package game

import (
	"encoding/json"
	"slices"
	"strings"

	"github.com/google/uuid"
	e "github.com/iliadenisov/galaxy/internal/error"
)

type Game struct {
	ID         uuid.UUID   `json:"id"`
	Age        uint        `json:"turn"` // Game's turn number
	Map        Map         `json:"map"`
	Race       []Race      `json:"races"`
	ShipGroups []ShipGroup `json:"shipGroup,omitempty"`
	Fleets     []Fleet     `json:"fleet,omitempty"`
}

func (g Game) Votes(raceID uuid.UUID) float64 {
	// XXX: calculate [Race]Population once when loading Game from Storage?
	var pop float64
	for i := range g.Map.Planet {
		if g.Map.Planet[i].Owner == raceID {
			pop += g.Map.Planet[i].Population
		}
	}
	return pop / 1000.
}

func (g Game) raceIndex(name string) (int, error) {
	i := slices.IndexFunc(g.Race, func(r Race) bool { return r.Name == name })
	if i < 0 {
		return i, e.NewRaceUnknownError(name)
	}
	return i, nil
}

func (g Game) UpdateRelation(race, opponent string, rel Relation) error {
	ri, err := g.raceIndex(race)
	if err != nil {
		return err
	}
	var other int
	if race == opponent {
		other = ri
	} else if other, err = g.raceIndex(opponent); err != nil {
		return err
	}
	if err != nil {
		return err
	}
	return g.updateRelationInternal(ri, other, rel)
}

func (g Game) updateRelationInternal(ri, other int, rel Relation) error {
	for o := range g.Race[ri].Relations {
		switch {
		case ri == other:
			g.Race[ri].Relations[o].Relation = rel
		case g.Race[ri].Relations[o].RaceID == g.Race[other].ID:
			g.Race[ri].Relations[o].Relation = rel
			return nil
		}
	}
	if ri != other {
		return e.NewGameStateError("UpdateRelation: opponent not found")
	}
	return nil
}

func (g Game) Relation(hostRace, opponentRace string) (RaceRelation, error) {
	ri, err := g.raceIndex(hostRace)
	if err != nil {
		return RaceRelation{}, err
	}
	other, err := g.raceIndex(opponentRace)
	if err != nil {
		return RaceRelation{}, err
	}
	return g.relationInternal(ri, other)
}

func (g Game) relationInternal(ri, other int) (RaceRelation, error) {
	rel := slices.IndexFunc(g.Race[ri].Relations, func(r RaceRelation) bool { return r.RaceID == g.Race[other].ID })
	if rel < 0 {
		return RaceRelation{}, e.NewGameStateError("Relation: opponent not found")
	}
	return g.Race[ri].Relations[rel], nil
}

// -----------------------------------------------------------------------------

// validateTypeName always return v without leading and trailing spaces
func validateTypeName(v string) (string, bool) {
	s := strings.TrimSpace(v)
	if len(s) > 0 {
		return s, true
	}
	// TODO: special symbols
	return s, false
}

func (g Game) MarshalBinary() (data []byte, err error) {
	return json.Marshal(&g)
}

func (g *Game) UnmarshalBinary(data []byte) error {
	return json.Unmarshal(data, g)
}