package parse

import (
	"fmt"

	"github.com/aziis98/cabret"
	"github.com/aziis98/cabret/config"
	"github.com/aziis98/cabret/operation"
)

// switchMapHasKey returns a function that returns true if the map "m" contains the given key and binds the corresponding value to the provided "target" pointer, useful for writing map key checks using a switch instead of an if chain
func switchMapHasKey(m map[string]any, target *any) func(k string) bool {
	return func(k string) bool {
		val, ok := m[k]
		if ok {
			*target = val
		}
		return ok
	}
}

func ParsePipeline(p config.Pipeline) ([]cabret.Operation, error) {
	ops := []cabret.Operation{}

	for _, operationConfig := range p.Pipeline {
		var rawValue any
		hasKey := switchMapHasKey(operationConfig, &rawValue)

		switch {
		case hasKey("source"):
			value, ok := rawValue.(string)
			if !ok {
				return nil, fmt.Errorf(`expected string but got "%v" of type %T`, rawValue, rawValue)
			}

			operationConfig[operation.ShortFormValueKey] = value

			op, err := ParseOperation("source", operationConfig)
			if err != nil {
				return nil, err
			}

			ops = append(ops, op)

		case hasKey("target"):
			value, ok := rawValue.(string)
			if !ok {
				return nil, fmt.Errorf(`expected string but got "%v" of type %T`, rawValue, rawValue)
			}

			operationConfig[operation.ShortFormValueKey] = value

			op, err := ParseOperation("target", operationConfig)
			if err != nil {
				return nil, err
			}

			ops = append(ops, op)

		case hasKey("use"):
			name, ok := rawValue.(string)
			if !ok {
				return nil, fmt.Errorf(`expected string but got "%v" of type %T`, rawValue, rawValue)
			}

			op, err := ParseOperation(name, operationConfig)
			if err != nil {
				return nil, err
			}

			ops = append(ops, op)

		default:
			return nil, fmt.Errorf(`pipeline entry is missing one of "use", "source" or "target", got %#v`, operationConfig)
		}
	}

	return ops, nil
}

func ParseOperation(name string, options map[string]any) (cabret.Operation, error) {
	op, err := operation.NewWithName(name)
	if err != nil {
		return nil, err
	}

	if err := op.Configure(options); err != nil {
		return nil, err
	}

	return op, nil
}