package gql

import (
	"fmt"
	"path/filepath"
	"time"

	"github.com/graph-gophers/dataloader"
	"github.com/graphql-go/graphql"
	"github.com/graphql-go/graphql/language/ast"

	helper "git.kapelle.org/niklas/s3browser/internal/helper"
	types "git.kapelle.org/niklas/s3browser/internal/types"
)

var graphqlDirType *graphql.Object
var graphqlFileType *graphql.Object
var graphqlLoginResultType *graphql.Object
var objIDType *graphql.Scalar

//GraphqlTypes create all graphql types and stores the in the global variables
func GraphqlTypes() {

	var dateTimeType = graphql.NewScalar(graphql.ScalarConfig{
		Name:        "DateTime",
		Description: "DateTime is a DateTime in ISO 8601 format",
		Serialize: func(value interface{}) interface{} {
			switch value := value.(type) {
			case time.Time:
				return value.Format(time.RFC3339)
			}

			return "INVALID"
		},
		ParseValue: func(value interface{}) interface{} {
			switch tvalue := value.(type) {
			case string:
				if tval, err := time.Parse(time.RFC3339, tvalue); err != nil {
					return nil
				} else {
					return tval
				}
			}
			return nil
		},
		ParseLiteral: func(valueAST ast.Value) interface{} {
			switch valueAST := valueAST.(type) {
			case *ast.StringValue:
				if tval, err := time.Parse(time.RFC3339, valueAST.Value); err != nil {
					return nil
				} else {
					return tval
				}
			}
			return nil
		},
	})

	objIDType = graphql.NewScalar(graphql.ScalarConfig{
		Name: "objID",
		Description: `String representing a bucket, key and version combination.
			Looks like this: "bucketName:/name/of/key" or "bucketName@version:/name/of/key"`,
		Serialize: func(value interface{}) interface{} {
			switch value := value.(type) {
			case types.ID:
				return value.String()
			}

			return "INVALID"
		},
		ParseValue: func(value interface{}) interface{} {
			switch tvalue := value.(type) {
			case string:
				return types.ParseID(tvalue)
			}
			return nil
		},
		ParseLiteral: func(valueAST ast.Value) interface{} {
			switch valueAST := valueAST.(type) {
			case *ast.StringValue:
				return types.ParseID(valueAST.Value)
			}
			return nil
		},
	})

	graphqlDirType = graphql.NewObject(graphql.ObjectConfig{
		Name:        "Directory",
		Description: "Represents a directory",
		Fields: graphql.Fields{
			"id": &graphql.Field{
				Type: graphql.NewNonNull(objIDType),
			},
			"name": &graphql.Field{
				Type: graphql.String,
				Resolve: func(p graphql.ResolveParams) (interface{}, error) {
					source, ok := p.Source.(types.Directory)
					if !ok {
						return nil, fmt.Errorf("Failed to parse source for resolve")
					}

					return filepath.Base(source.ID.Key), nil
				},
			},
		},
	})

	graphqlFileType = graphql.NewObject(graphql.ObjectConfig{
		Name:        "File",
		Description: "Represents a file, not a directory",
		Fields: graphql.Fields{
			"id": &graphql.Field{
				Type:        graphql.NewNonNull(objIDType),
				Description: "The uniqe ID of the file. Represents the path and the s3 key.",
			},
			"name": &graphql.Field{
				Type: graphql.String,
				Resolve: func(p graphql.ResolveParams) (interface{}, error) {
					source, ok := p.Source.(types.File)
					if !ok {
						return nil, fmt.Errorf("Failed to parse source for resolve")
					}

					return filepath.Base(source.ID.Key), nil
				},
			},
			"size": &graphql.Field{
				Type: graphql.NewNonNull(graphql.Int),
				Resolve: func(p graphql.ResolveParams) (interface{}, error) {
					file, err := loadFile(p)
					if err != nil {
						return nil, err
					}

