package handler

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

	"github.com/jackc/pgx/v5/pgtype"
	"github.com/multica-ai/multica/server/internal/events"
	"github.com/multica-ai/multica/server/internal/testutil"
	"github.com/multica-ai/multica/server/internal/util"
	db "github.com/multica-ai/multica/server/pkg/db/generated"
	"github.com/multica-ai/multica/server/pkg/protocol"
)

// seedBatchTask builds the running, issue-backed task the /messages endpoint
// needs: requireDaemonTaskAccess resolves the workspace through the issue, and a
// task with no issue / chat / autopilot link 404s before the body is read.
func seedBatchTask(t *testing.T, label string) string {
	t.Helper()
	agentID := dbfx.Agent(t, label+" agent", handlerTestRuntimeID(t), testutil.Cols{
		"instructions": "",
		"custom_env":   testutil.Raw("'{}'::jsonb"),
		"custom_args":  testutil.Raw("'[]'::jsonb"),
	})
	issueID := dbfx.Issue(t, label+" fixture", testutil.Cols{"status": "in_progress"})
	return dbfx.Task(t, agentID, testutil.Cols{
		"runtime_id": handlerTestRuntimeID(t),
		"issue_id":   issueID,
		"status":     "running",
		"started_at": testutil.Raw("now()"),
	})
}

// batchMessagesRequest builds the daemon-authenticated POST the daemon sends,
// with taskId bound as a chi URL param the way the router does in production.
func batchMessagesRequest(t *testing.T, taskID string, messages []any) *http.Request {
	t.Helper()
	req := testutil.JSONRequest(http.MethodPost,
		"/api/daemon/tasks/"+taskID+"/messages", map[string]any{"messages": messages})
	req = testutil.WithURLParams(req, "taskId", taskID)
	// The fixture runtime's owner, as a real daemon authenticates.
	req.Header.Set("X-User-ID", testUserID)
	return req
}

// TestReportTaskMessagesPersistsWholeBatch covers the multi-message shape of the
// /messages endpoint after it stopped issuing one INSERT per message. The row
// count, the seq values, and the NULL/non-NULL split all have to survive the
// jsonb round trip CreateTaskMessages does: a tool event carries tool + input +
// output, a text event carries only content, and everything the daemon omitted
// must land as SQL NULL rather than an empty string.
func TestReportTaskMessagesPersistsWholeBatch(t *testing.T) {
	if testHandler == nil {
		t.Skip("database not available")
	}
	ctx := context.Background()
	taskID := seedBatchTask(t, "batch-messages")
	// PostgreSQL timestamptz preserves microseconds, so keep the fixture on that
	// boundary while still proving daemon event precision survives.
	observedAt := time.Now().UTC().Add(-time.Second).Truncate(time.Microsecond)

	testutil.Call(t, testHandler.ReportTaskMessages, batchMessagesRequest(t, taskID, []any{
		map[string]any{
			"seq":        1,
			"type":       "thinking",
			"content":    "planning",
			"created_at": observedAt.Format(time.RFC3339Nano),
		},
		map[string]any{
			"seq":        2,
			"type":       "tool_use",
			"tool":       "fs_read",
			"input":      map[string]any{"path": "/etc/hosts", "nested": map[string]any{"depth": 2}},
			"output":     "127.0.0.1 localhost",
			"created_at": observedAt.Add(10 * time.Millisecond).Format(time.RFC3339Nano),
		},
		map[string]any{
			"seq":        3,
			"type":       "text",
			"content":    "done",
			"created_at": observedAt.Add(20 * time.Millisecond).Format(time.RFC3339Nano),
		},
	})).Want(http.StatusOK)

	stored, err := testHandler.Queries.ListTaskMessages(ctx, util.MustParseUUID(taskID))
	if err != nil {
		t.Fatalf("list persisted task messages: %v", err)
	}
	if len(stored) != 3 {
		t.Fatalf("persisted %d task messages, want 3", len(stored))
	}
	for i, want := range []int32{1, 2, 3} {
		if stored[i].Seq != want {
			t.Fatalf("row %d seq = %d, want %d", i, stored[i].Seq, want)
		}
	}

