package world

import (
	"fmt"
	"os"
	"path/filepath"

	"gopkg.in/yaml.v3"
	"thehouseoficarus/internal/behavior"
)

// HazardDef describes an environmental threat attached to a room (a sandstorm,
// solar radiation, falling rocks, etc.). It is a shared, ID-referenced
// definition loaded from data/hazards/<id>.yaml, so one hazard can be reused
// across a whole area and resolved by name for a future `examine` command.
//
// A hazard rolls an attack against everyone in the room every Speed ticks using
// the SAME combat formulas as a mob: accuracy comes from Attack/AttackBonus, max
// hit from MaxHit, and the player defends with their Defense level + equipment
// bonus selected by AttackType (so existing armour and the Defense skill apply).
// Tech protection (Kinetic Barrier / Projectile Screen / Neural Firewall) keys
// off AttackType automatically.
type HazardDef struct {
	Name         string  `yaml:"name"`
	Description  string  `yaml:"description"`
	AttackType   string  `yaml:"attack_type"` // stab/slash/crush/ranged/science
	Attack       int     `yaml:"attack"`
	AttackBonus  int     `yaml:"attack_bonus"`
	MaxHit       int     `yaml:"max_hit"`
	Speed        float64 `yaml:"speed"` // ticks between hazard rolls
	WarnMessage  string  `yaml:"warn_message"`
	HitMessage   string  `yaml:"hit_message"` // accepts a single %d for damage
	MissMessage  string  `yaml:"miss_message"`
	RequiredItem string  `yaml:"required_item"` // equipped item that negates the hazard
}

// LoadHazard returns the shared hazard definition for id, caching results.
func (w *World) LoadHazard(id string) (*HazardDef, error) {
	w.hazardMu.Lock()
	if w.hazardPathIndex == nil {
		w.hazardPathIndex = behavior.BuildPathIndex(filepath.Join(w.dataDir, "hazards"))
	}
	if def, ok := w.hazardDefs[id]; ok {
		w.hazardMu.Unlock()
		return def, nil
	}
	path, ok := w.hazardPathIndex[id]
	w.hazardMu.Unlock()
	if !ok {
		return nil, fmt.Errorf("read hazard %s: no such hazard", id)
	}

	data, err := os.ReadFile(path)
	if err != nil {
		return nil, fmt.Errorf("read hazard %s: %w", id, err)
	}
	var def HazardDef
	if err := yaml.Unmarshal(data, &def); err != nil {
		return nil, fmt.Errorf("parse hazard %s: %w", id, err)
	}

	w.hazardMu.Lock()
	w.hazardDefs[id] = &def
	w.hazardMu.Unlock()
	return &def, nil
}

// HazardIndex returns the set of known hazard IDs (used by startup validation).
func (w *World) HazardIndex() map[string]bool {
	w.hazardMu.Lock()
	defer w.hazardMu.Unlock()
	if w.hazardPathIndex == nil {
		w.hazardPathIndex = behavior.BuildPathIndex(filepath.Join(w.dataDir, "hazards"))
	}
	ids := make(map[string]bool, len(w.hazardPathIndex))
	for id := range w.hazardPathIndex {
		ids[id] = true
	}
	return ids
}