gopatterns/pkg/template/point.go

package template

import (
	"errors"
	"fmt"
	"git.wtrh.nl/patterns/gopatterns/pkg/path"
	"git.wtrh.nl/patterns/gopatterns/pkg/util"
	"maps"
	"math"
	"strconv"

	"git.wtrh.nl/patterns/gopatterns/pkg/point"
	"gopkg.in/Knetic/govaluate.v3"
)

const maxRecursionDepth = 100

var (
	// ErrPointNotFound is returned when a required point is not defined.
	ErrPointNotFound = errors.New("required point not found")

	// ErrRelativePointRecursion is returned when a points are relative to itself.
	ErrRelativePointRecursion = errors.New("point cannot be relative to itself")

	ErrInvalidArguments = errors.New("invalid arguments to call function")
)

// Points contains a map with points.
type Points map[util.ID]Point

// Point contains the template information for a point.
type Point struct {
	Position    Position      `yaml:"position"`
	RelativeTo  *util.ID      `yaml:"relativeTo,omitempty"`
	Description string        `yaml:"description"`
	Between     *BetweenPoint `yaml:"between"`
	Extend      *ExtendPoint  `yaml:"extend"`
	Hide        bool          `yaml:"hide"`
	Polar       *PolarPoint   `yaml:"polar"`
}

func (t Template) templatePoint(panelName string, id util.ID) (Point, error) {
	if id.Panel() != "" {
		panelName = id.Panel()
	}

	panel, err := t.Panel(panelName)
	if !errors.Is(err, ErrPanelNotFound) {
		p, ok := panel.Points[id.Deref()]
		if ok {
			return p, nil
		}
	}

	p, ok := t.Points[id.Deref()]
	if !ok {
		return Point{}, ErrPointNotFound
	}

	return p, nil
}

var ErrInvalidPointID = errors.New("type cannot be converted to a PointID")

func (t Template) functions(req request) map[string]govaluate.ExpressionFunction {
	functions := t.evaluationFunctions()

	maps.Copy(functions, map[string]govaluate.ExpressionFunction{
		"DistanceBetween": func(args ...interface{}) (interface{}, error) {
			if len(args) != 2 {
				return nil, fmt.Errorf("function DistanceBetween() requires 2 arguments: %w",
					ErrInvalidArguments)
			}

			points, err := t.getOrCreatePointsFromArgs(req, args...)
			if err != nil {
				return nil, err
			}
			return points[0].Position().Distance(points[1].Position()), nil
		},
		"AngleBetween": func(args ...interface{}) (interface{}, error) {
			if len(args) != 2 {
				return nil, fmt.Errorf("function AngleBetween() requires 2 arguments: %w",
					ErrInvalidArguments)
			}

			points, err := t.getOrCreatePointsFromArgs(req, args...)
			if err != nil {
				return nil, err
			}

			return points[0].Vector().AngleBetween(points[1].Vector()), nil
		},
		"YDistanceBetween": func(args ...interface{}) (interface{}, error) {
			if len(args) != 2 {
				return nil, fmt.Errorf("function DistanceBetween() requires 2 arguments: %w",
					ErrInvalidArguments)
			}

			points, err := t.getOrCreatePointsFromArgs(req, args...)
			if err != nil {
				return nil, err
			}

			return points[1].Vector().Y - points[0].Vector().Y, nil
		},
		"XDistanceBetween": func(args ...interface{}) (interface{}, error) {
			if len(args) != 2 {
				return nil, fmt.Errorf("function DistanceBetween() requires 2 arguments: %w",
					ErrInvalidArguments)
			}

			points, err := t.getOrCreatePointsFromArgs(req, args...)
			if err != nil {
				return nil, err
			}

			return points[1].Vector().X - points[0].Vector().X, nil
		},
		"LineLength": func(args ...interface{}) (interface{}, error) {
			if len(args) != 1 {
				return nil, fmt.Errorf("function LineLength() requires 2 arguments: %w", ErrInvalidArguments)
			}

			line, err := t.getOrCreateLinesFromArgs(req, args...)
			if err != nil {
				return nil, err
			}

			return line[0].Length()
		},
	})

	return functions
}

func (t Template) getOrCreatePointsFromArgs(req request, args ...interface{}) ([]point.Point, error) {
	points := make([]point.Point, 0, len(args))

	for i, arg := range args {
		id, err := toID(arg)
		if err != nil {
			return nil, fmt.Errorf("parsing args[%d] to ID: %w", i, err)
		}

		newPoint, err := t.getOrCreatePoint(id, req, 0)
		if err != nil {
			return nil, fmt.Errorf("get or create point %q: %w", id, err)
		}

		points = append(points, newPoint)
	}

	return points, nil
}

func (t Template) getOrCreateLinesFromArgs(req request, args ...interface{}) ([]path.Path, error) {
	points := make([]path.Path, 0, len(args))

