// Package gostate demonstrates an exact state round trip without decoding
// customer JSON into floating-point values. It performs no automatic retries.
package gostate

import (
	"bytes"
	"context"
	_ "embed"
	"errors"
	"io"
	"net/http"
	"net/url"
	"strings"
	"time"
)

//go:embed state.go
var Source string

// RoundTrip uses a caller-owned TLS client and authorized project credential.
// Production callers should use a transport without an ambient proxy and keep
// credentials in protected memory. A failed write may already have committed.
func RoundTrip(ctx context.Context, client *http.Client, origin, project, credential string) ([]byte, error) {
	parsed, err := url.Parse(origin)
	if err != nil || parsed.Scheme != "https" || parsed.Host == "" || parsed.User != nil || parsed.Path != "" || parsed.RawQuery != "" || parsed.Fragment != "" || client == nil || project == "" || strings.ContainsAny(project, "/\\\r\n") || credential == "" || strings.ContainsAny(credential, "\r\n") {
		return nil, errors.New("invalid example configuration")
	}
	bounded := *client
	bounded.CheckRedirect = func(*http.Request, []*http.Request) error { return http.ErrUseLastResponse }
	bounded.Timeout = 30 * time.Second
	ctx, cancel := context.WithTimeout(ctx, 30*time.Second)
	defer cancel()
	path := origin + "/api/v1/projects/" + url.PathEscape(project) + "/state/examples/go-checkpoint"
	value := []byte(`{"value":{"exact":9007199254740993}}`)
	for _, method := range []string{http.MethodPut, http.MethodGet} {
		var body io.Reader
		if method == http.MethodPut {
			body = bytes.NewReader(value)
		}
		request, err := http.NewRequestWithContext(ctx, method, path, body)
		if err != nil {
			return nil, errors.New("invalid example request")
		}
		request.Header.Set("Authorization", "Bearer "+credential)
		if method == http.MethodPut {
			request.Header.Set("Content-Type", "application/json")
			request.Header.Set("If-None-Match", "*")
		}
		response, err := bounded.Do(request)
		if err != nil {
			return nil, errors.New("transport failed; reconcile before retrying")
		}
		raw, readErr := io.ReadAll(io.LimitReader(response.Body, 131073))
		response.Body.Close()
		if readErr != nil || len(raw) > 131072 || response.StatusCode != 200 {
			return nil, errors.New("state request failed; inspect authorized status before retrying")
		}
		if method == http.MethodGet {
			return raw, nil
		}
	}
	return nil, errors.New("state read missing")
}