package rbxbuilder

import (
	"bytes"
	"encoding/json"
	"fmt"
	"git.itzana.me/itzaname/rbxfile"
	"git.itzana.me/itzaname/rbxfile/xml"
	"os"
	"path/filepath"
	"sort"
	"strings"
)

type PlaceBuilder struct {
	Options *BuildSettings
	root    *rbxfile.Root
	scripts map[string]string
}

func (b *PlaceBuilder) loadScript(path string) error {
	scriptName := strings.TrimSuffix(filepath.Base(path), ".lua")
	parentPath := filepath.Dir(path)
	parentName := filepath.Base(parentPath)
	basePath := strings.TrimSuffix(strings.TrimSuffix(path, parentName+string(os.PathSeparator)+filepath.Base(path)), seperator)
	if basePath == "" {
		basePath = parentPath
	}

	parentInstance := instanceFromScriptPath(b.root, parentPath)
	parentBaseInstance := instanceFromScriptPath(b.root, basePath)
	if parentBaseInstance == nil {
		return fmt.Errorf("base instance doesn't exist: %s", basePath)
	}
	if parentInstance == nil {
		class := "ModuleScript"
		path := parentPath + seperator + parentName + ".lua"
		if override, ok := b.scripts[path]; ok {
			class = override
		}
		script := loadScript(parentName, class, b.Options.Source+path)
		if script != nil {
			if err := parentBaseInstance.AddChild(script); err != nil {
				return err
			}
			parentInstance = script
		} else {
			if err := parentBaseInstance.AddChild(generateFolder(parentName)); err != nil {
				return err
			}
			parentInstance = script
		}
	}

	if scriptName == parentName {
		return nil
	}

	// Load normal scripts
	class := "ModuleScript"
	if override, ok := b.scripts[path]; ok {
		class = override
	}
	script := loadScript(scriptName, class, b.Options.Source+path)
	if script != nil {
		if err := parentInstance.AddChild(script); err != nil {
			return err
		}
	} else {
		return fmt.Errorf("failed to load script: %s", path)
	}

	return nil
}

func (b *PlaceBuilder) scriptTree() ([]string, error) {
	var filelist []string
	err := filepath.Walk(b.Options.Source, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}
		if !info.IsDir() {
			if filepath.Ext(path) == ".lua" {
				filelist = append(filelist, strings.TrimPrefix(path, b.Options.Source))
			}
		}
		return nil
	})

	sort.Slice(filelist, func(i, j int) bool {
		return strings.Count(filelist[i], string(os.PathSeparator)) < strings.Count(filelist[j], string(os.PathSeparator))
	})

	return filelist, err

}

func (b *PlaceBuilder) createScripts() error {
	tree, err := b.scriptTree()
	if err != nil {
		return err
	}

	for i := 0; i < len(tree); i++ {
		if err := b.loadScript(tree[i]); err != nil {
			return err
		}
	}

	return nil
}

func (b *PlaceBuilder) loadManifest() error {
	b.scripts = map[string]string{}
	file, err := os.Open(b.Options.Source + seperator + "manifest.json")
	if err != nil {
		return fmt.Errorf("failed to load manifest file")
	}
	defer file.Close()

	var manifest Manifest
	if err := json.NewDecoder(file).Decode(&manifest); err != nil {
		return fmt.Errorf("failed to load manifest file")
	}

	for i := 0; i < len(manifest.Override); i++ {
		b.scripts[manifest.Override[i].Path] = manifest.Override[i].Class
	}

	buffer := bytes.NewBuffer(manifest.Template)
	root, err := xml.Deserialize(buffer, nil)
	if err != nil {
		return fmt.Errorf("failed to load template from manifest")
	}
	b.root = root

	return nil
}

func (b PlaceBuilder) Build() error {
	if err := b.loadManifest(); err != nil {
		return err
	}

	if err := b.createScripts(); err != nil {
		return err
	}

	if b.Options.Writer != nil {
		return xml.Serialize(b.Options.Writer, nil, b.root)
	}

	file, err := os.OpenFile(b.Options.Output, os.O_CREATE|os.O_WRONLY, 0644)
	if err != nil {
		return fmt.Errorf("failed to open output file")
	}
	defer file.Close()

	return xml.Serialize(file, nil, b.root)
}