	for i, arg := range args {
		id, err := toID(arg)
		if err != nil {
			return nil, fmt.Errorf("parsing args[%d] to ID: %w", i, err)
		}

		newPoint, err := t.getOrCreateLine(id, req, 0)
		if err != nil {
			return nil, fmt.Errorf("get or create line %q: %w", id, err)
		}

		points = append(points, newPoint)
	}

	return points, nil
}

func toID(arg interface{}) (util.ID, error) {
	v1, ok := arg.(string)
	if !ok {
		f, ok := arg.(float64)
		if !ok {
			return "", fmt.Errorf("parsing %v as PointID: %w", arg, ErrInvalidPointID)
		}

		v1 = strconv.FormatFloat(f, 'f', -1, 64)
	}

	return util.ID(v1), nil
}

// BetweenPoint contains the template information for a point in between two other points.
type BetweenPoint struct {
	From   util.ID `yaml:"from"`
	To     util.ID `yaml:"to"`
	Offset *Value  `yaml:"offset"`
}

func (t Template) evaluationFunctions() map[string]govaluate.ExpressionFunction {
	return map[string]govaluate.ExpressionFunction{
		"acos": func(args ...interface{}) (interface{}, error) {
			if len(args) != 1 {
				return nil, fmt.Errorf("function acos() requires 1 argument: %w", ErrInvalidArguments)
			}

			x, ok := args[0].(float64)
			if !ok {
				return nil, fmt.Errorf("evaluate acos(): parsing %q as float64: %w", args[0], ErrInvalidArguments)
			}

			return math.Acos(x), nil
		},
		"asin": func(args ...interface{}) (interface{}, error) {
			if len(args) != 1 {
				return nil, fmt.Errorf("function asin() requires 1 argument: %w", ErrInvalidArguments)
			}

			x, ok := args[0].(float64)
			if !ok {
				return nil, fmt.Errorf("evaluate asin(): parsing %q as float64: %w", args[0], ErrInvalidArguments)
			}

			return math.Asin(x), nil
		},
		"abs": func(args ...interface{}) (interface{}, error) {
			if len(args) != 1 {
				return nil, fmt.Errorf("function abs() requires 1 argument: %w", ErrInvalidArguments)
			}

			x, ok := args[0].(float64)
			if !ok {
				return nil, fmt.Errorf("evaluate abs(): parsing %q as float64: %w", args[0], ErrInvalidArguments)
			}

			return math.Abs(x), nil
		},
		"atan2": func(args ...interface{}) (interface{}, error) {
			if len(args) != 2 {
				return nil, fmt.Errorf("function atan2() requires 2 arguments: %w", ErrInvalidArguments)
			}
			x, ok := args[0].(float64)
			if !ok {
				return nil, fmt.Errorf("evaluate atan2(): parsing %q as float64: %w", args[0], ErrInvalidArguments)
			}

			y, ok := args[1].(float64)
			if !ok {
				return nil, fmt.Errorf("evaluate atan2(): parsing %q as float64: %w", args[0], ErrInvalidArguments)
			}

			return math.Atan2(x, y), nil
		},
	}
}

func (t Template) createPoint(id util.ID, req request, depth int) (p point.Point, err error) {
	templatePoint, err := t.templatePoint(req.name, id)
	if err != nil {
		return nil, fmt.Errorf("creating point: %w", err)
	}

	var newPoint point.Point

	switch {
	case templatePoint.RelativeTo != nil && templatePoint.Polar != nil:
		newPoint, err = t.createPolar(id, req, depth)
		if err != nil {
			return nil, err
		}
	case templatePoint.RelativeTo != nil:
		newPoint, err = t.createRelative(id, req, depth)
		if err != nil {
			return nil, err
		}
	case templatePoint.Between != nil:
		newPoint, err = t.createBetween(id, req, depth)
		if err != nil {
			return nil, err
		}
	case templatePoint.Extend != nil:
		newPoint, err = t.createExtend(id, req, depth)
		if err != nil {
			return nil, err
		}
	default:
		x, y, r, err := templatePoint.Position.evaluate(req.dimensions.Parameters(), t.functions(req))
		if err != nil {
			return nil, err
		}

		newPoint = point.NewAbsolutePoint(x, y, r, id)
	}

	if templatePoint.Hide {
		newPoint.SetHide()
	}

	return newPoint, nil
}

func (t Template) createRelative(id util.ID, req request, depth int) (*point.RelativePoint, error) {
	templatePoint, err := t.templatePoint(req.name, id)
	if err != nil {
		return nil, err
	}

	relativePointID := *templatePoint.RelativeTo
	if relativePointID == id || depth > maxRecursionDepth {
		return nil, ErrRelativePointRecursion
	}

	relativePoint, err := t.getOrCreatePoint(relativePointID, req, depth)
	if err != nil {
		return nil, err
	}

	x, y, r, err := templatePoint.Position.evaluate(req.dimensions.Parameters(), t.functions(req))
	if err != nil {
		return nil, err
	}

	return point.NewRelativePoint(relativePoint).
		WithXOffset(x).WithYOffset(y).WithRotationOffset(r).
		MarkWith(id), nil
}

