package clientapi_test

import (
	"fmt"
	"net/http"
	"net/url"
	"testing"
	"time"
)

// Relations and threads: what /relations lists, what /threads lists, and
// the summaries a parent carries in unsigned.m.relations wherever it is
// served.

// sendEvent sends an event of any type and returns its ID.
func (ts *testServer) sendEvent(acc account, roomID, eventType string, content map[string]any) string {
	ts.t.Helper()
	path := fmt.Sprintf("/_matrix/client/v3/rooms/%s/send/%s/%s",
		url.PathEscape(roomID), url.PathEscape(eventType), fmt.Sprintf("txn-%d", time.Now().UnixNano()))
	rec := ts.put(path, acc.AccessToken, content)
	expectStatus(ts.t, rec, http.StatusOK)
	eventID, _ := jsonBody(ts.t, rec)["event_id"].(string)
	if eventID == "" {
		ts.t.Fatalf("send returned no event ID: %s", rec.Body.String())
	}
	return eventID
}

// threadReply sends a message in a thread.
func (ts *testServer) threadReply(acc account, roomID, rootID, body string) string {
	ts.t.Helper()
	return ts.sendEvent(acc, roomID, "m.room.message", map[string]any{
		"msgtype": "m.text", "body": body,
		"m.relates_to": map[string]any{"rel_type": "m.thread", "event_id": rootID},
	})
}

type relationsResult struct {
	Chunk          []syncEvent `json:"chunk"`
	NextBatch      string      `json:"next_batch"`
	RecursionDepth int         `json:"recursion_depth"`
}

func (ts *testServer) relations(acc account, roomID, path string, query url.Values) relationsResult {
	ts.t.Helper()
	full := "/_matrix/client/v1/rooms/" + url.PathEscape(roomID) + "/relations/" + path
	if encoded := query.Encode(); encoded != "" {
		full += "?" + encoded
	}
	rec := ts.get(full, acc.AccessToken)
	expectStatus(ts.t, rec, http.StatusOK)
	return decode[relationsResult](ts.t, rec)
}

// threadSummaryOf digs unsigned.m.relations.m.thread out of an event.
func threadSummaryOf(t *testing.T, event map[string]any) map[string]any {
	t.Helper()
	unsigned, _ := event["unsigned"].(map[string]any)
	relations, _ := unsigned["m.relations"].(map[string]any)
	summary, _ := relations["m.thread"].(map[string]any)
	return summary
}

func TestRelationsListsChildrenNewestFirst(t *testing.T) {
	ts := newTestServer(t, nil)
	alice := ts.register("alice", "correct-horse-battery-staple")
	roomID := ts.createRoom(alice, nil)

	root := ts.sendMessage(alice, roomID, "root")
	r1 := ts.threadReply(alice, roomID, root, "one")
	r2 := ts.threadReply(alice, roomID, root, "two")
	reaction := ts.sendEvent(alice, roomID, "m.reaction", map[string]any{
		"m.relates_to": map[string]any{"rel_type": "m.annotation", "event_id": root, "key": "👍"},
	})
	ts.sendMessage(alice, roomID, "unrelated")

	all := ts.relations(alice, roomID, url.PathEscape(root), nil)
	if got := idsOf(all.Chunk); !equalStrings(got, []string{reaction, r2, r1}) {
		t.Fatalf("relations = %v, want the reaction and the two replies newest first", got)
	}

	threads := ts.relations(alice, roomID, url.PathEscape(root)+"/m.thread", nil)
	if got := idsOf(threads.Chunk); !equalStrings(got, []string{r2, r1}) {
		t.Errorf("m.thread relations = %v, want the two replies", got)
	}
	reactions := ts.relations(alice, roomID, url.PathEscape(root)+"/m.annotation/m.reaction", nil)
	if got := idsOf(reactions.Chunk); !equalStrings(got, []string{reaction}) {
		t.Errorf("m.annotation m.reaction relations = %v, want the reaction", got)
	}