					return file.Size, nil
				},
			},
			"contentType": &graphql.Field{
				Type: graphql.String,
				Resolve: func(p graphql.ResolveParams) (interface{}, error) {
					file, err := loadFile(p)
					if err != nil {
						return nil, err
					}

					return file.ContentType, nil
				},
			},
			"etag": &graphql.Field{
				Type: graphql.String,
				Resolve: func(p graphql.ResolveParams) (interface{}, error) {
					file, err := loadFile(p)
					if err != nil {
						return nil, err
					}

					return file.ETag, nil
				},
			},
			"lastModified": &graphql.Field{
				Type: dateTimeType,
				Resolve: func(p graphql.ResolveParams) (interface{}, error) {
					file, err := loadFile(p)
					if err != nil {
						return nil, err
					}

					return file.LastModified, nil
				},
			},
			"parent": &graphql.Field{
				Type: graphqlDirType,
				Resolve: func(p graphql.ResolveParams) (interface{}, error) {
					source, ok := p.Source.(types.File)
					if !ok {
						return nil, fmt.Errorf("Failed to parse Source for parent resolve")
					}

					parent := source.ID.Parent()

					if parent == nil {
						return nil, nil
					}

					return types.Directory{
						ID: *source.ID.Parent(),
					}, nil
				},
			},
		},
	})

	graphqlDirType.AddFieldConfig("files", &graphql.Field{
		Type: graphql.NewList(graphqlFileType),
		Resolve: func(p graphql.ResolveParams) (interface{}, error) {
			source, ok := p.Source.(types.Directory)
			if !ok {
				return nil, fmt.Errorf("Failed to parse Source for files resolve")
			}

			loader := p.Context.Value("loader").(map[string]*dataloader.Loader)

			thunk := loader["getFiles"].Load(p.Context, source.ID)
			return thunk()
		},
	})

	graphqlDirType.AddFieldConfig("directorys", &graphql.Field{
		Type: graphql.NewList(graphqlDirType),
		Resolve: func(p graphql.ResolveParams) (interface{}, error) {
			source, ok := p.Source.(types.Directory)
			if !ok {
				return nil, fmt.Errorf("Failed to parse Source for directories resolve")
			}

			loader := p.Context.Value("loader").(map[string]*dataloader.Loader)
			thunk := loader["getDirs"].Load(p.Context, source.ID)

			return thunk()
		},
	})

	graphqlDirType.AddFieldConfig("parent", &graphql.Field{
		Type: graphqlDirType,
		Resolve: func(p graphql.ResolveParams) (interface{}, error) {
			source, ok := p.Source.(types.Directory)
			if !ok {
				return nil, fmt.Errorf("Failed to parse Source for directories resolve")
			}

			return types.Directory{
				ID: helper.GetParentDir(source.ID),
			}, nil
		},
	})

	graphqlLoginResultType = graphql.NewObject(graphql.ObjectConfig{
		Name:        "LoginResut",
		Description: "Result of a login",
		Fields: graphql.Fields{
			"token": &graphql.Field{
				Type:        graphql.String,
				Description: "JWT token if login was successful",
			},
			"successful": &graphql.Field{
				Type:        graphql.NewNonNull(graphql.Boolean),
				Description: "If the login was successful",
			},
		},
	})

}

//loadFile helper func for using the dataloader to get a file
func loadFile(p graphql.ResolveParams) (*types.File, error) {
	source, ok := p.Source.(types.File)
	if !ok {
		return nil, fmt.Errorf("Failed to parse source for resolve")
	}

	loader := p.Context.Value("loader").(map[string]*dataloader.Loader)

	thunk := loader["getFile"].Load(p.Context, source.ID)
	result, err := thunk()

	if err != nil {
		return nil, err
	}

	file, ok := result.(*types.File)

	if !ok {
		return nil, fmt.Errorf("Failed to load file")
	}

	return file, err
}