using Microsoft.AspNetCore.Mvc;
using Nexus.Api.Data;
using Nexus.Api.Models;
using Nexus.Api.Repositories;
using Nexus.Api.Services;

namespace Nexus.Api.Controllers;

[ApiController]
[Route("api/dashboard")]
public class DashboardController(
    OpenClawGatewayClient gateway,
    ITaskRepository taskRepo,
    IActivityRepository activityRepo,
    ILogger<DashboardController> logger)
    : ControllerBase
{
    /// <summary>
    /// Gateway health + session_status + subagents count.
    /// Returns HTTP 200 even when gateway is down (gatewayOk: false).
    /// </summary>
    [HttpGet("status")]
    public async Task<DashboardStatus> GetStatus()
    {
        try
        {
            return await gateway.GetStatusAsync();
        }
        catch (Exception ex)
        {
            logger.LogWarning(ex, "Dashboard status check failed");
            return new DashboardStatus(false, "Offline", 0, 0);
        }
    }

    /// <summary>
    /// Returns all agents with their current status.
    /// Combines sessions_list + sub_agents_list.
    /// </summary>
    [HttpGet("agents")]
    public async Task<List<DashboardAgentInfo>> GetAgents()
    {
        try
        {
            return await gateway.GetAgentsAsync();
        }
        catch (Exception ex)
        {
            logger.LogWarning(ex, "Dashboard agents fetch failed");
            return new List<DashboardAgentInfo>();
        }
    }

    /// <summary>
    /// Returns the latest assistant messages (operations/feed) from the Iris session.
    /// Filtered to role == "assistant" — those are the work feed entries.
    /// </summary>
    [HttpGet("operations")]
    public async Task<List<FeedEntry>> GetOperations([FromQuery] int limit = 20)
    {
        try
        {
            var messages = await gateway.GetSessionHistoryAsync("iris", Math.Clamp(limit, 1, 100));
            var feed = new List<FeedEntry>();

            foreach (var msg in messages)
            {
                if (!string.Equals(msg.Role, "assistant", StringComparison.OrdinalIgnoreCase))
                    continue;

                if (string.IsNullOrWhiteSpace(msg.Content))
                    continue;

                // Parse timestamp for display-friendly "time ago"
                var ts = ParseTimestamp(msg.Timestamp);
                var timeAgo = FormatTimeAgo(ts);

                // Extract a short agent indicator and action from content
                var (agent, action) = ExtractAgentAction(msg.Content);

                feed.Add(new FeedEntry(agent, action, msg.Timestamp, timeAgo));
            }

            return feed;
        }
        catch (Exception ex)
        {
            logger.LogWarning(ex, "Dashboard operations fetch failed");
            return new List<FeedEntry>();
        }
    }

    /// <summary>
    /// Send a chat message to the Iris session.
    /// </summary>
    [HttpPost("chat/send")]
    public async Task<ChatResponse> SendChat([FromBody] ChatRequest request)
    {
        if (string.IsNullOrWhiteSpace(request.Message))
            return new ChatResponse(false, null, "Message is required");

        try
        {
            var agentId = string.IsNullOrWhiteSpace(request.AgentId)
                ? "iris"
                : request.AgentId.Trim();

            return await gateway.SendChatMessageAsync(agentId, request.Message.Trim());
        }
        catch (Exception ex)
        {
            logger.LogWarning(ex, "Dashboard chat send failed");
            return new ChatResponse(false, null, "Gateway nicht erreichbar");
        }
    }

    /// <summary>
    /// Returns chat messages (user + assistant only, not tool messages).
    /// </summary>
    [HttpGet("chat/messages")]
    public async Task<List<MessageEntry>> GetMessages(
        [FromQuery] string? sessionKey,
        [FromQuery] int limit = 50,
        [FromQuery] int offset = 0)
    {
        try
        {
            var key = string.IsNullOrWhiteSpace(sessionKey) ? "agent:iris:main" : sessionKey.Trim();
            var messages = await gateway.GetSessionHistoryAsync(key, Math.Clamp(limit, 1, 200), Math.Max(0, offset));

            return messages
                .Where(m => string.Equals(m.Role, "user", StringComparison.OrdinalIgnoreCase)
                         || string.Equals(m.Role, "assistant", StringComparison.OrdinalIgnoreCase))
                .ToList();
        }
        catch (Exception ex)
        {
            logger.LogWarning(ex, "Dashboard messages fetch failed");
            return new List<MessageEntry>();
        }
    }

    /// <summary>
    /// Returns the cron queue / pending tasks.
    /// </summary>
    [HttpGet("queue")]
    public async Task<List<QueueItem>> GetQueue()
    {
        try
        {
            return await gateway.GetQueueAsync();
        }
        catch (Exception ex)
        {
            logger.LogWarning(ex, "Dashboard queue fetch failed");
            return new List<QueueItem>();
        }
    }

