package gateway

import (
	"context"
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"testing"

	"git.yeij.top/AskaEth/Cyrene_v2/internal/auth"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/history"
)

// These tests cover the D4 read-cursor contract (Android collaboration B3): the
// unreadCount carried by GET /api/v1/sessions, the advance endpoint
// POST /api/v1/sessions/{id}/read, and the `session_read` frame that clears the badge
// on the account's other browsers.

// unreadBySession decodes GET /api/v1/sessions into a map of session id → unreadCount via
// the wire key, so the test asserts the JSON contract rather than the in-package struct.
func unreadBySession(t *testing.T, ts *httptest.Server, tok string) map[string]int {
	t.Helper()
	resp, body := doReq(t, http.MethodGet, ts.URL+"/api/v1/sessions", nil, tok)
	if resp.StatusCode != http.StatusOK {
		t.Fatalf("list sessions status = %d, want 200 (body=%s)", resp.StatusCode, body)
	}
	var sessions []struct {
		ID          string `json:"id"`
		UnreadCount int    `json:"unreadCount"`
	}
	decodeDataSlice(t, body, &sessions)
	out := make(map[string]int, len(sessions))
	for _, s := range sessions {
		out[s.ID] = s.UnreadCount
	}
	return out
}

// TestSessionsUnreadCountAndMarkRead covers the happy path end to end: a session with
// unread messages reports the count, POST /read moves the cursor and answers
// {sessionId, readAt}, the list drops to the messages sent after the cursor, and a
// body-less POST (mark everything seen) clears the badge.
func TestSessionsUnreadCountAndMarkRead(t *testing.T) {
	t.Parallel()
	_, ts, jwt, st := newHistoryEnv(t)
	ctx := context.Background()
	sub, err := st.NewSubSession(ctx, "owner")
	if err != nil {
		t.Fatalf("new sub: %v", err)
	}
	for _, m := range []history.Message{
		{SessionID: history.MainSessionID, Role: history.RoleUser, Content: "a", CreatedAt: 1000},
		{SessionID: history.MainSessionID, Role: history.RoleAssistant, Content: "b", CreatedAt: 2000},
		{SessionID: history.MainSessionID, Role: history.RoleUser, Content: "c", CreatedAt: 3000},
		{SessionID: sub, Role: history.RoleUser, Content: "sub", CreatedAt: 1500},
	} {
		if err := st.Append(ctx, m); err != nil {
			t.Fatalf("seed %q: %v", m.Content, err)
		}
	}
	tok := signAny(t, jwt, "acct", auth.RoleOwner)
	base := ts.URL + "/api/v1/sessions/" + history.MainSessionID + "/read"

	// Nothing read yet: the main session is fully unread, the sub session independently so.
	if got := unreadBySession(t, ts, tok); got[history.MainSessionID] != 3 || got[sub] != 1 {
		t.Fatalf("initial unread = %+v, want main 3 / sub 1", got)
	}

	// Advance the main cursor to 2000: messages at or before it are read.
	resp, body := doReq(t, http.MethodPost, base, map[string]any{"before": 2000}, tok)
	if resp.StatusCode != http.StatusOK {
		t.Fatalf("mark read status = %d, want 200 (body=%s)", resp.StatusCode, body)
	}
	env := decodeBody(t, body)
	if len(env) != 1 {
		t.Fatalf("envelope = %v, want only a data field", env)
	}
	var data struct {
		SessionID string `json:"sessionId"`
		ReadAt    int64  `json:"readAt"`
	}
	if err := json.Unmarshal(env["data"], &data); err != nil {
		t.Fatalf("decode read data: %v (body=%s)", err, body)
	}
	if data.SessionID != history.MainSessionID || data.ReadAt != 2000 {
		t.Fatalf("read data = %+v, want sessionId %s readAt 2000", data, history.MainSessionID)
	}

	// Only the later message stays unread, and the sub session is untouched.
	if got := unreadBySession(t, ts, tok); got[history.MainSessionID] != 1 || got[sub] != 1 {
		t.Fatalf("unread after cursor 2000 = %+v, want main 1 / sub 1", got)
	}

	// No body = "mark everything I have seen read" (resolved to now server-side).
	resp, body = doReq(t, http.MethodPost, base, nil, tok)
	if resp.StatusCode != http.StatusOK {
		t.Fatalf("body-less mark status = %d, want 200 (body=%s)", resp.StatusCode, body)
	}
	if err := json.Unmarshal(decodeBody(t, body)["data"], &data); err != nil {
		t.Fatalf("decode body-less read data: %v (body=%s)", err, body)
	}
	if data.ReadAt < 3000 {
		t.Fatalf("body-less readAt = %d, want >= the newest message 3000", data.ReadAt)
	}
	if got := unreadBySession(t, ts, tok); got[history.MainSessionID] != 0 || got[sub] != 1 {
		t.Fatalf("unread after mark-now = %+v, want main 0 / sub 1", got)
	}
	markedNow := data.ReadAt

	// The cursor only moves forward: re-posting a stale cursor must not re-open the badge.
	resp, body = doReq(t, http.MethodPost, base, map[string]any{"before": 1000}, tok)
	if resp.StatusCode != http.StatusOK {
		t.Fatalf("stale mark status = %d, want 200 (body=%s)", resp.StatusCode, body)
	}
	if err := json.Unmarshal(decodeBody(t, body)["data"], &data); err != nil {
		t.Fatalf("decode stale read data: %v", err)
	}
	if data.ReadAt != markedNow {
		t.Fatalf("stale readAt = %d, want the cursor to stay at %d", data.ReadAt, markedNow)
	}
	if got := unreadBySession(t, ts, tok); got[history.MainSessionID] != 0 {
		t.Fatalf("unread after stale mark = %d, want 0", got[history.MainSessionID])
	}
}

