using Microsoft.Extensions.Logging;
using System.Net.Http;
using static BlueMine.Redmine.RedmineDto;

namespace BlueMine.Redmine
{
    public class RedmineManager : IRedmineManager
    {
        private readonly RedmineConnect _redmineConnect;
        private readonly AsyncLock _lock = new();
        private readonly RedmineCache<SimpleProject> _projectCache;
        private readonly RedmineCache<SimpleIssue> _issueCache;
        private readonly ILogger<RedmineManager> _logger;

        public RedmineManager(HttpClient httpClient, ILoggerFactory loggerFactory, RedmineConfig config)
        {
            ArgumentNullException.ThrowIfNull(httpClient);
            ArgumentNullException.ThrowIfNull(loggerFactory);
            ArgumentNullException.ThrowIfNull(config);

            _logger = loggerFactory.CreateLogger<RedmineManager>();
            _logger.LogDebug("Initializing RedmineManager with URL: {Url}", config.RedmineUrl);
            _redmineConnect = new RedmineConnect(httpClient, loggerFactory.CreateLogger<RedmineConnect>(), config);
            _projectCache = new(config.ProjectCacheDuration, loggerFactory.CreateLogger<RedmineCache<SimpleProject>>());
            _issueCache = new(config.IssueCacheDuration, loggerFactory.CreateLogger<RedmineCache<SimpleIssue>>());
            _logger.LogDebug("RedmineManager initialized");
        }

        /// <summary>
        /// Checks if the Redmine instance is available by verifying the API key.
        /// </summary>
        /// <returns>True if available, false otherwise.</returns>
        public async Task<bool> IsRedmineAvailable()
        {
            _logger.LogDebug("Checking if Redmine is available");
            try
            {
                using (await _lock.LockAsync())
                {
                    await _redmineConnect.VerifyApiKey();
                }
                _logger.LogDebug("Redmine is available");
                return true;
            }
            catch (Exception ex)
            {
                _logger.LogDebug("Redmine not available: {Message}", ex.Message);
                return false;
            }
        }
        /// <summary>
        /// Logs time for a specific issue.
        /// </summary>
        /// <param name="issueId">The issue ID.</param>
        /// <param name="hours">Hours to log.</param>
        /// <param name="comments">Comments for the time entry.</param>
        /// <param name="date">Date of the time entry.</param>
        /// <param name="activityId">Optional activity ID.</param>
        public async Task LogTimeAsync(int issueId, double hours, string comments, DateTime date, int? activityId = null)
        {
            _logger.LogDebug("Logging {Hours} hours for issue {IssueId} on {Date}", hours, issueId, date.ToShortDateString());
            using (await _lock.LockAsync())
            {
                await _redmineConnect.LogTimeAsync(issueId, hours, comments, date, activityId);
            }
            _logger.LogDebug("Time logged successfully");
        }
        /// <summary>
        /// Closes the specified issue.
        /// </summary>
        /// <param name="issueId">The issue ID to close.</param>
        public async Task CloseIssueAsync(int issueId)
        {
            _logger.LogDebug("Closing issue {IssueId}", issueId);
            using (await _lock.LockAsync())
            {
                await _redmineConnect.CloseIssueAsync(issueId);
            }
            _logger.LogDebug("Issue {IssueId} closed", issueId);
        }
        /// <summary>
        /// Creates a new issue in the specified project.
        /// </summary>
        /// <param name="projectId">The project ID.</param>
        /// <param name="trackerId">The tracker ID.</param>
        /// <param name="subject">Issue subject.</param>
        /// <param name="description">Optional description.</param>
        /// <param name="estimatedHours">Optional estimated hours.</param>
        /// <param name="priorityId">Optional priority ID.</param>
        /// <param name="parentIssueId">Optional parent issue ID.</param>
        /// <returns>The created issue ID.</returns>
        public async Task<int> CreateIssueAsync(string projectId, int trackerId, string subject, string? description = null,
            double? estimatedHours = null, int? priorityId = 9, int? parentIssueId = null)
        {
            _logger.LogDebug("Creating issue in project {ProjectId} with subject '{Subject}'", projectId, subject);
            using (await _lock.LockAsync())
            {
                var issueId = await _redmineConnect.CreateIssueAsync(projectId, trackerId, subject, description,
                    estimatedHours, priorityId, parentIssueId);
                _logger.LogDebug("Issue created with ID {IssueId}", issueId);
                return issueId;
            }
        }
        /// <summary>
        /// Retrieves the list of projects, using cache if valid.
        /// </summary>
        /// <param name="limit">Maximum number of projects to fetch per request.</param>
        /// <param name="progress">Optional progress reporter.</param>
        /// <returns>List of simple projects.</returns>
        public async Task<List<SimpleProject>> GetProjectsAsync(int limit = 100, IProgress<(int, int)>? progress = null)
        {
            _logger.LogDebug("Getting projects");
            using (await _lock.LockAsync())
            {
                List<SimpleProject> projects = [];

