package inventory

import (
	"encoding/json"
	"os"
	"time"
)

// Package represents a single installed package or application
type Package struct {
	Name      string `json:"name"`
	Version   string `json:"version"`
	Source    string `json:"source"` // homebrew, pip, npm, go, application
	Path      string `json:"path,omitempty"`
	BundleID  string `json:"bundle_id,omitempty"`
}

// SystemInfo contains macOS system information
type SystemInfo struct {
	OS           string `json:"os"`
	KernelRelease string `json:"kernel_release"`
	MacOSVersion string `json:"macos_version"`
	Hostname     string `json:"hostname"`
	Username     string `json:"username"`
}

// Inventory represents the full system inventory
type Inventory struct {
	Timestamp    time.Time   `json:"timestamp"`
	System       SystemInfo  `json:"system"`
	Homebrew     []Package   `json:"homebrew"`
	Python       []Package   `json:"python"`
	Node         []Package   `json:"node"`
	Go           []Package   `json:"go"`
	Applications []Package   `json:"applications"`
}

// LoadInventory reads the inventory JSON file
func LoadInventory(path string) (*Inventory, error) {
	data, err := os.ReadFile(path)
	if err != nil {
		return nil, err
	}

	var inv Inventory
	if err := json.Unmarshal(data, &inv); err != nil {
		return nil, err
	}

	return &inv, nil
}

// AllPackages returns all packages as a flat slice
func (i *Inventory) AllPackages() []Package {
	var all []Package
	all = append(all, i.Homebrew...)
	all = append(all, i.Python...)
	all = append(all, i.Node...)
	all = append(all, i.Go...)
	all = append(all, i.Applications...)
	return all
}

// CountPackages returns total number of packages
func (i *Inventory) CountPackages() int {
	return len(i.AllPackages())
}

// CountBySource returns count of packages by source type
func (i *Inventory) CountBySource() map[string]int {
	counts := make(map[string]int)
	for _, pkg := range i.AllPackages() {
		counts[pkg.Source]++
	}
	return counts
}