package pier_test

import (
	"context"
	"net/http"
	"strings"
	"testing"
	"time"

	"git.golem15.com/golem15/summercms/modules/pact"
)

// deleteSession sends DELETE for a session with a bearer.
func deleteSession(t *testing.T, ctx context.Context, url, token, sid string) int {
	t.Helper()
	req, err := http.NewRequestWithContext(ctx, http.MethodDelete, url, nil)
	if err != nil {
		t.Fatal(err)
	}
	req.Header.Set("Authorization", "Bearer "+token)
	req.Header.Set("Mcp-Session-Id", sid)
	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		t.Fatal(err)
	}
	_ = resp.Body.Close()
	return resp.StatusCode
}

// sessionCase is one store under test: the instance that opens sessions,
// the one that serves them next and the store's clock.
type sessionCase struct {
	name    string
	a, b    *instance
	advance func(time.Duration)
}

// TestSessions (D-25): on the Redis store shared by two instances and on
// the memory store of one instance, a session is bound to the identity that
// opened it (another binding is 403 on POST and DELETE), is served by
// whichever instance receives it (rehydrated from the stored protocol state,
// never from a stored identity: the call runs as the request's bearer),
// DELETE ends it everywhere (404 next), an idle session expires after
// mcp.sessions.idle_ttl (404, and the client initialises a new one) and
// mcp.sessions.max_per_binding caps a binding's open sessions (429).
func TestSessions(t *testing.T) {
	cfgTail := "  idle_ttl: 30m\n  max_per_binding: 2\n"
	plugin := acmePlugin{tools: []pact.MCPTool{echoTool()}}
	var cases []sessionCase
	{
		a, b, mr := twoInstances(t, appSpec{mcp: "enabled: false\nsessions:\n  store: redis\n" + cfgTail, guards: []pact.MCPGuard{&acmeGuard{}}}, plugin)
		cases = append(cases, sessionCase{"redis across two instances", a, b, mr.FastForward})
	}
	{
		one := startInstance(t, newApp(t, appSpec{mcp: "enabled: false\nsessions:\n  store: memory\n" + cfgTail, guards: []pact.MCPGuard{&acmeGuard{}}}), plugin)
		cases = append(cases, sessionCase{"memory on one instance", one, one, func(d time.Duration) {
			if !one.pier().AdvanceStoreClock(d) {
				t.Fatal("the memory instance has no memory store")
			}
		}})
	}

	for _, c := range cases {
		t.Run(c.name, func(t *testing.T) {
			ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
			defer cancel()
			sid := openSession(t, ctx, c.a, "oas_at_test")

			call := rpc(t, ctx, c.b.url(), "oas_at_test", sid, callBody)
			if call.status != http.StatusOK || !strings.Contains(call.body, `\"principal\":7`) || strings.Contains(call.body, `"isError":true`) {
				t.Fatalf("call on the second instance = %d %s", call.status, call.body)
			}

			if other := rpc(t, ctx, c.b.url(), "oas_at_other", sid, callBody); other.status != http.StatusForbidden || !strings.Contains(other.body, "session_binding") {
				t.Fatalf("another binding = %d %s", other.status, other.body)
			}
			if code := deleteSession(t, ctx, c.b.url(), "oas_at_other", sid); code != http.StatusForbidden {
				t.Fatalf("DELETE by another binding = %d", code)
			}

			if code := deleteSession(t, ctx, c.b.url(), "oas_at_test", sid); code != http.StatusNoContent {
				t.Fatalf("DELETE = %d", code)
			}
			for _, in := range []*instance{c.a, c.b} {
				if gone := rpc(t, ctx, in.url(), "oas_at_test", sid, callBody); gone.status != http.StatusNotFound {
					t.Fatalf("call after DELETE = %d %s", gone.status, gone.body)
				}
			}
			if code := deleteSession(t, ctx, c.a.url(), "oas_at_test", sid); code != http.StatusNotFound {
				t.Fatalf("second DELETE = %d", code)
			}

			idle := openSession(t, ctx, c.a, "oas_at_test")
			c.advance(31 * time.Minute)
			if expired := rpc(t, ctx, c.b.url(), "oas_at_test", idle, callBody); expired.status != http.StatusNotFound {
				t.Fatalf("call after the idle TTL = %d %s", expired.status, expired.body)
			}
			fresh := openSession(t, ctx, c.b, "oas_at_test")
			if again := rpc(t, ctx, c.a.url(), "oas_at_test", fresh, callBody); again.status != http.StatusOK {
				t.Fatalf("call on the re-initialised session = %d %s", again.status, again.body)
			}

			openSession(t, ctx, c.a, "oas_at_test")
			third := rpc(t, ctx, c.b.url(), "oas_at_test", "", initializeBody)
			if third.status != http.StatusTooManyRequests || !strings.Contains(third.body, "too_many_sessions") {
				t.Fatalf("session over max_per_binding = %d %s", third.status, third.body)
			}
			// Another binding has its own allowance.
			openSession(t, ctx, c.b, "oas_at_other")
		})
	}
}