package buildx

import (
	"errors"
	"os"

	"github.com/drone/envsubst"
	"gopkg.in/yaml.v3"
)

func subst(ref *string) error {
	result, err := envsubst.EvalEnv(*ref)
	*ref = result
	return err
}

func defaultValue(ref *string, value string) {
	if *ref == "" {
		*ref = value
	}
}

func LoadJob(path string) (*Job, error) {
	var job Job

	file, err := os.ReadFile(path)
	if err != nil {
		return nil, err
	}

	err = yaml.Unmarshal(file, &job)
	if err != nil {
		return nil, err
	}

	// check for empty fields

	// registry
	if job.Registries == nil {
		job.Registries = []string{"docker.io"}
	}

	// repos
	for i, repo := range job.Repositories {
		if repo.Name == "" {
			return nil, errors.New("missing repository name")
		}
		if repo.Library == "" {
			return nil, errors.New("missing library")
		}

		defaultValue(&job.Repositories[i].Path, repo.Name)

		// builds
		for j := range job.Repositories[i].Builds {
			defaultValue(&job.Repositories[i].Builds[j].Context, ".")
			defaultValue(&job.Repositories[i].Builds[j].Dockerfile, "Dockerfile")
		}
	}

	// envsubst

	// registries
	for i := range job.Registries {
		if err = subst(&job.Registries[i]); err != nil {
			return nil, err
		}
	}

	// repos
	for i := range job.Repositories {
		// name
		if err = subst(&job.Repositories[i].Name); err != nil {
			return nil, err
		}

		// library
		if err = subst(&job.Repositories[i].Library); err != nil {
			return nil, err
		}

		// path
		if err = subst(&job.Repositories[i].Path); err != nil {
			return nil, err
		}

		// global args
		for j := range job.Repositories[i].GlobalArguments {
			// key
			if err = subst(&job.Repositories[i].GlobalArguments[j].Key); err != nil {
				return nil, err
			}

			// value
			if err = subst(&job.Repositories[i].GlobalArguments[j].Value); err != nil {
				return nil, err
			}
		}

		// tags
		for j := range job.Repositories[i].Tags {
			// name
			if err = subst(&job.Repositories[i].Tags[j].Name); err != nil {
				return nil, err
			}

			// tags
			for u := range job.Repositories[i].Tags[j].Tags {
				if err = subst(&job.Repositories[i].Tags[j].Tags[u]); err != nil {
					return nil, err
				}
			}
		}

		// builds
		for j := range job.Repositories[i].Builds {
			// arch
			if err = subst(&job.Repositories[i].Builds[j].Architecture); err != nil {
				return nil, err
			}

			// dockerfile
			if err = subst(&job.Repositories[i].Builds[j].Dockerfile); err != nil {
				return nil, err
			}

			// tags
			for u := range job.Repositories[i].Builds[j].Tags {
				if err = subst(&job.Repositories[i].Builds[j].Tags[u]); err != nil {
					return nil, err
				}
			}
		}
	}

	return &job, err
}