#!/usr/bin/env awk -f

BEGIN {
	version = "0.1"

	help[""] = "Commands:\n" \
		"  help [cmd]   prints cmd help or this help text\n"

	help["help"] = "help [cmd]\n" \
		"  Prints cmd help or general help text.\n" \
		"  Example: help help\n"

	lnum = cnum = 0
	if (str) {
		lnum = 1
		line = ARGV[1]
		if (err = parse(v, "", line)) print "parse err: " err
		for (k in v) print k " " v[k]
		print "---"
		print format(v, "", 1)
		exit ERROR != 0
	} else file = ARGV[1]
	delete ARGV[1]
	if (file) parse(v)
	if (!notty) printf "%s\njp> ", "jp version " version ". Type \"help\" for help."
}
{
	ERROR = ""
	if ($1 == "help") {
		printf "%s", help[$2]
	} else if ($1 == "format") {
		if ($2 == "\"\"") $2 = ""
		print format(v, key(v, $2), !raw)
	} else if ($1 == "key") {
		print key(v, $2)
	} else if ($1 == "filter") {
		filter(v, "", $2)
	} else if ($1 == "dump") {
		if ($2 ~ /^\|/) {
			cmd = substr($0, 1+index($0, "|"))
			for (k in v) print k " " v[k] | cmd
			close(cmd)
		} else for (k in v) print k " " v[k]
	} else if ($1 == "parse_string") {
		delete v
		sub(/^[[:space:]]+/, "")
		$0 = substr($0, length($1)+2)
		parse("", v, "", $0)
	} else if ($1 == "parse") {
		delete v
		parse($2, v)
	} else if (NF) {
		error("invalid command: " $1)
	}
	if (ERROR) print ERROR > "/dev/stderr"
	if (!notty) printf "%sjp> ", s
}
END { exit ERROR != "" }

function error(s, n) { ERROR = s; print "#error: " s >"/dev/stderr"; return n }

function debug(s) { print s > "/dev/stderr" }

function scan(  c) {
	while (c = substr(line, 1, 1)) {
		if (c == "\n") { lnum++; cnum = 0 }
		else if (c ~ /[ \t]/) cnum++
		else break
		line = substr(line, 2)
	}
	if (file) {
		while (line == "") {
			if ((getline line < file) <= 0) return
			lnum++; cnum = 0
			if (match(line, /^[ \t]+/)) {
				cnum += RLENGTH
				line = substr(line, RLENGTH+1)
			}
		}
	}
	if (match(line, /^(null|true|false|[][}{,:])/)) {
		tok = substr(line, 1, 1)
	} else if (match(line, /^[.0-9Ee+-]+/)) {
		tok = "d" substr(line, 1, RLENGTH)
	} else if (match(line, /^"(\\.|[^\\"])*"/)) {
		tok = "s" substr(line, 2, RLENGTH-2)
	} else {
		tok = "b" substr(line, 1, 1)
	}
	cnum += RLENGTH
	line = substr(line, RLENGTH+1)
}

# parse gets the next object from source and return an error if any.
function parse(values, key, id, ids, i, k, err) {
	scan()
	if (tok == "[") {
		for (i = 0; tok != "]"; i++) {
			if (i > 0 && tok != ",") return error("not a ',': ", tok)
			if (err = parse(values, key SUBSEP i)) {
				if (tok == "]" && i == 0) continue
				return err
			}
			scan()
		}
		values[key] = "a" i
	} else if (tok == "{") {
		for (i = 0; tok != "}"; i++) {
			if (i > 0 && tok != ",") return "i: " i ", not a ','"
			scan()
			if (i == 0 && tok == "}") break
			if (tok !~ /^s/) return num ":" cnum ": not a string: " tok
			k = substr(tok, 2)
			ids = ids (i ? SUBSEP : "") substr(tok, 2)
			scan()
			if (tok != ":") return file ":" lnum ":" cnum -length(tok) ": not a ':'"
			if (err = parse(values, key SUBSEP i)) return err
			scan()
		}
		values[key] = "o" ids
	} else if (tok ~ /^[ntfsd]/) {
		values[key] = tok
    } else return "unexpected tok: " tok
}

function format(values, key, indent, id,    c, i, s, v, pre, post, sp) {
	if (! (key in values)) return
	if (indent) {
		pre = space(indent * 2)
		post = "\n"
		sp = " "
	}
	if (id) id = "\"" id "\":" sp
	v = values[key]
	c = substr(v, 1, 1)
	if (c == "n") return id "null"
	if (c == "t") return id "true"
	if (c == "f") return id "false"
	if (c == "d") return id substr(v, 2)
	if (c == "s") return id "\"" substr(v, 2) "\""
	if (c == "a") {
		s = "[" post
		for (i = 0; ((key, i) in values); i++) {
			if (i) s = s "," post
			s = s pre format(values, key SUBSEP i, indent ? indent+1 : 0)
		}
		if (substr(s, length(s)-2, 1) == "[") return id substr(s, 1, length(s)-1) "]"
		return id s post substr(pre, 3) "]"
	}
	if (c == "o") {
		s = "{" post
		v = substr(v, 2)
		for (i = 0; ((key, i) in values); i++) {
			if (i) s = s "," post
			v = tail(v, SUBSEP)
			s = s pre "\"" HEAD "\":" sp format(values, key SUBSEP i, indent ? indent+1 : 0)
		}
		if (substr(s, length(s)-2, 1) == "{") return id substr(s, 1, length(s)-1) "}"
		return id s post substr(pre, 3) "}"
	}
}

function space(n,  i, s) {
	for (i = 0; i < n; i++) s = s " "
	return s
}

function tail(str, sep,  i) {
	if (i = index(str, sep)) {
		HEAD = substr(str, 1, i-1)
		return substr(str, i+1)
	} else HEAD = str
}

function lindex(list, item, i, k) {
	for (i = 0; list; i++) {
		list = tail(list, SUBSEP)
		if (HEAD == item) return i
	}
	return -1
}

# TODO: remove recursivity
# TODO: handle spaces
function key(values, pattern, k1, result, i, k, s, w) {
	if (! (k1 in values)) return
	gsub(/[.]/, SUBSEP, pattern)
	pattern = tail(pattern, SUBSEP)
	k = HEAD
	if (k ~ /^[0-9]+$/) {
		result = result SUBSEP k
	} else {
		s = substr(values[k1], 2)
		if ((i = lindex(s, k)) >= 0) result = result SUBSEP i
	}
	if (pattern) return key(values, pattern, k1 SUBSEP i, result)
	return result
}

function filter(values, key, sk,   i, k, n, v) {
	v = values[key]
	if (v ~ /^o/) {
		v = substr(v, 2)
		for (i = 0; ((key, i) in values); i++) {
			v = tail(v, SUBSEP)
			k = HEAD
			sk = sk ? sk "." k : k
			print sk
			filter(values, key SUBSEP i, sk)
		} while (v)
		return
	}
	if (v ~ /^a/) {
		for (i = 0; ((key, i) in values); i++) {
			sk = sk ? sk "." i : i
			print sk
			filter(values, key SUBSEP i, sk)
		}
	}
}