// Package generator contains the code generator for the WebAwesome library.
package generator

import (
	"bytes"
	"fmt"
	"os"
	"sort"
	"text/template"

	"github.com/sonr-io/nebula/internal/parser"
)

// Generator handles code generation for Web Awesome components
type Generator struct {
	pkg     string
	verbose bool
	funcMap template.FuncMap
}

// New creates a new Generator instance
func New(pkg string, verbose bool) *Generator {
	g := &Generator{
		pkg:     pkg,
		verbose: verbose,
	}
	g.funcMap = template.FuncMap{
		"toPascal":       ToPascalCase,
		"toCamel":        ToCamelCase,
		"stripWa":        StripWaPrefix,
		"toGoType":       ToGoType,
		"toBuilderType":  ToBuilderType,
		"isBoolean":      IsBoolean,
		"isNumber":       IsNumber,
		"cleanDesc":      CleanDescription,
		"extractEnums":   ExtractEnumValues,
		"toEventName":    ToEventName,
		"toSlotName":     ToSlotName,
		"escapeGoString": EscapeGoString,
		"hasSlots":       g.hasSlots,
		"namedSlots":     g.namedSlots,
		"hasEvents":      g.hasEvents,
		"filterAttrs":    g.filterAttributes,
	}
	return g
}

// ComponentFilename returns the filename for a component
func (g *Generator) ComponentFilename(name string) string {
	return StripWaPrefix(name) + ".templ"
}

func (g *Generator) hasSlots(el parser.Element) bool {
	return len(el.Slots) > 0
}

func (g *Generator) namedSlots(el parser.Element) []parser.Slot {
	var named []parser.Slot
	for _, s := range el.Slots {
		if s.Name != "" {
			named = append(named, s)
		}
	}
	return named
}

func (g *Generator) hasEvents(el parser.Element) bool {
	return len(el.Events) > 0
}

func (g *Generator) filterAttributes(attrs []parser.Attribute) []parser.Attribute {
	var filtered []parser.Attribute
	skip := map[string]bool{"title": true} // Skip problematic attributes
	for _, a := range attrs {
		if !skip[a.Name] {
			filtered = append(filtered, a)
		}
	}
	return filtered
}

var componentTemplate = `// Code generated by wa-generator. DO NOT EDIT.
// Source: Web Awesome {{ .Element.Name }}

package {{ .Package }}

import (
	"github.com/a]h/templ"
)

{{- $name := stripWa .Element.Name | toPascal }}
{{- $el := .Element }}
{{- $attrs := filterAttrs .Element.Attributes }}

// {{ cleanDesc .Element.Description }}
//
// Web Awesome component: <{{ .Element.Name }}>
{{- if .Element.DocURL }}
// Documentation: {{ .Element.DocURL }}
{{- end }}

// {{ $name }}Props holds all properties for the {{ .Element.Name }} component
type {{ $name }}Props struct {
{{- range $attrs }}
	// {{ cleanDesc .Description }}
	{{- if extractEnums .Value.Type }}
	// Valid values: {{ range $i, $v := extractEnums .Value.Type }}{{ if $i }}, {{ end }}"{{ $v }}"{{ end }}
	{{- end }}
	{{ toPascal .Name }} {{ toGoType .Value.Type }} ` + "`attr:\"{{ .Name }}\"`" + `
{{- end }}

	// Events
{{- range $el.Events }}
	// {{ cleanDesc .Description }}
	{{ toEventName .Name }} string ` + "`attr:\"x-on:{{ .Name }}\"`" + `
{{- end }}

	// Slots contains named slot content
	Slots {{ $name }}Slots

	// Attrs contains additional HTML attributes
	Attrs templ.Attributes
}

{{- if namedSlots $el }}

// {{ $name }}Slots holds named slot content for the component
type {{ $name }}Slots struct {
{{- range namedSlots $el }}
	// {{ cleanDesc .Description }}
	{{ toSlotName .Name }} templ.Component
{{- end }}
}
{{- end }}