    /// <summary>
    /// Returns the current model and provider for a specific agent session.
    /// Calls session_status with the agent's session key.
    /// </summary>
    [HttpGet("agents/{id}/model")]
    public async Task<ActionResult<AgentModelInfo>> GetAgentModel(string id)
    {
        try
        {
            var info = await gateway.GetAgentModelAsync(id);
            if (info is null)
                return NotFound(new { error = $"Agent '{id}' not found or gateway unreachable" });
            return Ok(info);
        }
        catch (Exception ex)
        {
            logger.LogWarning(ex, "GetAgentModel failed for {AgentId}", id);
            return StatusCode(500, new { error = "Internal error" });
        }
    }

    /// <summary>
    /// Sets the model for a specific agent session.
    /// Calls session_status with model parameter.
    /// </summary>
    [HttpPut("agents/{id}/model")]
    public async Task<ActionResult> SetAgentModel(string id, [FromBody] SetModelRequest request)
    {
        if (string.IsNullOrWhiteSpace(request.Model))
            return BadRequest(new { error = "Model is required" });

        try
        {
            var ok = await gateway.SetAgentModelAsync(id, request.Model);
            if (!ok)
                return StatusCode(502, new { error = "Gateway did not accept the change" });
            return Ok(new { status = "ok", model = request.Model });
        }
        catch (Exception ex)
        {
            logger.LogWarning(ex, "SetAgentModel failed for {AgentId}", id);
            return StatusCode(500, new { error = "Internal error" });
        }
    }

    /// <summary>
    /// Returns the list of available models that can be assigned to agents.
    /// </summary>
    [HttpGet("models")]
    public ActionResult<List<ModelOption>> GetAvailableModels()
    {
        var models = new List<ModelOption>
        {
            new ModelOption("openai/gpt-5.4", "GPT-5.4", "openai"),
            new ModelOption("deepseek/deepseek-v4-flash", "DeepSeek V4 Flash", "deepseek"),
            new ModelOption("deepseek/deepseek-v4-pro", "DeepSeek V4 Pro", "deepseek")
        };
        return Ok(models);
    }

    // ========== Task Endpoints ==========

    /// <summary>
    /// Returns all non-done tasks (status != 'Done'), ordered by creation date descending.
    /// </summary>
    [HttpGet("tasks")]
    public async Task<List<DashboardTaskDto>> GetTasks(CancellationToken ct)
    {
        try
        {
            var tasks = await taskRepo.GetAllAsync(ct);
            return tasks
                .Where(t => !string.Equals(t.State, "Done", StringComparison.OrdinalIgnoreCase))
                .OrderByDescending(t => t.CreatedAt)
                .Select(MapToDto)
                .ToList();
        }
        catch (Exception ex)
        {
            logger.LogWarning(ex, "Dashboard tasks fetch failed");
            return new List<DashboardTaskDto>();
        }
    }

    /// <summary>
    /// Creates a new task and logs an activity event.
    /// </summary>
    [HttpPost("tasks")]
    public async Task<ActionResult<DashboardTaskDto>> CreateTask(
        [FromBody] CreateDashboardTaskRequest request, CancellationToken ct)
    {
        if (string.IsNullOrWhiteSpace(request.Title))
            return BadRequest(new { error = "Title is required." });

        var task = new WorkTask
        {
            Title = request.Title.Trim(),
            Detail = request.Detail?.Trim(),
            Source = string.IsNullOrWhiteSpace(request.Source) ? "bao" : request.Source.Trim(),
            Priority = string.IsNullOrWhiteSpace(request.Priority) ? "Normal" : request.Priority.Trim(),
            AssignedTo = request.AssignedTo?.Trim(),
        };

        await taskRepo.AddAsync(task, ct);
        await activityRepo.AddAsync(new ActivityEvent
        {
            Type = "task",
            Message = $"Task \"{task.Title}\" created ({task.Source})"
        }, ct);

        return Created($"/api/dashboard/tasks/{task.Id}", MapToDto(task));
    }

    /// <summary>
    /// Updates an existing task (title, detail, source, priority, assignedTo).
    /// </summary>
    [HttpPut("tasks/{id:guid}")]
    public async Task<ActionResult<DashboardTaskDto>> UpdateTask(
        Guid id, [FromBody] UpdateDashboardTaskRequest request, CancellationToken ct)
    {
        var task = await taskRepo.GetByIdAsync(id, ct);
        if (task is null)
            return NotFound(new { error = "Task not found." });

        if (!string.IsNullOrWhiteSpace(request.Title))
            task.Title = request.Title.Trim();
        if (request.Detail is not null)
            task.Detail = string.IsNullOrWhiteSpace(request.Detail) ? null : request.Detail.Trim();
        if (!string.IsNullOrWhiteSpace(request.Source))
            task.Source = request.Source.Trim();
        if (!string.IsNullOrWhiteSpace(request.Priority))
            task.Priority = request.Priority.Trim();
        if (request.AssignedTo is not null)
            task.AssignedTo = string.IsNullOrWhiteSpace(request.AssignedTo) ? null : request.AssignedTo.Trim();

