// Package invoicetxt implements structs ad routines for working with invoice.txt files
package invoicetxt

import "strings"

type Invoice struct {
	ID             int               `json:"id"`       // Invoice id
	Original       string            `json:"original"` // original raw invoice text
	Hours          float64           `json:"hours"`
	Rate           float64           `json:"rate"`
	RetainerHours  float64           `json:"retainerHours,omitempty"`
	RetainerRate   float64           `json:"retainerRate,omitempty"`
	Contexts       []string          `json:"contexts"`
	Projects       []string          `json:"projects"`
	AdditionalTags map[string]string `json:"additionalTags"`
}

// ParseInvoice parses the input test string into an Invoice struct
func ParseInvoice(text string) (*Invoice, error) {
	var err error
	invoice := Invoice{
		AdditionalTags: make(map[string]string),
	}
	invoice.Original = strings.Trim(text, "\t\n\r")
	parts := getParts(invoice.Original)
	var pIdx int
	for pIdx = range parts {
		if partIsSpecial(parts[pIdx]) {
			break
		}
	}

	return &invoice, err
}

func partIsSpecial(pt string) bool {
	if len(pt) == 0 {
		return false
	}
	return pt[0] == '#' || pt[0] == '@'
}

// getParts parses the text from 'text' pu
// Generally it just splits everything on spaces, except if we're in a double-quote
func getParts(text string) []string {
	var ret []string
	var wrk string
	quoteStart := -1
	for i := range text {
		if quoteStart >= 0 {
			if text[i] == '"' {
				quoteStart = -1
				ret = append(ret, wrk)
			} else {
				wrk = wrk + string(text[i])
			}
		} else {
			switch text[i] {
			case '"':
				quoteStart = i
			case ' ':
				if len(wrk) > 0 {
					ret = append(ret, wrk)
				}
				wrk = ""
			default:
				wrk = wrk + string(text[i])
			}
		}
	}
	if len(wrk) > 0 {
		ret = append(ret, wrk)
	}
	return ret
}