package main

import (
	"os"
	"bufio"
	"main/walk"
)

type Program []Command

type ProgramState struct {
	path, value, xreg []walk.Atom
	in walk.JSONIn
	out walk.JSONOut
	program []Command
}

func main() {
	quiet := false
	var input string
	hasInput := false
	
	for i := 1; i < len(os.Args); i += 1 {
		switch os.Args[i] {
			case "-n":
				quiet = true
				continue
		}
		if i < len(os.Args) - 1 {
			panic("Unexpected arguments after program")
		}
		input = os.Args[i]
		hasInput = true
	}
	if !hasInput {
		panic("Missing program")
	}

	tokens := Lex(input)
	program := Parse(tokens)

	stdin := bufio.NewReader(os.Stdin)

	state := ProgramState {
		in: walk.NewJSONIn(stdin),
		out: walk.NewJSONOut(),
		program: program,
	}

	for {
		walkItem, err := state.in.Read()
		if err != nil {
			break
		}
		state.value = walkItem.Value
		state.path = walkItem.Path
		for _, cmd := range state.program {
			cmd.exec(&state)
		}
		if !quiet {
			pathValues, err := walk.Compound(state.path)
			if err != nil {
				panic("Tried to convert invalid atoms to values")
			}
			path := walk.PathFromWalkValues(pathValues)
			state.out.Print(path, state.value)
		}
	}

	state.in.AssertDone()
	state.out.AssertDone()
}