//go:build gonavi_full_drivers || gonavi_dameng_driver

package db

import (
	"context"
	"database/sql"
	"fmt"
	"net"
	"net/url"
	"strconv"
	"strings"
	"time"

	"GoNavi-Wails/internal/connection"
	"GoNavi-Wails/internal/logger"
	"GoNavi-Wails/internal/ssh"
	"GoNavi-Wails/internal/utils"

	_ "gitee.com/chunanyong/dm"
)

type DamengDB struct {
	conn        *sql.DB
	pingTimeout time.Duration
	forwarder   *ssh.LocalForwarder // Store SSH tunnel forwarder
}

func (d *DamengDB) getDSN(config connection.ConnectionConfig) string {
	// dm://user:password@host:port?schema=...
	// or dm://user:password@host:port

	address := net.JoinHostPort(config.Host, strconv.Itoa(config.Port))
	escapedPassword := url.PathEscape(config.Password)
	q := url.Values{}
	if config.Database != "" {
		q.Set("schema", config.Database)
	}
	if config.UseSSL {
		if certPath := strings.TrimSpace(config.SSLCertPath); certPath != "" {
			q.Set("SSL_CERT_PATH", certPath)
		}
		if keyPath := strings.TrimSpace(config.SSLKeyPath); keyPath != "" {
			q.Set("SSL_KEY_PATH", keyPath)
		}
	}
	if escapedPassword != config.Password {
		// 达梦驱动要求：密码包含特殊字符时，password 需 PathEscape，并添加 escapeProcess=true 让驱动解码。
		q.Set("escapeProcess", "true")
	}
	mergeConnectionParamsFromConfig(q, config, "dm", "dameng")

	dsn := fmt.Sprintf("dm://%s:%s@%s", config.User, escapedPassword, address)
	encoded := q.Encode()
	if encoded == "" {
		return dsn
	}
	return dsn + "?" + encoded
}

func (d *DamengDB) Connect(config connection.ConnectionConfig) error {
	runConfig := config
	if runConfig.UseSSL {
		if strings.TrimSpace(runConfig.SSLCertPath) == "" || strings.TrimSpace(runConfig.SSLKeyPath) == "" {
			return fmt.Errorf("达梦启用 SSL 需要同时配置证书路径(sslCertPath)与私钥路径(sslKeyPath)")
		}
	}

	if config.UseSSH {
		// Create SSH tunnel with local port forwarding
		logger.Infof("达梦数据库使用 SSH 连接：地址=%s:%d 用户=%s", config.Host, config.Port, config.User)

		forwarder, err := ssh.GetOrCreateLocalForwarder(config.SSH, config.Host, config.Port)
		if err != nil {
			return fmt.Errorf("创建 SSH 隧道失败：%w", err)
		}
		d.forwarder = forwarder

		// Parse local address
		host, portStr, err := net.SplitHostPort(forwarder.LocalAddr)
		if err != nil {
			return fmt.Errorf("解析本地转发地址失败：%w", err)
		}

		port, err := strconv.Atoi(portStr)
		if err != nil {
			return fmt.Errorf("解析本地端口失败：%w", err)
		}

		// Create a modified config pointing to local forwarder
		localConfig := config
		localConfig.Host = host
		localConfig.Port = port
		localConfig.UseSSH = false

		runConfig = localConfig
		logger.Infof("达梦数据库通过本地端口转发连接：%s -> %s:%d", forwarder.LocalAddr, config.Host, config.Port)
	}

	attempts := []connection.ConnectionConfig{runConfig}
	if shouldTrySSLPreferredFallback(runConfig) {
		attempts = append(attempts, withSSLDisabled(runConfig))
	}

	var failures []string
	for idx, attempt := range attempts {
		dsn := d.getDSN(attempt)
		db, err := sql.Open("dm", dsn)
		if err != nil {
			failures = append(failures, fmt.Sprintf("第%d次连接打开失败: %v", idx+1, err))
			continue
		}
		d.conn = db
		d.pingTimeout = getConnectTimeout(attempt)
		if err := d.Ping(); err != nil {
			_ = db.Close()
			d.conn = nil
			failures = append(failures, fmt.Sprintf("第%d次连接验证失败: %v", idx+1, err))
			continue
		}
		if idx > 0 {
			logger.Warnf("达梦 SSL 优先连接失败，已回退至明文连接")
		}
		return nil
	}
	return fmt.Errorf("连接建立后验证失败：%s", strings.Join(failures, "；"))
}

func (d *DamengDB) Close() error {
	// Close SSH forwarder first if exists
	if d.forwarder != nil {
		if err := d.forwarder.Close(); err != nil {
			logger.Warnf("关闭达梦数据库 SSH 端口转发失败：%v", err)
		}
		d.forwarder = nil
	}

