using PlotLine.Data;
using PlotLine.Models;
using PlotLine.ViewModels;

namespace PlotLine.Services;

public interface IProjectRestorePointService
{
    Task<ProjectRestorePointListViewModel?> GetAsync(int projectId);
    Task<ProjectRestorePoint?> CreateManualAsync(int projectId, string? restorePointName, string? notes);
    Task<ProjectRestorePointDownload?> DownloadAsync(int projectRestorePointId, int projectId);
}

public sealed class ProjectRestorePointService(
    IProjectRepository projects,
    IProjectExportService projectExports,
    IProjectRestorePointRepository restorePoints,
    ILogger<ProjectRestorePointService> logger) : IProjectRestorePointService
{
    private const string ManualRestorePointType = "Manual";

    public async Task<ProjectRestorePointListViewModel?> GetAsync(int projectId)
    {
        var project = await projects.GetAsync(projectId);
        if (project is null)
        {
            return null;
        }

        return new ProjectRestorePointListViewModel
        {
            Project = project,
            RestorePoints = await restorePoints.ListAsync(projectId)
        };
    }

    public async Task<ProjectRestorePoint?> CreateManualAsync(int projectId, string? restorePointName, string? notes)
    {
        var export = await projectExports.ExportAsync(projectId);
        if (export is null)
        {
            logger.LogWarning("Manual restore point requested for missing project {ProjectID}.", projectId);
            return null;
        }

        var name = string.IsNullOrWhiteSpace(restorePointName)
            ? $"Manual restore point - {DateTime.Now:yyyy-MM-dd HH:mm}"
            : restorePointName.Trim();

        var created = await restorePoints.CreateAsync(projectId, name, ManualRestorePointType, export.Json, Clean(notes));
        logger.LogInformation("Manual restore point {ProjectRestorePointID} created for project {ProjectID} with {JsonSizeBytes} JSON bytes.",
            created.ProjectRestorePointID,
            projectId,
            created.JsonSizeBytes);

        return created;
    }

    public async Task<ProjectRestorePointDownload?> DownloadAsync(int projectRestorePointId, int projectId)
    {
        var restorePoint = await restorePoints.GetAsync(projectRestorePointId, projectId);
        if (restorePoint?.JsonData is null)
        {
            logger.LogWarning("Restore point download requested for missing restore point {ProjectRestorePointID} in project {ProjectID}.", projectRestorePointId, projectId);
            return null;
        }

        return new ProjectRestorePointDownload
        {
            FileName = BuildFileName(restorePoint.ProjectName, restorePoint.CreatedDateUtc),
            ContentType = "application/json",
            Json = restorePoint.JsonData
        };
    }

    private static string? Clean(string? value)
    {
        return string.IsNullOrWhiteSpace(value) ? null : value.Trim();
    }

    private static string BuildFileName(string projectName, DateTime createdDateUtc)
    {
        var safeTitle = new string(projectName
            .Select(c => Path.GetInvalidFileNameChars().Contains(c) ? '_' : c)
            .ToArray())
            .Trim();

        safeTitle = string.Join("_", safeTitle.Split(' ', StringSplitOptions.RemoveEmptyEntries));

        if (string.IsNullOrWhiteSpace(safeTitle))
        {
            safeTitle = "PlotWeaver_Project";
        }

        return $"{safeTitle}_RestorePoint_{createdDateUtc:yyyy-MM-dd_HHmm}.plotweaver";
    }
}