package notification

import (
	"os"
	"path/filepath"
	"regexp"
	"sort"
	"testing"

	"github.com/stretchr/testify/require"
)

const expectedPushPayloadMappingTable = `| ` + "`notification_type`" + ` | FlatBuffers table | Payload fields |
| --- | --- | --- |
| ` + "`game.turn.ready`" + ` | ` + "`notification.GameTurnReadyEvent`" + ` | ` + "`game_id`" + `, ` + "`turn_number`" + ` |
| ` + "`game.finished`" + ` | ` + "`notification.GameFinishedEvent`" + ` | ` + "`game_id`" + `, ` + "`final_turn_number`" + ` |
| ` + "`lobby.application.submitted`" + ` | ` + "`notification.LobbyApplicationSubmittedEvent`" + ` | ` + "`game_id`" + `, ` + "`applicant_user_id`" + ` |
| ` + "`lobby.membership.approved`" + ` | ` + "`notification.LobbyMembershipApprovedEvent`" + ` | ` + "`game_id`" + ` |
| ` + "`lobby.membership.rejected`" + ` | ` + "`notification.LobbyMembershipRejectedEvent`" + ` | ` + "`game_id`" + ` |
| ` + "`lobby.membership.blocked`" + ` | ` + "`notification.LobbyMembershipBlockedEvent`" + ` | ` + "`game_id`" + `, ` + "`membership_user_id`" + `, ` + "`reason`" + ` |
| ` + "`lobby.invite.created`" + ` | ` + "`notification.LobbyInviteCreatedEvent`" + ` | ` + "`game_id`" + `, ` + "`inviter_user_id`" + ` |
| ` + "`lobby.invite.redeemed`" + ` | ` + "`notification.LobbyInviteRedeemedEvent`" + ` | ` + "`game_id`" + `, ` + "`invitee_user_id`" + ` |
| ` + "`lobby.race_name.registration_eligible`" + ` | ` + "`notification.LobbyRaceNameRegistrationEligibleEvent`" + ` | ` + "`game_id`" + `, ` + "`race_name`" + `, ` + "`eligible_until_ms`" + ` |
| ` + "`lobby.race_name.registered`" + ` | ` + "`notification.LobbyRaceNameRegisteredEvent`" + ` | ` + "`race_name`" + ` |`

var expectedPushPayloadSchemaTableNames = []string{
	"GameTurnReadyEvent",
	"GameFinishedEvent",
	"LobbyApplicationSubmittedEvent",
	"LobbyMembershipApprovedEvent",
	"LobbyMembershipRejectedEvent",
	"LobbyMembershipBlockedEvent",
	"LobbyInviteCreatedEvent",
	"LobbyInviteRedeemedEvent",
	"LobbyRaceNameRegistrationEligibleEvent",
	"LobbyRaceNameRegisteredEvent",
}

var expectedPushPayloadSchemaFields = map[string][]string{
	"GameTurnReadyEvent": {
		"game_id:string;",
		"turn_number:int64;",
	},
	"GameFinishedEvent": {
		"game_id:string;",
		"final_turn_number:int64;",
	},
	"LobbyApplicationSubmittedEvent": {
		"game_id:string;",
		"applicant_user_id:string;",
	},
	"LobbyMembershipApprovedEvent": {
		"game_id:string;",
	},
	"LobbyMembershipRejectedEvent": {
		"game_id:string;",
	},
	"LobbyMembershipBlockedEvent": {
		"game_id:string;",
		"membership_user_id:string;",
		"reason:string;",
	},
	"LobbyInviteCreatedEvent": {
		"game_id:string;",
		"inviter_user_id:string;",
	},
	"LobbyInviteRedeemedEvent": {
		"game_id:string;",
		"invitee_user_id:string;",
	},
	"LobbyRaceNameRegistrationEligibleEvent": {
		"game_id:string;",
		"race_name:string;",
		"eligible_until_ms:int64;",
	},
	"LobbyRaceNameRegisteredEvent": {
		"race_name:string;",
	},
}

var expectedPushPayloadGeneratedFiles = []string{
	"GameFinishedEvent.go",
	"GameTurnReadyEvent.go",
	"LobbyApplicationSubmittedEvent.go",
	"LobbyInviteCreatedEvent.go",
	"LobbyInviteRedeemedEvent.go",
	"LobbyMembershipApprovedEvent.go",
	"LobbyMembershipBlockedEvent.go",
	"LobbyMembershipRejectedEvent.go",
	"LobbyRaceNameRegisteredEvent.go",
	"LobbyRaceNameRegistrationEligibleEvent.go",
}