// {{ $name }}Builder provides a fluent API for constructing {{ $name }}Props
type {{ $name }}Builder struct {
	props {{ $name }}Props
}

// New{{ $name }} creates a new builder for {{ .Element.Name }}
func New{{ $name }}() *{{ $name }}Builder {
	return &{{ $name }}Builder{}
}

{{- range $attrs }}

// {{ toPascal .Name }} sets the {{ .Name }} attribute
{{- if cleanDesc .Description }}
// {{ cleanDesc .Description }}
{{- end }}
func (b *{{ $name }}Builder) {{ toPascal .Name }}(v {{ toBuilderType .Value.Type }}) *{{ $name }}Builder {
	b.props.{{ toPascal .Name }} = v
	return b
}
{{- end }}

{{- range $el.Events }}

// {{ toEventName .Name }} sets the handler for {{ .Name }} event
// {{ cleanDesc .Description }}
func (b *{{ $name }}Builder) {{ toEventName .Name }}(handler string) *{{ $name }}Builder {
	b.props.{{ toEventName .Name }} = handler
	return b
}
{{- end }}

{{- range namedSlots $el }}

// {{ toSlotName .Name }}Slot sets the {{ .Name }} slot content
// {{ cleanDesc .Description }}
func (b *{{ $name }}Builder) {{ toSlotName .Name }}Slot(c templ.Component) *{{ $name }}Builder {
	b.props.Slots.{{ toSlotName .Name }} = c
	return b
}
{{- end }}

// Attr adds a custom HTML attribute
func (b *{{ $name }}Builder) Attr(name, value string) *{{ $name }}Builder {
	if b.props.Attrs == nil {
		b.props.Attrs = templ.Attributes{}
	}
	b.props.Attrs[name] = value
	return b
}

// Attrs merges multiple attributes
func (b *{{ $name }}Builder) Attrs(attrs templ.Attributes) *{{ $name }}Builder {
	if b.props.Attrs == nil {
		b.props.Attrs = templ.Attributes{}
	}
	for k, v := range attrs {
		b.props.Attrs[k] = v
	}
	return b
}

// Props returns the built properties
func (b *{{ $name }}Builder) Props() {{ $name }}Props {
	return b.props
}

// Build returns the props (alias for Props for semantic clarity)
func (b *{{ $name }}Builder) Build() {{ $name }}Props {
	return b.props
}

// {{ $name }} renders the {{ .Element.Name }} component
templ {{ $name }}(props {{ $name }}Props) {
	<{{ $el.Name }}
		{{- range $attrs }}
		{{- if isBoolean .Value.Type }}
		if props.{{ toPascal .Name }} {
			{{ .Name }}
		}
		{{- else if isNumber .Value.Type }}
		if props.{{ toPascal .Name }} != 0 {
			{{ .Name }}={ templ.Sprintf("%v", props.{{ toPascal .Name }}) }
		}
		{{- else }}
		if props.{{ toPascal .Name }} != "" {
			{{ .Name }}={ props.{{ toPascal .Name }} }
		}
		{{- end }}
		{{- end }}
		{{- range $el.Events }}
		if props.{{ toEventName .Name }} != "" {
			x-on:{{ .Name }}={ props.{{ toEventName .Name }} }
		}
		{{- end }}
		{ props.Attrs... }
	>
		{{- range namedSlots $el }}
		if props.Slots.{{ toSlotName .Name }} != nil {
			<div slot="{{ .Name }}">
				@props.Slots.{{ toSlotName .Name }}
			</div>
		}
		{{- end }}
		{ children... }
	</{{ $el.Name }}>
}

// {{ $name }}Func renders with a builder function for inline configuration
templ {{ $name }}Func(fn func(*{{ $name }}Builder)) {
	{{ "{{" }} b := New{{ $name }}(); fn(b) {{ "}}" }}
	@{{ $name }}(b.Props()) {
		{ children... }
	}
}
`

