ? AppMode.AiFirst : AppMode.Normal;
        await db.SaveChangesAsync();
        return Ok(ToProfile(user));
    }

    /// <summary>更新 AI 伙伴设置（性格设置页 P5）</summary>
    [HttpPut("companion")]
    public async Task<ActionResult<UserProfileResponse>> UpdateCompanion(UpdateCompanionRequest req)
    {
        var user = await db.Users
            .Include(u => u.AiCompanion)
            .Include(u => u.FeaturePermissions)
            .FirstOrDefaultAsync(u => u.Id == CurrentUserId);
        if (user is null) return NotFound(new ApiError("USER_NOT_FOUND", "用户不存在"));
        if (!await aiPermissions.IsEnabledAsync(CurrentUserId))
            return StatusCode(403, new ApiError("AI_PERMISSION_DENIED", "当前账号未开通 AI 功能"));
        if (user.AiCompanion is null) return BadRequest(new ApiError("ONBOARDING_REQUIRED", "请先完成引导"));

        if (req.AvatarKey != null)
        {
            if (!await db.AiAvatars.AnyAsync(a => a.Key == req.AvatarKey && a.IsEnabled))
                return BadRequest(new ApiError("AVATAR_INVALID", "形象不存在"));
            user.AiCompanion.AvatarKey = req.AvatarKey;
        }
        if (req.PersonaKey != null)
        {
            if (!await db.AiPersonas.AnyAsync(p => p.Key == req.PersonaKey && p.IsEnabled))
                return BadRequest(new ApiError("PERSONA_INVALID", "性格不存在"));
            user.AiCompanion.PersonaKey = req.PersonaKey;
        }
        if (req.CustomName != null)
            user.AiCompanion.CustomName = string.IsNullOrWhiteSpace(req.CustomName) ? null : req.CustomName.Trim();
        if (req.RoastLevel is >= 0 and <= 100) user.AiCompanion.RoastLevel = req.RoastLevel.Value;
        if (req.StickerFrequency is >= 0 and <= 100) user.AiCompanion.StickerFrequency = req.StickerFrequency.Value;
        if (req.ProactiveLevel is >= 0 and <= 100) user.AiCompanion.ProactiveLevel = req.ProactiveLevel.Value;

        await db.SaveChangesAsync();
        return Ok(ToProfile(user));
    }

    [HttpPut("profile")]
    public async Task<ActionResult<UserProfileResponse>> UpdateProfile(UpdateProfileRequest req)
    {
        var user = await db.Users.Include(u => u.AiCompanion).Include(u => u.FeaturePermissions)
            .FirstOrDefaultAsync(u => u.Id == CurrentUserId);
        if (user is null) return NotFound(new ApiError("USER_NOT_FOUND", "用户不存在"));
        var nickname = req.Nickname?.Trim();
        if (nickname?.Length > 32)
            return BadRequest(new ApiError("NICKNAME_INVALID", "昵称最多 32 个字"));
        user.Nickname = string.IsNullOrWhiteSpace(nickname) ? null : nickname;
        await db.SaveChangesAsync();
        return Ok(ToProfile(user));
    }

    [HttpPut("password")]
    public async Task<ActionResult<AuthResponse>> ChangePassword(ChangePasswordRequest req)
    {
        if (req.NewPassword.Length < 6)
            return BadRequest(new ApiError("PASSWORD_TOO_SHORT", "新密码至少 6 位"));
        var user = await db.Users.FirstOrDefaultAsync(u => u.Id == CurrentUserId);
        if (user is null) return NotFound(new ApiError("USER_NOT_FOUND", "用户不存在"));
        if (!BCrypt.Net.BCrypt.Verify(req.CurrentPassword, user.PasswordHash))
            return Unauthorized(new ApiError("BAD_CREDENTIALS", "当前密码错误"));
        user.PasswordHash = BCrypt.Net.BCrypt.HashPassword(req.NewPassword);
        user.AuthVersion++;
        await db.SaveChangesAsync();
        var (token, expires) = jwt.Issue(user);
        return Ok(new AuthResponse(user.Id, user.Username, token, expires));
    }

