package pipeline

// Custom palette projections (*palcus.itp) are generated artifacts: the Toolset
// derives them from the category frameworks plus the blueprints present in the
// module. Crucible reproduces that projection deterministically at build time so
// the module source only carries descriptor-free category skeletons and the
// blueprint files themselves. Extract never writes palcus files back.

import (
	"encoding/json"
	"fmt"
	"os"
	"path/filepath"
	"sort"
	"strings"

	"git.westgate.pw/ShadowsOverWestgate/sow-tools/internal/gff"
	"git.westgate.pw/ShadowsOverWestgate/sow-tools/internal/project"
)

const noStrref = 0xFFFFFFFF

// hiddenPaletteID suppresses a blueprint from the Custom palette (engine
// convention; see docs in sow-module's palette research notes).
const hiddenPaletteID = 255

var paletteFamilyByExtension = map[string]string{
	".utc": "creaturepalcus",
	".utd": "doorpalcus",
	".ute": "encounterpalcus",
	".uti": "itempalcus",
	".utm": "storepalcus",
	".utp": "placeablepalcus",
	".uts": "soundpalcus",
	".utt": "triggerpalcus",
	".utw": "waypointpalcus",
}

type paletteDescriptor struct {
	name     string
	strref   uint32
	resref   string
	creature bool
	cr       float32
	faction  string
}

func (d paletteDescriptor) sortKey() string {
	if d.strref != noStrref || d.name == "" {
		return strings.ToLower(d.resref)
	}
	return strings.ToLower(d.name)
}

// palette resref (e.g. "itempalcus") -> terminal category ID -> descriptors.
type paletteProjection map[string]map[uint8][]paletteDescriptor

func isPaletteProjectionResref(name string) bool {
	return strings.HasSuffix(strings.ToLower(name), "palcus")
}

func collectPaletteDescriptors(p *project.Project) (paletteProjection, error) {
	projection := paletteProjection{}
	factions, err := loadFactionNames(p)
	if err != nil {
		return nil, err
	}

	for _, rel := range p.Inventory.SourceFiles {
		abs := filepath.Join(p.SourceDir(), filepath.FromSlash(rel))
		name, extension, err := splitSourceName(abs)
		if err != nil {
			return nil, err
		}
		family, ok := paletteFamilyByExtension[extension]
		if !ok {
			continue
		}

		raw, err := os.ReadFile(abs)
		if err != nil {
			return nil, fmt.Errorf("read %s: %w", abs, err)
		}
		var document gff.Document
		if err := json.Unmarshal(raw, &document); err != nil {
			return nil, fmt.Errorf("parse gff json %s: %w", abs, err)
		}

		descriptor, paletteID, ok := blueprintDescriptor(document.Root, name, extension, factions)
		if !ok {
			continue
		}
		if projection[family] == nil {
			projection[family] = map[uint8][]paletteDescriptor{}
		}
		projection[family][paletteID] = append(projection[family][paletteID], descriptor)
	}

	for _, byID := range projection {
		for _, descriptors := range byID {
			sort.SliceStable(descriptors, func(i, j int) bool {
				a, b := descriptors[i], descriptors[j]
				if a.sortKey() != b.sortKey() {
					return a.sortKey() < b.sortKey()
				}
				return a.resref < b.resref
			})
		}
	}
	return projection, nil
}

func blueprintDescriptor(root gff.Struct, fileName, extension string, factions []string) (paletteDescriptor, uint8, bool) {
	descriptor := paletteDescriptor{
		strref:   noStrref,
		resref:   strings.ToLower(fileName),
		creature: extension == ".utc",
	}
	paletteID := -1

	for _, field := range root.Fields {
		switch field.Label {
		case "PaletteID":
			if v, ok := field.Value.(gff.ByteValue); ok {
				paletteID = int(v)
			}
		case "TemplateResRef":
			if v, ok := field.Value.(gff.ResRefValue); ok && v != "" {
				descriptor.resref = strings.ToLower(string(v))
			}
		case "LocalizedName", "LocName", "FirstName":
			if v, ok := field.Value.(gff.LocString); ok {
				name, strref := locStringLabel(v)
				if field.Label == "FirstName" {
					descriptor.name = strings.TrimSpace(descriptor.name + " " + name)
					if descriptor.strref == noStrref {
						descriptor.strref = strref
					}
				} else {
					descriptor.name = name
					descriptor.strref = strref
				}
			}
		case "LastName":
			if v, ok := field.Value.(gff.LocString); ok {
				name, _ := locStringLabel(v)
				descriptor.name = strings.TrimSpace(descriptor.name + " " + name)
			}
		case "ChallengeRating":
			if v, ok := field.Value.(gff.FloatValue); ok {
				descriptor.cr = float32(v)
			}
		case "FactionID":
			if v, ok := field.Value.(gff.WordValue); ok && int(v) < len(factions) {
				descriptor.faction = factions[v]
			}
		}
	}