// GenerateComponent generates a templ file for a component
func (g *Generator) GenerateComponent(filename string, el parser.Element) error {
	tmpl, err := template.New("component").Funcs(g.funcMap).Parse(componentTemplate)
	if err != nil {
		return fmt.Errorf("parsing template: %w", err)
	}

	var buf bytes.Buffer
	data := map[string]interface{}{
		"Package": g.pkg,
		"Element": el,
	}

	if err := tmpl.Execute(&buf, data); err != nil {
		return fmt.Errorf("executing template: %w", err)
	}

	return os.WriteFile(filename, buf.Bytes(), 0644)
}

var typesTemplate = `// Code generated by wa-generator. DO NOT EDIT.

package {{ .Package }}

import "github.com/a]h/templ"

// Variant represents component theme variants
type Variant string

const (
	VariantBrand   Variant = "brand"
	VariantNeutral Variant = "neutral"
	VariantSuccess Variant = "success"
	VariantWarning Variant = "warning"
	VariantDanger  Variant = "danger"
)

// Size represents component sizes
type Size string

const (
	SizeSmall  Size = "small"
	SizeMedium Size = "medium"
	SizeLarge  Size = "large"
)

// Appearance represents visual appearance styles
type Appearance string

const (
	AppearanceAccent        Appearance = "accent"
	AppearanceFilled        Appearance = "filled"
	AppearanceOutlined      Appearance = "outlined"
	AppearanceFilledOutlined Appearance = "filled-outlined"
	AppearancePlain         Appearance = "plain"
)

// Orientation represents layout orientation
type Orientation string

const (
	OrientationHorizontal Orientation = "horizontal"
	OrientationVertical   Orientation = "vertical"
)

// Placement represents popup/tooltip placement
type Placement string

const (
	PlacementTop         Placement = "top"
	PlacementTopStart    Placement = "top-start"
	PlacementTopEnd      Placement = "top-end"
	PlacementBottom      Placement = "bottom"
	PlacementBottomStart Placement = "bottom-start"
	PlacementBottomEnd   Placement = "bottom-end"
	PlacementLeft        Placement = "left"
	PlacementLeftStart   Placement = "left-start"
	PlacementLeftEnd     Placement = "left-end"
	PlacementRight       Placement = "right"
	PlacementRightStart  Placement = "right-start"
	PlacementRightEnd    Placement = "right-end"
)

// SlotContent is a helper for creating slot content
type SlotContent struct {
	Name    string
	Content templ.Component
}

// NewSlot creates a new SlotContent
func NewSlot(name string, content templ.Component) SlotContent {
	return SlotContent{Name: name, Content: content}
}

// EmptyComponent returns a no-op templ component
func EmptyComponent() templ.Component {
	return templ.ComponentFunc(func(ctx context.Context, w io.Writer) error {
		return nil
	})
}

// Text creates a simple text component
func Text(s string) templ.Component {
	return templ.Raw(s)
}
`

// GenerateTypes generates shared types
func (g *Generator) GenerateTypes(filename string) error {
	tmpl, err := template.New("types").Parse(typesTemplate)
	if err != nil {
		return err
	}

	var buf bytes.Buffer
	if err := tmpl.Execute(&buf, map[string]string{"Package": g.pkg}); err != nil {
		return err
	}

	return os.WriteFile(filename, buf.Bytes(), 0644)
}

var buildersTemplate = `// Code generated by wa-generator. DO NOT EDIT.

package {{ .Package }}

import "github.com/a]h/templ"

// PropsBuilder is the interface all component builders implement
type PropsBuilder[T any] interface {
	Attr(name, value string) PropsBuilder[T]
	Attrs(attrs templ.Attributes) PropsBuilder[T]
	Build() T
}

// BaseBuilder provides common builder functionality
type BaseBuilder struct {
	attrs templ.Attributes
}

// SetAttr sets a single attribute
func (b *BaseBuilder) SetAttr(name, value string) {
	if b.attrs == nil {
		b.attrs = templ.Attributes{}
	}
	b.attrs[name] = value
}