    [HttpGet("export")]
    public async Task<IActionResult> Export()
    {
        var userId = CurrentUserId;
        var user = await db.Users.Include(u => u.AiCompanion).Include(u => u.FeaturePermissions)
            .FirstOrDefaultAsync(u => u.Id == userId);
        if (user is null) return NotFound(new ApiError("USER_NOT_FOUND", "用户不存在"));

        var ledgers = await db.Ledgers.Where(l => l.OwnerId == userId)
            .OrderBy(l => l.Id).ToListAsync();
        var transactions = await db.Transactions.IgnoreQueryFilters()
            .Include(t => t.Category)
            .Where(t => t.UserId == userId)
            .OrderBy(t => t.Id).ToListAsync();
        var budgets = await db.Budgets.Where(b => b.UserId == userId)
            .OrderBy(b => b.Id).ToListAsync();
        var categories = await db.Categories
            .Where(c => c.UserId == null || c.UserId == userId)
            .OrderBy(c => c.Type).ThenBy(c => c.SortOrder).ToListAsync();
        var messages = await db.ChatMessages.Where(m => m.UserId == userId)
            .OrderBy(m => m.Id).ToListAsync();

        var snapshot = new
        {
            formatVersion = 1,
            exportedAt = DateTime.UtcNow,
            timezone = "Asia/Shanghai",
            user = new
            {
                user.Id,
                user.Username,
                user.Nickname,
                appMode = user.AppMode.ToString(),
                user.CreatedAt,
                companion = user.AiCompanion is null ? null : new
                {
                    user.AiCompanion.AvatarKey,
                    user.AiCompanion.CustomName,
                    user.AiCompanion.PersonaKey,
                    user.AiCompanion.RoastLevel,
                    user.AiCompanion.StickerFrequency,
                },
            },
            ledgers = ledgers.Select(l => new
            {
                l.Id, l.Name, l.IconKey, l.IsDefault, l.CreatedAt,
            }),
            categories = categories.Select(c => new
            {
                c.Id, c.UserId, type = c.Type.ToString().ToLowerInvariant(),
                c.Name, c.IconKey, c.ColorKey, c.SortOrder, c.IsDeleted,
            }),
            transactions = transactions.Select(t => new
            {
                t.Id, t.LedgerId, t.CategoryId,
                type = t.Type.ToString().ToLowerInvariant(),
                transferDirection = t.TransferDirection.ToWire(),
                t.Counterparty, t.Amount, t.Note, t.PaymentMethod, t.OccurredAt,
                t.Provider, t.ProviderTransactionId, t.RecognitionOccurrenceId,
                t.EvidenceFingerprint, t.RecognitionConfidence,
                source = t.Source.ToString(), t.SourceText,
                t.IsDeleted, t.DeletedAt, t.CreatedAt, t.UpdatedAt,
            }),
            budgets = budgets.Select(b => new
            {
                b.Id, b.LedgerId, b.CategoryId, b.Period, b.Amount,
            }),
            chatMessages = messages.Select(m => new
            {
                m.Id, role = m.Role.ToString(), type = m.Type.ToString(),
                m.Content, m.TransactionId, m.CreatedAt,
            }),
        };

        var ledgerNames = ledgers.ToDictionary(l => l.Id, l => l.Name);
        var transactionCsv = new StringBuilder(
            "ID,账本,类型,转账方向,对方,金额,分类,备注,支付方式,发生时间,来源,已删除\r\n");
        foreach (var tx in transactions)
        {
            transactionCsv.AppendJoin(',', new[]
            {
                Csv(tx.Id),
                Csv(ledgerNames.GetValueOrDefault(tx.LedgerId, "")),
                Csv(tx.Type switch
                {
                    TransactionType.Income => "收入",
                    TransactionType.Transfer => "转账",
                    _ => "支出",
                }),
                Csv(tx.TransferDirection switch
                {
                    TransferDirection.In => "转入",
                    TransferDirection.Out => "转出",
                    _ => "",
                }),
                Csv(tx.Counterparty),
                Csv(tx.Amount),
                Csv(tx.Category.Name),
                Csv(tx.Note),
                Csv(tx.PaymentMethod),
                Csv(ChinaClock.ToLocal(tx.OccurredAt).ToString("yyyy-MM-dd HH:mm:ss")),
                Csv(tx.Source.ToString()),
                Csv(tx.IsDeleted ? "是" : "否"),
            }).Append("\r\n");
        }

        var categoryNames = categories.ToDictionary(c => c.Id, c => c.Name);
        var budgetCsv = new StringBuilder("ID,账本,周期,分类,金额\r\n");
        foreach (var budget in budgets)
        {
            budgetCsv.AppendJoin(',', new[]
            {
                Csv(budget.Id),
                Csv(ledgerNames.GetValueOrDefault(budget.LedgerId, "")),
                Csv(budget.Period == 0 ? "周期预算" : budget.Period.ToString()),
                Csv(budget.CategoryId.HasValue
                    ? categoryNames.GetValueOrDefault(budget.CategoryId.Value, "")
                    : "总预算"),
                Csv(budget.Amount),
            }).Append("\r\n");
        }

