using System;
using System.Collections.Generic;
using System.Globalization;
using System.Web.Script.Serialization;

namespace HikvisionAttendanceService;

/// <summary>Parses UserInfo/Search JSON into <see cref="UserDto"/> rows (best-effort, firmware-tolerant).</summary>
internal static class UserSyncJsonParser
{
    public static List<UserDto> ParseUserInfoSearchPage(string json)
    {
        var list = new List<UserDto>();
        if (string.IsNullOrWhiteSpace(json))
            return list;

        try
        {
            var ser = new JavaScriptSerializer();
            object? root = ser.DeserializeObject(json);
            if (root == null)
                return list;

            var userInfos = FindUserInfoArray(root);
            if (userInfos == null)
                return list;

            foreach (var item in userInfos)
            {
                if (item is Dictionary<string, object> d)
                {
                    var u = MapUser(d);
                    if (!string.IsNullOrWhiteSpace(u.EmployeeNo))
                        list.Add(u);
                }
            }
        }
        catch
        {
            // caller logs
        }

        return list;
    }

    private static object[]? FindUserInfoArray(object root)
    {
        var stack = new Stack<object>();
        stack.Push(root);
        while (stack.Count > 0)
        {
            var cur = stack.Pop();
            if (cur is Dictionary<string, object> map)
            {
                if (map.TryGetValue("UserInfo", out var ui) && ui is object[] arr)
                    return arr;

                foreach (var kv in map)
                {
                    if (kv.Value is Dictionary<string, object> nd)
                        stack.Push(nd);
                    else if (kv.Value is object[] oa)
                    {
                        foreach (var it in oa)
                            if (it != null)
                                stack.Push(it);
                    }
                }
            }
            else if (cur is object[] top)
            {
                foreach (var it in top)
                    if (it != null)
                        stack.Push(it);
            }
        }

        return null;
    }

    internal static UserDto MapUser(Dictionary<string, object> d)
    {
        var u = new UserDto
        {
            EmployeeNo = GetString(d, "employeeNo") ?? "",
            Name = GetString(d, "name") ?? "",
            UserType = GetString(d, "userType") ?? "normal",
            NumOfFace = GetInt(d, "numOfFace"),
            NumOfFp = GetInt(d, "numOfFP", "numOfFp", "numOfFingerPrint"),
            Gender = GetString(d, "gender") ?? "",
            FaceUrl = GetString(d, "faceURL", "faceUrl") ?? ""
        };

        if (d.TryGetValue("Valid", out var vObj) && vObj is Dictionary<string, object> vd)
        {
            u.ValidEnable = GetBool(vd, "enable", defaultValue: true);
            var b = GetString(vd, "beginTime");
            var e = GetString(vd, "endTime");
            if (!string.IsNullOrWhiteSpace(b))
                u.ValidBeginTime = b!;
            if (!string.IsNullOrWhiteSpace(e))
                u.ValidEndTime = e!;
        }

        u.DoorRight = GetString(d, "doorRight") ?? u.DoorRight;

        if (d.TryGetValue("RightPlan", out var rpObj) && rpObj is object[] rpArr && rpArr.Length > 0 &&
            rpArr[0] is Dictionary<string, object> rp0)
        {
            u.RightPlanDoorNo = GetIntWithDefault(rp0, 1, "doorNo");
            u.RightPlanTemplateNo = GetString(rp0, "planTemplateNo") ?? u.RightPlanTemplateNo;
        }

        if (string.IsNullOrWhiteSpace(u.UserType))
            u.UserType = "normal";

        return u;
    }

    private static string? GetString(Dictionary<string, object> d, params string[] keys)
    {
        foreach (var k in keys)
        {
            if (!d.TryGetValue(k, out var v) || v == null)
                continue;
            var s = v.ToString();
            if (!string.IsNullOrWhiteSpace(s))
                return s.Trim();
        }

        return null;
    }

    private static int GetInt(Dictionary<string, object> d, params string[] keys)
    {
        return GetIntWithDefault(d, 0, keys);
    }

    private static int GetIntWithDefault(Dictionary<string, object> d, int defaultValue, params string[] keys)
    {
        foreach (var k in keys)
        {
            if (!d.TryGetValue(k, out var v) || v == null)
                continue;
            switch (v)
            {
                case int i:
                    return i;
                case long l:
                    return l > int.MaxValue ? int.MaxValue : (int)l;
                case double db:
                    return (int)db;
                case string s when int.TryParse(s, NumberStyles.Integer, CultureInfo.InvariantCulture, out var n):
                    return n;
            }
        }

        return defaultValue;
    }

    private static bool GetBool(Dictionary<string, object> d, string key, bool defaultValue)
    {
        if (!d.TryGetValue(key, out var v) || v == null)
            return defaultValue;
        if (v is bool b)
            return b;
        var s = v.ToString();
        if (bool.TryParse(s, out var pb))
            return pb;
        if (string.Equals(s, "1", StringComparison.Ordinal))
            return true;
        if (string.Equals(s, "0", StringComparison.Ordinal))
            return false;
        return defaultValue;
    }
}