package db

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

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

	_ "github.com/lib/pq"
)

type PostgresDB struct {
	conn        *sql.DB
	pingTimeout time.Duration
}

func (p *PostgresDB) getDSN(config connection.ConnectionConfig) string {
	// postgres://user:password@host:port/dbname?sslmode=disable
	dbname := config.Database
	if dbname == "" {
		dbname = "postgres" // Default DB
	}

	u := &url.URL{
		Scheme: "postgres",
		Host:   net.JoinHostPort(config.Host, strconv.Itoa(config.Port)),
		Path:   "/" + dbname,
	}
	u.User = url.UserPassword(config.User, config.Password)
	q := url.Values{}
	q.Set("sslmode", "disable")
	q.Set("connect_timeout", strconv.Itoa(getConnectTimeoutSeconds(config)))
	u.RawQuery = q.Encode()

	return u.String()
}

func (p *PostgresDB) Connect(config connection.ConnectionConfig) error {
	dsn := p.getDSN(config)
	db, err := sql.Open("postgres", dsn)
	if err != nil {
		return fmt.Errorf("打开数据库连接失败：%w", err)
	}
	p.conn = db
	p.pingTimeout = getConnectTimeout(config)
		
	// Force verification
	if err := p.Ping(); err != nil {
		return fmt.Errorf("连接建立后验证失败：%w", err)
	}
	return nil
}

func (p *PostgresDB) Close() error {
	if p.conn != nil {
		return p.conn.Close()
	}
	return nil
}

func (p *PostgresDB) Ping() error {
	if p.conn == nil {
		return fmt.Errorf("connection not open")
	}
	timeout := p.pingTimeout
	if timeout <= 0 {
		timeout = 5 * time.Second
	}
	ctx, cancel := utils.ContextWithTimeout(timeout)
	defer cancel()
	return p.conn.PingContext(ctx)
}

func (p *PostgresDB) Query(query string) ([]map[string]interface{}, []string, error) {
	if p.conn == nil {
		return nil, nil, fmt.Errorf("connection not open")
	}


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

	columns, err := rows.Columns()
	if err != nil {
		return nil, nil, err
	}

	var resultData []map[string]interface{}

	for rows.Next() {
		values := make([]interface{}, len(columns))
		valuePtrs := make([]interface{}, len(columns))
		for i := range columns {
			valuePtrs[i] = &values[i]
		}

		if err := rows.Scan(valuePtrs...); err != nil {
			continue
		}

		entry := make(map[string]interface{})
		for i, col := range columns {
			var v interface{}
			val := values[i]
			b, ok := val.([]byte)
			if ok {
				if b == nil {
					v = nil
				} else {
					v = string(b)
				}
			} else {
				v = val
			}
			entry[col] = v
		}
		resultData = append(resultData, entry)
	}

	return resultData, columns, nil
}

func (p *PostgresDB) Exec(query string) (int64, error) {
	if p.conn == nil {
		return 0, fmt.Errorf("connection not open")
	}
	res, err := p.conn.Exec(query)
	if err != nil {
		return 0, err
	}
	return res.RowsAffected()
}

func (p *PostgresDB) GetDatabases() ([]string, error) {
	data, _, err := p.Query("SELECT datname FROM pg_database WHERE datistemplate = false")
	if err != nil {
		return nil, err
	}
	var dbs []string
	for _, row := range data {
		if val, ok := row["datname"]; ok {
			dbs = append(dbs, fmt.Sprintf("%v", val))
		}
	}
	return dbs, nil
}

func (p *PostgresDB) GetTables(dbName string) ([]string, error) {
	query := "SELECT schemaname, tablename FROM pg_catalog.pg_tables WHERE schemaname != 'information_schema' AND schemaname NOT LIKE 'pg_%' ORDER BY schemaname, tablename"
	data, _, err := p.Query(query)
	if err != nil {
		return nil, err
	}
	
	var tables []string
	for _, row := range data {
		schema, okSchema := row["schemaname"]
		name, okName := row["tablename"]
		if okSchema && okName {
			tables = append(tables, fmt.Sprintf("%v.%v", schema, name))
			continue
		}
		if okName {
			tables = append(tables, fmt.Sprintf("%v", name))
		}
	}
	return tables, nil
}

func (p *PostgresDB) GetCreateStatement(dbName, tableName string) (string, error) {
	return fmt.Sprintf("-- SHOW CREATE TABLE not fully supported for PostgreSQL in this MVP.\n-- Table: %s", tableName), nil
}

func (p *PostgresDB) GetColumns(dbName, tableName string) ([]connection.ColumnDefinition, error) {
	return []connection.ColumnDefinition{}, nil
}

func (p *PostgresDB) GetIndexes(dbName, tableName string) ([]connection.IndexDefinition, error) {
	return []connection.IndexDefinition{}, nil
}

func (p *PostgresDB) GetForeignKeys(dbName, tableName string) ([]connection.ForeignKeyDefinition, error) {
	return []connection.ForeignKeyDefinition{}, nil
}

func (p *PostgresDB) GetTriggers(dbName, tableName string) ([]connection.TriggerDefinition, error) {
	return []connection.TriggerDefinition{}, nil
}

func (p *PostgresDB) GetAllColumns(dbName string) ([]connection.ColumnDefinitionWithTable, error) {
	return []connection.ColumnDefinitionWithTable{}, nil
}