package models

import (
	"errors"

	"gorm.io/gorm"
)

// GetAllModels 数据库迁移用模型列表
func GetAllModels() []interface{} {
	return []interface{}{
		&LogEvent{},
		&AlertOutbox{},
		&ResourceMapping{},
		&ResourceEventDedup{},
		&TrapDictionaryEntry{},
		&SyslogRule{},
		&TrapRule{},
		&TrapShield{},
		&AuditLog{},
		&DangerousOperationApproval{},
	}
}

// InitData 初始化默认规则数据（幂等）
func InitData(db *gorm.DB) error {
	if db == nil {
		return nil
	}
	if err := backfillDispatchOutboxIDs(db); err != nil {
		return err
	}
	if err := seedDefaultSyslogRules(db); err != nil {
		return err
	}
	if err := seedDefaultTrapRules(db); err != nil {
		return err
	}
	if err := seedDefaultTrapDictionary(db); err != nil {
		return err
	}
	return nil
}

func backfillDispatchOutboxIDs(db *gorm.DB) error {
	const postgresUpdate = `
WITH latest AS (
    SELECT target_event.id AS log_event_id, current_outbox.id, current_outbox.status
    FROM logs_events AS target_event
    JOIN LATERAL (
        SELECT id, status
        FROM logs_alert_outbox
        WHERE log_event_id = target_event.id
        ORDER BY id DESC
        LIMIT 1
    ) AS current_outbox ON TRUE
    WHERE target_event.dispatch_outbox_id = 0
)
UPDATE logs_events AS target_event
SET dispatch_outbox_id = latest.id,
    dispatch_status = CASE latest.status WHEN 'processing' THEN 'retrying' ELSE latest.status END,
    alert_sent = CASE WHEN latest.status = 'sent' THEN TRUE ELSE FALSE END
FROM latest
WHERE target_event.id = latest.log_event_id
  AND target_event.dispatch_outbox_id = 0`
	const mysqlUpdate = `
UPDATE logs_events AS target_event
JOIN (
    SELECT candidate.id AS log_event_id, MAX(outbox.id) AS id
    FROM logs_events AS candidate
    JOIN logs_alert_outbox AS outbox ON outbox.log_event_id = candidate.id
    WHERE candidate.dispatch_outbox_id = 0
    GROUP BY candidate.id
) AS latest_id ON latest_id.log_event_id = target_event.id
JOIN logs_alert_outbox AS latest ON latest.id = latest_id.id
SET dispatch_outbox_id = latest.id,
    dispatch_status = CASE latest.status WHEN 'processing' THEN 'retrying' ELSE latest.status END,
    alert_sent = CASE WHEN latest.status = 'sent' THEN TRUE ELSE FALSE END
WHERE target_event.dispatch_outbox_id = 0`

	switch db.Dialector.Name() {
	case "postgres":
		return db.Exec(postgresUpdate).Error
	case "mysql":
		return db.Exec(mysqlUpdate).Error
	default:
		return gorm.ErrUnsupportedDriver
	}
}

func seedDefaultSyslogRules(db *gorm.DB) error {
	rows := []SyslogRule{
		{
			Name:               "默认-系统严重错误",
			Enabled:            true,
			Priority:           100,
			DeviceNameContains: "",
			KeywordRegex:       "(?i)(panic|fatal|segmentation fault|kernel panic|out of memory|oom)",
			AlertName:          "Syslog严重错误",
			SeverityCode:       "critical",
			PolicyID:           0,
		},
		{
			Name:                    "默认-链路中断告警",
			Enabled:                 true,
			Priority:                90,
			DeviceNameContains:      "",
			KeywordRegex:            "(?i)(link down|interface .* down|port .* down)",
			SourceMatch:             "",
			MessageRegex:            "(?i)(link down|interface .* down|port .* down|LINK_DOWN)",
			AlertName:               "Syslog链路中断",
			SeverityCode:            "major",
			SeverityMappingJSON:     `{"(?i)(critical|fatal|emergency)":"critical","(?i)(error|LINK_DOWN|down)":"major","(?i)(warning|warn)":"warning"}`,
			ResourceUIDExtractRegex: `(?i)(?:resource_uid=|resource=)(?P<resource_uid>[a-z0-9_-]+:[a-z0-9_.:/-]+)|Interface (?P<iface>[A-Za-z0-9/._-]+)`,
			PolicyID:                0,
		},
		{
			Name:                    "H3C-Syslog-接口中断",
			Enabled:                 true,
			Priority:                120,
			SourceMatch:             "h3c",
			MessageRegex:            `(?i)(LINK_DOWN|Interface .* down|port .* down)`,
			AlertName:               "H3C Syslog接口中断",
			SeverityCode:            "major",
			SeverityMappingJSON:     `{"(?i)(LINK_DOWN|down)":"major","(?i)(LINK_UP|up)":"info"}`,
			ResourceUIDExtractRegex: `(?i)(?:resource_uid=|resource=)(?P<resource_uid>network:[a-z0-9_.:/-]+)|Interface (?P<iface>[A-Za-z0-9/._-]+)`,
			PolicyID:                0,
		},
	}
	for _, row := range rows {
		var existing SyslogRule
		err := db.Where("name = ?", row.Name).First(&existing).Error
		if errors.Is(err, gorm.ErrRecordNotFound) {
			if err := db.Create(&row).Error; err != nil {
				return err
			}
			continue
		}
		if err != nil {
			return err
		}
		if err := db.Model(&existing).Omit("updated_at").Select(
			"name",
			"enabled",
			"priority",
			"device_name_contains",
			"source_match",
			"keyword_regex",
			"message_regex",
			"alert_name",
			"severity_code",
			"severity_mapping_json",
			"resource_uid_extract_regex",
			"policy_id",
		).Updates(&row).Error; err != nil {
			return err
		}
	}
	return nil
}

