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

namespace Nexus.Api.Controllers;

[Authorize]
[ApiController]
[Route("api/dashboard")]
public class DashboardController(
    IDashboardService dashboardService,
    ITaskService taskService,
    IActivityRepository activityService,
    IHttpContextAccessor httpContextAccessor) : ControllerBase
{
    [HttpGet("status")]
    public async Task<DashboardStatus> GetStatus()
        => await dashboardService.GetStatusAsync();

    [HttpGet("agents")]
    public async Task<List<DashboardAgentInfo>> GetAgents()
        => await dashboardService.GetAgentsAsync();

    [HttpGet("operations")]
    public async Task<List<FeedEntry>> GetOperations(
        [FromQuery] int limit = 20,
        [FromQuery] string? agent = null)
        => await dashboardService.GetOperationsAsync(limit, agent);

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

        var agentId = string.IsNullOrWhiteSpace(request.AgentId) ? "iris" : request.AgentId.Trim();
        return await dashboardService.SendChatAsync(agentId, request.Message.Trim());
    }

    [HttpGet("chat/messages")]
    public async Task<List<MessageEntry>> GetMessages(
        [FromQuery] string? sessionKey,
        [FromQuery] int limit = 50,
        [FromQuery] int offset = 0)
        => await dashboardService.GetMessagesAsync(sessionKey, limit, offset);

    [HttpGet("queue")]
    public async Task<List<QueueItem>> GetQueue(CancellationToken ct)
        => await dashboardService.GetQueueAsync(ct);

    [HttpDelete("queue/{id}")]
    public async Task<ActionResult> DeleteQueueItem(string id, [FromQuery] string? source, CancellationToken ct)
    {
        var result = await dashboardService.DeleteQueueItemAsync(id, source, ct);
        return result.Outcome switch
        {
            QueueDeleteOutcome.Deleted => NoContent(),
            QueueDeleteOutcome.NotFound => NotFound(new { error = "Queue item not found" }),
            QueueDeleteOutcome.GatewayError => StatusCode(502, new { error = "Gateway could not delete cron job" }),
            QueueDeleteOutcome.TaskNotFound => NotFound(new { error = "Task not found" }),
            QueueDeleteOutcome.InvalidTaskId => BadRequest(new { error = "Invalid task id" }),
            _ => StatusCode(500, new { error = "Internal error" })
        };
    }

    [HttpPut("queue/{id}/priority")]
    public async Task<ActionResult> ChangeQueuePriority(string id, CancellationToken ct)
    {
        var result = await dashboardService.CycleQueuePriorityAsync(id, ct);
        return result.Outcome switch
        {
            QueuePriorityOutcome.Ignored => Ok(new { status = "ignored", reason = "Cron job priorities are managed by the gateway" }),
            QueuePriorityOutcome.TaskNotFound => NotFound(new { error = "Task not found" }),
            QueuePriorityOutcome.InvalidTaskId => BadRequest(new { error = "Invalid task id" }),
            _ => Ok(new { status = "ok", priority = result.NewPriority })
        };
    }

    [HttpGet("agents/{id}/model")]
    public async Task<ActionResult<AgentModelInfo>> GetAgentModel(string id)
    {
        var info = await dashboardService.GetAgentModelAsync(id);
        return info is null
            ? NotFound(new { error = $"Agent '{id}' not found or gateway unreachable" })
            : Ok(info);
    }

    [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" });

        var ok = await dashboardService.SetAgentModelAsync(id, request.Model);
        return ok ? Ok(new { status = "ok", model = request.Model }) : StatusCode(502, new { error = "Gateway did not accept the change" });
    }

    [HttpGet("agents/{id}/activity")]
    public async Task<List<AgentActivityEntry>> GetAgentActivity(string id, [FromQuery] int limit = 5)
        => await dashboardService.GetAgentActivityAsync(id, limit);

    [HttpGet("models")]
    public ActionResult<List<ModelOption>> GetAvailableModels()
        => Ok(dashboardService.GetAvailableModels());

    // ── Task Endpoints ──

    [HttpGet("tasks")]
    public async Task<List<DashboardTaskDto>> GetTasks(CancellationToken ct)
    {
        var tasks = await taskService.GetOpenAsync(ct);
        return tasks.Select(MapToDto).ToList();
    }

    [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." });

        try
        {
            var task = await taskService.CreateDashboardTaskAsync(
                request.Title, request.Detail, request.Source, request.Priority, request.AssignedTo, request.ParentTaskId, ct);
            return Created($"/api/dashboard/tasks/{task.Id}", MapToDto(task));
        }
        catch (ArgumentException ex)
        {
            return BadRequest(new { error = ex.Message });
        }
    }