        await using var output = new MemoryStream();
        using (var archive = new ZipArchive(output, ZipArchiveMode.Create, true))
        {
            await WriteEntry(archive, "transactions.csv", transactionCsv.ToString(), new UTF8Encoding(true));
            await WriteEntry(archive, "budgets.csv", budgetCsv.ToString(), new UTF8Encoding(true));
            var json = JsonSerializer.Serialize(
                snapshot,
                new JsonSerializerOptions(JsonSerializerDefaults.Web) { WriteIndented = true });
            await WriteEntry(archive, "backup.json", json, new UTF8Encoding(false));
        }
        return File(
            output.ToArray(),
            "application/zip",
            $"miaoji-export-{ChinaClock.Now:yyyyMMdd-HHmmss}.zip");
    }

    [HttpPost("closure")]
    public Task<IActionResult> RequestAccountClosure(
        DeleteAccountRequest request) =>
        ScheduleAccountClosure(request, requireConfirmation: true);

    // 兼容旧客户端：不再立即物理删除，统一进入 15 天注销等待期。
    [HttpDelete]
    public Task<IActionResult> DeleteAccount(DeleteAccountRequest request) =>
        ScheduleAccountClosure(request, requireConfirmation: false);

    private async Task<IActionResult> ScheduleAccountClosure(
        DeleteAccountRequest request,
        bool requireConfirmation)
    {
        var user = await db.Users.FirstOrDefaultAsync(
            item => item.Id == CurrentUserId);
        if (user is null)
            return NotFound(new ApiError("USER_NOT_FOUND", "用户不存在"));
        if (!BCrypt.Net.BCrypt.Verify(request.Password, user.PasswordHash))
            return Unauthorized(new ApiError("BAD_CREDENTIALS", "密码错误"));
        if (requireConfirmation &&
            request.ConfirmationText?.Trim() != "注销账号")
            return BadRequest(new ApiError(
                "CONFIRMATION_INVALID",
                "请输入“注销账号”完成确认"));

        if (!user.AccountClosureScheduledAt.HasValue)
        {
            var now = DateTime.UtcNow;
            user.AccountClosureRequestedAt = now;
            user.AccountClosureScheduledAt = now.AddDays(15);
            user.AuthVersion++;
            await db.SaveChangesAsync();
        }

        return Accepted(new AccountClosureResponse(
            user.AccountClosureRequestedAt!.Value,
            user.AccountClosureScheduledAt.Value));
    }
    private static async Task WriteEntry(
        ZipArchive archive,
        string name,
        string content,
        Encoding encoding)
    {
        var entry = archive.CreateEntry(name, CompressionLevel.Fastest);
        await using var stream = entry.Open();
        await using var writer = new StreamWriter(stream, encoding);
        await writer.WriteAsync(content);
    }

    private static string Csv(object? value)
    {
        var text = value switch
        {
            null => "",
            IFormattable formattable => formattable.ToString(null, System.Globalization.CultureInfo.InvariantCulture),
            _ => value.ToString() ?? "",
        };
        if (text.Length > 0 && "=+-@".Contains(text[0])) text = "'" + text;
        return "\"" + text.Replace("\"", "\"\"") + "\"";
    }

    private static UserProfileResponse ToProfile(User u)
    {
        var aiEnabled = u.FeaturePermissions
            .FirstOrDefault(x => x.PermissionKey == FeaturePermissionKeys.Ai)?.IsEnabled ?? true;
        var quota = AiChatQuotaService.GetStatus(u);
        return new UserProfileResponse(
        u.Id,
        u.Username,
        u.Nickname,
        u.AppMode == AppMode.AiFirst ? "ai" : "normal",
        u.AiCompanion is null
            ? null
            : new AiCompanionDto(
                u.AiCompanion.AvatarKey,
                u.AiCompanion.PersonaKey,
                u.AiCompanion.CustomName,
                u.AiCompanion.RoastLevel,
                u.AiCompanion.StickerFrequency,
                u.AiCompanion.ProactiveLevel),
        u.AiCompanion is not null || !aiEnabled,
        new UserPermissionsDto(aiEnabled),
        new AiChatQuotaDto(
            quota.Limit,
            quota.Used,
            quota.Remaining,
            AiChatQuotaService.PeriodKey(quota.Period),
            quota.ResetAt));
    }
}