package cli

import (
	"context"
	"errors"
	"fmt"
	"strings"

	"tsne.dev/hopper/internal/log"
)

// errorVerboser is implemented by error types that can contribute extra
// technical detail to failure reports under --verbose (e.g. *bunny.apiError
// exposing verb/path/status/cause). reportFailures prints it indented below the
// friendly message when verbose is enabled.
type errorVerboser interface {
	ErrorVerbose() string
}

// usageError marks a parse or validation failure that should print a short
// usage line and exit 2, distinct from a runtime failure (exit 1).
type usageError struct {
	msg string
}

func (e usageError) Error() string { return e.msg }

// exitError signals that the command has already emitted all its user-facing
// output (e.g. a failure list followed by the summary) and the process should
// simply exit with the given code, printing nothing further. This keeps the
// summary as the last line.
type exitError struct {
	code int
}

func (e exitError) Error() string { return fmt.Sprintf("exit status %d", e.code) }

// reportFailures prints a batch of per-file failures to stderr under a headline,
// using the same layout everywhere or the context's cancellation cause.
// It returns true if it reported an error, false otherwise.
func reportFailures(ctx context.Context, msg string, errs []error) bool {
	if len(errs) > 0 {
		sb := strings.Builder{}
		sb.WriteString(msg)
		for _, err := range errs {
			sb.WriteString("\n  ")
			sb.WriteString(err.Error())
			if log.Verbose() {
				var v errorVerboser
				if errors.As(err, &v) {
					sb.WriteString("\n    ")
					sb.WriteString(v.ErrorVerbose())
				}
			}
		}
		log.Error(sb.String())
		return true
	} else if ctxErr := context.Cause(ctx); ctxErr != nil {
		log.Error(ctxErr.Error())
		return true
	} else {
		return false
	}
}

// fileError attaches the storage path to an operation failure so the report can
// name the offending file. It preserves the wrapped cause (e.g. the bunny API
// error) in the chain so both friendly rendering (Error) and verbose detail
// (ErrorVerbose) still work via errors.As.
type fileError struct {
	path string
	err  error
}

func (e fileError) Error() string { return e.path + ": " + e.err.Error() }
func (e fileError) Unwrap() error { return e.err }

type cancellationError struct {
	msg string
}

// CancellationError returns an error that wraps `context.Canceled` but
// with a custom error message.
func CancellationError(msg string) error {
	return cancellationError{msg}
}

func (e cancellationError) Error() string { return e.msg }
func (e cancellationError) Unwrap() error { return context.Canceled }