package validate

import (
	"fmt"
	"sort"
	"strings"

	"thehouseoficarus/internal/behavior"
	"thehouseoficarus/internal/world"
)

func validateRooms(s Source) []Issue {
	var issues []Issue
	roomIndex := s.World.RoomIndex()
	itemIDs := s.Items.IDSet()
	mobIDs := s.Mobs.AllDefIDs()
	objIDs := s.Objects.IDSet()
	hazardIDs := s.World.HazardIndex()

	for id := range roomIndex {
		room, err := s.World.LoadRoom(id)
		if err != nil {
			issues = append(issues, Issue{
				Level:   "ERROR",
				Type:    "reference",
				Message: fmt.Sprintf("Room %d: failed to load: %v", id, err),
			})
			continue
		}
		if room.Name == "" {
			issues = append(issues, Issue{
				Level:   "WARN",
				Type:    "reference",
				Message: fmt.Sprintf("Room %d: has no name", id),
			})
		}

		for dir, exit := range room.Exits {
			switch dir {
			case world.North, world.South, world.East, world.West, world.Up, world.Down:
			default:
				issues = append(issues, Issue{
					Level:   "ERROR",
					Type:    "reference",
					Message: fmt.Sprintf("Room %d: invalid exit direction %q (only north/south/east/west/up/down supported)", id, dir),
				})
				continue
			}
			if exit.Room <= 0 {
				continue
			}
			if _, ok := roomIndex[exit.Room]; !ok {
				issues = append(issues, Issue{
					Level: "ERROR",
					Type:  "reference",
					Message: fmt.Sprintf("Room %d: exit %q targets nonexistent room %d",
						id, dir, exit.Room),
				})
			}
		}

		for _, rm := range room.Mobs {
			if rm.ID == "" {
				continue
			}
			if _, ok := mobIDs[rm.ID]; !ok {
				issues = append(issues, Issue{
					Level: "ERROR",
					Type:  "reference",
					Message: fmt.Sprintf("Room %d: references nonexistent mob %q",
						id, rm.ID),
				})
			}
			for _, wr := range rm.WanderRooms {
				if _, ok := roomIndex[wr]; !ok {
					issues = append(issues, Issue{
						Level: "ERROR",
						Type:  "reference",
						Message: fmt.Sprintf("Room %d: mob %q wander_rooms references nonexistent room %d",
							id, rm.ID, wr),
					})
				}
			}
		}

		for _, sp := range room.ItemSpawns {
			if sp.ID != "" && !itemIDs[sp.ID] {
				issues = append(issues, Issue{
					Level: "ERROR",
					Type:  "reference",
					Message: fmt.Sprintf("Room %d: spawns nonexistent item %q",
						id, sp.ID),
				})
			}
		}

		for _, robj := range room.Objects {
			if robj.ID != "" && !objIDs[robj.ID] {
				issues = append(issues, Issue{
					Level: "ERROR",
					Type:  "reference",
					Message: fmt.Sprintf("Room %d: references nonexistent object %q",
						id, robj.ID),
				})
			}
			for _, wr := range robj.WanderRooms {
				if _, ok := roomIndex[wr]; !ok {
					issues = append(issues, Issue{
						Level: "ERROR",
						Type:  "reference",
						Message: fmt.Sprintf("Room %d: object %q wander_rooms references nonexistent room %d",
							id, robj.ID, wr),
					})
				}
			}
		}

		if room.Hazard != "" && !hazardIDs[room.Hazard] {
			issues = append(issues, Issue{
				Level: "ERROR",
				Type:  "reference",
				Message: fmt.Sprintf("Room %d: references nonexistent hazard %q",
					id, room.Hazard),
			})
		}
	}

	return issues
}

func validateMobs(s Source) []Issue {
	var issues []Issue
	itemIDs := s.Items.IDSet()
	dropIDs := dropTableIDSet(s.DataDir)
	mobIDs := s.Mobs.AllDefIDs()

