package coderd

import (
	"context"
	"database/sql"
	"encoding/json"
	"testing"
	"time"

	"github.com/google/uuid"
	"github.com/sqlc-dev/pqtype"
	"github.com/stretchr/testify/require"
	"go.uber.org/mock/gomock"

	"cdr.dev/slog/v3/sloggers/slogtest"
	"github.com/coder/coder/v2/coderd/database"
	"github.com/coder/coder/v2/coderd/database/dbgen"
	"github.com/coder/coder/v2/coderd/database/dbmock"
	"github.com/coder/coder/v2/codersdk"
)

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

	ctrl := gomock.NewController(t)
	db := dbmock.NewMockStore(ctrl)
	chatID := uuid.New()
	createdAt := time.Date(2026, time.April, 9, 13, 0, 0, 0, time.UTC)
	oldAgentID := uuid.New()
	newAgentID := uuid.New()

	oldContent, err := json.Marshal([]codersdk.ChatMessagePart{{
		Type:               codersdk.ChatMessagePartTypeContextFile,
		ContextFilePath:    "/old/AGENTS.md",
		ContextFileContent: "old instructions",
		ContextFileAgentID: uuid.NullUUID{UUID: oldAgentID, Valid: true},
	}})
	require.NoError(t, err)
	newContent, err := json.Marshal([]codersdk.ChatMessagePart{{
		Type:               codersdk.ChatMessagePartTypeContextFile,
		ContextFilePath:    "/new/AGENTS.md",
		ContextFileContent: "new instructions",
		ContextFileAgentID: uuid.NullUUID{UUID: newAgentID, Valid: true},
	}})
	require.NoError(t, err)

	db.EXPECT().GetChatMessagesByChatID(gomock.Any(), database.GetChatMessagesByChatIDParams{
		ChatID:  chatID,
		AfterID: 0,
	}).Return([]database.ChatMessage{
		{
			ID:        2,
			CreatedAt: createdAt,
			Content: pqtype.NullRawMessage{
				RawMessage: newContent,
				Valid:      true,
			},
		},
		{
			ID:        1,
			CreatedAt: createdAt,
			Content: pqtype.NullRawMessage{
				RawMessage: oldContent,
				Valid:      true,
			},
		},
	}, nil)

	db.EXPECT().UpdateChatLastInjectedContext(gomock.Any(), gomock.Any()).DoAndReturn(
		func(_ context.Context, arg database.UpdateChatLastInjectedContextParams) (database.Chat, error) {
			require.Equal(t, chatID, arg.ID)
			require.True(t, arg.LastInjectedContext.Valid)
			var cached []codersdk.ChatMessagePart
			require.NoError(t, json.Unmarshal(arg.LastInjectedContext.RawMessage, &cached))
			require.Len(t, cached, 1)
			require.Equal(t, "/new/AGENTS.md", cached[0].ContextFilePath)
			require.Equal(t, uuid.NullUUID{UUID: newAgentID, Valid: true}, cached[0].ContextFileAgentID)
			return database.Chat{}, nil
		},
	)

	err = updateAgentChatLastInjectedContextFromMessages(
		context.Background(),
		slogtest.Make(t, &slogtest.Options{IgnoreErrors: true}),
		db,
		chatID,
	)
	require.NoError(t, err)
}

func insertAgentChatTestModelConfig(
	t testing.TB,
	db database.Store,
	userID uuid.UUID,
) database.ChatModelConfig {
	t.Helper()

	createdBy := uuid.NullUUID{UUID: userID, Valid: true}

	provider := dbgen.AIProvider(t, db, database.AIProvider{
		Type:        database.AiProviderTypeOpenai,
		Name:        "test-openai",
		DisplayName: sql.NullString{String: "OpenAI", Valid: true},
	})
	dbgen.AIProviderKey(t, db, database.AIProviderKey{
		ProviderID: provider.ID,
		APIKey:     "test-api-key",
	})

	return dbgen.ChatModelConfig(t, db, database.ChatModelConfig{
		Provider:     "openai",
		AIProviderID: uuid.NullUUID{UUID: provider.ID, Valid: true},
		CreatedBy:    createdBy,
		UpdatedBy:    createdBy,
		IsDefault:    true,
	})
}