using Health.Application.Diets;
using Health.Application.Notifications;
using Health.Application.Reports;

namespace Health.Infrastructure.AI.AgentHandlers;

/// <summary>
/// 统一助手使用的患者本人业务数据只读工具。
/// </summary>
public static class PatientReadAgentHandler
{
    public static readonly ToolDefinition QueryDietRecordsTool = new()
    {
        Function = new()
        {
            Name = "query_diet_records",
            Description = "查询当前用户指定北京时间日期的饮食记录和总热量",
            Parameters = new
            {
                type = "object",
                properties = new
                {
                    date = new { type = "string", description = "北京时间日期 yyyy-MM-dd，默认今天" },
                    meal_type = new { type = "string", @enum = new[] { "Breakfast", "Lunch", "Dinner", "Snack" }, description = "可选餐次" },
                }
            }
        }
    };

    public static readonly ToolDefinition QueryFollowUpsTool = new()
    {
        Function = new()
        {
            Name = "query_followups",
            Description = "查询当前用户的复查随访安排",
            Parameters = new
            {
                type = "object",
                properties = new
                {
                    scope = new { type = "string", @enum = new[] { "next", "upcoming", "completed", "date", "all" }, description = "查询时必填：下一次/未来安排/已完成/指定日期/全部" },
                    date = new { type = "string", description = "scope=date 时的北京时间日期 yyyy-MM-dd" },
                    limit = new { type = "integer", description = "最多返回条数，1到20" },
                }
            }
        }
    };

    public static readonly ToolDefinition QueryReportsTool = new()
    {
        Function = new()
        {
            Name = "query_reports",
            Description = "查询当前用户已经保存的检查报告状态、AI摘要和医生审核结论，不读取其他用户报告",
            Parameters = new
            {
                type = "object",
                properties = new
                {
                    limit = new { type = "integer", description = "最多返回条数，1到10，默认5" },
                    status = new { type = "string", description = "可选报告状态" },
                }
            }
        }
    };

    public static readonly ToolDefinition QueryNotificationsTool = new()
    {
        Function = new()
        {
            Name = "query_notifications",
            Description = "查询当前用户的站内通知",
            Parameters = new
            {
                type = "object",
                properties = new
                {
                    scope = new { type = "string", @enum = new[] { "unread", "today", "recent" }, description = "默认 unread" },
                    limit = new { type = "integer", description = "最多返回条数，1到20" },
                }
            }
        }
    };

    public static async Task<object> QueryDietAsync(
        IDietService diets,
        Guid userId,
        JsonElement args,
        CancellationToken ct)
    {
        if (args.TryGetProperty("date", out var suppliedDate) && !DateOnly.TryParse(suppliedDate.GetString(), out _))
            return new { success = false, message = "查询饮食记录时提供了无效的 date" };
        var date = args.TryGetProperty("date", out var dateValue) && DateOnly.TryParse(dateValue.GetString(), out var parsedDate)
            ? parsedDate
            : AiDateTime.BeijingToday;
        var mealType = args.TryGetProperty("meal_type", out var mealValue) ? mealValue.GetString() : null;
        var records = await diets.ListAsync(userId, date.ToString("yyyy-MM-dd"), mealType, ct);
        return new
        {
            query_date = date.ToString("yyyy-MM-dd"),
            count = records.Count,
            total_calories = records.Sum(record => record.TotalCalories ?? 0),
            records = records.Select(record => new
            {
                record.Id,
                record.MealType,
                record.TotalCalories,
                record.HealthScore,
                record.RecordedAt,
                record.FoodItems,
            }),
        };
    }

    public static async Task<object> QueryFollowUpsAsync(
        AppDbContext db,
        Guid userId,
        JsonElement args,
        CancellationToken ct)
    {
        var scope = args.TryGetProperty("scope", out var scopeValue)
            ? scopeValue.GetString()?.ToLowerInvariant()
            : null;
        if (scope is not ("next" or "upcoming" or "completed" or "date" or "all"))
            return new
            {
                success = false,
                message = "查询复查安排时必须明确 scope：next、upcoming、completed、date 或 all",
            };
        var limit = ReadLimit(args, 10, 20);
        var nowUtc = DateTime.UtcNow;
        var query = db.FollowUps.AsNoTracking().Where(item => item.UserId == userId);

