package ckconfig

import (
	"errors"
	"fmt"

	commandkit "gitea.maximumdirect.net/eric/CommandKit"
)

func runConfigDiff[I, S any](invocation commandkit.Invocation, plan *configOperationPlan[I, S], state S) commandkit.Outcome {
	if plan.comparison == nil || plan.comparison.scope == nil {
		cause := errors.New("configuration comparison was not prepared")
		return configFailure("Configuration comparison was not prepared.", commandkit.Explanation{}, cause)
	}
	selected := plan.comparison
	if err := invocation.Context.Err(); err != nil {
		return configFailure("Configuration comparison was canceled.", commandkit.Explanation{}, err)
	}
	compare := selected.scope.scope.Compare
	if compare == nil {
		cause := fmt.Errorf("configuration scope %q has no comparison callback", selected.scope.scope.Name)
		return configFailure("Configuration scope does not support comparison.", commandkit.Explanation{}, cause)
	}
	acquired, err := compare(invocation.Context, selected.request, state)
	reporter := invocation.Reporter()
	queueConfigDiagnostics(reporter, acquired.Diagnostics)
	if err != nil {
		return configFailure(fmt.Sprintf("Unable to compare configuration scope %q.", selected.scope.scope.Name), acquired.Explanation, err)
	}
	if err := invocation.Context.Err(); err != nil {
		return configFailure("Configuration comparison was canceled.", acquired.Explanation, err)
	}
	return renderPreparedConfigReport(invocation, acquired.Explanation, func() ([]byte, error) {
		return renderDiffReport(acquired.Value)
	})
}