// Copyright © 2016 Abcum Ltd
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package sql

// --------------------------------------------------
// Queries
// --------------------------------------------------

// Query represents a multi statement SQL query
type Query struct {
	Statements Statements
}

// Statement represents a single SQL AST
type Statement interface{}

// Statements represents multiple SQL ASTs
type Statements []Statement

// --------------------------------------------------
// Select
// --------------------------------------------------

// UseStatement represents a SQL USE statement.
type UseStatement struct {
	NS string // Namespace
	DB string // Database
	CK string // Cipherkey
}

// --------------------------------------------------
// Select
// --------------------------------------------------

// SelectStatement represents a SQL SELECT statement.
type SelectStatement struct {
	EX      bool     // Explain
	KV      string   // Bucket
	NS      string   // Namespace
	DB      string   // Database
	Expr    []*Field // Which fields
	What    []Expr   // What to select
	Cond    []Expr   // Select conditions
	Group   []*Group // Group by
	Order   []*Order // Order by
	Limit   Expr     // Limit by
	Start   Expr     // Start at
	Version Expr     // Version
}

// --------------------------------------------------
// Items
// --------------------------------------------------

// CreateStatement represents a SQL CREATE statement.
//
// CREATE person SET column = 'value' RETURN ID
type CreateStatement struct {
	EX   bool   // Explain
	KV   string // Bucket
	NS   string // Namespace
	DB   string // Database
	What []Expr // What to create
	Data []Expr // Create data
	Echo Token  // What to return
}

// UpdateStatement represents a SQL UPDATE statement.
//
// UPDATE person SET column = 'value' WHERE age < 18 RETURN ID
type UpdateStatement struct {
	EX   bool   // Explain
	KV   string // Bucket
	NS   string // Namespace
	DB   string // Database
	What []Expr // What to update
	Data []Expr // Update data
	Cond []Expr // Update conditions
	Echo Token  // What to return
}

// ModifyStatement represents a SQL UPDATE statement.
//
// MODIFY @person:123 WITH {} RETURN ID
type ModifyStatement struct {
	EX   bool   // Explain
	KV   string // Bucket
	NS   string // Namespace
	DB   string // Database
	What []Expr // What to modify
	Diff []Expr // Diff object
	Cond []Expr // Update conditions
	Echo Token  // What to return
}

// DeleteStatement represents a SQL DELETE statement.
//
// DELETE FROM person WHERE age < 18 RETURN ID
type DeleteStatement struct {
	EX   bool   // Explain
	KV   string // Bucket
	NS   string // Namespace
	DB   string // Database
	Hard bool   // Expunge
	What []Expr // What to delete
	Cond []Expr // Delete conditions
	Echo Token  // What to return
}

// RelateStatement represents a SQL RELATE statement.
//
// RELATE friend FROM @person:123 TO @person:456 SET column = 'value' RETURN ID
type RelateStatement struct {
	EX   bool   // Explain
	KV   string // Bucket
	NS   string // Namespace
	DB   string // Database
	Type []Expr
	From []Expr
	To   []Expr
	Data []Expr
	Echo Token // What to return
}

// RecordStatement represents a SQL CREATE EVENT statement.
//
// RECORD login ON @person:123 AT 2016-01-29T22:42:56.478Z SET column = true
type RecordStatement struct {
	EX   bool   // Explain
	KV   string // Bucket
	NS   string // Namespace
	DB   string // Database
	Type []Expr
	On   []Expr
	At   Expr
	Data []Expr
	Echo Token // What to return
}

// --------------------------------------------------
// Rules
// --------------------------------------------------

// DefineRulesStatement represents an SQL DEFINE RULES statement.
//
// DEFINE RULES person
type DefineRulesStatement struct {
	EX   bool    // Explain
	KV   string  // Bucket
	NS   string  // Namespace
	DB   string  // Database
	What []Table // Table names
}

// RemoveRulesStatement represents an SQL REMOVE RULES statement.
//
// REMOVE RULES person
type RemoveRulesStatement struct {
	EX   bool    // Explain
	KV   string  // Bucket
	NS   string  // Namespace
	DB   string  // Database
	What []Table // Table names
}

// --------------------------------------------------
// Table
// --------------------------------------------------

// DefineTableStatement represents an SQL DEFINE TABLE statement.
//
// DEFINE TABLE person
type DefineTableStatement struct {
	EX   bool    // Explain
	KV   string  // Bucket
	NS   string  // Namespace
	DB   string  // Database
	What []Table // Table names
}