        if (scope is "next" or "upcoming")
            query = query.Where(item => item.Status == FollowUpStatus.Upcoming && item.ScheduledAt >= nowUtc);
        else if (scope == "completed")
            query = query.Where(item => item.Status == FollowUpStatus.Completed);
        else if (scope == "date")
        {
            if (!args.TryGetProperty("date", out var dateValue) || !DateOnly.TryParse(dateValue.GetString(), out var date))
                return new { success = false, message = "按日期查询复查时必须提供有效的 date" };
            var (startUtc, endUtc) = AiDateTime.BeijingDateWindowUtc(date);
            query = query.Where(item => item.ScheduledAt >= startUtc && item.ScheduledAt < endUtc);
        }

        var take = scope == "next" ? 1 : limit;
        var orderedQuery = scope is "all" or "completed"
            ? query.OrderByDescending(item => item.ScheduledAt)
            : query.OrderBy(item => item.ScheduledAt);
        var matchingCount = await query.CountAsync(ct);
        var items = await orderedQuery
            .Take(take)
            .Select(item => new
            {
                item.Id,
                item.Title,
                item.DoctorName,
                item.Department,
                item.ScheduledAt,
                item.Notes,
                item.Status,
            })
            .ToListAsync(ct);
        return new
        {
            success = true,
            scope,
            count = items.Count,
            matching_count = matchingCount,
            results_truncated = matchingCount > items.Count,
            followups = items.Select(item => new
            {
                item.Id,
                item.Title,
                item.DoctorName,
                item.Department,
                scheduled_at_beijing = AiDateTime.ToBeijingText(item.ScheduledAt),
                item.Notes,
                status = item.Status.ToString(),
            }),
        };
    }

    public static async Task<object> QueryReportsAsync(
        IReportService reports,
        Guid userId,
        JsonElement args,
        CancellationToken ct)
    {
        var limit = ReadLimit(args, 5, 10);
        var status = args.TryGetProperty("status", out var statusValue) ? statusValue.GetString() : null;
        var records = await reports.GetReportsAsync(userId, ct);
        var filtered = records
            .Where(report => string.IsNullOrWhiteSpace(status) || report.Status.Equals(status, StringComparison.OrdinalIgnoreCase))
            .OrderByDescending(report => report.CreatedAt)
            .Take(limit)
            .Select(report => new
            {
                report.Id,
                report.Category,
                report.Status,
                report.AiStatus,
                report.ReviewStatus,
                report.Severity,
                ai_summary = Truncate(report.AiSummary, 1800),
                doctor_comment = Truncate(report.DoctorComment, 1000),
                doctor_recommendation = Truncate(report.DoctorRecommendation, 1000),
                report.DoctorName,
                reviewed_at_beijing = report.ReviewedAt.HasValue ? AiDateTime.ToBeijingText(report.ReviewedAt.Value) : null,
                created_at_beijing = AiDateTime.ToBeijingText(report.CreatedAt),
            })
            .ToList();
        return new { count = filtered.Count, reports = filtered };
    }

    public static async Task<object> QueryNotificationsAsync(
        IInAppNotificationService notifications,
        Guid userId,
        JsonElement args,
        CancellationToken ct)
    {
        var scope = args.TryGetProperty("scope", out var scopeValue)
            ? scopeValue.GetString()?.ToLowerInvariant() ?? "unread"
            : "unread";
        if (scope is not ("unread" or "today" or "recent")) scope = "unread";
        var limit = ReadLimit(args, 10, 20);
        var records = scope == "unread"
            ? await notifications.GetPendingAsync(userId, ct)
            : await notifications.GetHistoryAsync(userId, ct);
        var (todayStartUtc, todayEndUtc) = AiDateTime.BeijingDateWindowUtc(AiDateTime.BeijingToday);
        var filtered = records
            .Where(item => scope != "today" ||
                (AiDateTime.ToUtc(item.CreatedAt) >= todayStartUtc && AiDateTime.ToUtc(item.CreatedAt) < todayEndUtc))
            .OrderByDescending(item => item.CreatedAt)
            .Take(limit)
            .Select(item => new
            {
                item.Id,
                item.Type,
                item.Title,
                item.Message,
                item.Severity,
                item.IsRead,
                created_at_beijing = AiDateTime.ToBeijingText(item.CreatedAt),
            })
            .ToList();
        return new { scope, count = filtered.Count, notifications = filtered };
    }

    private static int ReadLimit(JsonElement args, int defaultValue, int max) =>
        args.TryGetProperty("limit", out var value) && value.TryGetInt32(out var parsed)
            ? Math.Clamp(parsed, 1, max)
            : defaultValue;

    private static string? Truncate(string? value, int maxLength) =>
        string.IsNullOrWhiteSpace(value) || value.Length <= maxLength ? value : value[..maxLength] + "…";
}