	for id := range mobIDs {
		def, err := s.Mobs.LoadDef(id)
		if err != nil {
			issues = append(issues, Issue{
				Level:   "ERROR",
				Type:    "reference",
				Message: fmt.Sprintf("Mob %q: failed to load: %v", id, err),
			})
			continue
		}
		if def.Name == "" {
			issues = append(issues, Issue{
				Level:   "WARN",
				Type:    "reference",
				Message: fmt.Sprintf("Mob %q: has no name", id),
			})
		}

		if !def.Protected && def.HP <= 0 {
			issues = append(issues, Issue{
				Level:   "ERROR",
				Type:    "reference",
				Message: fmt.Sprintf("Mob %q: is not protected but has HP=%d — mobs must have hp > 0 (or set protected: true)", id, def.HP),
			})
		}

		if def.Kind != "" && def.Kind != "combat" && def.Kind != "task" {
			issues = append(issues, Issue{
				Level:   "ERROR",
				Type:    "reference",
				Message: fmt.Sprintf("Mob %q: invalid kind %q (must be \"combat\" or \"task\")", id, def.Kind),
			})
		}

		if def.Drops.Remains != "" && !itemIDs[def.Drops.Remains] {
			issues = append(issues, Issue{
				Level: "ERROR",
				Type:  "reference",
				Message: fmt.Sprintf("Mob %q: drops remains (item %q) does not exist",
					id, def.Drops.Remains),
			})
		}

		for _, d := range def.Drops.Loot {
			if d.ItemID != "" && !itemIDs[d.ItemID] {
				issues = append(issues, Issue{
					Level: "ERROR",
					Type:  "reference",
					Message: fmt.Sprintf("Mob %q: loot item %q does not exist",
						id, d.ItemID),
				})
			}
			if d.Table != "" && !dropIDs[d.Table] {
				issues = append(issues, Issue{
					Level: "ERROR",
					Type:  "reference",
					Message: fmt.Sprintf("Mob %q: loot table %q does not exist",
						id, d.Table),
				})
			}
		}

		if def.StealTable != "" && !dropIDs[def.StealTable] {
			issues = append(issues, Issue{
				Level: "ERROR",
				Type:  "reference",
				Message: fmt.Sprintf("Mob %q: steal_table %q does not exist",
					id, def.StealTable),
			})
		}

		if def.FinishingBlow != "" && !itemIDs[def.FinishingBlow] {
			issues = append(issues, Issue{
				Level: "ERROR",
				Type:  "reference",
				Message: fmt.Sprintf("Mob %q: finishing_blow item %q does not exist",
					id, def.FinishingBlow),
			})
		}
	}

	return issues
}

func validateHazards(s Source) []Issue {
	var issues []Issue
	itemIDs := s.Items.IDSet()
	validTypes := map[string]bool{"stab": true, "slash": true, "crush": true, "ranged": true, "science": true}

	for id := range s.World.HazardIndex() {
		def, err := s.World.LoadHazard(id)
		if err != nil {
			issues = append(issues, Issue{
				Level:   "ERROR",
				Type:    "reference",
				Message: fmt.Sprintf("Hazard %q: failed to load: %v", id, err),
			})
			continue
		}
		if def.AttackType != "" && !validTypes[def.AttackType] {
			issues = append(issues, Issue{
				Level:   "ERROR",
				Type:    "reference",
				Message: fmt.Sprintf("Hazard %q: invalid attack_type %q (must be stab/slash/crush/ranged/science)", id, def.AttackType),
			})
		}
		if def.RequiredItem != "" && !itemIDs[def.RequiredItem] {
			issues = append(issues, Issue{
				Level:   "ERROR",
				Type:    "reference",
				Message: fmt.Sprintf("Hazard %q: required_item %q does not exist", id, def.RequiredItem),
			})
		}
	}

