package langV2

import (
	participle "github.com/alecthomas/participle/v2"
)

// Root AST node containing all definitions
type AST struct {
	Definitions []Definition `parser:"@@*"`
}

type Definition struct {
	Entity    *EntityDef    `parser:"@@"`
	Server    *ServerDef    `parser:"| @@"`
	Page      *PageDef      `parser:"| @@"`
	Component *ComponentDef `parser:"| @@"`
}

type EntityDef struct {
	Name   string  `parser:"'entity' @Ident"`
	Fields []Field `parser:"'{' @@* '}'"`
}

type Field struct {
	Name         string        `parser:"@Ident ':'"`
	Type         string        `parser:"@Ident"`
	Required     bool          `parser:"@'required'?"`
	Unique       bool          `parser:"@'unique'?"`
	Index        bool          `parser:"@'indexed'?"`
	Default      *string       `parser:"('default' @String)?"`
	Validations  []Validation  `parser:"@@*"`
	Relationship *Relationship `parser:"@@?"`
}

type Validation struct {
	Type  string  `parser:"'validate' @Ident"`
	Value *string `parser:"@String?"`
}

type Relationship struct {
	Type        string  `parser:"'relates' 'to' @Ident"`
	Cardinality string  `parser:"'as' @('one' | 'many')"`
	ForeignKey  *string `parser:"('via' @String)?"`
}

type ServerDef struct {
	Name      string        `parser:"'server' @Ident"`
	Endpoints []EndpointDef `parser:"'{' @@* '}'"`
}

type EndpointDef struct {
	Method    string `parser:"@('GET'|'POST'|'PUT'|'DELETE')"`
	Path      string `parser:"@String"`
	EntityRef string `parser:"'entity' @Ident"`
}

type ComponentDef struct {
	EntityRef string `parser:"@Ident"`
	ServerRef string `parser:"('from' @Ident)?"`
}

type PageDef struct {
	Name       string         `parser:"'page' @Ident"`
	Components []ComponentDef `parser:"'{' @@* '}'"`
}

func ParseInput(input string) (AST, error) {
	parser, err := participle.Build[AST](
		participle.Unquote("String"),
	)
	if err != nil {
		return AST{}, err
	}
	ast, err := parser.ParseString("", input)
	if err != nil {
		return AST{}, err
	}
	return *ast, nil
}