package providers

import (
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"github.com/sblinch/kdl-go"
	"github.com/sblinch/kdl-go/document"
)

type NiriKeyBinding struct {
	Mods        []string
	Key         string
	Action      string
	Args        []string
	Description string
}

type NiriSection struct {
	Name     string
	Keybinds []NiriKeyBinding
	Children []NiriSection
}

type NiriParser struct {
	configDir      string
	processedFiles map[string]bool
	bindMap        map[string]*NiriKeyBinding
	bindOrder      []string
}

func NewNiriParser(configDir string) *NiriParser {
	return &NiriParser{
		configDir:      configDir,
		processedFiles: make(map[string]bool),
		bindMap:        make(map[string]*NiriKeyBinding),
		bindOrder:      []string{},
	}
}

func (p *NiriParser) Parse() (*NiriSection, error) {
	configPath := filepath.Join(p.configDir, "config.kdl")
	section, err := p.parseFile(configPath, "")
	if err != nil {
		return nil, err
	}

	section.Keybinds = p.finalizeBinds()
	return section, nil
}

func (p *NiriParser) finalizeBinds() []NiriKeyBinding {
	binds := make([]NiriKeyBinding, 0, len(p.bindOrder))
	for _, key := range p.bindOrder {
		if kb, ok := p.bindMap[key]; ok {
			binds = append(binds, *kb)
		}
	}
	return binds
}

func (p *NiriParser) addBind(kb *NiriKeyBinding) {
	key := p.formatBindKey(kb)
	if _, exists := p.bindMap[key]; !exists {
		p.bindOrder = append(p.bindOrder, key)
	}
	p.bindMap[key] = kb
}

func (p *NiriParser) formatBindKey(kb *NiriKeyBinding) string {
	parts := make([]string, 0, len(kb.Mods)+1)
	parts = append(parts, kb.Mods...)
	parts = append(parts, kb.Key)
	return strings.Join(parts, "+")
}

func (p *NiriParser) parseFile(filePath, sectionName string) (*NiriSection, error) {
	absPath, err := filepath.Abs(filePath)
	if err != nil {
		return nil, fmt.Errorf("failed to resolve path %s: %w", filePath, err)
	}

	if p.processedFiles[absPath] {
		return &NiriSection{Name: sectionName}, nil
	}
	p.processedFiles[absPath] = true

	data, err := os.ReadFile(absPath)
	if err != nil {
		return nil, fmt.Errorf("failed to read %s: %w", absPath, err)
	}

	doc, err := kdl.Parse(strings.NewReader(string(data)))
	if err != nil {
		return nil, fmt.Errorf("failed to parse KDL in %s: %w", absPath, err)
	}

	section := &NiriSection{
		Name: sectionName,
	}

	baseDir := filepath.Dir(absPath)
	p.processNodes(doc.Nodes, section, baseDir)

	return section, nil
}

func (p *NiriParser) processNodes(nodes []*document.Node, section *NiriSection, baseDir string) {
	for _, node := range nodes {
		name := node.Name.String()

		switch name {
		case "include":
			p.handleInclude(node, section, baseDir)
		case "binds":
			p.extractBinds(node, section, "")
		case "recent-windows":
			p.handleRecentWindows(node, section)
		}
	}
}

func (p *NiriParser) handleInclude(node *document.Node, section *NiriSection, baseDir string) {
	if len(node.Arguments) == 0 {
		return
	}

	includePath := node.Arguments[0].String()
	includePath = strings.Trim(includePath, "\"")

	var fullPath string
	if filepath.IsAbs(includePath) {
		fullPath = includePath
	} else {
		fullPath = filepath.Join(baseDir, includePath)
	}

	includedSection, err := p.parseFile(fullPath, "")
	if err != nil {
		return
	}

	section.Children = append(section.Children, includedSection.Children...)
}

func (p *NiriParser) handleRecentWindows(node *document.Node, section *NiriSection) {
	if node.Children == nil {
		return
	}

	for _, child := range node.Children {
		if child.Name.String() != "binds" {
			continue
		}
		p.extractBinds(child, section, "Alt-Tab")
	}
}

func (p *NiriParser) extractBinds(node *document.Node, section *NiriSection, subcategory string) {
	if node.Children == nil {
		return
	}

	for _, child := range node.Children {
		kb := p.parseKeybindNode(child, subcategory)
		if kb == nil {
			continue
		}
		p.addBind(kb)
	}
}

func (p *NiriParser) parseKeybindNode(node *document.Node, subcategory string) *NiriKeyBinding {
	keyCombo := node.Name.String()
	if keyCombo == "" {
		return nil
	}

	mods, key := p.parseKeyCombo(keyCombo)

	var action string
	var args []string

	if len(node.Children) > 0 {
		actionNode := node.Children[0]
		action = actionNode.Name.String()
		for _, arg := range actionNode.Arguments {
			args = append(args, strings.Trim(arg.String(), "\""))
		}
	}

	description := ""
	if node.Properties != nil {
		if val, ok := node.Properties.Get("hotkey-overlay-title"); ok {
			description = strings.Trim(val.String(), "\"")
		}
	}

	return &NiriKeyBinding{
		Mods:        mods,
		Key:         key,
		Action:      action,
		Args:        args,
		Description: description,
	}
}

func (p *NiriParser) parseKeyCombo(combo string) ([]string, string) {
	parts := strings.Split(combo, "+")
	if len(parts) == 0 {
		return nil, combo
	}

	if len(parts) == 1 {
		return nil, parts[0]
	}

	mods := parts[:len(parts)-1]
	key := parts[len(parts)-1]

	return mods, key
}

func ParseNiriKeys(configDir string) (*NiriSection, error) {
	parser := NewNiriParser(configDir)
	return parser.Parse()
}