package deploy

import (
	"bytes"
	"context"
	"fmt"
	"io"
	"io/fs"
	"net/http"
	"net/url"
	"strings"

	"github.com/databricks/cli/bundle"
	"github.com/databricks/cli/libs/filer"
	"github.com/databricks/databricks-sdk-go/client"
)

// FilerFactory is a function that returns a filer.Filer.
type FilerFactory func(b *bundle.Bundle) (filer.Filer, error)

type stateFiler struct {
	filer filer.Filer

	apiClient *client.DatabricksClient
	root      filer.WorkspaceRootPath
}

func (s stateFiler) Delete(ctx context.Context, path string, mode ...filer.DeleteMode) error {
	return s.filer.Delete(ctx, path, mode...)
}

// Mkdir implements filer.Filer.
func (s stateFiler) Mkdir(ctx context.Context, path string) error {
	return s.filer.Mkdir(ctx, path)
}

func (s stateFiler) Read(ctx context.Context, path string) (io.ReadCloser, error) {
	absPath, err := s.root.Join(path)
	if err != nil {
		return nil, err
	}

	stat, err := s.Stat(ctx, path)
	if err != nil {
		return nil, err
	}
	if stat.IsDir() {
		return nil, fmt.Errorf("not a file: %s", absPath)
	}

	var buf bytes.Buffer
	urlPath := "/api/2.0/workspace-files/" + url.PathEscape(strings.TrimLeft(absPath, "/"))
	err = s.apiClient.Do(ctx, http.MethodGet, urlPath, nil, nil, nil, &buf)
	if err != nil {
		return nil, err
	}

	return io.NopCloser(&buf), nil
}

func (s stateFiler) ReadDir(ctx context.Context, path string) ([]fs.DirEntry, error) {
	return s.filer.ReadDir(ctx, path)
}

func (s stateFiler) Stat(ctx context.Context, name string) (fs.FileInfo, error) {
	return s.filer.Stat(ctx, name)
}

func (s stateFiler) Write(ctx context.Context, path string, reader io.Reader, mode ...filer.WriteMode) error {
	return s.filer.Write(ctx, path, reader, mode...)
}

// StateFiler returns a filer.Filer that can be used to read/write state files.
// We use a custom workspace filer which uses workspace-files API to read state files.
// This API has a higher than 10 MB limits and allows to export large state files.
// We don't use the same API for read because it doesn't correct get the file content for notebooks and returns
// "File Not Found" error instead.
func StateFiler(b *bundle.Bundle) (filer.Filer, error) {
	f, err := filer.NewWorkspaceFilesClient(b.WorkspaceClient(), b.Config.Workspace.StatePath)
	if err != nil {
		return nil, err
	}

	apiClient, err := client.New(b.WorkspaceClient().Config)
	if err != nil {
		return nil, fmt.Errorf("failed to create API client: %w", err)
	}

	return stateFiler{
		filer:     f,
		root:      filer.NewWorkspaceRootPath(b.Config.Workspace.StatePath),
		apiClient: apiClient,
	}, nil
}