package lang

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

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

// Union type for top-level definitions
type Definition struct {
	Server   *Server   `parser:"@@"`
	Entity   *Entity   `parser:"| @@"`
	Endpoint *Endpoint `parser:"| @@"`
	Page     *Page     `parser:"| @@"`
}

// Clean server syntax
type Server struct {
	Name     string          `parser:"'server' @Ident"`
	Settings []ServerSetting `parser:"@@*"`
}

type ServerSetting struct {
	Host *string `parser:"('host' @String)"`
	Port *int    `parser:"| ('port' @Int)"`
}

// Clean entity syntax with better readability
type Entity struct {
	Name        string  `parser:"'entity' @Ident"`
	Description *string `parser:"('desc' @String)?"`
	Fields      []Field `parser:"@@*"`
}

// Much cleaner field syntax
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:"@@?"`
}

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

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

// Endpoint definitions with clean, readable syntax
type Endpoint struct {
	Method      string          `parser:"'endpoint' @('GET' | 'POST' | 'PUT' | 'DELETE' | 'PATCH')"`
	Path        string          `parser:"@String"`
	Entity      *string         `parser:"('for' @Ident)?"`
	Description *string         `parser:"('desc' @String)?"`
	Auth        bool            `parser:"@'auth'?"`
	Params      []EndpointParam `parser:"@@*"`
	Response    *ResponseSpec   `parser:"@@?"`
	CustomLogic *string         `parser:"('custom' @String)?"`
}

// Clean parameter syntax
type EndpointParam struct {
	Name     string `parser:"'param' @Ident ':'"`
	Type     string `parser:"@Ident"`
	Required bool   `parser:"@'required'?"`
	Source   string `parser:"'from' @('path' | 'query' | 'body')"`
}

// Response specification
type ResponseSpec struct {
	Type   string   `parser:"'returns' @Ident"`
	Format *string  `parser:"('as' @String)?"`
	Fields []string `parser:"('fields' '[' @Ident (',' @Ident)* ']')?"`
}

// Page definitions for frontend with clean syntax
type Page struct {
	Name        string      `parser:"'page' @Ident"`
	Path        string      `parser:"'at' @String"`
	Layout      string      `parser:"'layout' @Ident"`
	Title       *string     `parser:"('title' @String)?"`
	Description *string     `parser:"('desc' @String)?"`
	Auth        bool        `parser:"@'auth'?"`
	Meta        []MetaTag   `parser:"@@*"`
	Components  []Component `parser:"@@*"`
}

// Meta tags for SEO
type MetaTag struct {
	Name    string `parser:"'meta' @Ident"`
	Content string `parser:"@String"`
}

// Component definitions with endpoint references
type Component struct {
	Type   string          `parser:"'component' @Ident"`
	Entity *string         `parser:"('for' @Ident)?"`
	Config []ComponentAttr `parser:"@@*"`
}

// Component attributes and configurations
type ComponentAttr struct {
	Fields     *ComponentFields     `parser:"@@"`
	Actions    *ComponentActions    `parser:"| @@"`
	DataSource *ComponentDataSource `parser:"| @@"`
	Style      *ComponentStyle      `parser:"| @@"`
	Pagination *ComponentPagination `parser:"| @@"`
	Filters    *ComponentFilters    `parser:"| @@"`
	Validation bool                 `parser:"| @'validate'"`
}

// Component field specification
type ComponentFields struct {
	Fields []string `parser:"'fields' '[' @Ident (',' @Ident)* ']'"`
}

// Component actions (can reference endpoints)
type ComponentActions struct {
	Actions []ComponentAction `parser:"'actions' '[' @@ (',' @@)* ']'"`
}

type ComponentAction struct {
	Name     string  `parser:"@Ident"`
	Endpoint *string `parser:"('via' @String)?"`
}

// Data source configuration (can reference endpoints)
type ComponentDataSource struct {
	Endpoint string `parser:"'data' 'from' @String"`
}

// Component styling
type ComponentStyle struct {
	Theme   *string  `parser:"'style' @Ident"`
	Classes []string `parser:"('classes' '[' @String (',' @String)* ']')?"`
}

// Pagination configuration
type ComponentPagination struct {
	PageSize *int `parser:"'pagination' ('size' @Int)?"`
}

// Filter specifications
type ComponentFilters struct {
	Filters []ComponentFilter `parser:"'filters' '[' @@ (',' @@)* ']'"`
}

type ComponentFilter struct {
	Field string  `parser:"@Ident"`
	Type  string  `parser:"'as' @('text' | 'select' | 'date' | 'number')"`
	Label *string `parser:"('label' @String)?"`
}

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
}