package metadatautil

import (
	"fmt"
	"io"
	"io/ioutil"

	"github.com/goccy/go-yaml"
	"github.com/goccy/go-yaml/parser"
	"github.com/hasura/graphql-engine/cli/internal/hasura"
)

func getMetadataAsYaml(exportMetadata func() (io.Reader, error)) ([]byte, error) {
	metadata, err := exportMetadata()
	if err != nil {
		return nil, err
	}
	jsonb, err := ioutil.ReadAll(metadata)
	if err != nil {
		return nil, err
	}
	yamlb, err := yaml.JSONToYAML(jsonb)
	if err != nil {
		return nil, err
	}
	return yamlb, err
}

func GetSourceKind(exportMetadata func() (io.Reader, error), sourceName string) (*hasura.SourceKind, error) {
	metadata, err := getMetadataAsYaml(exportMetadata)
	if err != nil {
		return nil, err
	}
	ast, err := parser.ParseBytes(metadata, 0)
	if err != nil {
		return nil, err
	}
	if len(ast.Docs) <= 0 {
		return nil, fmt.Errorf("failed listing sources from metadata")
	}
	var sources []struct {
		Name string            `yaml:"name"`
		Kind hasura.SourceKind `yaml: "kind"`
	}
	path, err := yaml.PathString("$.sources[*]")
	if err != nil {
		return nil, err
	}
	if err := path.Read(ast.Docs[0], &sources); err != nil {
		return nil, err
	}
	for _, s := range sources {
		if s.Name == sourceName {
			return &s.Kind, nil
		}
	}
	return nil, nil
}

func GetSources(exportMetadata func() (io.Reader, error)) ([]string, error) {
	metadata, err := getMetadataAsYaml(exportMetadata)
	if err != nil {
		return nil, err
	}
	ast, err := parser.ParseBytes(metadata, 0)
	if err != nil {
		return nil, err
	}
	if len(ast.Docs) <= 0 {
		return nil, fmt.Errorf("failed listing sources from metadata")
	}
	var sources []string
	path, err := yaml.PathString("$.sources[*].name")
	if err != nil {
		return nil, err
	}
	if err := path.Read(ast.Docs[0], &sources); err != nil {
		return nil, err
	}
	return sources, nil
}