// Package config resolves where godeez reads its session from and writes its
// downloads to. There is no config file: the output directory defaults to
// ~/Music/GoDeez but can be overridden with GODEEZ_OUTPUT_DIR, and the only
// other setting is the DEEZER_ARL environment variable, which exists as an
// escape hatch for users who would rather not store credentials in the system
// keyring.
package config

import (
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"github.com/mathismqn/godeez/internal/fsutil"
)

type Config struct {
	ARLCookie string
	OutputDir string
}

// Load resolves the configuration and creates the output directory.
//
// An empty ARLCookie is normal and not an error: it means fall back to the
// stored credentials, which is the usual path. Creating the directory here
// rather than at first write means a bad path fails immediately instead of
// after the first track has been fetched.
func Load() (*Config, error) {
	arl := os.Getenv("DEEZER_ARL")

	outputDir, err := resolveOutputDir()
	if err != nil {
		return nil, err
	}

	if err := fsutil.EnsureDir(outputDir); err != nil {
		return nil, fmt.Errorf("failed to create output directory: %w", err)
	}

	return &Config{
		ARLCookie: arl,
		OutputDir: outputDir,
	}, nil
}

// resolveOutputDir honours GODEEZ_OUTPUT_DIR when set, falling back to
// ~/Music/GoDeez otherwise.
//
// A leading "~" is expanded by hand because the shell only does that for
// unquoted arguments, not for values read out of the environment, so users
// setting this in a profile file would otherwise end up with a literal "~"
// directory.
func resolveOutputDir() (string, error) {
	homeDir, err := os.UserHomeDir()
	if err != nil {
		return "", fmt.Errorf("failed to get home directory: %w", err)
	}

	if dir := strings.TrimSpace(os.Getenv("GODEEZ_OUTPUT_DIR")); dir != "" {
		if dir == "~" {
			return homeDir, nil
		}
		if rest, ok := strings.CutPrefix(dir, "~/"); ok {
			return filepath.Join(homeDir, rest), nil
		}
		return dir, nil
	}

	return filepath.Join(homeDir, "Music", "GoDeez"), nil
}