package schema

import (
	"fmt"
	"regexp"
	"strings"

	"github.com/samber/lo"

	"git.fsdpf.net/go/db"
)

type Sqlite3Grammar struct {
}

var sqlite3DefaultModifiers = []string{"VirtualAs", "StoredAs", "Nullable", "Default", "Increment"}

var sqlite3Serials = []string{"bigInteger", "integer", "mediumInteger", "smallInteger", "tinyInteger"}

func (this Sqlite3Grammar) CompileTableExists() string {
	// 兼容其他数据库查询
	// 其他数据库查看都是同时传入, 数据库名 和 数据表名
	return "select count(*) from sqlite_master where type = 'table' and name = ?||?"
}

func (this Sqlite3Grammar) CompileColumnListing(table string) string {
	// 兼容其他数据库查询
	// 其他数据库查看都是同时传入, 数据库名 和 数据表名
	return "pragma table_info(" + table + ")"
}

// 创建表
func (this Sqlite3Grammar) CompileCreate(bp *Blueprint, command *Command, conn *db.Connection) string {
	temporary := "create"
	if bp.temporary {
		temporary = "create temporary"
	}
	return fmt.Sprintf("%s table %s (%s)", temporary, bp.table, strings.Join(this.getAddedColumns(bp), ", "))
}

// 添加字段
func (this Sqlite3Grammar) CompileAdd(bp *Blueprint, command *Command, conn *db.Connection) []string {
	columns := PrefixArray("add column", this.getAddedColumns(bp))

	return lo.Map(columns, func(column string, _ int) string {
		return "alter table `" + bp.table + "` " + column
	})
}

// 修改字段
func (this Sqlite3Grammar) CompileChange(bp *Blueprint, command *Command, conn *db.Connection) (sqls []string) {
	// 创建表的sql
	cTableSql := this.getCreateTable(bp, conn)

	// 旧表字段
	oldColumns := []string{}
	if _, err := conn.Select("select '`'||name||'`' from pragma_table_info(?)", []any{bp.table}, &oldColumns); err != nil {
		panic(fmt.Errorf("获取 SQLite 建表字段失败, %s", err))
	}

	// 数据同步
	insert_sql := fmt.Sprintf("insert into `"+bp.table+"` (%s)", strings.Join(oldColumns, ", "))
	select_sql := fmt.Sprintf("select %s from `"+bp.table+"_old`", strings.Join(oldColumns, ", "))

	for _, column := range bp.getChangedColumns() {
		name := column.Name
		rename := column.rename

		// 旧字段(查询) -> 新字段(插入)
		if column.rename != "" {
			select_sql = strings.ReplaceAll(select_sql, name, name+"` as `"+rename)
			insert_sql = strings.ReplaceAll(insert_sql, name, rename)
		} else {
			rename = name
		}

		// 修改表字段
		sql := "`" + rename + "` " + this.GetColumnType(column)
		sql = this.addModifiers(sql, bp, column)
		reg := regexp.MustCompile(fmt.Sprintf("(?iUm)^(?P<prefix>\\s*)(?P<content>`%s`.*)(?P<end>(,\\s|\\s)?)$", name))
		cTableSql = reg.ReplaceAllString(cTableSql, fmt.Sprintf("${prefix}%s${end}", sql))
	}

	// 开启事物
	// sqls = append(sqls, "BEGIN TRANSACTION")
	// 1. 重命名已存在的表
	sqls = append(sqls, fmt.Sprintf("alter table `%s` rename to `%s_old`", bp.table, bp.table))
	// 2. 创建新结构表
	sqls = append(sqls, cTableSql)
	// 3. 复制数据
	sqls = append(sqls, insert_sql+" "+select_sql)
	// 4. 删除旧表
	sqls = append(sqls, fmt.Sprintf("drop table `%s_old`", bp.table))
	// 提交事物
	// sqls = append(sqls, "COMMIT")

	// @todo 复制索引

	return sqls
}

// 创建唯一索引
func (this Sqlite3Grammar) CompileUnique(bp *Blueprint, command *Command, conn *db.Connection) string {
	columns := lo.Map(command.Columns, func(column string, _ int) string {
		return "`" + column + "`"
	})
	return fmt.Sprintf("create unique index `%s` on `%s` (%s)", command.Index, bp.table, strings.Join(columns, ", "))
}