	return issues
}

func validateObjects(s Source) []Issue {
	var issues []Issue
	objIDs := s.Objects.IDSet()
	itemIDs := s.Items.IDSet()
	mobIDs := s.Mobs.AllDefIDs()
	dropIDs := dropTableIDSet(s.DataDir)
	roomIndex := s.World.RoomIndex()

	for id := range objIDs {
		obj, err := s.Objects.Load(id)
		if err != nil {
			issues = append(issues, Issue{
				Level:   "ERROR",
				Type:    "reference",
				Message: fmt.Sprintf("Object %q: failed to load: %v", id, err),
			})
			continue
		}
		if obj.Name == "" {
			issues = append(issues, Issue{
				Level:   "WARN",
				Type:    "reference",
				Message: fmt.Sprintf("Object %q: has no name", id),
			})
		}

		if obj.RemovalItem != "" && !itemIDs[obj.RemovalItem] {
			issues = append(issues, Issue{
				Level: "ERROR",
				Type:  "reference",
				Message: fmt.Sprintf("Object %q: removal_item %q does not exist",
					id, obj.RemovalItem),
			})
		}

		if obj.StealTable != "" && !dropIDs[obj.StealTable] {
			issues = append(issues, Issue{
				Level: "ERROR",
				Type:  "reference",
				Message: fmt.Sprintf("Object %q: steal_table %q does not exist",
					id, obj.StealTable),
			})
		}

		if obj.GuardMob != "" && !mobIDs[obj.GuardMob] {
			issues = append(issues, Issue{
				Level: "ERROR",
				Type:  "reference",
				Message: fmt.Sprintf("Object %q: guard_mob %q does not exist",
					id, obj.GuardMob),
			})
		}

		for _, ui := range obj.UseInteractions {
			if ui.Item != "" && !itemIDs[ui.Item] {
				issues = append(issues, Issue{
					Level: "ERROR",
					Type:  "reference",
					Message: fmt.Sprintf("Object %q: use_interaction item %q does not exist",
						id, ui.Item),
				})
			}
			if ui.Action != nil {
				issues = append(issues, validateNodeAction(fmt.Sprintf("Object %q: use_interaction", id), ui.Action, itemIDs, roomIndex)...)
			}
		}

		if obj.Gather != nil {
			issues = append(issues, validateGather(fmt.Sprintf("Object %q: gather", id), obj.Gather, itemIDs, dropIDs)...)
		}

		if obj.Talk != nil {
			issues = append(issues, validateTalkConfig(fmt.Sprintf("Object %q: talk", id), obj.Talk, itemIDs, roomIndex)...)
		}

		if obj.Use != nil {
			issues = append(issues, validateUseConfig(fmt.Sprintf("Object %q: use", id), obj.Use, itemIDs)...)
		}

		if obj.OnLook != nil {
			issues = append(issues, validateNodeAction(fmt.Sprintf("Object %q: on_look", id), obj.OnLook, itemIDs, roomIndex)...)
		}
	}

	return issues
}

func validateItems(s Source) []Issue {
	var issues []Issue
	itemIDs := s.Items.IDSet()
	dropIDs := dropTableIDSet(s.DataDir)

	for id := range itemIDs {
		def, err := s.Items.Load(id)
		if err != nil {
			issues = append(issues, Issue{
				Level:   "ERROR",
				Type:    "reference",
				Message: fmt.Sprintf("Item %q: failed to load: %v", id, err),
			})
			continue
		}
		if def.Name == "" {
			issues = append(issues, Issue{
				Level:   "WARN",
				Type:    "reference",
				Message: fmt.Sprintf("Item %q: has no name", id),
			})
		}

		if def.SearchTable != "" && !dropIDs[def.SearchTable] {
			issues = append(issues, Issue{
				Level: "ERROR",
				Type:  "reference",
				Message: fmt.Sprintf("Item %q: search_table %q does not exist",
					id, def.SearchTable),
			})
		}