	if stored[0].Type != "thinking" || stored[0].Content.String != "planning" {
		t.Fatalf("thinking row = %+v, want type=thinking content=planning", stored[0])
	}
	if !stored[0].CreatedAt.Time.Equal(observedAt) {
		t.Fatalf("daemon-observed created_at = %s, want %s", stored[0].CreatedAt.Time, observedAt)
	}
	if want := observedAt.Add(10 * time.Millisecond); !stored[1].CreatedAt.Time.Equal(want) {
		t.Fatalf("second daemon-observed created_at = %s, want %s", stored[1].CreatedAt.Time, want)
	}
	// Fields the daemon did not send must be NULL, not "".
	if stored[0].Tool.Valid || stored[0].Output.Valid || stored[0].Input != nil {
		t.Fatalf("thinking row should have NULL tool/output/input, got %+v", stored[0])
	}
	if stored[1].Tool.String != "fs_read" {
		t.Fatalf("tool_use row tool = %q, want fs_read", stored[1].Tool.String)
	}
	if stored[1].Output.String != "127.0.0.1 localhost" {
		t.Fatalf("tool_use row output = %q", stored[1].Output.String)
	}
	if stored[1].Content.Valid {
		t.Fatalf("tool_use row content should be NULL, got %q", stored[1].Content.String)
	}
	// The jsonb argument must arrive as an object, not as a string holding JSON,
	// or `input->>'path'` stops resolving for every consumer of this column.
	var inputPath string
	dbfx.QueryRow(t,
		`SELECT input->>'path' FROM task_message WHERE task_id = $1 AND seq = 2`,
		taskID).Scan(&inputPath)
	if inputPath != "/etc/hosts" {
		t.Fatalf("input->>path = %q, want /etc/hosts", inputPath)
	}
	if stored[2].Type != "text" || stored[2].Content.String != "done" {
		t.Fatalf("text row = %+v, want type=text content=done", stored[2])
	}
}

func TestReportTaskMessagesFallsBackWholeBatchForClockSkew(t *testing.T) {
	if testHandler == nil {
		t.Skip("database not available")
	}
	taskID := seedBatchTask(t, "batch-clock-skew")
	validAt := time.Now().UTC().Add(-time.Second)
	invalidAt := validAt.Add(-maxTaskMessageClockSkew - time.Minute)
	// The fallback is generated by PostgreSQL, whose clock may differ from
	// the test host (for example, a local container VM). Bound it on that clock.
	var fallbackBefore time.Time
	dbfx.QueryRow(t, `SELECT clock_timestamp()`).Scan(&fallbackBefore)

	testutil.Call(t, testHandler.ReportTaskMessages, batchMessagesRequest(t, taskID, []any{
		map[string]any{
			"seq":        1,
			"type":       "tool_use",
			"tool":       "bash",
			"created_at": validAt.Format(time.RFC3339Nano),
		},
		map[string]any{
			"seq":        2,
			"type":       "tool_result",
			"tool":       "bash",
			"created_at": invalidAt.Format(time.RFC3339Nano),
		},
	})).Want(http.StatusOK)
	var fallbackAfter time.Time
	dbfx.QueryRow(t, `SELECT clock_timestamp()`).Scan(&fallbackAfter)

	stored, err := testHandler.Queries.ListTaskMessages(context.Background(), util.MustParseUUID(taskID))
	if err != nil {
		t.Fatalf("list persisted task messages: %v", err)
	}
	if len(stored) != 2 {
		t.Fatalf("persisted %d task messages, want 2", len(stored))
	}
	for _, row := range stored {
		if got := row.CreatedAt.Time; got.Before(fallbackBefore) || got.After(fallbackAfter) {
			t.Fatalf("seq %d created_at = %s, want database fallback between %s and %s", row.Seq, got, fallbackBefore, fallbackAfter)
		}
	}
}