// 创建普通索引
func (this Sqlite3Grammar) CompileIndex(bp *Blueprint, command *Command, conn *db.Connection) string {
	columns := lo.Map(command.Columns, func(column string, _ int) string {
		return "`" + column + "`"
	})
	return fmt.Sprintf("create  index `%s` on `%s` (%s)", command.Index, bp.table, strings.Join(columns, ", "))
}

// 创建空间索引
func (this Sqlite3Grammar) CompileSpatialIndex(bp *Blueprint, command *Command, conn *db.Connection) string {
	panic("Sqlite 不支持 SpatialIndex")
}

// 删除表
func (this Sqlite3Grammar) CompileDrop(bp *Blueprint, command *Command, conn *db.Connection) string {
	return "drop table `" + bp.table + "`"
}

// 删除表, 先判断再删除
func (this Sqlite3Grammar) CompileDropIfExists(bp *Blueprint, command *Command, conn *db.Connection) string {
	return "drop table if exists `" + bp.table + "`"
}

// 删除列
func (this Sqlite3Grammar) CompileDropColumn(bp *Blueprint, command *Command, conn *db.Connection) (sqls []string) {
	// 创建表的sql, 排除不要的字段
	cTableSql := this.getCreateTable(bp, conn, command.Columns...)

	// 旧表字段
	oldColumns := []string{}

	if _, err := conn.Select(
		"select '`'||name||'`' from pragma_table_info(?) where `name` not in("+strings.Trim(strings.Repeat("?,", len(command.Columns)), ",")+")",
		append([]any{bp.table}, lo.ToAnySlice(command.Columns)...),
		&oldColumns); err != nil {
		panic(fmt.Errorf("获取 SQLite 建表字段失败, %s", err))
	}

	copy_data_sql := fmt.Sprintf("insert into `%s` select %s from `%s_old`", bp.table, strings.Join(oldColumns, ", "), bp.table)

	for _, column := range bp.getChangedColumns() {
		name := column.Name
		rename := column.rename

		if rename != "" {
			copy_data_sql = strings.ReplaceAll(copy_data_sql, "`"+name+"`", "`"+rename+"`")
		}

		// 修改表字段
		sql := "`" + rename + "` " + this.GetColumnType(column)
		sql = this.addModifiers(sql, bp, column)
		reg := regexp.MustCompile(fmt.Sprintf("(?iUm)^(?P<prefix>\\s*)(?P<content>`%s`.*)(?P<end>(,\\s|\\s)?)$", name))
		cTableSql = reg.ReplaceAllString(cTableSql, fmt.Sprintf("${prefix}%s${end}", sql))
	}

	// 开启事物
	// sqls = append(sqls, "BEGIN TRANSACTION")
	// 1. 重命名已存在的表
	sqls = append(sqls, fmt.Sprintf("alter table `%s` rename to `%s_old`", bp.table, bp.table))
	// 2. 创建新结构表
	sqls = append(sqls, cTableSql)
	// 3. 复制数据
	sqls = append(sqls, copy_data_sql)
	// 4. 删除旧表
	sqls = append(sqls, fmt.Sprintf("drop table `%s_old`", bp.table))
	// 提交事物
	// sqls = append(sqls, "COMMIT")

	// @todo 复制索引

	return sqls
}

// 删除唯一索引
func (this Sqlite3Grammar) CompileDropUnique(bp *Blueprint, command *Command, conn *db.Connection) string {
	return this.CompileDropIndex(bp, command, conn)
}

// 删除索引
func (this Sqlite3Grammar) CompileDropIndex(bp *Blueprint, command *Command, conn *db.Connection) string {
	return "drop index `" + command.Index + "`"
}

// 删除空间索引
func (this Sqlite3Grammar) CompileDropSpatialIndex(bp *Blueprint, command *Command, conn *db.Connection) string {
	return this.CompileSpatialIndex(bp, command, conn)
}

func (this Sqlite3Grammar) CompileRename(bp *Blueprint, command *Command, conn *db.Connection) string {
	return "alter table `" + bp.table + "` rename to `" + command.To + "`"
}

func (this Sqlite3Grammar) CompileRenameIndex(bp *Blueprint, command *Command, conn *db.Connection) string {
	// 先删除索引, 后创建索引
	return "alter table `" + bp.table + "` rename to `" + command.To + "`"
}

// 删除所有表
func (this Sqlite3Grammar) CompileDropAllTables() string {
	return "delete from sqlite_master where type in ('table', 'index', 'trigger')"
}

