package device

import (
	"fmt"
	"strconv"
	"strings"
)

// ProcessCommand handles incoming BLE commands and returns the response
func (s *DeviceState) ProcessCommand(cmd string) string {
	cmd = strings.TrimSpace(cmd)

	// Handle global commands
	switch cmd {
	case "PROG_ON":
		s.SetProgMode(true)
		return "PROG_MODE: ON"

	case "PROG_OFF":
		s.SetProgMode(false)
		return "PROG_MODE: OFF"

	case "RESET":
		s.ResetAlarm()
		return "INFO: Uscita allarme resettata (BT)."

	case "CALI":
		active := s.ToggleCaliMode()
		if active {
			return "--- MODALITA CALIBRAZIONE ATTIVA ---"
		}
		return "--- MODALITA CALIBRAZIONE DISATTIVA ---"

	case "FACTORY":
		s.ResetToDefaults()
		return "FACTORY RESET DONE"
	}

	// Handle write commands (W1, W2, etc.)
	if strings.HasPrefix(cmd, "W") {
		return s.handleWriteCommand(cmd)
	}

	// Handle read commands (R1, R2, etc.)
	if strings.HasPrefix(cmd, "R") {
		return s.handleReadCommand(cmd)
	}

	return "ERRORE: Formato comando non valido"
}

// handleWriteCommand processes Wxx <value> commands
func (s *DeviceState) handleWriteCommand(cmd string) string {
	// Check if in programming mode
	if !s.GetProgMode() {
		return "ERRORE: I comandi 'W' sono accettati solo in modalità programmazione."
	}

	// Parse command format: "W<id> <value>"
	parts := strings.Fields(cmd)
	if len(parts) != 2 {
		return "ERRORE: Formato comando non valido"
	}

	// Extract parameter ID
	idStr := strings.TrimPrefix(parts[0], "W")
	id, err := strconv.Atoi(idStr)
	if err != nil {
		return "ERRORE: Formato comando non valido"
	}

	// Check if parameter ID is valid
	if !isValidParamID(id) {
		return "ERRORE: ID Sconosciuto"
	}

	// Parse value
	value, err := strconv.Atoi(parts[1])
	if err != nil {
		return "ERRORE: Formato comando non valido"
	}

	// Validate range based on parameter ID
	if !validateParamRange(id, value) {
		return fmt.Sprintf("ERRORE: Valore fuori range per W%d", id)
	}

	// Set the parameter
	s.SetParam(id, value)
	return fmt.Sprintf("PARAM: W%d=%d", id, value)
}

// handleReadCommand processes Rxx commands
func (s *DeviceState) handleReadCommand(cmd string) string {
	// Check if in programming mode
	if !s.GetProgMode() {
		return "ERRORE: I comandi 'W' sono accettati solo in modalità programmazione."
	}

	// Extract parameter ID
	idStr := strings.TrimPrefix(cmd, "R")
	id, err := strconv.Atoi(idStr)
	if err != nil {
		return "ERRORE: Formato comando non valido"
	}

	// Check if parameter ID is valid for reading
	if !isReadableParamID(id) {
		return "ERRORE: ID Sconosciuto"
	}

	// Get the parameter value
	value, ok := s.GetParam(id)
	if !ok {
		return "ERRORE: ID Sconosciuto"
	}

	return fmt.Sprintf("PARAM: W%d=%d", id, value)
}

// isValidParamID checks if the parameter ID is writable
func isValidParamID(id int) bool {
	validIDs := []int{1, 2, 3, 4, 11, 12, 20}
	for _, v := range validIDs {
		if id == v {
			return true
		}
	}
	return false
}

// isReadableParamID checks if the parameter ID is readable
func isReadableParamID(id int) bool {
	// According to docs.toon, only R1, R2, R20 are documented
	readableIDs := []int{1, 2, 20}
	for _, v := range readableIDs {
		if id == v {
			return true
		}
	}
	return false
}

// validateParamRange checks if value is within acceptable range for parameter
func validateParamRange(id, value int) bool {
	ranges := map[int][2]int{
		1:  {0, 2000},   // W1 - Min Threshold
		2:  {0, 4095},   // W2 - Max Threshold
		3:  {1, 50},     // W3 - Pulse Count
		4:  {10, 1000},  // W4 - Time Window
		11: {0, 1000},   // W11 - Min Pulse Duration
		12: {0, 1000},   // W12 - Max Pulse Duration
		20: {0, 255},    // W20 - Gain (Wiper)
	}

	r, ok := ranges[id]
	if !ok {
		return false
	}
	return value >= r[0] && value <= r[1]
}