// Copyright 2024 Matthew Rich <matthewrich.conf@gmail.com>. All rights reserved.

package folio

import (
	"encoding/json"
	"fmt"
	"gopkg.in/yaml.v3"
	"io"
	"io/fs"
_	"os"
	"log/slog"
	"github.com/sters/yaml-diff/yamldiff"
	"strings"
	"decl/internal/codec"
_	"decl/internal/types"
	"decl/internal/mapper"
	"decl/internal/data"
	"decl/internal/schema"
	"context"
	"path/filepath"
)

type DocumentType struct {
	Schema URI `json:"schema,omitempty" yaml:"schema,omitempty"`
	URI URI `json:"source,omitempty" yaml:"source,omitempty"`
	Format codec.Format `json:"format,omitempty" yaml:"format,omitempty"`
	Requires Dependencies `json:"requires,omitempty" yaml:"requires,omitempty"`
	Imports []URI `json:"imports,omitempty" yaml:"imports,omitempty"`
	Errors   []string `json:"error,omitempty" yaml:"error,omitempty"`
}

type Document struct {
	Schema URI `json:"schema,omitempty" yaml:"schema,omitempty"`
	URI URI `json:"source,omitempty" yaml:"source,omitempty"`
	Format codec.Format `json:"format,omitempty" yaml:"format,omitempty"`
	Requires Dependencies `json:"requires,omitempty" yaml:"requires,omitempty"`
	Imports []URI `json:"imports,omitempty" yaml:"imports,omitempty"`
	Errors   []string `json:"error,omitempty" yaml:"error,omitempty"`
	uris mapper.Store[string, data.Declaration]
	ResourceDeclarations []*Declaration `json:"resources,omitempty" yaml:"resources,omitempty"`
	configNames mapper.Store[string, data.Block] `json:"-" yaml:"-"`
	Configurations []*Block `json:"configurations,omitempty" yaml:"configurations,omitempty"`
	config data.Document
	Registry *Registry `json:"-" yaml:"-"`
	failedResources int `json:"-" yaml:"-"`
	importPaths *SearchPath `json:"-" yaml:"-"`
}

func NewDocument(r *Registry) *Document {
	if r == nil {
		r = DocumentRegistry
	}

	var configImportPath ConfigKey = "system.importpath"

	return &Document{
		Registry: r,
		Format: codec.FormatYaml,
		uris: mapper.New[string, data.Declaration](),
		configNames: mapper.New[string, data.Block](),
		importPaths: NewSearchPath(configImportPath.GetStringSlice()),
	 }
}

func (d *Document) GetURI() string {
	return string(d.URI)
}

func (d *Document) SetURI(uri string) {
	d.URI = URI(uri)
	d.AddProjectPath()
}

func (d *Document) AddProjectPath() {
	exists := d.URI.Exists()
	if exists {
		if u := d.URI.Parse().(*ParsedURI); u != nil {
			projectPath := filepath.Dir(filepath.Join(u.Hostname(), u.Path))
			if err := d.importPaths.AddPath(projectPath); err != nil {
				panic(err)
			}
		}
	}
}

func (d *Document) Types() data.TypesRegistry[data.Resource] {
	return d.Registry.ResourceTypes
}

func (d *Document) ConfigFilter(filter data.BlockSelector) []data.Block {
	configurations := make([]data.Block, 0, len(d.Configurations))
	for i := range d.Configurations {
		filterConfiguration := d.Configurations[i]
		if filter == nil || filter(filterConfiguration) {
			configurations = append(configurations, d.Configurations[i])
		}
	}
	return configurations
}

func (d *Document) Filter(filter data.DeclarationSelector) []data.Declaration {
	resources := make([]data.Declaration, 0, len(d.ResourceDeclarations))
	for i := range d.ResourceDeclarations {
		filterResource := d.ResourceDeclarations[i]
		if filter == nil || filter(filterResource) {
			resources = append(resources, d.ResourceDeclarations[i])
		}
	}
	return resources
}