// 删除所有视图
func (this Sqlite3Grammar) CompileDropAllViews() string {
	return "delete from sqlite_master where type in ('view')"
}

func (this Sqlite3Grammar) addModifiers(sql string, bp *Blueprint, column *ColumnDefinition) string {
	for _, modifier := range mysqlDefaultModifiers {
		sql = sql + this.GetColumnModifier(modifier, bp, column)
	}
	return sql
}

func (this Sqlite3Grammar) GetColumnModifier(modifier string, bp *Blueprint, column *ColumnDefinition) string {
	switch modifier {
	case "VirtualAs":
		if column.virtualAs != "" {
			return fmt.Sprintf(" as (%s)", column.virtualAs)
		}
	case "StoredAs":
		if column.storedAs != "" {
			return fmt.Sprintf(" as (%s) stored", column.storedAs)
		}
	case "Nullable":
		if !column.nullable {
			return " not null"
		}
	case "Default":
		if column.useCurrent {
			return ""
		}
		switch v := column.def.(type) {
		case db.Expression:
			return fmt.Sprintf(" default %s", v)
		case nil:
		default:
			return fmt.Sprintf(" default '%v'", v)
		}
	case "Increment":
		if column.autoIncrement && lo.Contains(mysqlSerials, column.Type) {
			return " primary key autoincrement"
		}
	}

	return ""
}

func (this Sqlite3Grammar) GetColumnType(column *ColumnDefinition) string {
	switch column.Type {
	case "char", "string":
		return fmt.Sprintf("varchar(%d)", column.Length)
	case "text":
		return "text"
	case "year", "integer":
		return "integer"
	case "bigInteger":
		return "bigint"
	case "tinyInteger":
		return "tinyint"
	case "smallInteger":
		return "smallint"
	case "decimal":
		return fmt.Sprintf("numeric(%d,%d)", column.Total, column.Places)
	case "boolean":
		return "tinyint(1)"
	case "enum":
		return fmt.Sprintf(`varchar check ("%s" in (%s))`, column.Name, QuoteString(column.Allowed))
	case "json":
		return "json"
	case "date":
		return "date"
	case "binary":
		return "blob"
	case "datetime", "timestamp":
		columnType := column.Type
		if column.useCurrent {
			columnType = columnType + " default CURRENT_TIMESTAMP"
		}
		return columnType
	case "time":
		return "time"
	case "uuid":
		return "varchar(36)"
	}
	panic("不支持的数据类型: " + column.Type)
}

// 获取新增表结构字段
func (this Sqlite3Grammar) getAddedColumns(bp *Blueprint) (columns []string) {
	for _, column := range bp.getAddedColumns() {
		sql := "`" + column.Name + "` " + this.GetColumnType(column)
		columns = append(columns, this.addModifiers(sql, bp, column))
	}
	return
}

// 获取修改表结构字段
func (this Sqlite3Grammar) getChangedColumns(bp *Blueprint) map[string]string {
	columns := map[string]string{}
	for _, column := range bp.getChangedColumns() {
		sql := "`" + column.Name + "` " + this.GetColumnType(column)
		columns[column.Name] = this.addModifiers(sql, bp, column)
	}
	return columns
}

// 数据库表字段
func (this Sqlite3Grammar) getCreateTable(bp *Blueprint, conn *db.Connection, without ...string) (sql string) {
	dbColumns := []struct {
		Name    string        `db:"name"`
		Type    string        `db:"type"`
		Default db.NullString `db:"dflt_value"`
		NotNull bool          `db:"notnull"`
		Pk      bool          `db:"pk"`
	}{}

	if _, err := conn.Select("select * from pragma_table_info(?) order by cid", []any{bp.table}, &dbColumns); err != nil {
		panic(fmt.Errorf("获取 SQLite 建表字段失败, %s", err))
	}

	cols := []string{}
	for _, column := range dbColumns {
		if lo.Contains(without, column.Name) {
			continue
		}
		col := "  `" + column.Name + "`"
		col += " " + column.Type
		if column.NotNull {
			col += " not null"
		}
		if column.Pk {
			col += " primary key autoincrement"
		}
		if column.Default != "" {
			col += " default " + string(column.Default)
		}
		cols = append(cols, col)
	}

	return fmt.Sprintf("CREATE TABLE `%s` (\n%s\n)", bp.table, strings.Join(cols, ", \n"))
}