// TestReportTaskMessagesPublishesInSeqOrder pins the realtime ordering the batch
// insert has to preserve. The per-message loop it replaced published in request
// order; `INSERT ... RETURNING` has no row-order guarantee, so the order now
// comes from CreateTaskMessages' ORDER BY seq. Subscribers render these events
// as they arrive, so an out-of-order batch is a visible transcript bug.
//
// The request deliberately lists the messages out of seq order: if the ORDER BY
// were dropped, the events would come back in array order and this fails. That
// also makes seq — the daemon's own counter — the single ordering authority,
// rather than however the rows happen to land.
func TestReportTaskMessagesPublishesInSeqOrder(t *testing.T) {
	if testHandler == nil {
		t.Skip("database not available")
	}
	taskID := seedBatchTask(t, "batch-order")

	// The shared bus has no unsubscribe, so a listener registered on it would
	// outlive this test and keep firing for the rest of the package. Swap in a
	// bus of this test's own and put the shared one back afterwards.
	sharedBus := testHandler.Bus
	testHandler.Bus = events.New()
	t.Cleanup(func() { testHandler.Bus = sharedBus })

	var mu sync.Mutex
	var gotSeqs []int
	testHandler.Bus.Subscribe(protocol.EventTaskMessage, func(e events.Event) {
		mu.Lock()
		defer mu.Unlock()
		if e.TaskID != taskID {
			return
		}
		if payload, ok := e.Payload.(protocol.TaskMessagePayload); ok {
			gotSeqs = append(gotSeqs, payload.Seq)
		}
	})

	testutil.Call(t, testHandler.ReportTaskMessages, batchMessagesRequest(t, taskID, []any{
		map[string]any{"seq": 3, "type": "text", "content": "third"},
		map[string]any{"seq": 1, "type": "text", "content": "first"},
		map[string]any{"seq": 2, "type": "text", "content": "second"},
	})).Want(http.StatusOK)

	mu.Lock()
	defer mu.Unlock()
	want := []int{1, 2, 3}
	if len(gotSeqs) != len(want) {
		t.Fatalf("published %v task:message events, want seqs %v", gotSeqs, want)
	}
	for i := range want {
		if gotSeqs[i] != want[i] {
			t.Fatalf("published seq order = %v, want %v — subscribers render these "+
				"events in arrival order, so the transcript would show the batch scrambled",
				gotSeqs, want)
		}
	}
}

// A chat task's transcript is the agent's half of a private conversation, so
// its task:message events must name the chat session and its creator for the
// realtime layer to deliver them to that member only. The creator here is not
// the daemon's user, so the owner cannot have come from the request.
func TestReportTaskMessagesStampsChatSessionOwner(t *testing.T) {
	if testHandler == nil {
		t.Skip("database not available")
	}
	creatorID := dbfx.User(t, "Chat owner", "task-message-chat-owner@example.test")
	dbfx.Member(t, testWorkspaceID, creatorID, "member")
	agentID := dbfx.Agent(t, "chat transcript agent", handlerTestRuntimeID(t), testutil.Cols{
		"instructions": "",
		"custom_env":   testutil.Raw("'{}'::jsonb"),
		"custom_args":  testutil.Raw("'[]'::jsonb"),
	})
	chatSessionID := dbfx.ChatSession(t, agentID, testutil.Cols{"creator_id": creatorID})
	chatTaskID := dbfx.Task(t, agentID, testutil.Cols{
		"runtime_id":      handlerTestRuntimeID(t),
		"chat_session_id": chatSessionID,
		"status":          "running",
		"started_at":      testutil.Raw("now()"),
	})
	issueTaskID := seedBatchTask(t, "issue transcript")

	sharedBus := testHandler.Bus
	testHandler.Bus = events.New()
	t.Cleanup(func() { testHandler.Bus = sharedBus })
	var mu sync.Mutex
	got := map[string]events.Event{}
	testHandler.Bus.Subscribe(protocol.EventTaskMessage, func(e events.Event) {
		mu.Lock()
		defer mu.Unlock()
		got[e.TaskID] = e
	})

	for _, taskID := range []string{chatTaskID, issueTaskID} {
		testutil.Call(t, testHandler.ReportTaskMessages, batchMessagesRequest(t, taskID, []any{
			map[string]any{"seq": 1, "type": "text", "content": "transcript"},
		})).Want(http.StatusOK)
	}

	mu.Lock()
	defer mu.Unlock()
	chat, ok := got[chatTaskID]
	if !ok {
		t.Fatal("chat task published no task:message")
	}
	if chat.ChatSessionID != chatSessionID || chat.ChatSessionOwnerID != creatorID {
		t.Fatalf("chat task:message hints = session %q owner %q, want %q / %q",
			chat.ChatSessionID, chat.ChatSessionOwnerID, chatSessionID, creatorID)
	}
	issue, ok := got[issueTaskID]
	if !ok {
		t.Fatal("issue task published no task:message")
	}
	if issue.ChatSessionID != "" || issue.ChatSessionOwnerID != "" || issue.WorkspaceID != testWorkspaceID {
		t.Fatalf("issue task:message = %+v, want workspace-scoped without chat hints", issue)
	}
}