func (d *Document) Has(key string) bool {
	return d.uris.Has(key)
}

func (d *Document) Get(key string) (any, bool) {
	return d.uris.Get(key)
}

func (d *Document) Set(key string, value any) {
	d.uris.Set(key, value.(data.Declaration))
}

func (d *Document) Delete(key string) {
	d.uris.Delete(key)
}

func (d *Document) GetResource(uri string) *Declaration {
	if decl, ok := d.uris[uri]; ok {
		return decl.(*Declaration)
	}
	return nil
}

func (d *Document) Failures() int {
	return d.failedResources
}

func (d *Document) Clone() data.Document {
	clone := NewDocument(d.Registry)
	clone.config = d.config

	clone.Configurations = make([]*Block, len(d.Configurations))
	for i, res := range d.Configurations {
		clone.Configurations[i] = res.Clone().(*Block)
	}

	clone.ResourceDeclarations = make([]*Declaration, len(d.ResourceDeclarations))
	for i, res := range d.ResourceDeclarations {
		clone.ResourceDeclarations[i] = res.Clone().(*Declaration)
		clone.ResourceDeclarations[i].SetDocument(clone)
		clone.ResourceDeclarations[i].SetConfig(d.config)
	}
	clone.Requires = d.Requires
	return clone
}

func (d *Document) ImportedDocuments() (documents []data.Document) {
	documents = make([]data.Document, 0, len(d.Imports))
	for _, uri := range d.Imports {
		if doc, ok := DocumentRegistry.GetDocument(uri); ok {
			documents = append(documents, doc)
		}
	}
	return
}

func (d *Document) loadImports() (err error) {
	for _, uri := range d.Imports {
		if ! DocumentRegistry.HasDocument(uri) {
			var load URI = uri
			if ! load.Exists() {
				foundURI := d.importPaths.FindURI(load)
				if foundURI != "" {
					load = foundURI
				}
			}
			slog.Info("Document.loadImports()", "load", load, "uri", uri, "importpaths", d.importPaths, "doc", d.URI)
			if _, err = DocumentRegistry.Load(load); err != nil {
				return
			}
		}
	}
	return
}

func (d *Document) assignResourcesDocument() {
	slog.Info("Document.assignResourcesDocument()", "declarations", d.ResourceDeclarations, "len", len(d.ResourceDeclarations))
	for i := range d.ResourceDeclarations {
		if d.ResourceDeclarations[i] == nil {
			d.ResourceDeclarations[i] = NewDeclaration()
		}
		slog.Info("Document.assignResourcesDocument()", "declaration", d.ResourceDeclarations[i])
		d.ResourceDeclarations[i].SetDocument(d)
		slog.Info("Document.assignResourcesDocument()", "declaration", d.ResourceDeclarations[i])
		d.MapResourceURI(d.ResourceDeclarations[i].Attributes.URI(), d.ResourceDeclarations[i])
		d.Registry.DeclarationMap[d.ResourceDeclarations[i]] = d
	}
}

func (d *Document) assignConfigurationsDocument() {
	slog.Info("Document.assignConfigurationsDocument()", "configurations", d.Configurations, "len", len(d.Configurations))
	for i := range d.Configurations {
		if d.Configurations[i] == nil {
			d.Configurations[i] = NewBlock()
		}
		slog.Info("Document.assignConfigurationsDocument()", "configuration", d.Configurations[i])
		//d.Configurations[i].SetDocument(d)
		slog.Info("Document.assignConfigurationsDocument()", "configuration", d.Configurations[i])
		//d.MapConfigurationURI(d.Configurations[i].URI(), d.Configurations[i])
		d.configNames[d.Configurations[i].Name] = d.Configurations[i]
		d.Registry.ConfigurationMap[d.Configurations[i]] = d
		d.Registry.ConfigNameMap[d.Configurations[i].Name] = d.Configurations[i]
	}
}

func (d *Document) LoadString(docData string, f codec.Format) (err error) {
	err = f.StringDecoder(docData).Decode(d)
	return
}

