using System.Text.Json;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging;
using RobotNet10.NavigationTune.Data;
using RobotNet10.NavigationTune.Shared.Models;
using StraightLineScenario = RobotNet10.NavigationTune.Scenarios.StraightLineScenario;
using CircleScenario = RobotNet10.NavigationTune.Scenarios.CircleScenario;
using CustomPathScenario = RobotNet10.NavigationTune.Scenarios.CustomPathScenario;

namespace RobotNet10.NavigationTune.Controllers;

/// <summary>
/// DTO for TestScenario API responses
/// </summary>
public class TestScenarioDto
{
    public Guid Id { get; set; }
    public string Name { get; set; } = string.Empty;
    public string Description { get; set; } = string.Empty;
    public TrajectoryType Type { get; set; }
    public DateTime CreatedAt { get; set; }
    public bool IsDefault { get; set; }
    public string ConfigJson { get; set; } = string.Empty;

    public static TestScenarioDto FromTestScenario(TestScenario scenario, TestScenarioEntity entity)
    {
        return new TestScenarioDto
        {
            Id = scenario.Id,
            Name = scenario.Name,
            Description = scenario.Description,
            Type = scenario.Type,
            CreatedAt = scenario.CreatedAt,
            IsDefault = scenario.IsDefault,
            ConfigJson = entity.ConfigJson
        };
    }
}

/// <summary>
/// Request DTO for Create/Update scenario. Uses Type + ConfigJson to avoid deserializing abstract TestScenario.
/// </summary>
public class CreateOrUpdateScenarioRequest
{
    public Guid? Id { get; set; }
    public string Name { get; set; } = string.Empty;
    public string Description { get; set; } = string.Empty;
    public TrajectoryType Type { get; set; }
    public bool IsDefault { get; set; }
    /// <summary>JSON string of the scenario-specific config (serialized StraightLineScenario, CircleScenario, or CustomPathScenario).</summary>
    public string ConfigJson { get; set; } = string.Empty;
}

/// <summary>
/// REST API controller for test scenarios management
/// </summary>
[ApiController]
[Route("api/[controller]")]
public class ScenariosController(
    IScenarioRepository scenarioRepository,
    ILogger<ScenariosController> logger) : ControllerBase
{
    private readonly IScenarioRepository _scenarioRepository = scenarioRepository;
    private readonly ILogger<ScenariosController> _logger = logger;

    /// <summary>
    /// Get all scenarios
    /// </summary>
    [HttpGet]
    public async Task<ActionResult<List<TestScenarioDto>>> GetAll()
    {
        try
        {
            var entities = await _scenarioRepository.GetAllEntitiesAsync();
            var dtos = new List<TestScenarioDto>();
            
            foreach (var entity in entities)
            {
                var scenario = entity.ToTestScenario();
                dtos.Add(TestScenarioDto.FromTestScenario(scenario, entity));
            }
            
            return Ok(dtos);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error getting all scenarios");
            return StatusCode(500, new { error = "Failed to retrieve scenarios" });
        }
    }

    /// <summary>
    /// Get default scenarios
    /// </summary>
    [HttpGet("defaults")]
    public async Task<ActionResult<List<TestScenarioDto>>> GetDefaults()
    {
        try
        {
            var entities = await _scenarioRepository.GetDefaultScenarioEntitiesAsync();
            var dtos = new List<TestScenarioDto>();
            
            foreach (var entity in entities)
            {
                var scenario = entity.ToTestScenario();
                dtos.Add(TestScenarioDto.FromTestScenario(scenario, entity));
            }
            
            return Ok(dtos);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error getting default scenarios");
            return StatusCode(500, new { error = "Failed to retrieve default scenarios" });
        }
    }

    /// <summary>
    /// Get scenario by ID
    /// </summary>
    [HttpGet("{id:guid}")]
    public async Task<ActionResult<TestScenarioDto>> GetById(Guid id)
    {
        try
        {
            var entity = await _scenarioRepository.GetEntityByIdAsync(id);
            if (entity == null)
                return NotFound(new { error = $"Scenario with ID {id} not found" });

            var scenario = entity.ToTestScenario();
            return Ok(TestScenarioDto.FromTestScenario(scenario, entity));
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error getting scenario {Id}", id);
            return StatusCode(500, new { error = "Failed to retrieve scenario" });
        }
    }