	// Then close database connection
	if d.conn != nil {
		return d.conn.Close()
	}
	return nil
}

func (d *DamengDB) Ping() error {
	if d.conn == nil {
		return fmt.Errorf("连接未打开")
	}
	timeout := d.pingTimeout
	if timeout <= 0 {
		timeout = 5 * time.Second
	}
	ctx, cancel := utils.ContextWithTimeout(timeout)
	defer cancel()
	return d.conn.PingContext(ctx)
}

func (d *DamengDB) QueryContext(ctx context.Context, query string) ([]map[string]interface{}, []string, error) {
	if d.conn == nil {
		return nil, nil, fmt.Errorf("连接未打开")
	}

	rows, err := d.conn.QueryContext(ctx, query)
	if err != nil {
		return nil, nil, err
	}
	defer rows.Close()

	return scanRows(rows)
}

func (d *DamengDB) Query(query string) ([]map[string]interface{}, []string, error) {
	if d.conn == nil {
		return nil, nil, fmt.Errorf("连接未打开")
	}

	rows, err := d.conn.Query(query)
	if err != nil {
		return nil, nil, err
	}
	defer rows.Close()
	return scanRows(rows)
}

func (d *DamengDB) ExecContext(ctx context.Context, query string) (int64, error) {
	if d.conn == nil {
		return 0, fmt.Errorf("连接未打开")
	}
	res, err := d.conn.ExecContext(ctx, query)
	if err != nil {
		return 0, err
	}
	return res.RowsAffected()
}

func (d *DamengDB) Exec(query string) (int64, error) {
	if d.conn == nil {
		return 0, fmt.Errorf("连接未打开")
	}
	res, err := d.conn.Exec(query)
	if err != nil {
		return 0, err
	}
	return res.RowsAffected()
}

func (d *DamengDB) GetDatabases() ([]string, error) {
	// 达梦在本项目中将 schema/owner 作为“数据库”展示口径。
	// 先查当前 schema / 当前用户，再聚合可见用户与 owner，避免权限受限时返回空列表。
	return collectDamengDatabaseNames(d.Query)
}

func (d *DamengDB) GetTables(dbName string) ([]string, error) {
	query := fmt.Sprintf("SELECT owner, table_name FROM all_tables WHERE owner = '%s' ORDER BY table_name", strings.ToUpper(dbName))
	if dbName == "" {
		query = "SELECT table_name FROM user_tables"
	}

	data, _, err := d.Query(query)
	if err != nil {
		return nil, err
	}

	var tables []string
	for _, row := range data {
		if dbName != "" {
			if owner, okOwner := row["OWNER"]; okOwner {
				if name, okName := row["TABLE_NAME"]; okName {
					tables = append(tables, fmt.Sprintf("%v.%v", owner, name))
					continue
				}
			}
		}
		if val, ok := row["TABLE_NAME"]; ok {
			tables = append(tables, fmt.Sprintf("%v", val))
		}
	}
	return tables, nil
}

func (d *DamengDB) GetCreateStatement(dbName, tableName string) (string, error) {
	// DM: SP_TABLEDEF usually returns definition
	// Or standard Oracle way if supported.
	// We'll try a common DM approach.
	// SELECT DBMS_METADATA.GET_DDL('TABLE', 'TABLE_NAME', 'OWNER') FROM DUAL;

	query := fmt.Sprintf("SELECT DBMS_METADATA.GET_DDL('TABLE', '%s', '%s') as ddl FROM DUAL",
		strings.ToUpper(tableName), strings.ToUpper(dbName))

	if dbName == "" {
		query = fmt.Sprintf("SELECT DBMS_METADATA.GET_DDL('TABLE', '%s') as ddl FROM DUAL", strings.ToUpper(tableName))
	}

