package device

import (
	"encoding/json"
	"fmt"
	"os"
	"path/filepath"

	"netdome.biz/paul/impact-80/internal/hid"
)

// Keyboard represents a keyboard definition from keyboards.json.
type Keyboard struct {
	Name       string `json:"name"`
	VendorID   uint16 `json:"vendorId"`
	ProductID  uint16 `json:"productId"`
	Protocol   string `json:"protocol"`
	VIAVersion int    `json:"viaVersion"`
	LEDLayout  string `json:"ledLayout"`
}

// Device represents a connected keyboard device.
type Device struct {
	Keyboard
	Path string
}

// LoadKeyboards reads keyboard definitions from keyboards.json.
func LoadKeyboards() ([]Keyboard, error) {
	path, err := findKeyboardsJSON()
	if err != nil {
		return nil, fmt.Errorf("find keyboards.json: %w", err)
	}

	data, err := os.ReadFile(path)
	if err != nil {
		return nil, fmt.Errorf("read keyboards.json: %w", err)
	}

	var keyboards []Keyboard
	if err := json.Unmarshal(data, &keyboards); err != nil {
		return nil, fmt.Errorf("parse keyboards.json: %w", err)
	}

	return keyboards, nil
}

// findKeyboardsJSON searches for keyboards.json in common locations.
var findKeyboardsJSON = func() (string, error) {
	exe, err := os.Executable()
	if err == nil {
		path := filepath.Join(filepath.Dir(exe), "keyboards.json")
		if _, err := os.Stat(path); err == nil {
			return path, nil
		}
	}

	path := "keyboards.json"
	if _, err := os.Stat(path); err == nil {
		return path, nil
	}

	cwd, err := os.Getwd()
	if err == nil {
		path := filepath.Join(cwd, "keyboards.json")
		if _, err := os.Stat(path); err == nil {
			return path, nil
		}
	}

	return "", fmt.Errorf("keyboards.json not found")
}

// UnknownDevice represents a QMK Raw HID keyboard not yet in keyboards.json.
type UnknownDevice struct {
	VendorID  uint16 `json:"vendorId"`
	ProductID uint16 `json:"productId"`
	Path      string `json:"path"`
	Supported bool   `json:"supported"`
}

// DiscoverAllQMK scans for all connected QMK keyboards (both known and unknown).
func DiscoverAllQMK(keyboards []Keyboard) ([]UnknownDevice, error) {
	qmkDevices, err := hid.DiscoverAll()
	if err != nil {
		return nil, fmt.Errorf("discover qmk devices: %w", err)
	}

	known := make(map[string]bool)
	for _, kb := range keyboards {
		known[fmt.Sprintf("%04x:%04x", kb.VendorID, kb.ProductID)] = true
	}

	var results []UnknownDevice
	for _, q := range qmkDevices {
		key := fmt.Sprintf("%04x:%04x", q.VendorID, q.ProductID)
		results = append(results, UnknownDevice{
			VendorID:  q.VendorID,
			ProductID: q.ProductID,
			Path:      q.Path,
			Supported: known[key],
		})
	}
	return results, nil
}
func Discover(keyboards []Keyboard) ([]Device, error) {
	var found []Device
	for _, kb := range keyboards {
		err := hid.Enumerate(kb.VendorID, kb.ProductID, func(info *hid.DeviceInfo) error {
			found = append(found, Device{
				Keyboard: kb,
				Path:     info.Path,
			})
			return nil
		})
		if err != nil {
			return nil, fmt.Errorf("enumerate VID=0x%04x PID=0x%04x: %w", kb.VendorID, kb.ProductID, err)
		}
	}

	if len(found) > 0 {
		fmt.Fprintf(os.Stderr, "Discovered %d keyboard(s):\n", len(found))
		for _, d := range found {
			fmt.Fprintf(os.Stderr, "  - %s (VID=0x%04x PID=0x%04x) %s\n", d.Name, d.VendorID, d.ProductID, d.Path)
		}
	} else {
		fmt.Fprintln(os.Stderr, "No keyboards found.")
	}
	return found, nil
}