package diff

import (
	"fmt"

	"github.com/spf13/cobra"
	"tangled.org/eric.wien/tng-cli/api"
	"tangled.org/eric.wien/tng-cli/pkg/cmdutil"
	"tangled.org/eric.wien/tng-cli/pkg/iostreams"
)

type Options struct {
	IO        *iostreams.IOStreams
	ApiClient func() (*api.Client, error)
	Rkey      string
	Author    string
}

func NewCmdDiff(f *cmdutil.Factory) *cobra.Command {
	opts := &Options{
		IO:        f.IOStreams,
		ApiClient: f.ApiClient,
	}

	cmd := &cobra.Command{
		Use:   "diff <rkey>",
		Short: "View pull request diff",
		Long: `Display the patch content of a pull request.

Downloads and decompresses the patch blob from the PR's AT Protocol record.`,
		Example: `  tng pr diff 3jxn7q7bklr2r`,
		Args:    cmdutil.ExactArgs(1, "pull request rkey is required"),
		RunE: func(cmd *cobra.Command, args []string) error {
			opts.Rkey = args[0]
			return diffRun(cmd, opts)
		},
	}

	cmd.Flags().StringVar(&opts.Author, "author", "", "DID of the PR author (defaults to you)")

	return cmd
}

func diffRun(cmd *cobra.Command, opts *Options) error {
	client, err := opts.ApiClient()
	if err != nil {
		return err
	}

	authorDID := opts.Author
	if authorDID == "" {
		authorDID = client.DID().String()
	}

	patch, err := client.GetPullPatch(cmd.Context(), authorDID, opts.Rkey)
	if err != nil {
		return fmt.Errorf("failed to fetch diff: %w", err)
	}

	fmt.Fprint(opts.IO.Out, patch)
	return nil
}