// Package sqldb provides support for access the database.
package sqldb

import (
	"context"
	"database/sql"
	"errors"
	"fmt"
	"strings"
	"time"

	"management/internal/pkg/config"

	"github.com/drhin/logger"
	"github.com/jackc/pgx/v5/pgconn"
	_ "github.com/jackc/pgx/v5/stdlib"
	"github.com/jmoiron/sqlx"
	"go.uber.org/zap"
)

// lib/pq errorCodeNames
// https://github.com/lib/pq/blob/master/error.go#L178
const (
	uniqueViolation = "23505"
	undefinedTable  = "42P01"
)

// Set of error variables for CRUD operations.
var (
	ErrDBNotFound        = sql.ErrNoRows
	ErrDBDuplicatedEntry = errors.New("duplicated entry")
	ErrUndefinedTable    = errors.New("undefined table")
)

// Config is the required properties to use the database.
//type Config struct {
//	User         string
//	Password     string
//	Host         string
//	Name         string
//	Schema       string
//	MaxIdleConns int
//	MaxOpenConns int
//	DisableTLS   bool
//}

// Open knows how to open a database connection based on the configuration.
//func Open(cfg Config) (*sqlx.DB, error) {
//	sslMode := "require"
//	if cfg.DisableTLS {
//		sslMode = "disable"
//	}
//
//	q := make(url.Values)
//	q.Set("sslmode", sslMode)
//	q.Set("timezone", "utc")
//	if cfg.Schema != "" {
//		q.Set("search_path", cfg.Schema)
//	}
//
//	u := url.URL{
//		Scheme:   "postgres",
//		User:     url.UserPassword(cfg.User, cfg.Password),
//		Host:     cfg.Host,
//		Path:     cfg.Name,
//		RawQuery: q.Encode(),
//	}
//
//	db, err := sqlx.Open("pgx", u.String())
//	if err != nil {
//		return nil, err
//	}
//	db.SetMaxIdleConns(cfg.MaxIdleConns)
//	db.SetMaxOpenConns(cfg.MaxOpenConns)
//
//	return db, nil
//}

type Config struct {
	User            string
	Password        string
	Host            string
	Port            int
	Name            string
	MaxIdleConns    int
	MaxOpenConns    int
	ConnMaxLifetime time.Duration
	ConnMaxIdleTime time.Duration
}

func NewDB(config *config.Config, log *logger.Logger) (*sqlx.DB, func(), error) {
	dsn := fmt.Sprintf("postgresql://%s:%s@%s:%d/%s?sslmode=disable",
		config.DB.Username,
		config.DB.Password,
		config.DB.Host,
		config.DB.Port,
		config.DB.DBName,
	)

	db, err := sqlx.Open("pgx", dsn)
	if err != nil {
		return nil, nil, fmt.Errorf("sqlx open db: %w", err)
	}

	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
	defer cancel()

	if err := db.PingContext(ctx); err != nil {
		return nil, nil, err
	}

	// 设置最大空闲连接数(默认 2)
	db.SetMaxIdleConns(config.DB.MaxIdleConns)

	// 设置最大打开连接数(默认 0 无限制)
	db.SetMaxOpenConns(config.DB.MaxOpenConns)

	// 设置连接最大存活时间
	db.SetConnMaxLifetime(config.DB.ConnMaxLifetime)

	// 设置连接最大空闲时间
	db.SetConnMaxIdleTime(config.DB.ConnMaxIdleTime)

	cleanup := func() {
		if err := db.Close(); err != nil {
			log.Error("sql db close error", err)
		}
	}

	return db, cleanup, nil
}

// StatusCheck returns nil if it can successfully talk to the database. It
// returns a non-nil error otherwise.
func StatusCheck(ctx context.Context, db *sqlx.DB) error {

	// If the user doesn't give us a deadline set 1 second.
	if _, ok := ctx.Deadline(); !ok {
		var cancel context.CancelFunc
		ctx, cancel = context.WithTimeout(ctx, time.Second)
		defer cancel()
	}

	for attempts := 1; ; attempts++ {
		if err := db.Ping(); err == nil {
			break
		}

		time.Sleep(time.Duration(attempts) * 100 * time.Millisecond)

		if ctx.Err() != nil {
			return ctx.Err()
		}
	}

	if ctx.Err() != nil {
		return ctx.Err()
	}

	// Run a simple query to determine connectivity.
	// Running this query forces a round trip through the database.
	const q = `SELECT TRUE`
	var tmp bool
	return db.QueryRowContext(ctx, q).Scan(&tmp)
}

// ExecContext is a helper function to execute a CUD operation with
// logging and tracing.
func ExecContext(ctx context.Context, log *logger.Logger, db sqlx.ExtContext, query string) error {
	return NamedExecContext(ctx, log, db, query, struct{}{})
}

// NamedExecContext is a helper function to execute a CUD operation with
// logging and tracing where field replacement is necessary.
func NamedExecContext(ctx context.Context, log *logger.Logger, db sqlx.ExtContext, query string, data any) (err error) {
	q := queryString(query, data)

	defer func() {
		if err != nil {
			switch data.(type) {
			case struct{}:
				log.Info("database.NamedExecContext", zap.String("query", q), zap.Int("type", 6), zap.Error(err))
			default:
				log.Info("database.NamedExecContext", zap.String("query", q), zap.Int("type", 5), zap.Error(err))
			}
		}
	}()

	if _, err := sqlx.NamedExecContext(ctx, db, query, data); err != nil {
		var pqerr *pgconn.PgError
		if errors.As(err, &pqerr) {
			switch pqerr.Code {
			case undefinedTable:
				return ErrUndefinedTable
			case uniqueViolation:
				return ErrDBDuplicatedEntry
			}
		}
		return err
	}

	return nil
}

// QuerySlice is a helper function for executing queries that return a
// collection of data to be unmarshalled into a slice.
func QuerySlice[T any](ctx context.Context, log *logger.Logger, db sqlx.ExtContext, query string, dest *[]T) error {
	return namedQuerySlice(ctx, log, db, query, struct{}{}, dest, false)
}