                if(!_projectCache.IsCacheValid())
                {
                    _logger.LogDebug("Cache invalid, refreshing");
                    _projectCache.RefreshCache([..(await _redmineConnect.GetProjectsAsync(limit, progress))]);
                }
                else
                {
                    _logger.LogDebug("Using cached projects");
                }

                projects = _projectCache.GetItems();
                _logger.LogDebug("Retrieved {Count} projects", projects.Count);
                return projects;
            }
        }
        /// <summary>
        /// Retrieves trackers for the specified project.
        /// </summary>
        /// <param name="projectId">The project ID.</param>
        /// <param name="token">Optional cancellation token.</param>
        /// <returns>List of simple trackers.</returns>
        public async Task<List<SimpleTracker>> GetTrackersAsync(string projectId, CancellationToken? token = null)
        {
            _logger.LogDebug("Getting trackers for project {ProjectId}", projectId);
            try
            {
                using (await _lock.LockAsync())
                {
                    var trackers = await _redmineConnect.GetTrackersAsync(projectId, token);
                    _logger.LogDebug("Retrieved {Count} trackers", trackers.Count);
                    return trackers;
                }
            }
            catch (OperationCanceledException)
            {
                _logger.LogDebug("GetTrackersAsync cancelled");
                throw;
            }
        }
        /// <summary>
        /// Retrieves current issues with spent time.
        /// </summary>
        /// <param name="progress">Optional progress reporter.</param>
        /// <returns>List of issue items.</returns>
        public async Task<List<IssueItem>> GetCurrentIssuesAsync(IProgress<(int, int)>? progress = null)
        {
            _logger.LogDebug("Getting current issues");
            using (await _lock.LockAsync())
            {
                List<SimpleIssue> simpleIssues;
                if (!_issueCache.IsCacheValid())
                {
                    _logger.LogDebug("Issue cache invalid, refreshing");
                    simpleIssues = [.. (await _redmineConnect.GetMyIssuesAsync())];
                    _issueCache.RefreshCache(simpleIssues);
                }
                else
                {
                    _logger.LogDebug("Using cached issues");
                    simpleIssues = _issueCache.GetItems();
                }
                var issues = await _redmineConnect.GetSpentTimeForIssuesAsync(simpleIssues, progress);
                _logger.LogDebug("Retrieved {Count} issues", issues.Count);
                return issues;
            }
        }
        /// <summary>
        /// Retrieves logged hours for the specified date range.
        /// </summary>
        /// <param name="startDate">Start date.</param>
        /// <param name="endDate">End date.</param>
        /// <returns>Total logged hours.</returns>
        public async Task<double> GetLoggedHoursAsync(DateTime? startDate = null, DateTime? endDate = null)
        {
            var start = DateTime.Today;
            var end = DateTime.Today;
            if (startDate.HasValue)
                start = startDate.Value;
            if(endDate.HasValue)
                end = endDate.Value;
            _logger.LogDebug("Getting logged hours from {Start} to {End}", start.ToShortDateString(), end.ToShortDateString());
            using (await _lock.LockAsync())
            {
                var hours = await _redmineConnect.GetTodaysHoursAsync(start, end);
                _logger.LogDebug("Retrieved {Hours} hours", hours);
                return hours;
            }
        }
    }
}