package world

import (
	"wh/config"
	"wh/fixed"
	"wh/rng"
)

// Ore identifies a raw material.
type Ore int

const (
	Iron Ore = iota
	Nickel
	Ice
	Platinum
	NumOre
)

func (o Ore) String() string {
	return [...]string{"iron", "nickel", "ice", "platinum"}[o]
}

type Asteroid struct {
	ID    int64
	Orbit Orbit
	Ore   [NumOre]int64 // remaining kilograms of each ore
}

func (a *Asteroid) TotalOre() int64 {
	var t int64
	for _, v := range a.Ore {
		t += v
	}
	return t
}

// Station is the dropoff point, on a circular orbit in the ecliptic plane.
type Station struct {
	Orbit Orbit
}

// Stream labels keep independent generation phases from sharing randomness.
const (
	labelBelt = iota + 1
	labelStation
)

// Generate builds the asteroid field and station from the config seed.
func Generate(cfg config.Config) ([]Asteroid, Station) {
	r := rng.Derive(cfg.Seed, labelBelt)
	asts := make([]Asteroid, cfg.AsteroidCount)
	for i := range asts {
		a := r.FixedRange(cfg.BeltInner, cfg.BeltOuter)
		asts[i] = Asteroid{
			ID: int64(i + 1),
			Orbit: Orbit{
				A:      a,
				Period: PeriodFor(a, cfg.OrbitSpeed),
				M0:     r.FixedRange(0, fixed.TwoPi),
				Node:   r.FixedRange(0, fixed.TwoPi),
				// Bias inclination low (squared uniform).
				Inc: r.Fixed().Mul(r.Fixed()).Mul(cfg.MaxInclination),
			},
		}
		// Each asteroid has a total mass and a random mix of ores.
		total := int64(50_000) + int64(r.Intn(950_000))
		var weights [NumOre]uint64
		var wsum uint64
		for o := range weights {
			weights[o] = r.Intn(100) + 1
			wsum += weights[o]
		}
		// Platinum is rare: only a fifth of asteroids carry much of it.
		if r.Intn(5) != 0 {
			wsum -= weights[Platinum]
			weights[Platinum] = 0
		}
		for o := range weights {
			asts[i].Ore[o] = total * int64(weights[o]) / int64(wsum)
		}
	}
	sr := rng.Derive(cfg.Seed, labelStation)
	a := (cfg.BeltInner + cfg.BeltOuter).DivInt(2)
	st := Station{Orbit: Orbit{
		A:      a,
		Period: PeriodFor(a, cfg.OrbitSpeed),
		M0:     sr.FixedRange(0, fixed.TwoPi),
	}}
	return asts, st
}