using System.Security.Claims;
using Campaign_Tracker.Server.Audit;
using Campaign_Tracker.Server.Authorization;
using Campaign_Tracker.Server.LegacyData.Schema;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;

namespace Campaign_Tracker.Server.Controllers;

/// <summary>
/// Admin-only API for the legacy schema compatibility check (Story 1.7 AC #5).
/// Exposes a manual trigger and a recent-history view.
/// </summary>
[ApiController]
[Authorize(Policy = ApplicationPolicy.AdminAccess)]
[Route("api/admin/legacy-schema")]
public sealed class LegacySchemaController : ControllerBase
{
    private readonly ILegacySchemaCompatibilityCheck _check;
    private readonly ILegacySchemaCheckHistory _history;
    private readonly IAuditService _audit;
    private readonly TimeProvider _timeProvider;

    public LegacySchemaController(
        ILegacySchemaCompatibilityCheck check,
        ILegacySchemaCheckHistory history,
        IAuditService audit,
        TimeProvider timeProvider)
    {
        _check = check;
        _history = history;
        _audit = audit;
        _timeProvider = timeProvider;
    }

    [HttpPost("check")]
    public async Task<ActionResult<LegacySchemaCheckResponse>> RunCheck(CancellationToken cancellationToken)
    {
        var result = await _check.RunAsync(cancellationToken);
        _history.Record(result);

        var actor = User.Identity?.Name
            ?? User.FindFirstValue(ClaimTypes.NameIdentifier)
            ?? "unknown";
        _audit.Record(new AuditEvent(
            EventType: result.Passed
                ? "LEGACY_SCHEMA_CHECK_PASSED"
                : "LEGACY_SCHEMA_CHECK_FAILED",
            ActorIdentity: actor,
            Resource: "legacy-schema/compatibility-check",
            Outcome: result.Passed ? "pass" : "fail",
            TraceIdentifier: HttpContext.TraceIdentifier,
            RecordedAt: _timeProvider.GetUtcNow()));

        return Ok(LegacySchemaCheckResponse.From(result));
    }

    [HttpGet("history")]
    public ActionResult<IReadOnlyList<LegacySchemaCheckResponse>> GetHistory([FromQuery] int max = 50)
    {
        var items = _history.GetRecent(max);
        return Ok(items.Select(LegacySchemaCheckResponse.From).ToArray());
    }
}

public sealed record LegacySchemaCheckResponse(
    bool Passed,
    int TablesVerified,
    int DriftCount,
    DateTimeOffset CheckedAt,
    string BaselineSource,
    IReadOnlyList<LegacySchemaDriftResponse> Drifts)
{
    public static LegacySchemaCheckResponse From(LegacySchemaCheckResult result) =>
        new(result.Passed,
            result.TablesVerified,
            result.DriftCount,
            result.CheckedAt,
            result.BaselineSource,
            result.Drifts
                .Select(d => new LegacySchemaDriftResponse(
                    d.TableName, d.ColumnName, d.ChangeType.ToString(), d.Detail))
                .ToArray());
}

public sealed record LegacySchemaDriftResponse(
    string TableName,
    string? ColumnName,
    string ChangeType,
    string Detail);