package main

import (
	"context"
	"errors"
	"fmt"
	"io"
	"os"

	"github.com/google/go-github/v72/github"
	"github.com/manifoldco/promptui"
	"github.com/spf13/cobra"
	"github.com/spf13/viper"
)

const gitignoreFileName string = ".gitignore"

// newCmd represents the new command.
var newCmd = &cobra.Command{
	Use:   "new",
	Short: "Create a new .gitignore file",
	Args:  cobra.NoArgs,
	RunE: func(cmd *cobra.Command, args []string) error {
		return runNewCommand(cmd, args)
	},
}

func init() {
	rootCmd.AddCommand(newCmd)
}

type promptConfig struct {
	Height      int
	StartSearch bool
	FilterType  string
}

// runNewCommand is the handler for the 'new' command.
// It retrieves the selected .gitignore template from GitHub and writes it to the .gitignore file.
func runNewCommand(cmd *cobra.Command, _ []string) error {
	pc := promptConfig{
		Height:      viper.GetInt("height"),
		StartSearch: viper.GetBool("start-search"),
		FilterType:  viper.GetString("filter"),
	}
	if pc.Height <= 0 {
		return errors.New("height must be a positive integer")
	}

	client, ok := ClientFromContext(cmd.Context())
	if !ok {
		return errors.New("failed to get GitHub client from context")
	}

	content, err := runPrompt(client, &pc)
	if err != nil {
		return fmt.Errorf("error running selection prompt: %w", err)
	}

	f, err := os.OpenFile(gitignoreFileName, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0o600)
	if err != nil {
		return fmt.Errorf("error opening file '%s': %w", gitignoreFileName, err)
	}
	defer f.Close()

	if err = commitGitignore(content, f); err != nil {
		return fmt.Errorf("error committing gitignore file: %w", err)
	}

	return nil
}

// runPrompt is a helper function to run the selection prompt for .gitignore templates.
func runPrompt(client *github.Client, pc *promptConfig) (*github.Gitignore, error) {
	templates, _, err := client.Gitignores.List(context.Background())
	if err != nil {
		return nil, fmt.Errorf("error retrieving gitignore template list: %w", err)
	}

	selectTemplates := &promptui.SelectTemplates{
		Label:    `  {{ "\U0000007C" | faint }} {{ . | magenta | bold }}`,
		Active:   `{{ "\U0000007C" | faint }} {{ "🌶" | red }}  {{ . | cyan | italic }}`,
		Inactive: `{{ "\U0000007C" | faint }}    {{ . | faint }}`,
		Selected: `{{ "Created" | green }} {{ . }} {{ ".gitignore file ✓" | green }}`,
	}

	prompt := promptui.Select{
		Label:             "Select a .gitignore template",
		Items:             templates,
		Templates:         selectTemplates,
		Size:              pc.Height,
		Searcher:          filterFunc(templates, pc.FilterType),
		StartInSearchMode: pc.StartSearch,
	}

	i, _, err := prompt.Run()
	if err != nil {
		return nil, err
	}

	content, _, err := client.Gitignores.Get(context.Background(), templates[i])
	if err != nil {
		return nil, fmt.Errorf("error retrieving gitignore template '%s': %w", templates[i], err)
	}

	return content, nil
}

// commitGitignore writes the content of the selected gitignore template to the .gitignore file.
func commitGitignore(content *github.Gitignore, w io.Writer) error {
	if _, err := fmt.Fprintf(w, "# Generated by ignr: github.com/onyx-and-iris/ignr\n\n## %s ##\n", content.GetName()); err != nil {
		return fmt.Errorf("error writing header to file '%s': %w", gitignoreFileName, err)
	}

	if _, err := fmt.Fprintf(w, "%s", *content.Source); err != nil {
		return fmt.Errorf("error writing to file '%s': %w", gitignoreFileName, err)
	}

	if _, err := fmt.Fprintf(w, "\n# End of ignr\n"); err != nil {
		return fmt.Errorf("error writing footer to file '%s': %w", gitignoreFileName, err)
	}

	return nil
}