// TestCreateTaskMessagesBatchIsAtomic exercises the production query, not a copy
// of it: a batch that violates the primary key must persist nothing. This is the
// property the single statement buys over the per-message loop, which could
// leave a prefix of the batch behind and no way to complete it (the daemon does
// not retry this endpoint).
//
// Note what this does and does not guarantee: the batch is consistent, not
// complete. A failing batch is now lost whole. Closing that gap needs a retry
// plus a (task_id, seq) uniqueness rule, which is not part of this change.
func TestCreateTaskMessagesBatchIsAtomic(t *testing.T) {
	if testHandler == nil {
		t.Skip("database not available")
	}
	ctx := context.Background()
	taskID := seedBatchTask(t, "batch-atomic")

	// The existing row is built as a fixture, not through the query under
	// test: test setup that shares code with the code being exercised can pass
	// for the wrong reason.
	const dupID = "018f0000-0000-7000-8000-000000000001"
	dbfx.Insert(t, "task_message", testutil.Cols{
		"id":      dupID,
		"task_id": taskID,
		"seq":     1,
		"type":    "text",
		"content": "first",
	})

	_, err := testHandler.Queries.CreateTaskMessages(ctx, db.CreateTaskMessagesParams{
		TaskID:            util.MustParseUUID(taskID),
		Ids:               []pgtype.UUID{util.MustParseUUID("018f0000-0000-7000-8000-000000000002"), util.MustParseUUID("018f0000-0000-7000-8000-000000000003")},
		Seqs:              []int32{2, 3},
		Types:             []string{"text", "text"},
		Tools:             []string{"", ""},
		Contents:          []string{"ok", "invalid input"},
		Inputs:            []string{"", "not-json"},
		Outputs:           []string{"", ""},
		CreatedAts:        []string{"", ""},
		OutputTruncations: []string{"", ""},
	})
	if err == nil {
		t.Fatal("CreateTaskMessages accepted a batch with invalid JSON input")
	}

	count := dbfx.Count(t, `SELECT COUNT(*) FROM task_message WHERE task_id = $1`, taskID)
	if count != 1 {
		t.Fatalf("task_message rows after the failed batch = %d, want 1 (only the seeded row) — "+
			"the batch persisted a prefix instead of rolling back", count)
	}
}

func TestTaskMessageCreatedAtRejectsImplausibleClockSkew(t *testing.T) {
	t.Parallel()

	serverNow := time.Date(2026, time.September, 10, 12, 0, 0, 0, time.UTC)
	zero := time.Time{}
	insidePast := serverNow.Add(-maxTaskMessageClockSkew)
	insideFuture := serverNow.Add(maxTaskMessageClockSkew)
	outsidePast := insidePast.Add(-time.Nanosecond)
	outsideFuture := insideFuture.Add(time.Nanosecond)

	tests := []struct {
		name string
		at   *time.Time
		want string
	}{
		{name: "missing"},
		{name: "zero", at: &zero},
		{name: "past boundary", at: &insidePast, want: insidePast.Format(time.RFC3339Nano)},
		{name: "future boundary", at: &insideFuture, want: insideFuture.Format(time.RFC3339Nano)},
		{name: "too far in the past", at: &outsidePast},
		{name: "too far in the future", at: &outsideFuture},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			t.Parallel()
			if got := taskMessageCreatedAt(tt.at, serverNow); got != tt.want {
				t.Fatalf("taskMessageCreatedAt() = %q, want %q", got, tt.want)
			}
		})
	}
}

func TestTaskMessageCreatedAtsFallsBackWholeBatch(t *testing.T) {
	t.Parallel()