		if def.SearchMiscTable != "" && !dropIDs[def.SearchMiscTable] {
			issues = append(issues, Issue{
				Level: "ERROR",
				Type:  "reference",
				Message: fmt.Sprintf("Item %q: search_misc_table %q does not exist",
					id, def.SearchMiscTable),
			})
		}

		if def.FarmProduct != "" && !itemIDs[def.FarmProduct] {
			issues = append(issues, Issue{
				Level: "ERROR",
				Type:  "reference",
				Message: fmt.Sprintf("Item %q (seed): farm_product %q does not exist",
					id, def.FarmProduct),
			})
		}
	}

	return issues
}

func validateCraftBlocks(s Source) []Issue {
	var issues []Issue
	itemIDs := s.Items.IDSet()
	objIDs := s.Objects.IDSet()

	allItems, err := s.Items.LoadAll()
	if err != nil {
		issues = append(issues, Issue{
			Level:   "ERROR",
			Type:    "reference",
			Message: fmt.Sprintf("Failed to load items: %v", err),
		})
		return issues
	}

	for _, item := range allItems {
		if len(item.Craft) == 0 {
			continue
		}
		for ci := range item.Craft {
			c := &item.Craft[ci]

			for _, e := range c.Consume {
				for _, consumeItem := range e.Items {
					if consumeItem != "" && !itemIDs[consumeItem] {
						issues = append(issues, Issue{
							Level: "ERROR",
							Type:  "reference",
							Message: fmt.Sprintf("Item %q (craft: %s): consumes nonexistent item %q",
								item.ID, c.Type, consumeItem),
						})
					}
				}
			}

			if c.Fail != "" && !itemIDs[c.Fail] {
				issues = append(issues, Issue{
					Level: "ERROR",
					Type:  "reference",
					Message: fmt.Sprintf("Item %q (craft: %s): fail product %q does not exist",
						item.ID, c.Type, c.Fail),
				})
			}

			for _, sid := range c.Station {
				if sid != "" && !objIDs[sid] {
					issues = append(issues, Issue{
						Level: "ERROR",
						Type:  "reference",
						Message: fmt.Sprintf("Item %q (craft: %s): station object %q does not exist",
							item.ID, c.Type, sid),
					})
				}
			}
		}
	}

	return issues
}

func validateDropTables(s Source) []Issue {
	var issues []Issue
	dropIDs := dropTableIDSet(s.DataDir)
	itemIDs := s.Items.IDSet()

	for id := range dropIDs {
		dt, err := behavior.LoadDropTable(s.DataDir, id)
		if err != nil {
			issues = append(issues, Issue{
				Level:   "ERROR",
				Type:    "reference",
				Message: fmt.Sprintf("Drop table %q: failed to load: %v", id, err),
			})
			continue
		}
		for _, d := range dt.Drops {
			if d.ItemID != "" && !itemIDs[d.ItemID] {
				issues = append(issues, Issue{
					Level: "ERROR",
					Type:  "reference",
					Message: fmt.Sprintf("Drop table %q: drops nonexistent item %q",
						id, d.ItemID),
				})
			}
			if d.Table != "" && !dropIDs[d.Table] && d.Table != id {
				issues = append(issues, Issue{
					Level: "ERROR",
					Type:  "reference",
					Message: fmt.Sprintf("Drop table %q: references nonexistent sub-table %q",
						id, d.Table),
				})
			}
		}
	}

	return issues
}

func validateCourses(s Source) []Issue {
	var issues []Issue
	roomIndex := s.World.RoomIndex()

	for _, cv := range s.Courses {
		if cv.StartRoom > 0 {
			if _, ok := roomIndex[cv.StartRoom]; !ok {
				issues = append(issues, Issue{
					Level: "ERROR",
					Type:  "reference",
					Message: fmt.Sprintf("Course %q: start_room %d does not exist",
						cv.ID, cv.StartRoom),
				})
			}
		}
		for _, rid := range cv.ObstacleRooms {
			if _, ok := roomIndex[rid]; !ok {
				issues = append(issues, Issue{
					Level: "ERROR",
					Type:  "reference",
					Message: fmt.Sprintf("Course %q: obstacle room %d does not exist",
						cv.ID, rid),
				})
			}
		}
	}