// RemoveTableStatement represents an SQL REMOVE TABLE statement.
//
// REMOVE TABLE person
type RemoveTableStatement struct {
	EX   bool    // Explain
	KV   string  // Bucket
	NS   string  // Namespace
	DB   string  // Database
	What []Table // Table names
}

// --------------------------------------------------
// Field
// --------------------------------------------------

// DefineFieldStatement represents an SQL DEFINE INDEX statement.
//
// DEFINE FIELD name ON person TYPE string CODE {}
// DEFINE FIELD name ON person TYPE number MIN 0 MAX 5 DEFAULT 0
// DEFINE FIELD name ON person TYPE custom ENUM [0,1,2,3,4,5] DEFAULT 0
type DefineFieldStatement struct {
	EX        bool          // Explain
	KV        string        // Bucket
	NS        string        // Namespace
	DB        string        // Database
	Name      Ident         // Field name
	What      []Table       // Table names
	Type      Ident         // Field type
	Enum      []interface{} // Custom options
	Code      string        // Field code
	Min       float64       // Minimum value / length
	Max       float64       // Maximum value / length
	Match     string        // Regex value
	Default   interface{}   // Default value
	Notnull   bool          // Notnull - can not be NULL?
	Readonly  bool          // Readonly - can not be changed?
	Mandatory bool          // Mandatory - can not be VOID?
	Validate  bool          // Validate - can not be INCORRECT?
}

// RemoveFieldStatement represents an SQL REMOVE INDEX statement.
//
// REMOVE FIELD name ON person
type RemoveFieldStatement struct {
	EX   bool    // Explain
	KV   string  // Bucket
	NS   string  // Namespace
	DB   string  // Database
	Name Ident   // Field name
	What []Table // Table names
}

// --------------------------------------------------
// Index
// --------------------------------------------------

// DefineIndexStatement represents an SQL DEFINE INDEX statement.
//
// DEFINE INDEX name ON person COLUMNS (account, age) UNIQUE
type DefineIndexStatement struct {
	EX   bool     // Explain
	KV   string   // Bucket
	NS   string   // Namespace
	DB   string   // Database
	Name Ident    // Index name
	What []Table  // Table names
	Code string   // Index code
	Cols []*Field // Index cols
	Uniq bool     // Unique index
}

// RemoveIndexStatement represents an SQL REMOVE INDEX statement.
//
// REMOVE INDEX name ON person
type RemoveIndexStatement struct {
	EX   bool    // Explain
	KV   string  // Bucket
	NS   string  // Namespace
	DB   string  // Database
	Name Ident   // Index name
	What []Table // Table names
}

// ResyncIndexStatement represents an SQL RESYNC INDEX statement.
//
// RESYNC INDEX name ON person
type ResyncIndexStatement struct {
	EX   bool    // Explain
	KV   string  // Bucket
	NS   string  // Namespace
	DB   string  // Database
	What []Table // Table names
}

// --------------------------------------------------
// Literals
// --------------------------------------------------

// Expr represents a sql expression
type Expr interface{}

// All represents a wildcard expression.
type All struct{}

// Asc represents the ASC expression.
type Asc struct{}

// Desc represents the DESC expression.
type Desc struct{}

// Null represents a null expression.
type Null struct{}

// Void represents an expression which is not set.
type Void struct{}

// Empty represents an expression which is null or "".
type Empty struct{}

// Wildcard represents a wildcard expression.
type Wildcard struct{}

// ClosedExpression represents a parenthesized expression.
type ClosedExpression struct {
	Expr Expr
}

// BinaryExpression represents a binary expression tree,
type BinaryExpression struct {
	LHS Expr
	Op  string
	RHS Expr
}

// DiffExpression represents a JSON DIFF PATCH
type DiffExpression struct {
	JSON interface{}
}

// MergeExpression represents JSON to MERGE
type MergeExpression struct {
	JSON interface{}
}

// ContentExpression represents JSON to REPLACE
type ContentExpression struct {
	JSON interface{}
}

// --------------------------------------------------
// Parts
// --------------------------------------------------

type Table string

func (this Table) String() string {
	return string(this)
}

func (this Table) MarshalText() ([]byte, error) {
	return []byte(string(this)), nil
}

type Ident string

func (this Ident) String() string {
	return string(this)
}
func (this Ident) MarshalText() ([]byte, error) {
	return []byte(string(this)), nil
}

// Thing comment
type Thing struct {
	TB string
	ID interface{}
}

// Field comment
type Field struct {
	Expr  Expr
	Alias Expr
}

// Group comment
type Group struct {
	Expr Expr
}

// Order comment
type Order struct {
	Expr Expr
	Dir  Expr
}