using Management.Data;
using Management.Security;
using Microsoft.AspNetCore.Mvc;
using System.Text.Json;

namespace Management.Controllers;

/// <summary>
/// Monitoring endpoints for system health and stats.
/// Requires Admin session.
/// 
/// ENDPOINTS:
/// GET /api/monitoring/health  - System health overview
/// GET /api/monitoring/stats   - Detailed statistics
/// </summary>
[ApiController]
[Route("api/monitoring")]
public sealed class MonitoringController : ControllerBase
{
    private readonly SqlService _sql;
    private readonly ClientContext _client;
    private readonly ILogger<MonitoringController> _log;

    private readonly Management.Services.GraphService _graph;

    public MonitoringController(SqlService sql, ClientContext client, Management.Services.GraphService graph, ILogger<MonitoringController> log)
    {
        _sql = sql;
        _client = client;
        _graph = graph;
        _log = log;
    }

    /// <summary>
    /// System health overview.
    /// </summary>
    [HttpGet("health")]
    public async Task<IActionResult> Health(CancellationToken ct)
    {
        try
        {
            var resp = await _sql.ExecProcAsync("dbo.spMonitoring", "health", "{}", ct: ct);

            if (string.IsNullOrWhiteSpace(resp))
                return StatusCode(500, new { ok = false, error = "Service unavailable" });

            return Content(resp, "application/json");
        }
        catch (Exception ex)
        {
            _log.LogError(ex, "[Monitoring] Health error");
            return StatusCode(500, new { ok = false, error = "Health check failed", detail = ex.Message });
        }
    }

    /// <summary>
    /// Detailed system statistics.
    /// </summary>
    [HttpPost("stats")]
    public async Task<IActionResult> Stats([FromBody] JsonElement body, CancellationToken ct)
    {
        var rqst = body.ToString();

        try
        {
            var resp = await _sql.ExecProcAsync("dbo.spMonitoring", "stats", rqst, ct: ct);

            if (string.IsNullOrWhiteSpace(resp))
                return StatusCode(500, new { ok = false, error = "Service unavailable" });

            return Content(resp, "application/json");
        }
        catch (Exception ex)
        {
            _log.LogError(ex, "[Monitoring] Stats error");
            return StatusCode(500, new { ok = false, error = "Stats failed", detail = ex.Message });
        }
    }

    /// <summary>
    /// Staff user list — distinct staff who have ever performed an action,
    /// derived directly from tbAdminActivity.
    /// </summary>
    [HttpGet("staff")]
    public async Task<IActionResult> Staff(CancellationToken ct)
    {
        try
        {
            var json = await _sql.ExecProcAsync("dbo.spAdminActivity", "distinct-staff", "{}", ct: ct);
            return Content(json, "application/json");
        }
        catch (Exception ex)
        {
            _log.LogError(ex, "[Monitoring] Staff list error");
            return StatusCode(500, new { ok = false, error = "Staff list failed", detail = ex.Message });
        }
    }

    /// <summary>
    /// Admin activity log — all mutating requests by staff members.
    /// Accessible to Staff.Admin and Staff.Tech.
    /// Body: { oid?, dateFrom?, dateTo?, page?, pageSize? }
    /// </summary>
    [HttpPost("activity")]
    public async Task<IActionResult> Activity([FromBody] JsonElement body, CancellationToken ct)
    {
        try
        {
            var resp = await _sql.ExecProcAsync("dbo.spAdminActivity", "list", body.ToString(), ct: ct);

            if (string.IsNullOrWhiteSpace(resp))
                return StatusCode(500, new { ok = false, error = "Service unavailable" });

            return Content(resp, "application/json");
        }
        catch (Exception ex)
        {
            _log.LogError(ex, "[Monitoring] Activity log error");
            return StatusCode(500, new { ok = false, error = "Activity log failed", detail = ex.Message });
        }
    }
}