	return issues
}

func validateRoomWiring(s Source) []Issue {
	var issues []Issue
	roomIndex := s.World.RoomIndex()

	sourceSet := make(map[int]bool)
	for _, src := range s.CheckSources {
		sourceSet[src] = true
	}

	ignoreTo := make(map[int]bool)
	for _, r := range s.IgnoreUnreachable {
		ignoreTo[r] = true
	}

	hasExitTo := make(map[int]bool)
	for id := range roomIndex {
		room, err := s.World.LoadRoom(id)
		if err != nil {
			continue
		}
		for _, exit := range room.Exits {
			if exit.Room > 0 {
				hasExitTo[exit.Room] = true
			}
		}
	}

	var orphans []int
	for id := range roomIndex {
		if ignoreTo[id] {
			continue
		}
		if sourceSet[id] {
			continue
		}
		if !hasExitTo[id] {
			orphans = append(orphans, id)
		}
	}
	if len(orphans) > 0 {
		sort.Ints(orphans)
		var strs []string
		for _, id := range orphans {
			strs = append(strs, fmt.Sprintf("%d", id))
		}
		issues = append(issues, Issue{
			Level: "WARN",
			Type:  "integrity",
			Message: fmt.Sprintf("Orphan rooms (no exit leads to them): %s",
				strings.Join(strs, ", ")),
		})
	}

	return issues
}

func validateTechs(s Source) []Issue {
	var issues []Issue
	seen := make(map[string]bool)
	for _, def := range s.Techs {
		if def.ID == "" {
			issues = append(issues, Issue{
				Level:   "ERROR",
				Type:    "reference",
				Message: "Tech has empty id",
			})
			continue
		}
		if seen[def.ID] {
			issues = append(issues, Issue{
				Level:   "ERROR",
				Type:    "duplicate",
				Message: fmt.Sprintf("Duplicate tech %q", def.ID),
			})
		}
		seen[def.ID] = true

		if def.Name == "" {
			issues = append(issues, Issue{
				Level:   "WARN",
				Type:    "reference",
				Message: fmt.Sprintf("Tech %q: has no name", def.ID),
			})
		}
		if def.Category != "" && !knownTechCategories[def.Category] {
			issues = append(issues, Issue{
				Level:   "WARN",
				Type:    "reference",
				Message: fmt.Sprintf("Tech %q: unknown category %q", def.ID, def.Category),
			})
		}
		if def.DrainRate < 0 {
			issues = append(issues, Issue{
				Level:   "ERROR",
				Type:    "reference",
				Message: fmt.Sprintf("Tech %q: negative drain_rate %.2f", def.ID, def.DrainRate),
			})
		}
	}

	for id := range reservedTechIDs {
		if !s.TechIDs[id] {
			issues = append(issues, Issue{
				Level:   "ERROR",
				Type:    "reference",
				Message: fmt.Sprintf("Reserved tech %q does not exist — required by code (damage protection / retribution)", id),
			})
		}
	}

	return issues
}

func validateGather(prefix string, cfg *behavior.GatherConfig, itemIDs map[string]bool, dropIDs map[string]bool) []Issue {
	var issues []Issue

	if cfg.Bait != "" && !itemIDs[cfg.Bait] {
		issues = append(issues, Issue{
			Level: "ERROR",
			Type:  "reference",
			Message: fmt.Sprintf("%s: bait item %q does not exist",
				prefix, cfg.Bait),
		})
	}

