package rewriter

import (
	"context"
	"fmt"

	"forge.cadoles.com/cadoles/bouncer/internal/rule"
	"github.com/expr-lang/expr"
	"github.com/pkg/errors"
)

type errRedirect struct {
	statusCode int
	url        string
}

func (e *errRedirect) StatusCode() int {
	return e.statusCode
}

func (e *errRedirect) URL() string {
	return e.url
}

func (e *errRedirect) Error() string {
	return fmt.Sprintf("redirect %d %s", e.statusCode, e.url)
}

func newErrRedirect(statusCode int, url string) *errRedirect {
	return &errRedirect{
		url:        url,
		statusCode: statusCode,
	}
}

var _ error = &errRedirect{}

func redirectFunc() expr.Option {
	return expr.Function(
		"redirect",
		func(params ...any) (any, error) {
			_, err := rule.Assert[context.Context](params[0])
			if err != nil {
				return nil, errors.WithStack(err)
			}

			statusCode, err := rule.Assert[int](params[1])
			if err != nil {
				return nil, errors.WithStack(err)
			}

			if statusCode < 300 || statusCode >= 400 {
				return nil, errors.Errorf("unexpected redirect status code '%d'", statusCode)
			}

			url, err := rule.Assert[string](params[2])
			if err != nil {
				return nil, errors.WithStack(err)
			}

			return nil, newErrRedirect(statusCode, url)
		},
		new(func(context.Context, int, string) bool),
	)
}

func WithRewriterFuncs() rule.OptionFunc {
	return func(opts *rule.Options) {
		funcs := []expr.Option{
			redirectFunc(),
		}

		if len(opts.Expr) == 0 {
			opts.Expr = make([]expr.Option, 0)
		}

		opts.Expr = append(opts.Expr, funcs...)
	}
}