package main

import (
	"encoding/json"
	"fmt"
	"os"
)

type Config struct {
	Instrument    string   `json:"instrument"`
	Tuning        []string `json:"tuning"`
	Frets         int      `json:"frets"`
	MaxFingers    int      `json:"max_fingers"`
	BaselineShift int      `json:"baseline_shift"`
	RangeDown     int      `json:"range_down"`
	RangeUp       int      `json:"range_up"`
}

func LoadConfig(path string) (Config, error) {
	var cfg Config
	data, err := os.ReadFile(path)
	if err != nil {
		return cfg, err
	}
	err = json.Unmarshal(data, &cfg)
	return cfg, err
}

func SaveConfig(path string, cfg Config) error {
	data, err := json.MarshalIndent(cfg, "", "  ")
	if err != nil {
		return err
	}
	return os.WriteFile(path, data, 0644)
}

func ValidateConfig(cfg Config) error {
	if len(cfg.Tuning) == 0 {
		return fmt.Errorf("tuning must have at least one string")
	}
	for _, note := range cfg.Tuning {
		if _, ok := NoteToSemitone[note]; !ok {
			return fmt.Errorf("invalid note: %s", note)
		}
	}
	if cfg.Frets < 1 || cfg.Frets > 24 {
		return fmt.Errorf("frets must be between 1 and 24")
	}
	if cfg.MaxFingers < 1 || cfg.MaxFingers > 6 {
		return fmt.Errorf("max fingers must be between 1 and 6")
	}
	return nil
}