package internal

import (
	"errors"
	"os"

	"gopkg.in/yaml.v3"
)

type Config struct {
	Repository       string   `yaml:"repository"`
	Owner            string   `yaml:"owner"`
	BaseBranch       string   `yaml:"base_branch"`
	MergeBranch      string   `yaml:"merge_branch"`
	CommitBranch     string   `yaml:"commit_branch"`
	ApkoLocations    []string `yaml:"apko_locations"`
	DryRun           bool     `yaml:"dry_run"`
	GHPrivateKeyPath string   `yaml:"gh_app_private_key_path"`
	GHPrivateKey     string   `yaml:"gh_app_private_key"`
	GHAppID          int64    `yaml:"gh_app_id"`
	GHInstallationID int64    `yaml:"gh_installation_id"`
}

func NewConfigFromPath(path string) (*Config, error) {
	configBytes, err := os.ReadFile(path)
	if err != nil {
		return nil, err
	}
	config := &Config{}
	if err := yaml.Unmarshal(configBytes, config); err != nil {
		return nil, err
	}

	// ensure required fields
	if err := validateConfig(config); err != nil {
		return nil, err
	}

	return config, nil
}

func validateConfig(config *Config) error {
	// ensure required fields are filled out
	var missingFieldsErrors []error

	if config.Owner == "" {
		missingFieldsErrors = append(missingFieldsErrors, errors.New("required field owner missing"))
	}

	if config.Repository == "" {
		missingFieldsErrors = append(missingFieldsErrors, errors.New("required field repository missing"))
	}

	if config.BaseBranch == "" {
		missingFieldsErrors = append(missingFieldsErrors, errors.New("required field base-branch missing"))
	}

	if config.MergeBranch == "" {
		missingFieldsErrors = append(missingFieldsErrors, errors.New("required field merge-branch missing"))
	}

	if config.CommitBranch == "" {
		missingFieldsErrors = append(missingFieldsErrors, errors.New("required field commit-branch missing"))
	}

	if config.ApkoLocations == nil {
		missingFieldsErrors = append(missingFieldsErrors, errors.New("required field apko-locations missing"))
	}

	if config.GHPrivateKey == "" && config.GHPrivateKeyPath == "" {
		missingFieldsErrors = append(missingFieldsErrors, errors.New("either gh-app-private-key or gh-app-private-key-path must be set for Github app authentication"))
	}

	if config.GHPrivateKey != "" && config.GHPrivateKeyPath != "" {
		missingFieldsErrors = append(missingFieldsErrors, errors.New("gh-app-private-key-path and gh-app-private-key cannot both be set"))
	}

	if config.GHAppID == 0 {
		missingFieldsErrors = append(missingFieldsErrors, errors.New("required field gh-app-id missing"))
	}

	if len(missingFieldsErrors) == 0 {
		return nil
	}

	return errors.Join(missingFieldsErrors...)
}