// MergeAttrs merges attributes
func (b *BaseBuilder) MergeAttrs(attrs templ.Attributes) {
	if b.attrs == nil {
		b.attrs = templ.Attributes{}
	}
	for k, v := range attrs {
		b.attrs[k] = v
	}
}

// GetAttrs returns the attributes
func (b *BaseBuilder) GetAttrs() templ.Attributes {
	if b.attrs == nil {
		return templ.Attributes{}
	}
	return b.attrs
}

// Common builder method helpers

// WithClass is a helper to add CSS classes
func WithClass[B interface{ Attr(string, string) B }](b B, classes ...string) B {
	return b.Attr("class", strings.Join(classes, " "))
}

// WithID is a helper to set element ID
func WithID[B interface{ Attr(string, string) B }](b B, id string) B {
	return b.Attr("id", id)
}

// WithStyle is a helper to add inline styles
func WithStyle[B interface{ Attr(string, string) B }](b B, style string) B {
	return b.Attr("style", style)
}

// WithData is a helper to add data attributes
func WithData[B interface{ Attr(string, string) B }](b B, key, value string) B {
	return b.Attr("data-"+key, value)
}

// Component registry for dynamic component creation
var componentRegistry = map[string]func() interface{}{
{{- range .Elements }}
	"{{ .Name }}": func() interface{} { return New{{ stripWa .Name | toPascal }}() },
{{- end }}
}

// GetBuilder returns a builder for the given component name
func GetBuilder(name string) interface{} {
	if fn, ok := componentRegistry[name]; ok {
		return fn()
	}
	return nil
}

// ComponentNames returns all available component names
func ComponentNames() []string {
	names := make([]string, 0, len(componentRegistry))
	for name := range componentRegistry {
		names = append(names, name)
	}
	sort.Strings(names)
	return names
}
`

// GenerateBuilders generates builder utilities
func (g *Generator) GenerateBuilders(filename string, elements []parser.Element) error {
	tmpl, err := template.New("builders").Funcs(g.funcMap).Parse(buildersTemplate)
	if err != nil {
		return err
	}

	var buf bytes.Buffer
	data := map[string]interface{}{
		"Package":  g.pkg,
		"Elements": elements,
	}

	if err := tmpl.Execute(&buf, data); err != nil {
		return err
	}

	return os.WriteFile(filename, buf.Bytes(), 0644)
}

var cdnTemplate = `// Code generated by wa-generator. DO NOT EDIT.

package {{ .Package }}

// CDNVersion is the Web Awesome version used for CDN assets
const CDNVersion = "{{ .Version }}"

// CDNHead renders the required CSS and JS for Web Awesome from CDN
templ CDNHead() {
	<link rel="stylesheet" href={ "https://cdn.jsdelivr.net/npm/@aspect/web-awesome@" + CDNVersion + "/dist/themes/default.css" }/>
	<script type="module" src={ "https://cdn.jsdelivr.net/npm/@aspect/web-awesome@" + CDNVersion + "/dist/web-awesome.loader.js" }></script>
}

// CDNHeadPro renders the required CSS and JS for Web Awesome Pro from CDN
// Requires a valid license key configured in your environment
templ CDNHeadPro() {
	<link rel="stylesheet" href={ "https://cdn.jsdelivr.net/npm/@awesome.me/webawesome-pro@" + CDNVersion + "/dist/themes/default.css" }/>
	<script type="module" src={ "https://cdn.jsdelivr.net/npm/@awesome.me/webawesome-pro@" + CDNVersion + "/dist/webawesome.loader.js" }></script>
}

// CDNHeadWithTheme renders CDN assets with a specific theme
templ CDNHeadWithTheme(theme string) {
	<link rel="stylesheet" href={ "https://cdn.jsdelivr.net/npm/@aspect/web-awesome@" + CDNVersion + "/dist/themes/" + theme + ".css" }/>
	<script type="module" src={ "https://cdn.jsdelivr.net/npm/@aspect/web-awesome@" + CDNVersion + "/dist/web-awesome.loader.js" }></script>
}