    [HttpPut("tasks/{id:guid}")]
    public async Task<ActionResult<DashboardTaskDto>> UpdateTask(
        Guid id, [FromBody] UpdateDashboardTaskRequest request, CancellationToken ct)
    {
        var result = await taskService.UpdateDashboardTaskAsync(
            id, request.Title, request.Detail, request.Source, request.Priority, request.AssignedTo, request.DueDate, ct);
        return result.Outcome switch
        {
            TaskOperationOutcome.NotFound => NotFound(new { error = "Task not found." }),
            _ => Ok(MapToDto(result.Task!))
        };
    }

    [HttpDelete("tasks/{id:guid}")]
    public async Task<ActionResult> DeleteTask(Guid id, CancellationToken ct)
    {
        var result = await taskService.DeleteAsync(id, ct);
        return result.Outcome switch
        {
            TaskOperationOutcome.NotFound => NotFound(new { error = "Task not found." }),
            TaskOperationOutcome.InvalidState => StatusCode(403, new { error = "Only tasks in 'Done' or 'Backlog' state can be deleted." }),
            _ => NoContent()
        };
    }

    [HttpPatch("tasks/{id:guid}/status")]
    public async Task<ActionResult<DashboardTaskDto>> UpdateTaskStatus(
        Guid id, [FromBody] UpdateDashboardTaskStatusRequest request, CancellationToken ct)
    {
        // Enforce workflow rules based on caller agent
        var currentTask = await taskService.GetByIdAsync(id, ct);
        if (currentTask is null)
            return NotFound(new { error = "Task not found." });

        // Resolve caller agent from header or JWT
        var callerAgent = ResolveCallerAgent();

        // Nur Iris und Bao dürfen Status ändern
        if (!TaskStateHelper.CanChangeState(callerAgent, currentTask))
        {
            return StatusCode(403, new { error = "Statusänderungen sind nur Iris und Bao vorbehalten. Sub-Agenten können Tasks nicht verschieben." });
        }

        var result = await taskService.UpdateStatusAsync(id, request.Status, ct);
        return result.Outcome switch
        {
            TaskOperationOutcome.InvalidState => BadRequest(new { error = $"Unsupported status: '{request.Status}'. Valid: {string.Join(", ", TaskStateHelper.AllStates)}" }),
            TaskOperationOutcome.NotFound => NotFound(new { error = "Task not found." }),
            _ => Ok(MapToDto(result.Task!))
        };
    }

    // ── Task Board Endpoints ──

    [HttpGet("tasks/board")]
    public async Task<BoardResponse> GetBoard(CancellationToken ct)
        => await taskService.GetBoardAsync(ct);

    [HttpPatch("tasks/{id:guid}/move")]
    public async Task<ActionResult<DashboardTaskDto>> MoveTask(
        Guid id, [FromBody] MoveTaskRequest request, CancellationToken ct)
    {
        if (string.IsNullOrWhiteSpace(request.State))
            return BadRequest(new { error = "State is required." });

        // Enforce workflow rules based on caller agent
        var currentTask = await taskService.GetByIdAsync(id, ct);
        if (currentTask is null)
            return NotFound(new { error = "Task not found." });

        // Resolve caller agent from header or JWT
        var callerAgent = ResolveCallerAgent();

        // Nur Iris und Bao dürfen Status ändern
        if (!TaskStateHelper.CanChangeState(callerAgent, currentTask))
        {
            return StatusCode(403, new { error = "Statusänderungen sind nur Iris und Bao vorbehalten. Sub-Agenten können Tasks nicht verschieben." });
        }

        var result = await taskService.MoveTaskAsync(id, request.State, ct);
        return result.Outcome switch
        {
            TaskOperationOutcome.InvalidState => BadRequest(new { error = $"Unsupported state: '{request.State}'. Valid: {string.Join(", ", TaskStateHelper.AllStates)}" }),
            TaskOperationOutcome.NotFound => NotFound(new { error = "Task not found." }),
            _ => Ok(MapToDto(result.Task!))
        };
    }

    /// <summary>
    /// Resolves the caller identity: checks X-Agent-Id header, then JWT name claim.
    /// Falls back to empty string (which authorization helpers reject accordingly).
    /// </summary>
    private string ResolveCallerAgent()
    {
        var httpContext = httpContextAccessor.HttpContext;
        if (httpContext is null) return "";

        var agentHeader = httpContext.Request.Headers["X-Agent-Id"].FirstOrDefault();
        if (!string.IsNullOrWhiteSpace(agentHeader))
            return agentHeader.Trim().ToLowerInvariant();

        var user = httpContext.User;
        var nameClaim = user?.FindFirst(System.Security.Claims.ClaimTypes.NameIdentifier)?.Value;
        return nameClaim?.ToLowerInvariant() ?? "";
    }

