using System.Security.Claims;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;

/// <summary>
/// Approval and promotion of verified digitization batches to VigilCareClinical live tables.
/// </summary>
[ApiController]
[Route("api/v1/digitization-batches")]
[Produces("application/json")]
[Authorize]
public class ApprovalController : ControllerBase
{
    private readonly IPromotionService _promotion;
    private readonly ILogger<ApprovalController> _logger;

    public ApprovalController(IPromotionService promotion, ILogger<ApprovalController> logger)
    {
        _promotion = promotion;
        _logger = logger;
    }

    /// <summary>
    /// Approves a verified or awaiting-clinical-approval batch and promotes its draft data
    /// into live VigilCareClinical tables (Patient, Encounter, Observations).
    ///
    /// Requires the Idempotency-Key header for safe retries. If the same key is resubmitted,
    /// the original response is returned without re-executing the promotion.
    ///
    /// Separation of duties: the approver cannot be the entry clerk or verifier of the same batch.
    /// </summary>
    /// <param name="id">The batch ID to approve.</param>
    /// <param name="request">Optional request body with alert configuration.</param>
    /// <returns>Promotion result with live IDs for patient, encounter, and observations.</returns>
    [HttpPost("{id:guid}/approve")]
    [Authorize(Roles = "CLINICAL_APPROVER,ADMINISTRATOR")]
    [ProducesResponseType(typeof(ApiResponse<PromotionResultResponse>), StatusCodes.Status200OK)]
    [ProducesResponseType(typeof(ApiResponse<object>), StatusCodes.Status400BadRequest)]
    [ProducesResponseType(typeof(ApiResponse<object>), StatusCodes.Status404NotFound)]
    [ProducesResponseType(typeof(ApiResponse<object>), StatusCodes.Status409Conflict)]
    [ProducesResponseType(typeof(ApiResponse<object>), StatusCodes.Status422UnprocessableEntity)]
    public async Task<IActionResult> Approve(Guid id, [FromBody] ApproveRequest? request)
    {
        var idempotencyKey = Request.Headers["Idempotency-Key"].FirstOrDefault();

        if (string.IsNullOrWhiteSpace(idempotencyKey))
            return BadRequest(ApiResponse<object>.Fail(400,
                "Idempotency-Key header is required for promotion operations.",
                "MISSING_IDEMPOTENCY_KEY"));

        if (idempotencyKey.Length > 100)
            return BadRequest(ApiResponse<object>.Fail(400,
                "Idempotency-Key must be at most 100 characters.",
                "INVALID_IDEMPOTENCY_KEY"));

        var approverUserId = Guid.Parse(User.FindFirstValue(ClaimTypes.NameIdentifier)!);
        var enableRetroactiveAlerts = request?.EnableRetroactiveAlerts ?? false;

        _logger.LogInformation(
            "Approve request for batch {BatchId} by user {UserId} with idempotency key {Key}",
            id, approverUserId, idempotencyKey);

        var result = await _promotion.ApproveAndPromoteAsync(
            id, approverUserId, enableRetroactiveAlerts, idempotencyKey);

        return Ok(ApiResponse<PromotionResultResponse>.Ok(result));
    }

    /// <summary>
    /// Returns the promotion result for an already-promoted batch, including the live IDs
    /// for Patient, Encounter, and Observations that were created during promotion.
    /// </summary>
    /// <param name="id">The batch ID to query.</param>
    /// <returns>Promotion result with live clinical entity IDs.</returns>
    [HttpGet("{id:guid}/promotion-result")]
    [Authorize]
    [ProducesResponseType(typeof(ApiResponse<PromotionResultResponse>), StatusCodes.Status200OK)]
    [ProducesResponseType(typeof(ApiResponse<object>), StatusCodes.Status404NotFound)]
    [ProducesResponseType(typeof(ApiResponse<object>), StatusCodes.Status409Conflict)]
    public async Task<IActionResult> GetPromotionResult(Guid id)
    {
        var result = await _promotion.GetPromotionResultAsync(id);
        return Ok(ApiResponse<PromotionResultResponse>.Ok(result));
    }
}