// LocalHead renders Web Awesome assets from local paths
templ LocalHead(cssPath, jsPath string) {
	<link rel="stylesheet" href={ cssPath }/>
	<script type="module" src={ jsPath }></script>
}

// FontAwesomeKit renders Font Awesome kit script
templ FontAwesomeKit(kitCode string) {
	<script src={ "https://kit.fontawesome.com/" + kitCode + ".js" } crossorigin="anonymous"></script>
}
`

// GenerateCDN generates CDN loader templates
func (g *Generator) GenerateCDN(filename string, version string) error {
	tmpl, err := template.New("cdn").Parse(cdnTemplate)
	if err != nil {
		return err
	}

	var buf bytes.Buffer
	data := map[string]string{
		"Package": g.pkg,
		"Version": version,
	}

	if err := tmpl.Execute(&buf, data); err != nil {
		return err
	}

	return os.WriteFile(filename, buf.Bytes(), 0644)
}

var eventsTemplate = `// Code generated by wa-generator. DO NOT EDIT.

package {{ .Package }}

// Event names for Web Awesome components
// Use with Alpine.js x-on: directive or vanilla JS addEventListener
const (
{{- range .Events }}
	// {{ .Name }} - {{ cleanDesc .Description }}
	Event{{ toPascal .Name }} = "{{ .Name }}"
{{- end }}
)

// EventHandler creates an Alpine.js event handler string
func EventHandler(jsCode string) string {
	return jsCode
}

// EventHandlerPrevent creates a handler that prevents default
func EventHandlerPrevent(jsCode string) string {
	return "$event.preventDefault(); " + jsCode
}

// EventHandlerStop creates a handler that stops propagation
func EventHandlerStop(jsCode string) string {
	return "$event.stopPropagation(); " + jsCode
}

// EventHandlerDebounce wraps handler with debounce
func EventHandlerDebounce(jsCode string, ms int) string {
	return fmt.Sprintf("$debounce(() => { %s }, %d)", jsCode, ms)
}

// Common event handler patterns

// ToggleHandler returns a handler that toggles a boolean value
func ToggleHandler(varName string) string {
	return varName + " = !" + varName
}

// SetValueHandler returns a handler that sets a value
func SetValueHandler(varName, value string) string {
	return fmt.Sprintf("%s = %s", varName, value)
}

// DispatchHandler returns a handler that dispatches a custom event
func DispatchHandler(eventName string, detail string) string {
	if detail != "" {
		return fmt.Sprintf("$dispatch('%s', %s)", eventName, detail)
	}
	return fmt.Sprintf("$dispatch('%s')", eventName)
}

// FetchHandler returns a handler that performs a fetch request
func FetchHandler(url, method, body string) string {
	if body != "" {
		return fmt.Sprintf("fetch('%s', {method: '%s', body: JSON.stringify(%s), headers: {'Content-Type': 'application/json'}})", url, method, body)
	}
	return fmt.Sprintf("fetch('%s', {method: '%s'})", url, method)
}
`

// GenerateEvents generates event constants and helpers
func (g *Generator) GenerateEvents(filename string, elements []parser.Element) error {
	// Collect all unique events
	eventMap := make(map[string]parser.Event)
	for _, el := range elements {
		for _, ev := range el.Events {
			if _, exists := eventMap[ev.Name]; !exists {
				eventMap[ev.Name] = ev
			}
		}
	}

	// Convert to slice and sort
	events := make([]parser.Event, 0, len(eventMap))
	for _, ev := range eventMap {
		events = append(events, ev)
	}
	sort.Slice(events, func(i, j int) bool {
		return events[i].Name < events[j].Name
	})

	tmpl, err := template.New("events").Funcs(g.funcMap).Parse(eventsTemplate)
	if err != nil {
		return err
	}

	var buf bytes.Buffer
	data := map[string]interface{}{
		"Package": g.pkg,
		"Events":  events,
	}

	if err := tmpl.Execute(&buf, data); err != nil {
		return err
	}

	return os.WriteFile(filename, buf.Bytes(), 0644)
}