//nolint:ireturn,dupl
func (t Template) createBetween(id util.ID, req request, depth int) (point.Point, error) {
	newPoint, err := t.templatePoint(req.name, id)
	if err != nil {
		return nil, err
	}

	if newPoint.Between.To == id || newPoint.Between.From == id || depth > maxRecursionDepth {
		return nil, ErrRelativePointRecursion
	}

	fromPoint, err := t.getOrCreatePoint(newPoint.Between.From, req, depth)
	if err != nil {
		return nil, err
	}

	toPoint, err := t.getOrCreatePoint(newPoint.Between.To, req, depth)
	if err != nil {
		return nil, err
	}

	params := req.dimensions.Parameters()

	offset, err := newPoint.Between.Offset.Evaluate(params, t.functions(req))
	if err != nil {
		return nil, err
	}

	return point.NewBetweenPoint(fromPoint, toPoint, offset, id), nil
}

func (t Template) getOrCreatePoints(ids []util.ID, req request, depth int) ([]point.Point, error) {
	points := make([]point.Point, 0, len(ids))

	for _, id := range ids {
		createPoint, err := t.getOrCreatePoint(id, req, depth)
		if err != nil {
			return nil, err
		}

		points = append(points, createPoint)
	}

	return points, nil
}

//nolint:ireturn
func (t Template) getOrCreatePoint(id util.ID, req request, depth int) (point.Point, error) {
	p, ok := req.points[id]
	if ok {
		return p, nil
	}

	newPoint, err := t.createPoint(id, req, depth+1)
	if err != nil {
		return nil, fmt.Errorf("creating point %q: %w", id, err)
	}

	req.points[id] = newPoint

	return newPoint, nil
}

//nolint:ireturn,dupl
func (t Template) createExtend(id util.ID, req request, depth int) (point.Point, error) {
	newPoint, err := t.templatePoint(req.name, id)
	if err != nil {
		return nil, err
	}

	if newPoint.Extend.To == id || newPoint.Extend.From == id || depth > maxRecursionDepth {
		return nil, ErrRelativePointRecursion
	}

	fromPoint, err := t.getOrCreatePoint(newPoint.Extend.From, req, depth)
	if err != nil {
		return nil, err
	}

	toPoint, err := t.getOrCreatePoint(newPoint.Extend.To, req, depth)
	if err != nil {
		return nil, err
	}

	offset, err := newPoint.Extend.Offset.Evaluate(req.dimensions.Parameters(), t.functions(req))
	if err != nil {
		return nil, err
	}

	return point.NewExtendPoint(fromPoint, toPoint, offset, id), nil
}

//nolint:ireturn
func (t Template) createPolar(id util.ID, req request, depth int) (point.Point, error) {
	templatePoint, err := t.templatePoint(req.name, id)
	if err != nil {
		return nil, err
	}

	relativePointID := *templatePoint.RelativeTo
	if relativePointID == id || depth > maxRecursionDepth {
		return nil, ErrRelativePointRecursion
	}

	relativePoint, err := t.getOrCreatePoint(relativePointID, req, depth)
	if err != nil {
		return nil, err
	}

	x, y, r, err := templatePoint.Polar.evaluate(req.dimensions.Parameters(), t.functions(req))
	if err != nil {
		return nil, err
	}

	return point.NewRelativePoint(relativePoint).
		WithXOffset(x).WithYOffset(y).MarkWith(id).WithRotationOffset(r), nil
}

// ExtendPoint describes how to draw a new point that extends in line with two points.
type ExtendPoint struct {
	From   util.ID `yaml:"from"`
	To     util.ID `yaml:"to"`
	Offset *Value  `yaml:"offset"`
}

// PolarPoint describes how to draw a new point with a direction and a distance from the current
// position.
type PolarPoint struct {
	Length   *Value `yaml:"length"`
	Rotation *Value `yaml:"rotation"`
}

func (p PolarPoint) evaluate(
	params govaluate.MapParameters,
	funcs map[string]govaluate.ExpressionFunction,
) (x, y, r float64, err error) {
	rotation, err := p.Rotation.Evaluate(params, funcs)
	if err != nil {
		return 0, 0, 0, err
	}

	length, err := p.Length.Evaluate(params, funcs)
	if err != nil {
		return 0, 0, 0, err
	}

	return math.Cos(rotation) * length, math.Sin(rotation) * length, rotation, nil
}