	data, _, err := d.Query(query)
	if err != nil {
		return "", err
	}

	if len(data) > 0 {
		if val, ok := data[0]["DDL"]; ok {
			return fmt.Sprintf("%v", val), nil
		}
	}
	return "", fmt.Errorf("未找到建表语句")
}

func (d *DamengDB) GetColumns(dbName, tableName string) ([]connection.ColumnDefinition, error) {
	data, _, err := d.Query(buildDamengColumnsQuery(dbName, tableName))
	if err != nil {
		return nil, err
	}

	return buildDamengColumnDefinitions(data), nil
}

func (d *DamengDB) GetIndexes(dbName, tableName string) ([]connection.IndexDefinition, error) {
	query := fmt.Sprintf(`SELECT index_name, column_name, uniqueness 
		FROM all_ind_columns 
		JOIN all_indexes USING (index_name, owner) 
		WHERE table_owner = '%s' AND table_name = '%s'`,
		strings.ToUpper(dbName), strings.ToUpper(tableName))

	if dbName == "" {
		query = fmt.Sprintf(`SELECT index_name, column_name, uniqueness 
			FROM user_ind_columns 
			JOIN user_indexes USING (index_name) 
			WHERE table_name = '%s'`, strings.ToUpper(tableName))
	}

	data, _, err := d.Query(query)
	if err != nil {
		return nil, err
	}

	var indexes []connection.IndexDefinition
	for _, row := range data {
		unique := 1
		if val, ok := row["UNIQUENESS"]; ok && val == "UNIQUE" {
			unique = 0
		}

		idx := connection.IndexDefinition{
			Name:       fmt.Sprintf("%v", row["INDEX_NAME"]),
			ColumnName: fmt.Sprintf("%v", row["COLUMN_NAME"]),
			NonUnique:  unique,
			IndexType:  "BTREE",
		}
		indexes = append(indexes, idx)
	}
	return indexes, nil
}

func (d *DamengDB) GetForeignKeys(dbName, tableName string) ([]connection.ForeignKeyDefinition, error) {
	// Reusing Oracle style query as DM is highly compatible
	query := fmt.Sprintf(`SELECT a.constraint_name, a.column_name, c_pk.table_name r_table_name, b.column_name r_column_name
		FROM all_cons_columns a
		JOIN all_constraints c ON a.owner = c.owner AND a.constraint_name = c.constraint_name
		JOIN all_constraints c_pk ON c.r_owner = c_pk.owner AND c.r_constraint_name = c_pk.constraint_name
		JOIN all_cons_columns b ON c_pk.owner = b.owner AND c_pk.constraint_name = b.constraint_name AND a.position = b.position
		WHERE c.constraint_type = 'R' AND a.owner = '%s' AND a.table_name = '%s'`,
		strings.ToUpper(dbName), strings.ToUpper(tableName))

	data, _, err := d.Query(query)
	if err != nil {
		return nil, err
	}

	var fks []connection.ForeignKeyDefinition
	for _, row := range data {
		fk := connection.ForeignKeyDefinition{
			Name:           fmt.Sprintf("%v", row["CONSTRAINT_NAME"]),
			ColumnName:     fmt.Sprintf("%v", row["COLUMN_NAME"]),
			RefTableName:   fmt.Sprintf("%v", row["R_TABLE_NAME"]),
			RefColumnName:  fmt.Sprintf("%v", row["R_COLUMN_NAME"]),
			ConstraintName: fmt.Sprintf("%v", row["CONSTRAINT_NAME"]),
		}
		fks = append(fks, fk)
	}
	return fks, nil
}

func (d *DamengDB) GetTriggers(dbName, tableName string) ([]connection.TriggerDefinition, error) {
	query := fmt.Sprintf(`SELECT trigger_name, trigger_type, triggering_event 
		FROM all_triggers 
		WHERE table_owner = '%s' AND table_name = '%s'`,
		strings.ToUpper(dbName), strings.ToUpper(tableName))

	data, _, err := d.Query(query)
	if err != nil {
		return nil, err
	}

	var triggers []connection.TriggerDefinition
	for _, row := range data {
		trig := connection.TriggerDefinition{
			Name:      fmt.Sprintf("%v", row["TRIGGER_NAME"]),
			Timing:    fmt.Sprintf("%v", row["TRIGGER_TYPE"]),
			Event:     fmt.Sprintf("%v", row["TRIGGERING_EVENT"]),
			Statement: "SOURCE HIDDEN",
		}
		triggers = append(triggers, trig)
	}
	return triggers, nil
}