	serverNow := time.Date(2026, time.September, 10, 12, 0, 0, 0, time.UTC)
	valid := serverNow.Add(-time.Second)
	invalid := serverNow.Add(-maxTaskMessageClockSkew - time.Nanosecond)

	got := taskMessageCreatedAts([]TaskMessageRequest{
		{CreatedAt: &valid},
		{CreatedAt: &invalid},
	}, serverNow)
	if want := []string{"", ""}; !slices.Equal(got, want) {
		t.Fatalf("taskMessageCreatedAts() = %q, want whole-batch fallback %q", got, want)
	}

	got = taskMessageCreatedAts([]TaskMessageRequest{
		{CreatedAt: &valid},
		{CreatedAt: &serverNow},
	}, serverNow)
	if want := []string{valid.Format(time.RFC3339Nano), serverNow.Format(time.RFC3339Nano)}; !slices.Equal(got, want) {
		t.Fatalf("taskMessageCreatedAts() = %q, want %q", got, want)
	}
}

func TestReportTaskMessagesIdempotencyIsTaskScoped(t *testing.T) {
	if testHandler == nil {
		t.Skip("database not available")
	}
	first := seedBatchTask(t, "idempotent-first")
	second := seedBatchTask(t, "idempotent-second")
	sharedBus := testHandler.Bus
	testHandler.Bus = events.New()
	t.Cleanup(func() { testHandler.Bus = sharedBus })
	var mu sync.Mutex
	published := 0
	testHandler.Bus.Subscribe(protocol.EventTaskMessage, func(e events.Event) {
		if e.TaskID == first || e.TaskID == second {
			mu.Lock()
			published++
			mu.Unlock()
		}
	})
	eventTime := time.Now().UTC().Truncate(time.Microsecond)
	message := map[string]any{"seq": 1, "type": "text", "content": "original", "idempotency_key": "qoder:evt_1", "call_id": "call_original", "created_at": eventTime, "output_truncated": true}
	for _, taskID := range []string{first, first, second} {
		testutil.Call(t, testHandler.ReportTaskMessages, batchMessagesRequest(t, taskID, []any{message})).Want(http.StatusOK)
	}
	// Replaying the key with a changed payload must not overwrite the first report.
	message["content"] = "changed"
	message["call_id"] = "call_changed"
	message["created_at"] = eventTime.Add(time.Second)
	message["output_truncated"] = false
	testutil.Call(t, testHandler.ReportTaskMessages, batchMessagesRequest(t, first, []any{message})).Want(http.StatusOK)
	for _, taskID := range []string{first, second} {
		rows, err := testHandler.Queries.ListTaskMessages(context.Background(), util.MustParseUUID(taskID))
		if err != nil {
			t.Fatal(err)
		}
		if len(rows) != 1 || rows[0].Content.String != "original" {
			t.Fatalf("task %s replay changed persisted messages: %+v", taskID, rows)
		}
		if rows[0].CallID.String != "call_original" || !rows[0].CreatedAt.Time.Equal(eventTime) || !rows[0].OutputTruncated.Valid || !rows[0].OutputTruncated.Bool {
			t.Fatalf("task %s replay changed event metadata: %+v", taskID, rows[0])
		}
	}
	mu.Lock()
	defer mu.Unlock()
	if published != 2 {
		t.Fatalf("published %d events, want one per task", published)
	}
}

func TestReportTaskMessagesRejectsOversizedIdempotencyKeyAtomically(t *testing.T) {
	if testHandler == nil {
		t.Skip("database not available")
	}
	taskID := seedBatchTask(t, "idempotency-key-limit")
	testutil.Call(t, testHandler.ReportTaskMessages, batchMessagesRequest(t, taskID, []any{
		map[string]any{"seq": 1, "type": "text", "content": "valid"},
		map[string]any{"seq": 2, "type": "text", "idempotency_key": strings.Repeat("x", 513)},
	})).Want(http.StatusBadRequest)
	if n := dbfx.Count(t, `SELECT COUNT(*) FROM task_message WHERE task_id=$1`, taskID); n != 0 {
		t.Fatalf("persisted %d rows before validation failed", n)
	}
}