var expectedPushPayloadDocumentationSnippets = []string{
	"Only the ten user-facing push notification types above are represented in `notification.fbs`.",
	"`geo.review_recommended`, `game.generation_failed`, `lobby.runtime_paused_after_start`, `lobby.invite.expired`, and `lobby.race_name.registration_denied` remain outside this schema because they are email-only in v1.",
	"`notification_type` alone determines the concrete FlatBuffers table.",
	"No extra envelope or FlatBuffers `union` is added in v1.",
	"The push payload must stay lightweight and must not attempt to mirror full game, lobby, or profile state.",
	"`game_name`, human-readable user names, and other full business-state fields stay out of the push schema.",
}

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

	schema := loadTextFile(t, filepath.Join("..", "pkg", "schema", "fbs", "notification.fbs"))
	require.Contains(t, schema, "namespace notification;")
	require.Contains(t, schema, "root_type GameTurnReadyEvent;")
	require.NotContains(t, schema, "union ")

	tablePattern := regexp.MustCompile(`(?m)^table ([A-Za-z0-9_]+) \{$`)
	matches := tablePattern.FindAllStringSubmatch(schema, -1)
	actualTableNames := make([]string, 0, len(matches))
	for _, match := range matches {
		actualTableNames = append(actualTableNames, match[1])
	}

	require.Equal(t, expectedPushPayloadSchemaTableNames, actualTableNames)

	for _, tableName := range expectedPushPayloadSchemaTableNames {
		tableBody := extractFlatBuffersTableBody(t, schema, tableName)
		for _, field := range expectedPushPayloadSchemaFields[tableName] {
			require.Contains(t, tableBody, field)
		}
	}
}

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

	dirPath := filepath.Join(moduleRoot(t), "..", "pkg", "schema", "fbs", "notification")
	entries, err := os.ReadDir(dirPath)
	require.NoError(t, err)

	actualFiles := make([]string, 0, len(entries))
	for _, entry := range entries {
		require.Falsef(t, entry.IsDir(), "unexpected directory in generated bindings: %s", entry.Name())
		actualFiles = append(actualFiles, entry.Name())

		fileContents := loadTextFile(t, filepath.Join("..", "pkg", "schema", "fbs", "notification", entry.Name()))
		require.Contains(t, fileContents, "// Code generated by the FlatBuffers compiler. DO NOT EDIT.")
		require.Contains(t, fileContents, "package notification")
	}

	sort.Strings(actualFiles)
	require.Equal(t, expectedPushPayloadGeneratedFiles, actualFiles)
}

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

	readme := loadTextFile(t, "README.md")
	flowsDoc := loadTextFile(t, filepath.Join("docs", "flows.md"))
	examplesDoc := loadTextFile(t, filepath.Join("docs", "examples.md"))
	docsIndex := loadTextFile(t, filepath.Join("docs", "README.md"))
	normalizedReadme := normalizeWhitespace(readme)
	normalizedFlowsDoc := normalizeWhitespace(flowsDoc)
	normalizedExamplesDoc := normalizeWhitespace(examplesDoc)

	require.Contains(t, readme, expectedPushPayloadMappingTable)
	require.Contains(t, docsIndex, "- [Main flows](flows.md)")
	require.Contains(t, docsIndex, "- [Configuration and contract examples](examples.md)")

	for _, snippet := range expectedPushPayloadDocumentationSnippets {
		normalizedSnippet := normalizeWhitespace(snippet)
		require.Contains(t, normalizedReadme, normalizedSnippet)
	}

	require.Contains(t, normalizedFlowsDoc, normalizeWhitespace("encode FlatBuffers notification payload"))
	require.Contains(t, normalizedExamplesDoc, normalizeWhitespace("payload_bytes '<flatbuffers-bytes>'"))
}

func extractFlatBuffersTableBody(t *testing.T, schema, tableName string) string {
	t.Helper()

	pattern := regexp.MustCompile(`(?s)table ` + regexp.QuoteMeta(tableName) + ` \{(.*?)\}`)
	match := pattern.FindStringSubmatch(schema)
	if match == nil {
		require.FailNowf(t, "test failed", "table %s not found in schema", tableName)
	}

	return match[1]
}