// NamedQuerySlice is a helper function for executing queries that return a
// collection of data to be unmarshalled into a slice where field replacement is
// necessary.
func NamedQuerySlice[T any](ctx context.Context, log *logger.Logger, db sqlx.ExtContext, query string, data any, dest *[]T) error {
	return namedQuerySlice(ctx, log, db, query, data, dest, false)
}

// NamedQuerySliceUsingIn is a helper function for executing queries that return
// a collection of data to be unmarshalled into a slice where field replacement
// is necessary. Use this if the query has an IN clause.
func NamedQuerySliceUsingIn[T any](ctx context.Context, log *logger.Logger, db sqlx.ExtContext, query string, data any, dest *[]T) error {
	return namedQuerySlice(ctx, log, db, query, data, dest, true)
}

func namedQuerySlice[T any](ctx context.Context, log *logger.Logger, db sqlx.ExtContext, query string, data any, dest *[]T, withIn bool) (err error) {
	q := queryString(query, data)

	defer func() {
		if err != nil {
			log.Info("database.NamedQuerySlice", zap.String("query", q), zap.Int("type", 6), zap.Error(err))
		}
	}()

	var rows *sqlx.Rows

	switch withIn {
	case true:
		rows, err = func() (*sqlx.Rows, error) {
			named, args, err := sqlx.Named(query, data)
			if err != nil {
				return nil, err
			}

			query, args, err := sqlx.In(named, args...)
			if err != nil {
				return nil, err
			}

			query = db.Rebind(query)
			return db.QueryxContext(ctx, query, args...)
		}()

	default:
		rows, err = sqlx.NamedQueryContext(ctx, db, query, data)
	}

	if err != nil {
		var pqErr *pgconn.PgError
		if errors.As(err, &pqErr) && pqErr.Code == undefinedTable {
			return ErrUndefinedTable
		}
		return err
	}
	defer func(rows *sqlx.Rows) {
		_ = rows.Close()
	}(rows)

	var slice []T
	for rows.Next() {
		v := new(T)
		if err := rows.StructScan(v); err != nil {
			return err
		}
		slice = append(slice, *v)
	}
	*dest = slice

	return nil
}

// QueryStruct is a helper function for executing queries that return a
// single value to be unmarshalled into a struct type where field replacement is necessary.
func QueryStruct(ctx context.Context, log *logger.Logger, db sqlx.ExtContext, query string, dest any) error {
	return namedQueryStruct(ctx, log, db, query, struct{}{}, dest, false)
}

// NamedQueryStruct is a helper function for executing queries that return a
// single value to be unmarshalled into a struct type where field replacement is necessary.
func NamedQueryStruct(ctx context.Context, log *logger.Logger, db sqlx.ExtContext, query string, data any, dest any) error {
	return namedQueryStruct(ctx, log, db, query, data, dest, false)
}

// NamedQueryStructUsingIn is a helper function for executing queries that return
// a single value to be unmarshalled into a struct type where field replacement
// is necessary. Use this if the query has an IN clause.
func NamedQueryStructUsingIn(ctx context.Context, log *logger.Logger, db sqlx.ExtContext, query string, data any, dest any) error {
	return namedQueryStruct(ctx, log, db, query, data, dest, true)
}

func namedQueryStruct(ctx context.Context, log *logger.Logger, db sqlx.ExtContext, query string, data any, dest any, withIn bool) (err error) {
	q := queryString(query, data)

	defer func() {
		if err != nil {
			log.Info("database.NamedQuerySlice", zap.String("query", q), zap.Int("type", 6), zap.Error(err))
		}
	}()

	var rows *sqlx.Rows

	switch withIn {
	case true:
		rows, err = func() (*sqlx.Rows, error) {
			named, args, err := sqlx.Named(query, data)
			if err != nil {
				return nil, err
			}

			query, args, err := sqlx.In(named, args...)
			if err != nil {
				return nil, err
			}

			query = db.Rebind(query)
			return db.QueryxContext(ctx, query, args...)
		}()

	default:
		rows, err = sqlx.NamedQueryContext(ctx, db, query, data)
	}

	if err != nil {
		var pqErr *pgconn.PgError
		if errors.As(err, &pqErr) && pqErr.Code == undefinedTable {
			return ErrUndefinedTable
		}
		return err
	}
	defer func(rows *sqlx.Rows) {
		_ = rows.Close()
	}(rows)

	if !rows.Next() {
		return ErrDBNotFound
	}

	if err := rows.StructScan(dest); err != nil {
		return err
	}

	return nil
}

// queryString provides a pretty print version of the query and parameters.
func queryString(query string, args any) string {
	query, params, err := sqlx.Named(query, args)
	if err != nil {
		return err.Error()
	}

	for _, param := range params {
		var value string
		switch v := param.(type) {
		case string:
			value = fmt.Sprintf("'%s'", v)
		case []byte:
			value = fmt.Sprintf("'%s'", string(v))
		default:
			value = fmt.Sprintf("%v", v)
		}
		query = strings.Replace(query, "?", value, 1)
	}

	query = strings.ReplaceAll(query, "\t", "")
	query = strings.ReplaceAll(query, "\n", " ")

	return strings.Trim(query, " ")
}