	if paletteID < 0 || paletteID == hiddenPaletteID {
		return paletteDescriptor{}, 0, false
	}
	return descriptor, uint8(paletteID), true
}

func locStringLabel(value gff.LocString) (string, uint32) {
	if value.StringRef != noStrref {
		return "", value.StringRef
	}
	for _, entry := range value.Entries {
		if entry.Value != "" {
			return entry.Value, noStrref
		}
	}
	return "", noStrref
}

func loadFactionNames(p *project.Project) ([]string, error) {
	for _, rel := range p.Inventory.SourceFiles {
		if !strings.HasSuffix(strings.ToLower(rel), "repute.fac.json") {
			continue
		}
		abs := filepath.Join(p.SourceDir(), filepath.FromSlash(rel))
		raw, err := os.ReadFile(abs)
		if err != nil {
			return nil, fmt.Errorf("read %s: %w", abs, err)
		}
		var document gff.Document
		if err := json.Unmarshal(raw, &document); err != nil {
			return nil, fmt.Errorf("parse gff json %s: %w", abs, err)
		}
		var names []string
		for _, field := range document.Root.Fields {
			if field.Label != "FactionList" {
				continue
			}
			list, ok := field.Value.(gff.ListValue)
			if !ok {
				continue
			}
			for _, faction := range list {
				name := ""
				for _, f := range faction.Fields {
					if f.Label == "FactionName" {
						if v, ok := f.Value.(gff.StringValue); ok {
							name = string(v)
						}
					}
				}
				names = append(names, name)
			}
		}
		return names, nil
	}
	return nil, nil
}

// projectPaletteDocument strips every blueprint descriptor from the palette
// tree and re-inserts the descriptors derived from module source. Category
// structure (branches, terminal IDs, labels) passes through untouched.
func projectPaletteDocument(document *gff.Document, byID map[uint8][]paletteDescriptor) {
	for i, field := range document.Root.Fields {
		if field.Label != "MAIN" {
			continue
		}
		if list, ok := field.Value.(gff.ListValue); ok {
			document.Root.Fields[i] = gff.NewField("MAIN", projectPaletteNodes(list, byID))
		}
	}
}

func projectPaletteNodes(nodes gff.ListValue, byID map[uint8][]paletteDescriptor) gff.ListValue {
	out := make(gff.ListValue, 0, len(nodes))
	for _, node := range nodes {
		if structHasField(node, "RESREF") {
			continue // blueprint descriptor — regenerated below
		}

		terminalID := -1
		fields := make([]gff.Field, 0, len(node.Fields))
		for _, field := range node.Fields {
			if field.Label == "LIST" {
				continue // rebuilt for terminals, recursed for branches
			}
			if field.Label == "ID" {
				if v, ok := field.Value.(gff.ByteValue); ok {
					terminalID = int(v)
				}
			}
			fields = append(fields, field)
		}

		switch {
		case terminalID >= 0:
			if descriptors := byID[uint8(terminalID)]; len(descriptors) > 0 {
				fields = append(fields, gff.NewField("LIST", descriptorList(descriptors)))
			}
		default:
			for _, field := range node.Fields {
				if field.Label == "LIST" {
					if list, ok := field.Value.(gff.ListValue); ok {
						fields = append(fields, gff.NewField("LIST", projectPaletteNodes(list, byID)))
					}
				}
			}
		}
		out = append(out, gff.Struct{Type: node.Type, Fields: fields})
	}
	return out
}

func descriptorList(descriptors []paletteDescriptor) gff.ListValue {
	list := make(gff.ListValue, 0, len(descriptors))
	for _, d := range descriptors {
		fields := make([]gff.Field, 0, 4)
		if d.strref != noStrref {
			fields = append(fields, gff.NewField("STRREF", gff.DWordValue(d.strref)))
		} else {
			fields = append(fields, gff.NewField("NAME", gff.StringValue(d.name)))
		}
		fields = append(fields, gff.NewField("RESREF", gff.ResRefValue(d.resref)))
		if d.creature {
			fields = append(fields, gff.NewField("CR", gff.FloatValue(d.cr)))
			fields = append(fields, gff.NewField("FACTION", gff.StringValue(d.faction)))
		}
		list = append(list, gff.Struct{Fields: fields})
	}
	return list
}

func structHasField(s gff.Struct, label string) bool {
	for _, field := range s.Fields {
		if field.Label == label {
			return true
		}
	}
	return false
}