	// Paging one at a time walks every child and stops.
	var paged []string
	from := ""
	for range 10 {
		query := url.Values{"limit": {"1"}}
		if from != "" {
			query.Set("from", from)
		}
		page := ts.relations(alice, roomID, url.PathEscape(root), query)
		paged = append(paged, idsOf(page.Chunk)...)
		if page.NextBatch == "" {
			break
		}
		from = page.NextBatch
	}
	if !equalStrings(paged, []string{reaction, r2, r1}) {
		t.Errorf("paged relations = %v", paged)
	}
}

func TestRelationsRecurse(t *testing.T) {
	ts := newTestServer(t, nil)
	alice := ts.register("alice", "correct-horse-battery-staple")
	roomID := ts.createRoom(alice, nil)

	root := ts.sendMessage(alice, roomID, "root")
	reply := ts.threadReply(alice, roomID, root, "reply")
	edit := ts.sendEvent(alice, roomID, "m.room.message", map[string]any{
		"msgtype": "m.text", "body": "* reply!",
		"m.new_content": map[string]any{"msgtype": "m.text", "body": "reply!"},
		"m.relates_to":  map[string]any{"rel_type": "m.replace", "event_id": reply},
	})

	flat := ts.relations(alice, roomID, url.PathEscape(root), nil)
	if got := idsOf(flat.Chunk); !equalStrings(got, []string{reply}) {
		t.Errorf("non-recursive relations = %v, want only the reply", got)
	}
	deep := ts.relations(alice, roomID, url.PathEscape(root), url.Values{"recurse": {"true"}})
	if got := idsOf(deep.Chunk); !equalStrings(got, []string{edit, reply}) {
		t.Errorf("recursive relations = %v, want the edit of the reply too", got)
	}
	if deep.RecursionDepth != 2 {
		t.Errorf("recursion_depth = %d, want 2", deep.RecursionDepth)
	}
}

func TestBundledAggregations(t *testing.T) {
	ts := newTestServer(t, nil)
	alice := ts.register("alice", "correct-horse-battery-staple")
	bob := ts.register("bob", "correct-horse-battery-staple")
	roomID := ts.createRoom(alice, map[string]any{"preset": "public_chat"})
	escaped := url.PathEscape(roomID)
	expectStatus(t, ts.post("/_matrix/client/v3/join/"+escaped, bob.AccessToken, map[string]any{}), http.StatusOK)

	root := ts.sendMessage(alice, roomID, "root")
	ts.threadReply(bob, roomID, root, "first")
	latest := ts.threadReply(bob, roomID, root, "second")
	edit := ts.sendEvent(alice, roomID, "m.room.message", map[string]any{
		"msgtype": "m.text", "body": "* root, edited",
		"m.new_content": map[string]any{"msgtype": "m.text", "body": "root, edited"},
		"m.relates_to":  map[string]any{"rel_type": "m.replace", "event_id": root},
	})
	// An edit by somebody else is not an edit.
	ts.sendEvent(bob, roomID, "m.room.message", map[string]any{
		"msgtype": "m.text", "body": "* hijacked",
		"m.new_content": map[string]any{"msgtype": "m.text", "body": "hijacked"},
		"m.relates_to":  map[string]any{"rel_type": "m.replace", "event_id": root},
	})

	check := func(who string, acc account, participated bool) {
		t.Helper()
		rec := ts.get("/_matrix/client/v3/rooms/"+escaped+"/event/"+url.PathEscape(root), acc.AccessToken)
		expectStatus(t, rec, http.StatusOK)
		event := jsonBody(t, rec)
		summary := threadSummaryOf(t, event)
		if summary == nil {
			t.Fatalf("%s: the root has no m.thread summary: %v", who, event["unsigned"])
		}
		if summary["count"] != float64(2) {
			t.Errorf("%s: thread count = %v, want 2", who, summary["count"])
		}
		latestEvent, _ := summary["latest_event"].(map[string]any)
		if latestEvent["event_id"] != latest {
			t.Errorf("%s: latest_event = %v, want %s", who, latestEvent["event_id"], latest)
		}
		if summary["current_user_participated"] != participated {
			t.Errorf("%s: current_user_participated = %v, want %v", who, summary["current_user_participated"], participated)
		}
		unsigned, _ := event["unsigned"].(map[string]any)
		relations, _ := unsigned["m.relations"].(map[string]any)
		replace, _ := relations["m.replace"].(map[string]any)
		if replace["event_id"] != edit {
			t.Errorf("%s: m.replace = %v, want alice's own edit %s", who, replace["event_id"], edit)
		}
	}
	// Alice started the thread and Bob replied in it: both took part.
	check("alice", alice, true)
	check("bob", bob, true)

	carol := ts.register("carol", "correct-horse-battery-staple")
	expectStatus(t, ts.post("/_matrix/client/v3/join/"+escaped, carol.AccessToken, map[string]any{}), http.StatusOK)
	check("carol", carol, false)

