package hostactors_test

import (
	"bytes"
	"context"
	"crypto/ed25519"
	"errors"
	"fmt"
	"io"
	"net/http"
	"strings"
	"sync"
	"testing"
	"time"

	awss3 "github.com/aws/aws-sdk-go-v2/service/s3"

	"github.com/carlosframework/platform/internal/hostactors"
	"github.com/carlosframework/platform/internal/hostops"
	"github.com/carlosframework/platform/internal/release"
)

// sdkRequest is one HTTP request the AWS SDK sent: its method, its path,
// its If-Match condition, and how long its context had left when it was
// sent (zero: no deadline).
type sdkRequest struct {
	method, path, ifMatch string
	left                  time.Duration
}

// recordingHTTP stands in for the network under the SDK: a bucket that
// honours S3's conditional headers. It records each request's context
// deadline. A GET answers the object and its ETag, or NoSuchKey; a PUT
// with If-Match succeeds only on the current ETag, one with
// If-None-Match: * only when the key is absent, and gets a new ETag.
type recordingHTTP struct {
	mu      sync.Mutex
	seen    []sdkRequest
	objects map[string]bucketObject
	next    int
}

type bucketObject struct {
	body []byte
	etag string
}

func (h *recordingHTTP) Do(r *http.Request) (*http.Response, error) {
	var left time.Duration
	if dl, ok := r.Context().Deadline(); ok {
		left = time.Until(dl)
	}
	var body []byte
	if r.Body != nil {
		body, _ = io.ReadAll(r.Body)
	}
	h.mu.Lock()
	defer h.mu.Unlock()
	h.seen = append(h.seen, sdkRequest{r.Method, r.URL.Path, r.Header.Get("If-Match"), left})
	resp := &http.Response{Header: http.Header{}, Request: r, Proto: "HTTP/1.1", ProtoMajor: 1, ProtoMinor: 1, Body: io.NopCloser(strings.NewReader(""))}
	reply := func(code int, xml string) (*http.Response, error) {
		resp.StatusCode = code
		resp.Header.Set("Content-Type", "application/xml")
		resp.Body = io.NopCloser(strings.NewReader(`<?xml version="1.0" encoding="UTF-8"?><Error><Code>` + xml + `</Code><Message>fake</Message></Error>`))
		return resp, nil
	}
	key := r.URL.Path
	cur, exists := h.objects[key]
	switch r.Method {
	case http.MethodPut:
		if m := r.Header.Get("If-Match"); m != "" && (!exists || strings.Trim(m, `"`) != strings.Trim(cur.etag, `"`)) {
			return reply(http.StatusPreconditionFailed, "PreconditionFailed")
		}
		if r.Header.Get("If-None-Match") == "*" && exists {
			return reply(http.StatusPreconditionFailed, "PreconditionFailed")
		}
		h.next++
		obj := bucketObject{body, fmt.Sprintf(`"e%d"`, h.next)}
		h.objects[key] = obj
		resp.StatusCode = http.StatusOK
		resp.Header.Set("ETag", obj.etag)
		return resp, nil
	case http.MethodGet:
		if !exists {
			return reply(http.StatusNotFound, "NoSuchKey")
		}
		resp.StatusCode = http.StatusOK
		resp.Header.Set("ETag", cur.etag)
		resp.Header.Set("Content-Length", fmt.Sprint(len(cur.body)))
		resp.Body = io.NopCloser(bytes.NewReader(cur.body))
		resp.ContentLength = int64(len(cur.body))
		return resp, nil
	}
	return reply(http.StatusNotFound, "NoSuchKey")
}

func (h *recordingHTTP) take() []sdkRequest {
	h.mu.Lock()
	defer h.mu.Unlock()
	out := h.seen
	h.seen = nil
	return out
}

