package cli

import (
	"errors"
	"flag"
	"fmt"
	"io"

	configkit "gitea.maximumdirect.net/eric/ConfigKit"
	appconfig "gitea.maximumdirect.net/eric/scriptorium/internal/config"
)

// applicationOverrides keeps explicit application flags separate from invocation state.
func applicationOverrides(fs *flag.FlagSet) []configkit.Override {
	var overrides []configkit.Override
	fs.Visit(func(selected *flag.Flag) {
		var path configkit.Path
		switch selected.Name {
		case "prompt-dir":
			path = configkit.Keys("prompt_dir")
		case "profile-dir":
			path = configkit.Keys("profile_dir")
		case "schema-dir":
			path = configkit.Keys("schema_dir")
		case "addr":
			path = configkit.Keys("server", "addr")
		case "artifact-root":
			path = configkit.Keys("server", "artifact_root")
		case "max-request-bytes":
			path = configkit.Keys("server", "max_request_bytes")
		case "max-artifact-bytes":
			path = configkit.Keys("server", "max_artifact_bytes")
		case "max-response-bytes":
			path = configkit.Keys("server", "max_response_bytes")
		default:
			return
		}
		overrides = append(overrides, configkit.Override{
			Path: path, Value: selected.Value.(flag.Getter).Get(), Flag: "--" + selected.Name,
		})
	})
	return overrides
}

func loadApplicationSettings(configPath, overlay string, explicit bool, overrides []configkit.Override) (appconfig.AppSettings, []configkit.Diagnostic, error) {
	result, err := appconfig.Load(appconfig.LoadOptions{
		Path: configPath, Overlay: overlay, Explicit: explicit, Overrides: overrides,
	})
	if err != nil {
		return appconfig.AppSettings{}, nil, err
	}
	return appconfig.Settings(result.Config), result.Diagnostics(), nil
}

func writeApplicationError(output io.Writer, label string, err error) {
	var loadError *configkit.LoadError
	if errors.As(err, &loadError) {
		if writeErr := configkit.WriteDiagnostics(output, loadError.Diagnostics()); writeErr != nil {
			_, _ = fmt.Fprintf(output, "%s diagnostic write error: %v\n", label, writeErr)
		}
		return
	}
	_, _ = fmt.Fprintf(output, "%s error: %v\n", label, err)
}

func writeApplicationWarnings(output io.Writer, diagnostics []configkit.Diagnostic) error {
	if len(diagnostics) == 0 {
		return nil
	}
	return configkit.WriteDiagnostics(output, diagnostics)
}