	// The same summary rides along on /messages.
	page := ts.get("/_matrix/client/v3/rooms/"+escaped+"/messages?dir=b&limit=50", alice.AccessToken)
	expectStatus(t, page, http.StatusOK)
	chunk, _ := jsonBody(t, page)["chunk"].([]any)
	found := false
	for _, raw := range chunk {
		e, _ := raw.(map[string]any)
		if e["event_id"] == root {
			found = threadSummaryOf(t, e) != nil
		}
	}
	if !found {
		t.Error("the root in /messages carries no m.thread summary")
	}
}

func TestThreadsEndpoint(t *testing.T) {
	ts := newTestServer(t, nil)
	alice := ts.register("alice", "correct-horse-battery-staple")
	bob := ts.register("bob", "correct-horse-battery-staple")
	roomID := ts.createRoom(alice, map[string]any{"preset": "public_chat"})
	escaped := url.PathEscape(roomID)
	expectStatus(t, ts.post("/_matrix/client/v3/join/"+escaped, bob.AccessToken, map[string]any{}), http.StatusOK)

	first := ts.sendMessage(alice, roomID, "first root")
	second := ts.sendMessage(bob, roomID, "second root")
	ts.sendMessage(alice, roomID, "not a thread")
	ts.threadReply(alice, roomID, first, "in the first")
	ts.threadReply(alice, roomID, second, "in the second")
	ts.threadReply(alice, roomID, first, "the first again")

	threads := func(acc account, query string) relationsResult {
		t.Helper()
		rec := ts.get("/_matrix/client/v1/rooms/"+escaped+"/threads"+query, acc.AccessToken)
		expectStatus(t, rec, http.StatusOK)
		return decode[relationsResult](t, rec)
	}

	all := threads(bob, "")
	if got := idsOf(all.Chunk); !equalStrings(got, []string{first, second}) {
		t.Fatalf("threads = %v, want the first (latest activity) then the second", got)
	}

	// Bob started the second thread and never replied in the first.
	mine := threads(bob, "?include=participated")
	if got := idsOf(mine.Chunk); !equalStrings(got, []string{second}) {
		t.Errorf("participated threads = %v, want only bob's own", got)
	}

	page1 := threads(bob, "?limit=1")
	if got := idsOf(page1.Chunk); !equalStrings(got, []string{first}) || page1.NextBatch == "" {
		t.Fatalf("first page = %v, next_batch %q", got, page1.NextBatch)
	}
	page2 := threads(bob, "?limit=1&from="+url.QueryEscape(page1.NextBatch))
	if got := idsOf(page2.Chunk); !equalStrings(got, []string{second}) || page2.NextBatch != "" {
		t.Errorf("second page = %v, next_batch %q", got, page2.NextBatch)
	}

	rec := ts.get("/_matrix/client/v1/rooms/"+escaped+"/threads?include=everything", bob.AccessToken)
	expectStatus(t, rec, http.StatusBadRequest)
}

func TestRedactedRelationDisappears(t *testing.T) {
	ts := newTestServer(t, nil)
	alice := ts.register("alice", "correct-horse-battery-staple")
	roomID := ts.createRoom(alice, nil)
	escaped := url.PathEscape(roomID)

	root := ts.sendMessage(alice, roomID, "root")
	reply := ts.threadReply(alice, roomID, root, "reply")
	expectStatus(t, ts.put("/_matrix/client/v3/rooms/"+escaped+"/redact/"+url.PathEscape(reply)+"/r1",
		alice.AccessToken, map[string]any{}), http.StatusOK)

	if got := ts.relations(alice, roomID, url.PathEscape(root), nil); len(got.Chunk) != 0 {
		t.Errorf("relations after the reply was redacted = %v", idsOf(got.Chunk))
	}
	rec := ts.get("/_matrix/client/v3/rooms/"+escaped+"/event/"+url.PathEscape(root), alice.AccessToken)
	if summary := threadSummaryOf(t, jsonBody(t, rec)); summary != nil {
		t.Errorf("the root still has a thread summary: %v", summary)
	}
}

func TestRelationsOfAnInvisibleEvent(t *testing.T) {
	ts := newTestServer(t, nil)
	alice := ts.register("alice", "correct-horse-battery-staple")
	bob := ts.register("bob", "correct-horse-battery-staple")
	roomID := ts.createRoom(alice, nil)
	root := ts.sendMessage(alice, roomID, "secret")

	rec := ts.get("/_matrix/client/v1/rooms/"+url.PathEscape(roomID)+"/relations/"+url.PathEscape(root),
		bob.AccessToken)
	expectStatus(t, rec, http.StatusForbidden)
}

func idsOf(events []syncEvent) []string {
	out := make([]string, 0, len(events))
	for _, e := range events {
		out = append(out, e.EventID)
	}
	return out
}

func equalStrings(a, b []string) bool {
	if len(a) != len(b) {
		return false
	}
	for i := range a {
		if a[i] != b[i] {
			return false
		}
	}
	return true
}