	for _, d := range cfg.Drops {
		if d.ItemID != "" && !itemIDs[d.ItemID] {
			issues = append(issues, Issue{
				Level: "ERROR",
				Type:  "reference",
				Message: fmt.Sprintf("%s: drop item %q does not exist",
					prefix, d.ItemID),
			})
		}
		if d.Table != "" && !dropIDs[d.Table] {
			issues = append(issues, Issue{
				Level: "ERROR",
				Type:  "reference",
				Message: fmt.Sprintf("%s: drop table %q does not exist",
					prefix, d.Table),
			})
		}
	}

	return issues
}

func validateTalkConfig(prefix string, cfg *behavior.TalkConfig, itemIDs map[string]bool, roomIndex map[int]bool) []Issue {
	var issues []Issue
	if cfg == nil {
		return issues
	}
	for nodeID, node := range cfg.Nodes {
		nodePrefix := fmt.Sprintf("%s: node %q", prefix, nodeID)
		if node.Action != nil {
			issues = append(issues, validateNodeAction(nodePrefix, node.Action, itemIDs, roomIndex)...)
		}
		if node.Next != "" {
			if _, ok := cfg.Nodes[node.Next]; !ok {
				issues = append(issues, Issue{
					Level:   "ERROR",
					Type:    "reference",
					Message: fmt.Sprintf("%s: next points to nonexistent node %q", nodePrefix, node.Next),
				})
			}
		}
		for i, opt := range node.Options {
			optPrefix := fmt.Sprintf("%s: option %d", nodePrefix, i+1)
			if opt.Action != nil {
				issues = append(issues, validateNodeAction(optPrefix, opt.Action, itemIDs, roomIndex)...)
			}
		}
	}
	return issues
}

func validateUseConfig(prefix string, cfg *behavior.UseConfig, itemIDs map[string]bool) []Issue {
	var issues []Issue
	if cfg == nil {
		return issues
	}

	for itemID := range cfg.Consume {
		if itemID != "" && !itemIDs[itemID] {
			issues = append(issues, Issue{
				Level: "ERROR",
				Type:  "reference",
				Message: fmt.Sprintf("%s: consumes nonexistent item %q",
					prefix, itemID),
			})
		}
	}

	if cfg.Reward.ItemID != "" && !itemIDs[cfg.Reward.ItemID] {
		issues = append(issues, Issue{
			Level: "ERROR",
			Type:  "reference",
			Message: fmt.Sprintf("%s: reward item %q does not exist",
				prefix, cfg.Reward.ItemID),
		})
	}

	return issues
}

func validateNodeAction(prefix string, na *behavior.NodeAction, itemIDs map[string]bool, roomIndex map[int]bool) []Issue {
	var issues []Issue
	if na == nil {
		return issues
	}

	if na.GiveItem != "" && !itemIDs[na.GiveItem] {
		issues = append(issues, Issue{
			Level: "ERROR",
			Type:  "reference",
			Message: fmt.Sprintf("%s: give_item %q does not exist",
				prefix, na.GiveItem),
		})
	}

	if na.TakeItem != "" && !itemIDs[na.TakeItem] {
		issues = append(issues, Issue{
			Level: "ERROR",
			Type:  "reference",
			Message: fmt.Sprintf("%s: take_item %q does not exist",
				prefix, na.TakeItem),
		})
	}

	if na.Teleport > 0 {
		if _, ok := roomIndex[na.Teleport]; !ok {
			issues = append(issues, Issue{
				Level: "ERROR",
				Type:  "reference",
				Message: fmt.Sprintf("%s: teleport to nonexistent room %d",
					prefix, na.Teleport),
			})
		}
	}

	if na.Shop != nil {
		for _, si := range na.Shop.Items {
			if si.ItemID != "" && !itemIDs[si.ItemID] {
				issues = append(issues, Issue{
					Level: "ERROR",
					Type:  "reference",
					Message: fmt.Sprintf("%s: shop item %q does not exist",
						prefix, si.ItemID),
				})
			}
		}
	}

	return issues
}