// productionStores builds the console's stores as claim_runtime.go does:
// the release S3 store (its own construction, s3compat and all, with only
// the network replaced), the conditional record store over it, and the
// observed mutation boundary with the production mutation check over
// that: the store the enrolment pass's Directory carries.
func productionStores(t *testing.T) (raw *release.S3Store, data release.Store, h *recordingHTTP, root release.Signer) {
	t.Helper()
	t.Setenv("AWS_ACCESS_KEY_ID", "k")
	t.Setenv("AWS_SECRET_ACCESS_KEY", "s")
	t.Setenv("AWS_SESSION_TOKEN", "")
	t.Setenv("AWS_REGION", "eu-west-1")
	t.Setenv("AWS_EC2_METADATA_DISABLED", "true")
	t.Setenv("AWS_CONFIG_FILE", "/nonexistent")
	t.Setenv("AWS_SHARED_CREDENTIALS_FILE", "/nonexistent")
	t.Setenv("CARLOS_S3_ENDPOINT", "http://127.0.0.1:9")
	raw, err := release.NewS3Store(context.Background(), "deployment")
	if err != nil {
		t.Fatal(err)
	}
	h = &recordingHTTP{objects: map[string]bucketObject{}}
	raw.Client = awss3.New(raw.Client.Options(), func(o *awss3.Options) { o.HTTPClient = h; o.RetryMaxAttempts = 1 })
	pub, priv, err := ed25519.GenerateKey(nil)
	if err != nil {
		t.Fatal(err)
	}
	control, err := hostops.NewControlWriter(raw, pub, time.Now)
	if err != nil {
		t.Fatal(err)
	}
	check, err := hostops.NewProductionMutationCheck(raw, control)
	if err != nil {
		t.Fatal(err)
	}
	records, err := hostops.NewConditionalRecordStore(raw, pub)
	if err != nil {
		t.Fatal(err)
	}
	data, err = hostops.NewObservedMutationBoundary(true, records, check, nil)
	if err != nil {
		t.Fatal(err)
	}
	return raw, data, h, release.RootSigner(priv)
}

// V2 and W1 (platform-1e): the per-call context of a bound write reaches
// the AWS SDK's HTTP request through the console's production stores, so
// the 15-second limit is enforced where the request is sent. The roster
// write is a successful conditional PUT through the whole stack: the
// bound's deadline store, the observed mutation boundary (its pre-read,
// the production mutation check, which admits a root-signed roster, and
// its forwarding), the conditional record store's forwarding and the S3
// store. Every request it sends, the PUT included, carries a deadline of
// 15 seconds from its call, or the write deadline when that comes first.
// A wrapper anywhere on the path that drops the context, or a bound that
// does not give each call its own, fails here.
func TestTheBoundReachesTheSDKRequest(t *testing.T) {
	_, data, h, root := productionStores(t)
	for name, c := range map[string]struct {
		readAge   time.Duration
		low, high time.Duration
	}{
		"the per-call limit":         {0, 14 * time.Second, 15 * time.Second},
		"the earlier write deadline": {50 * time.Second, 9 * time.Second, 10 * time.Second},
	} {
		t.Run(name, func(t *testing.T) {
			check := func(what string, got []sdkRequest, methods ...string) []sdkRequest {
				t.Helper()
				var sent []string
				for _, r := range got {
					sent = append(sent, r.method)
					if r.left <= c.low || r.left > c.high {
						t.Errorf("%s: %s %s had %s left, want (%s, %s]", what, r.method, r.path, r.left, c.low, c.high)
					}
				}
				if strings.Join(sent, " ") != strings.Join(methods, " ") {
					t.Fatalf("%s: the SDK sent %v, want %v", what, sent, methods)
				}
				return got
			}
			// The bucket holds a roster the pass has read.
			h.mu.Lock()
			h.objects = map[string]bucketObject{}
			h.mu.Unlock()
			before, err := release.SignRootEnvelope(root, map[string]int{"revision": 1})
			if err != nil {
				t.Fatal(err)
			}
			d := hostactors.Directory{Store: data, Bucket: "deployment"}
			etag, err := data.Put(context.Background(), hostactors.Key, before, "")
			if err != nil {
				t.Fatal(err)
			}
			h.take()
			bd, bctx, cancel := hostactors.BindForTest(context.Background(), d, time.Now().Add(-c.readAge), time.Now)
			defer cancel()
			if _, got, err := bd.Store.Get(bctx, hostactors.Key); err != nil || got != etag {
				t.Fatalf("roster read: %q %v", got, err)
			}
			check("the roster read", h.take(), http.MethodGet)
			// The enrolling write: conditional on that ETag, and admitted.
			next, err := release.SignRootEnvelope(root, map[string]int{"revision": 2})
			if err != nil {
				t.Fatal(err)
			}
			after, err := bd.Store.Put(bctx, hostactors.Key, next, etag)
			if err != nil || after == etag {
				t.Fatalf("the conditional roster write: %q %v", after, err)
			}
			sent := check("the roster write", h.take(), http.MethodGet, http.MethodPut)
			if strings.Trim(sent[1].ifMatch, `"`) != strings.Trim(etag, `"`) {
				t.Fatalf("the roster PUT was sent with If-Match %q, want the ETag read, %q", sent[1].ifMatch, etag)
			}
			// And it stays conditional: the old ETag now loses.
			if _, err := bd.Store.Put(bctx, hostactors.Key, next, etag); !errors.Is(err, release.ErrCASConflict) {
				t.Fatalf("a stale ETag was not refused: %v", err)
			}
			h.take()
		})
	}
}