func seedDefaultTrapRules(db *gorm.DB) error {
	rows := []TrapRule{
		{
			Name:              "默认-Trap链路中断",
			Enabled:           true,
			Priority:          100,
			OIDPrefix:         "1.3.6.1.6.3.1.1.5",
			VarbindMatchRegex: "(?i)(linkdown|ifdown|down)",
			AlertName:         "SNMP Trap链路中断",
			SeverityCode:      "major",
			PolicyID:          0,
		},
	}
	for _, row := range rows {
		var existing TrapRule
		err := db.Where("name = ?", row.Name).First(&existing).Error
		if errors.Is(err, gorm.ErrRecordNotFound) {
			if err := db.Create(&row).Error; err != nil {
				return err
			}
			continue
		}
		if err != nil {
			return err
		}
		if err := db.Model(&existing).Omit("updated_at").Select(
			"name",
			"enabled",
			"priority",
			"oid_prefix",
			"varbind_match_regex",
			"alert_name",
			"severity_code",
			"policy_id",
		).Updates(&row).Error; err != nil {
			return err
		}
	}
	return nil
}

func seedDefaultTrapDictionary(db *gorm.DB) error {
	rows := []TrapDictionaryEntry{
		{
			Vendor:              "H3C",
			OID:                 "1.3.6.1.6.3.1.1.5.3",
			OIDPrefix:           "1.3.6.1.6.3.1.1.5.3",
			Name:                "H3C ifDown 接口中断",
			Title:               "ifDown 接口中断",
			Description:         "检测到设备接口状态变为 down。",
			SeverityCode:        "major",
			SeverityMappingJSON: `{"down":"major","up":"info"}`,
			ParseExpression:     `(?i)(ifName|interface)=?(?P<interface>[A-Za-z0-9/._-]+)`,
			RecoveryMessage:     "请检查链路、端口状态和对端设备。",
			Enabled:             true,
		},
		{
			Vendor:              "H3C",
			OID:                 "1.3.6.1.6.3.1.1.5.4",
			OIDPrefix:           "1.3.6.1.6.3.1.1.5.4",
			Name:                "H3C ifUp 接口恢复",
			Title:               "ifUp 接口恢复",
			Description:         "检测到设备接口状态恢复为 up。",
			SeverityCode:        "info",
			SeverityMappingJSON: `{"up":"info"}`,
			ParseExpression:     `(?i)(ifName|interface)=?(?P<interface>[A-Za-z0-9/._-]+)`,
			RecoveryMessage:     "接口已恢复，请确认业务连通性。",
			Enabled:             true,
		},
	}
	for _, row := range rows {
		var existing TrapDictionaryEntry
		err := db.Where("o_id_prefix = ?", row.OIDPrefix).First(&existing).Error
		if errors.Is(err, gorm.ErrRecordNotFound) {
			if err := db.Create(&row).Error; err != nil {
				return err
			}
			continue
		}
		if err != nil {
			return err
		}
		if err := db.Model(&existing).Omit("updated_at").Select(
			"o_id_prefix",
			"vendor",
			"o_id",
			"name",
			"title",
			"description",
			"severity_code",
			"severity_mapping_json",
			"parse_expression",
			"recovery_message",
			"enabled",
		).Updates(&row).Error; err != nil {
			return err
		}
	}
	return nil
}