    // ── New Endpoints: Reset Stale, Children, Activity ──

    [HttpPost("tasks/reset-stale")]
    public async Task<ActionResult<ResetStaleResponse>> ResetStale(
        [FromBody] ResetStaleRequest request, CancellationToken ct)
    {
        var threshold = TimeSpan.FromHours(Math.Max(1, request.StaleHours));
        var count = await taskService.ResetStaleInProgressTasksAsync(threshold, ct);
        return Ok(new ResetStaleResponse(count));
    }

    [HttpGet("tasks/{id:guid}/children")]
    public async Task<ActionResult<List<DashboardTaskDto>>> GetChildren(Guid id, CancellationToken ct)
    {
        var children = await taskService.GetChildTasksAsync(id, ct);
        return Ok(children.Select(MapToDto).ToList());
    }

    [HttpGet("tasks/{id:guid}")]
    public async Task<ActionResult<DashboardTaskDto>> GetTask(Guid id, CancellationToken ct)
    {
        var task = await taskService.GetByIdAsync(id, ct);
        if (task is null) return NotFound(new { error = "Task not found." });
        return Ok(MapToDto(task));
    }

    [HttpGet("tasks/{id:guid}/activity")]
    public async Task<ActionResult<List<ActivityEvent>>> GetTaskActivity(Guid id, CancellationToken ct)
    {
        var events = await taskService.GetTaskActivityAsync(id, ct);
        return Ok(events);
    }

    [HttpPost("tasks/{id:guid}/activity")]
    public async Task<ActionResult<ActivityEvent>> PostTaskActivity(
        Guid id, [FromBody] PostActivityRequest request, CancellationToken ct)
    {
        var task = await taskService.GetByIdAsync(id, ct);
        if (task is null) return NotFound(new { error = "Task not found." });

        if (string.IsNullOrWhiteSpace(request.Message))
            return BadRequest(new { error = "Message is required." });

        var ev = new ActivityEvent
        {
            Type = request.Type ?? "comment",
            Message = request.Message.Trim(),
            TaskId = id
        };

        await activityService.AddAsync(ev, ct);
        return Created($"/api/dashboard/tasks/{id}/activity/{ev.Id}", ev);
    }

    // ── Agent Workflow Endpoints (Iris Overview) ──

    /// <summary>
    /// Returns agent-tasks that are still open and waiting for input.
    /// Iris uses this to see who she is waiting for.
    /// </summary>
    [HttpGet("tasks/agent-waiting")]
    public async Task<ActionResult<List<DashboardTaskDto>>> GetAgentWaitingTasks(CancellationToken ct)
    {
        var waiting = await taskService.GetWaitingTasksAsync(ct);
        return Ok(waiting.Select(MapToDto).ToList());
    }

    /// <summary>
    /// Returns a complete agent-workflow overview grouped by expected respondent
    /// + stale detection. This is the main Iris dashboard data.
    /// </summary>
    [HttpGet("tasks/agent-overview")]
    public async Task<ActionResult<AgentWorkflowOverview>> GetAgentOverview(
        CancellationToken ct, [FromQuery] int staleHours = 2)
    {
        var threshold = TimeSpan.FromHours(Math.Max(1, staleHours));
        return Ok(await taskService.GetAgentWorkflowOverviewAsync(threshold, ct));
    }

    /// <summary>
    /// Creates an agent-task: a task that is tracked as originating from the agent workflow.
    /// Sub-agents (programmer, reviewer) can only CREATE, not move state.
    /// </summary>
    [HttpPost("tasks/agent")]
    public async Task<ActionResult<DashboardTaskDto>> CreateAgentTask(
        [FromBody] CreateAgentTaskRequest request, CancellationToken ct)
    {
        if (string.IsNullOrWhiteSpace(request.Title))
            return BadRequest(new { error = "Title is required." });

        try
        {
            var task = await taskService.CreateAgentTaskAsync(
                request.Title, request.Detail, request.Source ?? "iris",
                request.Priority, request.AssignedTo, request.ExpectedFrom,
                request.ParentTaskId, ct);

            return Created($"/api/dashboard/tasks/{task.Id}", MapToDto(task));
        }
        catch (ArgumentException ex)
        {
            return BadRequest(new { error = ex.Message });
        }
    }

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