package config

import (
	"encoding/json"
	"errors"
	"os"
	"path/filepath"
	"strings"

	"sgg-ai-skill-manager/internal/domain"
)

const (
	AuthPassword = "password"
	AuthToken    = "token"
)

func Default() domain.Config {
	return domain.Config{
		Gitea: domain.GiteaConfig{
			AuthType:      AuthPassword,
			CredentialKey: "sgg-ai-skill-manager:gitea",
		},
		Update: domain.UpdateConfig{
			AutoUpdate:      true,
			CheckOnStartup:  true,
			IntervalMinutes: 60,
		},
	}
}

func Load(path string) (domain.Config, error) {
	cfg := Default()
	raw, err := os.ReadFile(path)
	if errors.Is(err, os.ErrNotExist) {
		return cfg, nil
	}
	if err != nil {
		return cfg, err
	}
	if strings.TrimSpace(string(raw)) == "" {
		return cfg, nil
	}
	if err := json.Unmarshal(raw, &cfg); err != nil {
		return cfg, err
	}
	applyDefaults(&cfg)
	return cfg, nil
}

func Save(path string, cfg domain.Config) error {
	applyDefaults(&cfg)
	if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
		return err
	}
	raw, err := json.MarshalIndent(cfg, "", "  ")
	if err != nil {
		return err
	}
	return os.WriteFile(path, append(raw, '\n'), 0o600)
}

func Validate(cfg domain.Config) error {
	if strings.TrimSpace(cfg.Gitea.BaseURL) == "" {
		return errors.New("gitea baseURL is required")
	}
	if strings.TrimSpace(cfg.Gitea.Org) == "" {
		return errors.New("gitea org is required")
	}
	if strings.TrimSpace(cfg.Gitea.Username) == "" {
		return errors.New("gitea username is required")
	}
	if cfg.Gitea.AuthType != AuthPassword && cfg.Gitea.AuthType != AuthToken {
		return errors.New("authType must be password or token")
	}
	if cfg.Update.IntervalMinutes <= 0 {
		return errors.New("update interval must be positive")
	}
	return nil
}

func applyDefaults(cfg *domain.Config) {
	if cfg.Gitea.AuthType == "" {
		cfg.Gitea.AuthType = AuthPassword
	}
	if cfg.Gitea.CredentialKey == "" {
		cfg.Gitea.CredentialKey = "sgg-ai-skill-manager:gitea"
	}
	if cfg.Update.IntervalMinutes <= 0 {
		cfg.Update.IntervalMinutes = 60
	}
}