func (d *DamengDB) ApplyChanges(tableName string, changes connection.ChangeSet) error {
	if d.conn == nil {
		return fmt.Errorf("连接未打开")
	}

	tx, err := d.conn.Begin()
	if err != nil {
		return err
	}
	defer tx.Rollback()

	quoteIdent := func(name string) string {
		n := strings.TrimSpace(name)
		n = strings.Trim(n, "\"")
		n = strings.ReplaceAll(n, "\"", "\"\"")
		if n == "" {
			return "\"\""
		}
		return `"` + n + `"`
	}

	schema := ""
	table := strings.TrimSpace(tableName)
	if parts := strings.SplitN(table, ".", 2); len(parts) == 2 {
		schema = strings.TrimSpace(parts[0])
		table = strings.TrimSpace(parts[1])
	}

	qualifiedTable := ""
	if schema != "" {
		qualifiedTable = fmt.Sprintf("%s.%s", quoteIdent(schema), quoteIdent(table))
	} else {
		qualifiedTable = quoteIdent(table)
	}

	// 1. Deletes
	for _, pk := range changes.Deletes {
		var wheres []string
		var args []interface{}
		idx := 0
		for k, v := range pk {
			idx++
			wheres = append(wheres, fmt.Sprintf("%s = :%d", quoteIdent(k), idx))
			args = append(args, v)
		}
		if len(wheres) == 0 {
			continue
		}
		query := fmt.Sprintf("DELETE FROM %s WHERE %s", qualifiedTable, strings.Join(wheres, " AND "))
		if _, err := tx.Exec(query, args...); err != nil {
			return fmt.Errorf("删除失败：%v", err)
		}
	}

	// 2. Updates
	for _, update := range changes.Updates {
		var sets []string
		var args []interface{}
		idx := 0

		for k, v := range update.Values {
			idx++
			sets = append(sets, fmt.Sprintf("%s = :%d", quoteIdent(k), idx))
			args = append(args, v)
		}

		if len(sets) == 0 {
			continue
		}

		var wheres []string
		for k, v := range update.Keys {
			idx++
			wheres = append(wheres, fmt.Sprintf("%s = :%d", quoteIdent(k), idx))
			args = append(args, v)
		}

		if len(wheres) == 0 {
			return fmt.Errorf("更新操作需要主键条件")
		}

		query := fmt.Sprintf("UPDATE %s SET %s WHERE %s", qualifiedTable, strings.Join(sets, ", "), strings.Join(wheres, " AND "))
		if _, err := tx.Exec(query, args...); err != nil {
			return fmt.Errorf("更新失败：%v", err)
		}
	}

	// 3. Inserts
	for _, row := range changes.Inserts {
		var cols []string
		var placeholders []string
		var args []interface{}
		idx := 0

		for k, v := range row {
			idx++
			cols = append(cols, quoteIdent(k))
			placeholders = append(placeholders, fmt.Sprintf(":%d", idx))
			args = append(args, v)
		}

		if len(cols) == 0 {
			continue
		}

		query := fmt.Sprintf("INSERT INTO %s (%s) VALUES (%s)", qualifiedTable, strings.Join(cols, ", "), strings.Join(placeholders, ", "))
		if _, err := tx.Exec(query, args...); err != nil {
			return fmt.Errorf("插入失败：%v", err)
		}
	}

	return tx.Commit()
}

func (d *DamengDB) GetAllColumns(dbName string) ([]connection.ColumnDefinitionWithTable, error) {
	query := fmt.Sprintf(`SELECT table_name, column_name, data_type 
		FROM all_tab_columns 
		WHERE owner = '%s'`, strings.ToUpper(dbName))

	data, _, err := d.Query(query)
	if err != nil {
		return nil, err
	}

	var cols []connection.ColumnDefinitionWithTable
	for _, row := range data {
		col := connection.ColumnDefinitionWithTable{
			TableName: fmt.Sprintf("%v", row["TABLE_NAME"]),
			Name:      fmt.Sprintf("%v", row["COLUMN_NAME"]),
			Type:      fmt.Sprintf("%v", row["DATA_TYPE"]),
		}
		cols = append(cols, col)
	}
	return cols, nil
}