using MiaoJiZhang.Api.Contracts;
using MiaoJiZhang.Api.Services;
using MiaoJiZhang.Domain.Entities;
using MiaoJiZhang.Domain.Enums;
using MiaoJiZhang.Infrastructure.Persistence;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.RateLimiting;
using Microsoft.EntityFrameworkCore;

namespace MiaoJiZhang.Api.Controllers;

[ApiController]
[EnableRateLimiting("auth")]
[Route("api/auth")]
public class AuthController(AppDbContext db, JwtService jwt) : ControllerBase
{
    [HttpPost("register")]
    public async Task<ActionResult<AuthResponse>> Register(RegisterRequest req)
    {
        if (!req.AgreedToTerms)
            return BadRequest(new ApiError("TERMS_NOT_ACCEPTED", "请先阅读并同意用户协议与隐私政策"));
        if (req.Username.Length is < 3 or > 32) return BadRequest(new ApiError("USERNAME_INVALID", "用户名长度需在 3-32 之间"));
        if (req.Password.Length < 6) return BadRequest(new ApiError("PASSWORD_TOO_SHORT", "密码至少 6 位"));
        if (await db.Users.AnyAsync(u => u.Username == req.Username)) return Conflict(new ApiError("USERNAME_TAKEN", "用户名已被占用"));

        var now = DateTime.UtcNow;
        var defaultAiEnabled = !string.Equals(
            (await db.AppConfigs.FirstOrDefaultAsync(c => c.Key == "permission.default.ai_enabled"))?.Value,
            "false",
            StringComparison.OrdinalIgnoreCase);
        var quotaConfig = await db.AppConfigs
            .Where(c => c.Key == "quota.default_ai_chat_limit" ||
                        c.Key == "quota.default_ai_chat_period")
            .ToDictionaryAsync(c => c.Key, c => c.Value);
        var defaultAiChatLimit =
            quotaConfig.TryGetValue("quota.default_ai_chat_limit", out var limitValue) &&
            int.TryParse(limitValue, out var parsedLimit)
                ? Math.Clamp(parsedLimit, 0, 1_000_000)
                : 50;
        var periodValue = quotaConfig.GetValueOrDefault(
            "quota.default_ai_chat_period",
            "day");
        if (!AiChatQuotaService.TryParsePeriod(periodValue, out var defaultAiChatPeriod))
            defaultAiChatPeriod = AiQuotaPeriod.Day;
        var (quotaWindowStart, _) =
            AiChatQuotaService.CurrentWindow(defaultAiChatPeriod);
        var user = new User
        {
            Username = req.Username,
            PasswordHash = BCrypt.Net.BCrypt.HashPassword(req.Password),
            AiChatLimit = defaultAiChatLimit,
            AiChatPeriod = defaultAiChatPeriod,
            AiChatWindowStartedAt = quotaWindowStart,
            CreatedAt = now,
        };
        user.FeaturePermissions.Add(new UserFeaturePermission
        {
            PermissionKey = FeaturePermissionKeys.Ai,
            IsEnabled = defaultAiEnabled,
            CreatedAt = now,
            UpdatedAt = now,
        });
        var defaultLedgerName = (await db.AppConfigs.FirstOrDefaultAsync(c => c.Key == "system.default_ledger_name"))?.Value ?? "日常账本";
        user.Ledgers.Add(new Ledger { Name = defaultLedgerName, IsDefault = true, CreatedAt = DateTime.UtcNow });
        db.Users.Add(user);
        await db.SaveChangesAsync();

        var (token, expires) = jwt.Issue(user);
        return Ok(new AuthResponse(user.Id, user.Username, token, expires));
    }

    [HttpPost("login")]
    public async Task<ActionResult<AuthResponse>> Login(LoginRequest req)
    {
        var user = await db.Users.FirstOrDefaultAsync(u => u.Username == req.Username);
        if (user is null || !BCrypt.Net.BCrypt.Verify(req.Password, user.PasswordHash)) return Unauthorized(new ApiError("BAD_CREDENTIALS", "用户名或密码错误"));
        if (user.IsBanned)
            return Unauthorized(new ApiError("USER_BANNED", "账号已被封禁"));

        var closureCancelled = false;
        if (user.AccountClosureScheduledAt.HasValue)
        {
            if (user.AccountClosureScheduledAt <= DateTime.UtcNow)
                return Unauthorized(new ApiError(
                    "ACCOUNT_CLOSED",
                    "账号注销等待期已结束，无法恢复"));
            user.AccountClosureRequestedAt = null;
            user.AccountClosureScheduledAt = null;
            user.AuthVersion++;
            closureCancelled = true;
        }

        user.LastLoginAt = DateTime.UtcNow;
        await db.SaveChangesAsync();
        var (token, expires) = jwt.Issue(user);
        return Ok(new AuthResponse(
            user.Id,
            user.Username,
            token,
            expires,
            closureCancelled));
    }
}