    /// <summary>
    /// Create new scenario. Accepts Type + ConfigJson to avoid deserializing abstract TestScenario.
    /// </summary>
    [HttpPost]
    public async Task<ActionResult<TestScenarioDto>> Create([FromBody] CreateOrUpdateScenarioRequest request)
    {
        try
        {
            var scenario = DeserializeScenarioFromRequest(request);
            if (scenario.Id == Guid.Empty)
                scenario.Id = Guid.NewGuid();

            var id = await _scenarioRepository.SaveAsync(scenario);
            var entity = await _scenarioRepository.GetEntityByIdAsync(id);
            if (entity == null)
                return StatusCode(500, new { error = "Failed to retrieve created scenario" });

            var dto = TestScenarioDto.FromTestScenario(entity.ToTestScenario(), entity);
            return CreatedAtAction(nameof(GetById), new { id }, dto);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error creating scenario");
            return StatusCode(500, new { error = "Failed to create scenario" });
        }
    }

    /// <summary>
    /// Update existing scenario. Accepts Type + ConfigJson to avoid deserializing abstract TestScenario.
    /// </summary>
    [HttpPut("{id:guid}")]
    public async Task<ActionResult> Update(Guid id, [FromBody] CreateOrUpdateScenarioRequest request)
    {
        try
        {
            var existing = await _scenarioRepository.GetEntityByIdAsync(id);
            if (existing == null)
                return NotFound(new { error = $"Scenario with ID {id} not found" });

            var scenario = DeserializeScenarioFromRequest(request);
            scenario.Id = id;
            await _scenarioRepository.UpdateAsync(scenario);
            return NoContent();
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error updating scenario {Id}", id);
            return StatusCode(500, new { error = "Failed to update scenario" });
        }
    }

    /// <summary>
    /// Deserialize ConfigJson to concrete TestScenario based on Type (avoids abstract type deserialization).
    /// </summary>
    private static TestScenario DeserializeScenarioFromRequest(CreateOrUpdateScenarioRequest request)
    {
        var jsonOptions = new JsonSerializerOptions { PropertyNameCaseInsensitive = true };
        TestScenario scenario = request.Type switch
        {
            TrajectoryType.StraightLine => JsonSerializer.Deserialize<StraightLineScenario>(request.ConfigJson, jsonOptions)
                ?? new StraightLineScenario(),
            TrajectoryType.Circle => JsonSerializer.Deserialize<CircleScenario>(request.ConfigJson, jsonOptions)
                ?? new CircleScenario(),
            TrajectoryType.Custom => JsonSerializer.Deserialize<CustomPathScenario>(request.ConfigJson, jsonOptions)
                ?? new CustomPathScenario(),
            _ => throw new NotSupportedException($"Scenario type {request.Type} is not supported")
        };
        scenario.Id = request.Id ?? Guid.Empty;
        scenario.Name = request.Name;
        scenario.Description = request.Description;
        scenario.Type = request.Type;
        scenario.IsDefault = request.IsDefault;
        return scenario;
    }

    /// <summary>
    /// Delete scenario. Only custom (non-default) scenarios can be deleted.
    /// </summary>
    [HttpDelete("{id:guid}")]
    public async Task<ActionResult> Delete(Guid id)
    {
        try
        {
            var existing = await _scenarioRepository.GetByIdAsync(id);
            if (existing == null)
                return NotFound(new { error = $"Scenario with ID {id} not found" });

            if (existing.IsDefault)
                return BadRequest(new { error = "Cannot delete default scenario. Only custom scenarios can be deleted." });

            await _scenarioRepository.DeleteAsync(id);
            return NoContent();
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error deleting scenario {Id}", id);
            return StatusCode(500, new { error = "Failed to delete scenario" });
        }
    }
}