        await taskRepo.UpdateAsync(task, ct);
        await activityRepo.AddAsync(new ActivityEvent
        {
            Type = "task",
            Message = $"Task \"{task.Title}\" updated"
        }, ct);

        return Ok(MapToDto(task));
    }

    /// <summary>
    /// Deletes a task (only if status is 'Done' or 'Backlog').
    /// </summary>
    [HttpDelete("tasks/{id:guid}")]
    public async Task<ActionResult> DeleteTask(Guid id, CancellationToken ct)
    {
        var task = await taskRepo.GetByIdAsync(id, ct);
        if (task is null)
            return NotFound(new { error = "Task not found." });

        if (!TaskStateHelper.IsDoneOrBacklog(task.State))
            return StatusCode(403, new { error = "Only tasks in 'Done' or 'Backlog' state can be deleted." });

        await activityRepo.AddAsync(new ActivityEvent
        {
            Type = "task",
            Message = $"Task \"{task.Title}\" deleted"
        }, ct);
        await taskRepo.DeleteAsync(task, ct);

        return NoContent();
    }

    /// <summary>
    /// Changes the status of a task.
    /// </summary>
    [HttpPatch("tasks/{id:guid}/status")]
    public async Task<ActionResult<DashboardTaskDto>> UpdateTaskStatus(
        Guid id, [FromBody] UpdateDashboardTaskStatusRequest request, CancellationToken ct)
    {
        if (!TaskStateHelper.IsValidState(request.Status))
            return BadRequest(new { error = $"Unsupported status: '{request.Status}'. Valid: {string.Join(", ", TaskStateHelper.AllStates)}" });

        var task = await taskRepo.GetByIdAsync(id, ct);
        if (task is null)
            return NotFound(new { error = "Task not found." });

        var canonicalState = TaskStateHelper.AllStates.First(s =>
            s.Equals(request.Status, StringComparison.OrdinalIgnoreCase));
        task.State = canonicalState;

        await taskRepo.UpdateAsync(task, ct);
        await activityRepo.AddAsync(new ActivityEvent
        {
            Type = "task",
            Message = $"Task \"{task.Title}\" → {canonicalState}"
        }, ct);

        return Ok(MapToDto(task));
    }

    // ========== Helpers ==========

    private static DashboardTaskDto MapToDto(WorkTask t) => new(
        t.Id,
        t.Title,
        t.Detail,
        t.Source,
        t.State,
        t.Priority,
        t.AssignedTo,
        t.CreatedAt,
        t.UpdatedAt
    );

    private static DateTimeOffset ParseTimestamp(string timestamp)
    {
        if (DateTimeOffset.TryParse(timestamp, null, System.Globalization.DateTimeStyles.None, out var dt))
            return dt;
        return DateTimeOffset.UtcNow;
    }

    private static string FormatTimeAgo(DateTimeOffset ts)
    {
        var diff = DateTimeOffset.UtcNow - ts;
        if (diff.TotalMinutes < 1) return "just now";
        if (diff.TotalMinutes < 60) return $"{(int)diff.TotalMinutes}m ago";
        if (diff.TotalHours < 24) return $"{(int)diff.TotalHours}h ago";
        if (diff.TotalDays < 7) return $"{(int)diff.TotalDays}d ago";
        return ts.ToString("MMM dd");
    }

    private static (string Agent, string Action) ExtractAgentAction(string content)
    {
        // Take first line or first ~80 chars as the action summary
        var firstLine = content.Split('\n', 2)[0].Trim();
        var summary = firstLine.Length > 80 ? firstLine[..80] + "…" : firstLine;

        // Try to identify which agent this came from
        var agent = "Iris";
        foreach (var marker in new[] { "**Agent:**", "**Agent:** ", "*Agent:* ", "Agent:" })
        {
            var idx = content.IndexOf(marker, StringComparison.OrdinalIgnoreCase);
            if (idx >= 0)
            {
                var after = content[(idx + marker.Length)..].TrimStart();
                var end = after.IndexOfAny(['\n', '\r', ',', '.']);
                var found = end > 0 ? after[..end].Trim() : after.Split('\n', 2)[0].Trim();
                if (!string.IsNullOrWhiteSpace(found) && found.Length < 30)
                {
                    agent = found;
                    break;
                }
            }
        }

        // Try to find agent name at the start in brackets like [Agent: Iris]
        if (agent == "Iris")
        {
            var bracketMatch = System.Text.RegularExpressions.Regex.Match(content, @"\[Agent:\s*([^\]]+)\]");
            if (bracketMatch.Success)
                agent = bracketMatch.Groups[1].Value.Trim();
        }

        return (agent, summary);
    }
}