package cli

import (
	"fmt"
	"strings"

	"gitea.zaclys.com/bvaudour/gob/number"
	"gitea.zaclys.com/bvaudour/gob/option"
	"gitea.zaclys.net/bvaudour/go-calc/calc"
)

type mstate struct {
	needMacro bool
	macro     []string
	cmd       []calc.MacroElement
}

func (s *mstate) reset() {
	s.needMacro = false
	s.macro = s.macro[:0]
	s.cmd = s.cmd[:0]
}

func (s mstate) strMacro() string {
	if len(s.macro) == 0 {
		return "[ ]"
	}

	return fmt.Sprintf("[ %s ]", strings.Join(s.macro, " "))
}

type astate struct {
	needAlt bool
	alt     []calc.MacroElement
}

func (s *astate) reset() {
	s.needAlt = false
	s.alt = s.alt[:0]
}

type Cli struct {
	c      *calc.Calc
	macros map[string]string
	mstate
	astate
}

func New() *Cli {
	c := Cli{
		c:      calc.New(),
		macros: make(map[string]string),
	}
	return &c
}

func (c *Cli) reset() {
	c.mstate.reset()
	c.astate.reset()
	c.c.Reset()
}

func (c *Cli) parse(arg string) option.Result[calc.MacroElement] {
	var me calc.MacroElement
	needExec := !c.needAlt && !c.needMacro

	var exec = func(err option.Option[error]) option.Result[calc.MacroElement] {
		var elt calc.MacroElement
		if e, ok := err.Get(); ok {
			return option.Err[calc.MacroElement](e)
		}
		return option.Ok(elt)
	}

	if cb, ok := otherFunctions[arg]; ok {
		if needExec {
			return exec(cb())
		}
		me = calc.MacroCommand(otherToCalcFunc(cb))
	} else if cb, ok := searchCalcFunction(arg); ok {
		if needExec {
			return exec(cb(c.c))
		}
		me = calc.MacroCommand(cb)
	} else if cb, ok, now := searchCliFunction(arg); ok {
		if needExec || now {
			return exec(cb(c))
		}
		me = calc.MacroCommand(cliToCalcFunc(c, cb))
	} else {
		n, ok := number.Parse(arg).Get()
		if !ok {
			return exec(option.Some(fmt.Errorf("Commande inconnue: %s", arg)))
		} else if needExec {
			c.c.Push(n)
		} else {
			me = calc.MacroNumber(n)
		}
	}

	return option.Ok(me)
}

func (c *Cli) Exec(arg string) {
	result := c.parse(arg)

	if err, ok := result.Err(); ok {
		printError(err)
		c.reset()
		return
	}

	if element, ok := result.Ok(); ok && !element.IsNil() {
		if c.needMacro {
			c.macro = append(c.macro, arg)
			c.cmd = append(c.cmd, element)
		} else if c.needAlt {
			c.alt = append(c.alt, element)
		}
	}

	if c.needAlt && len(c.alt) == 2 {
		err := c.c.If(c.alt[0], c.alt[1])
		c.astate.reset()
		if e, ok := err.Get(); ok {
			printError(e)
			c.reset()
		}
	}
}

func (c *Cli) ExecAll(args string) {
	for _, arg := range strings.Fields(args) {
		c.Exec(arg)
	}
}