package services

import (
	"fmt"

	"lostcavewireplanner/internal/db"
	"lostcavewireplanner/internal/models"
)

type Segment struct {
	DeviceID   int64
	DeviceName string
	ModelName  string
	PortID     int64
	PortName   string
	Side       string
}

type TraceResult struct {
	FarSegments      []Segment
	ConnectionID     int64
	ConnectionType   string
	Color            string
	Label1           string
	Label2           string
	ClickedPortID    int64
	ClickedPortName  string
	ClickedDeviceID  int64
	ClickedDeviceName string
	ClickedModelName string
	ClickedSide      string
	NearSegments     []Segment
	HasConnection    bool
}

func TraceConnection(store *db.Store, clickedPortID int64) (*TraceResult, error) {
	clickedPort, err := store.PortGetByID(clickedPortID)
	if err != nil {
		return nil, err
	}
	if clickedPort == nil {
		return nil, fmt.Errorf("port not found")
	}

	clickedDevice, err := store.DeviceGetByID(clickedPort.DeviceID)
	if err != nil {
		return nil, err
	}

	result := &TraceResult{
		ClickedPortID:    clickedPort.ID,
		ClickedPortName:  clickedPort.Name,
		ClickedDeviceID:  clickedDevice.ID,
		ClickedDeviceName: clickedDevice.Name,
		ClickedSide:      clickedPort.Side,
	}
	if clickedDevice.Model != nil {
		result.ClickedModelName = clickedDevice.Model.Name
	}

	conn, err := store.ConnectionGetByPortID(clickedPortID)
	if err != nil {
		return nil, err
	}
	if conn == nil {
		return result, nil
	}

	result.HasConnection = true
	result.ConnectionID = conn.ID
	result.Color = conn.Color
	if conn.Label1 != nil {
		result.Label1 = *conn.Label1
	}
	if conn.Label2 != nil {
		result.Label2 = *conn.Label2
	}
	if conn.ConnectionType != nil {
		result.ConnectionType = conn.ConnectionType.Name
	}

	var remotePort *models.DevicePort
	if conn.PortID1 != nil && *conn.PortID1 == clickedPortID {
		if conn.PortID2 != nil {
			remotePort, _ = store.PortGetByID(*conn.PortID2)
		}
	} else if conn.PortID2 != nil && *conn.PortID2 == clickedPortID {
		if conn.PortID1 != nil {
			remotePort, _ = store.PortGetByID(*conn.PortID1)
		}
	}

	if remotePort != nil {
		result.FarSegments = traceAway(store, remotePort.ID, conn.ID)
	}

	result.NearSegments = traceThrough(store, clickedPortID, conn.ID)

	return result, nil
}

func traceAway(store *db.Store, portID int64, excludeConnID int64) []Segment {
	var segments []Segment
	visitedPorts := map[int64]bool{}
	currentPortID := portID

	for {
		if visitedPorts[currentPortID] {
			break
		}
		visitedPorts[currentPortID] = true

		port, err := store.PortGetByID(currentPortID)
		if err != nil || port == nil {
			break
		}

		device, err := store.DeviceGetByID(port.DeviceID)
		if err != nil || device == nil {
			break
		}

		modelName := ""
		if device.Model != nil {
			modelName = device.Model.Name
		}

		segments = append(segments, Segment{
			DeviceID:   device.ID,
			DeviceName: device.Name,
			ModelName:  modelName,
			PortID:     port.ID,
			PortName:   port.Name,
			Side:       port.Side,
		})

		isPatch := device.Model != nil && (device.Model.IsPatchPanel || device.Model.IsWallSocket)
		if !isPatch {
			break
		}

		pairedSide := "back"
		if port.Side == "back" {
			pairedSide = "front"
		}

		pairedPort, err := store.PortGetPaired(port.DeviceID, port.Name, pairedSide)
		if err != nil || pairedPort == nil {
			break
		}

		if visitedPorts[pairedPort.ID] {
			break
		}

		nextConn, err := store.ConnectionGetByPortIDExcluding(pairedPort.ID, excludeConnID)
		if err != nil || nextConn == nil {
			break
		}

		var nextPortID int64
		if nextConn.PortID1 != nil && *nextConn.PortID1 != pairedPort.ID {
			nextPortID = *nextConn.PortID1
		} else if nextConn.PortID2 != nil && *nextConn.PortID2 != pairedPort.ID {
			nextPortID = *nextConn.PortID2
		} else {
			break
		}

		excludeConnID = nextConn.ID
		currentPortID = nextPortID
	}

	return segments
}

func traceThrough(store *db.Store, portID int64, excludeConnID int64) []Segment {
	var segments []Segment

	port, err := store.PortGetByID(portID)
	if err != nil || port == nil {
		return segments
	}

	device, err := store.DeviceGetByID(port.DeviceID)
	if err != nil || device == nil {
		return segments
	}

	isPatch := device.Model != nil && (device.Model.IsPatchPanel || device.Model.IsWallSocket)
	if !isPatch {
		return segments
	}

	pairedSide := "back"
	if port.Side == "back" {
		pairedSide = "front"
	}

	pairedPort, err := store.PortGetPaired(port.DeviceID, port.Name, pairedSide)
	if err != nil || pairedPort == nil {
		return segments
	}

	nextConn, err := store.ConnectionGetByPortIDExcluding(pairedPort.ID, excludeConnID)
	if err != nil || nextConn == nil {
		return segments
	}

	var nextPortID int64
	if nextConn.PortID1 != nil && *nextConn.PortID1 != pairedPort.ID {
		nextPortID = *nextConn.PortID1
	} else if nextConn.PortID2 != nil && *nextConn.PortID2 != pairedPort.ID {
		nextPortID = *nextConn.PortID2
	} else {
		return segments
	}

	return traceAway(store, nextPortID, nextConn.ID)
}