staskobzar / goagi

import (

	"strconv"

	"strings"

)

// Response interface that all commands return.

// Helps to access different parts of AGI response

type Response interface {

	// Code of response: 200, 510 etc

	Code() int

	// RawResponse return full text of AGI response

	RawResponse() string

	// Result returns value of result= field

	Result() int

	// Value returns value field: (timeout)

	Value() string

	// Data returns text for error responses and dtmf values for command like GetData

	Data() string

	// EndPos returns value for endpos= field

	EndPos() int64

	// Digit return digit from digit= field

	Digit() string

	// SResults return value for results= field

	SResults() int

}

type response struct {

	code   int

	result int

	raw    string

	data   string

}

func (r *response) Code() int           { return r.code }

func (r *response) RawResponse() string { return r.raw }

func (r *response) Result() int         { return r.result }

func (r *response) Value() string       { return r.data }

func (r *response) Data() string        { return r.data }

func (r *response) EndPos() int64       { return 0 }

func (r *response) Digit() string       { return "" }

func (r *response) SResults() int       { return 0 }

type responseSuccess struct {

	response

	value    string

	endpos   int64

	digit    string

	sresults int

}

func (r *responseSuccess) Value() string { return r.value }

func (r *responseSuccess) EndPos() int64 { return r.endpos }

func (r *responseSuccess) Digit() string { return r.digit }

func (r *responseSuccess) SResults() int { return r.sresults }

func (agi *AGI) sessionSetup(data []string) {

	agi.dbg("[>] sessionSetup")

	agi.env = make(map[string]string)

	agi.arg = make([]string, 0)

	for _, line := range data {

		idx := strings.Index(line, ": ")

		if idx == -1 || line[:4] != "agi_" {

			agi.dbg(" [!] ignore invalid line: %q", line)

			continue

		}

		if line[:8] == "agi_arg_" {

			arg := line[idx+2:]

			agi.arg = append(agi.arg, arg)

			agi.dbg(" [v] add arg: %q", arg)

			continue

		}

		key, val := line[4:idx], line[idx+2:]

		agi.dbg(" [v] add env: %s => %s", key, val)

		agi.env[key] = val

	}

}

// read and parse response

func (agi *AGI) parseResponse(data string, code int) (Response, error) {

	agi.dbg("[>] parseResponse")

	if len(data) < 4 {

		agi.dbg(" [!] response is invalid: %q", data)

		return nil, ErrAGI.Msg("Received response is invalid: %q", data)

	}

	if code == codeEarly {

		return agi.parseEarlyResponse(data, code)

	}

	if code == codeSucc {

		return agi.parseSuccessResponse(data)

	}

	if code > 500 && code < 600 {

		return agi.parseErrorResponse(data, code)

	}

	return nil, ErrAGI.Msg("Can not recognize the response: %q", data)

}

func (agi *AGI) parseSuccessResponse(data string) (Response, error) {

	agi.dbg("[>] parseSuccessResponse: %q", data)

	resp := &responseSuccess{}

	resp.code = codeSucc

	resp.raw = data

	data = data[4:]

	data = trimLastNL(data)

	data, result := scanResult(data)

	resp.result = result

	if len(data) == 0 {

		return resp, nil

	}

	// parse value

	data, value := parseValue(data)

	resp.value = value

	tokens := strings.Fields(data)

	resp.endpos = parseEndpos(tokens)

	resp.digit = parseDigit(tokens)

	resp.sresults = parseSResults(tokens)

	return resp, nil

}

func parseDigit(tokens []string) string {

	for _, tok := range tokens {

		if len(tok) < 7 || tok[:6] != "digit=" {

			continue

		}

		return tok[6:]

	}

	return ""

}

func parseEndpos(tokens []string) int64 {

	for _, tok := range tokens {

		if len(tok) < 8 || tok[:7] != "endpos=" {

			continue

		}

		if pos, err := strconv.ParseInt(tok[7:], 10, 64); err == nil {

			return pos

		}

		return 0

	}

	return 0

}

func parseValue(data string) (string, string) {

	if data[0] != '(' {

		return data, ""

	}

	if idx := strings.IndexByte(data, ')'); idx > 0 {

		return data[idx+1:], data[1:idx]

	}

	return data, ""

}

func (agi *AGI) parseEarlyResponse(data string, code int) (Response, error) {

	agi.dbg("[>] parseEarlyResponse %d: %q", code, data)

	resp := &response{}

	resp.code = code

	resp.raw = data

	data = data[4:]

	data = trimLastNL(data)

	data, result := scanResult(data)

	resp.result = result

	resp.data = data

	return resp, nil

}

func (agi *AGI) parseErrorResponse(data string, code int) (Response, error) {

	agi.dbg("[>] parseErrorResponse %d: %q", code, data)

	resp := &response{}

	resp.code = code

	resp.raw = data

	if code == codeE520 && data[:4] == "520-" {

		resp.data = scanE520Usage(data)

		return resp, nil

	}

	data = data[4:]

	data = trimLastNL(data)

	data, result := scanResult(data)

	resp.result = result

	resp.data = data

	return resp, nil

}

func trimLastNL(data string) string {

	l := len(data)

	if l > 0 && data[l-1:] == "\n" {

		return data[:l-1]

	}

	return data

}

func scanResult(data string) (string, int) {

	if len(data) < 7 || data[:7] != "result=" {

		return data, 0

	}

	token := strings.SplitN(data, " ", 2)

	resultTok := strings.SplitN(token[0], "=", 2)

	if len(resultTok) > 1 {

		if num, err := strconv.Atoi(resultTok[1]); err == nil {

			return strings.Join(token[1:], " "), num

		}

	}

	return strings.Join(token[1:], " "), 0

}

func scanResultStrFromRaw(data string) string {

	raw := data[4:]

	raw = trimLastNL(raw)

	tokens := strings.Fields(raw)

	if strings.Compare(tokens[0], "result=") <= 0 {

		return ""

	}

	return tokens[0][7:]

}

func scanE520Usage(data string) string {

	token := strings.Split(data, "\n")

	return strings.Join(token[1:len(token)-2], "\n")

}