// TestMarkSessionReadValidation covers the failure contract: a present but unusable
// `before` answers 400, an unknown session 404, a viewer 403 and a missing HistoryStore
// 501 — none of which may be mistaken for a successful read.
func TestMarkSessionReadValidation(t *testing.T) {
	t.Parallel()
	_, ts, jwt, _ := newHistoryEnv(t)
	tok := signAny(t, jwt, "acct", auth.RoleOwner)
	base := ts.URL + "/api/v1/sessions/web/read"

	for _, tc := range []struct {
		name string
		body any
	}{
		{name: "zero", body: map[string]any{"before": 0}},
		{name: "negative", body: map[string]any{"before": -1}},
		{name: "non-numeric", body: map[string]any{"before": "abc"}},
		{name: "not an object", body: "not-an-object"},
	} {
		t.Run(tc.name, func(t *testing.T) {
			resp, body := doReq(t, http.MethodPost, base, tc.body, tok)
			if resp.StatusCode != http.StatusBadRequest {
				t.Fatalf("status = %d, want 400 (body=%s)", resp.StatusCode, body)
			}
			wantErrorShape(t, body)
		})
	}

	// An empty object means "now", not "no-op".
	resp, body := doReq(t, http.MethodPost, base, map[string]any{}, tok)
	if resp.StatusCode != http.StatusOK {
		t.Fatalf("empty object status = %d, want 200 (body=%s)", resp.StatusCode, body)
	}

	// Unknown session → 404; the session id is not auto-created.
	resp, body = doReq(t, http.MethodPost, ts.URL+"/api/v1/sessions/web:missing/read", map[string]any{"before": 1000}, tok)
	if resp.StatusCode != http.StatusNotFound {
		t.Fatalf("unknown session status = %d, want 404 (body=%s)", resp.StatusCode, body)
	}

	// A viewer cannot write the cursor (owner/admin history write, like PATCH /sessions).
	viewer := signAny(t, jwt, "acct", auth.RoleViewer)
	resp, body = doReq(t, http.MethodPost, base, map[string]any{"before": 1000}, viewer)
	if resp.StatusCode != http.StatusForbidden {
		t.Fatalf("viewer status = %d, want 403 (body=%s)", resp.StatusCode, body)
	}

	// And no token at all is 401, not a silent success.
	resp, body = doReq(t, http.MethodPost, base, map[string]any{"before": 1000}, "")
	if resp.StatusCode != http.StatusUnauthorized {
		t.Fatalf("anonymous status = %d, want 401 (body=%s)", resp.StatusCode, body)
	}
}

// TestMarkSessionReadNotWired pins the honest degradation: with no HistoryStore injected
// the endpoint answers 501 not_implemented rather than pretending the cursor moved.
func TestMarkSessionReadNotWired(t *testing.T) {
	t.Parallel()
	_, ts, jwt := buildEnv(t, cfgDefault(), Deps{})
	tok := signAny(t, jwt, "acct", auth.RoleOwner)

	resp, body := doReq(t, http.MethodPost, ts.URL+"/api/v1/sessions/web/read", map[string]any{"before": 1000}, tok)
	if resp.StatusCode != http.StatusNotImplemented {
		t.Fatalf("status = %d, want 501 (body=%s)", resp.StatusCode, body)
	}
	wantErrorShape(t, body)
}

// TestMarkSessionReadBroadcasts asserts the cross-end sync frame: a successful advance
// pushes exactly one `session_read` frame scoped to that session and carrying the new
// cursor, while a failed one (404) pushes nothing.
func TestMarkSessionReadBroadcasts(t *testing.T) {
	t.Parallel()
	srv, ts, jwt, _ := newHistoryEnv(t)
	c := newFakeConn(srv.hub, 32)
	srv.hub.register(c)
	tok := signAny(t, jwt, "acct", auth.RoleOwner)

	resp, body := doReq(t, http.MethodPost, ts.URL+"/api/v1/sessions/"+history.MainSessionID+"/read", map[string]any{"before": 2000}, tok)
	if resp.StatusCode != http.StatusOK {
		t.Fatalf("status = %d, want 200 (body=%s)", resp.StatusCode, body)
	}
	ev := readFakeFrame(t, c)
	if ev.Type != "session_read" {
		t.Fatalf("frame type = %q, want session_read (frame=%+v)", ev.Type, ev)
	}
	if ev.SessionID != history.MainSessionID {
		t.Fatalf("frame sessionId = %q, want %q", ev.SessionID, history.MainSessionID)
	}
	data, ok := ev.Data.(map[string]any)
	if !ok {
		t.Fatalf("frame data = %+v, want object", ev.Data)
	}
	if data["readAt"] != float64(2000) {
		t.Fatalf("frame data.readAt = %v, want 2000", data["readAt"])
	}
	if err := connHasNoFrame(c); err != nil {
		t.Fatal(err)
	}

	// A failed advance must not tell other ends the badge was cleared.
	resp, body = doReq(t, http.MethodPost, ts.URL+"/api/v1/sessions/web:missing/read", map[string]any{"before": 2000}, tok)
	if resp.StatusCode != http.StatusNotFound {
		t.Fatalf("unknown status = %d, want 404 (body=%s)", resp.StatusCode, body)
	}
	if err := connHasNoFrame(c); err != nil {
		t.Fatal(err)
	}
}