func (d *Document) Load(docData []byte, f codec.Format) (err error) {
	err = f.StringDecoder(string(docData)).Decode(d)
	return
}

func (d *Document) LoadReader(r io.ReadCloser, f codec.Format) (err error) {
	err = f.Decoder(r).Decode(d)
	return
}

func (d *Document) GetSchemaFiles() (schemaFs fs.FS) {
	var ok bool
	if schemaFs, ok = d.Registry.Schemas.Get(d.Schema); ok {
		return
	}
	schemaFs, _  = d.Registry.Schemas.Get(d.Registry.DefaultSchema)
	slog.Info("Document.GetSchemaFiles()", "schemaFs", schemaFs)
	return
}

func (d *Document) Validate() error {
	jsonDocument, jsonErr := d.JSON()
	slog.Info("Document.Validate() json", "err", jsonErr)
	if jsonErr == nil {
		s := schema.New("document", d.GetSchemaFiles())
		err := s.Validate(string(jsonDocument))
		slog.Info("Document.Validate()", "error", err)
		if err != nil {
			return err
		}
/*
		for i := range d.ResourceDeclarations {
			if e := d.ResourceDeclarations[i].Resource().Validate(); e != nil {
				return fmt.Errorf("failed to validate resource %s; %w", d.ResourceDeclarations[i].Resource().URI(), e)
			}
		}
*/
	}
	return nil
}

func (d *Document) SetConfig(config data.Document) {
	d.config = config
}

func (d *Document) ConfigDoc() data.Document {
	return d.config
}

func (d *Document) Resources() []*Declaration {
	return d.ResourceDeclarations
}

func (d *Document) Declarations() (declarations []data.Declaration) {
	for _, v := range d.ResourceDeclarations {
		declarations = append(declarations, data.Declaration(v))
	}
	return
}

func (d *Document) Len() int {
	return len(d.ResourceDeclarations)
}

func (d *Document) CheckConstraints() bool {
	return d.Requires.Check()
}

func (d *Document) ResolveIds(ctx context.Context) {
	for i := range d.ResourceDeclarations {
		d.ResourceDeclarations[i].ResolveId(ctx)
	}
}

func (d *Document) Apply(state string) error {
	if d == nil {
		panic("Undefined Document")
	}
	slog.Info("Document.Apply()", "declarations", d, "override", state)
	var start, i int = 0, 0
	if state == "delete" {
		start = len(d.ResourceDeclarations) - 1
	}
	if len(d.ResourceDeclarations) > 0 {
		for {
			idx := i - start
			if idx < 0 { idx = - idx }

			d.ResourceDeclarations[idx].SetConfig(d.config)

			slog.Info("Document.Apply() applying resource", "index", idx, "uri", d.ResourceDeclarations[idx].Resource().URI(), "state", state, "resource", d.ResourceDeclarations[idx].Resource())

			if d.ResourceDeclarations[idx].Requires.Check() {
				if e := d.ResourceDeclarations[idx].Apply(state); e != nil {
					d.ResourceDeclarations[idx].Error = e.Error()
					slog.Info("Document.Apply() ERROR", "index", idx, "uri", d.ResourceDeclarations[idx].Resource().URI(), "error", e.Error())
					switch d.ResourceDeclarations[idx].OnError.GetStrategy() {
					case OnErrorStop:
						return e
					case OnErrorFail:
						d.failedResources++
					}
				}
			} else {
				d.ResourceDeclarations[idx].Error = fmt.Sprintf("Constraint failure: %s", d.ResourceDeclarations[idx].Requires)
			}
			if i >= len(d.ResourceDeclarations) - 1 {
				break
			}
			i++
		}
	}
	return nil
}

func (d *Document) Generate(w io.Writer) (err error) {
	err = d.Format.Validate()
	if err == nil {
		if e := d.Format.Encoder(w); e != nil {
			defer func() {
				if closeErr := e.Close(); closeErr != nil && err == nil {
					err = closeErr
				}
			}()
			err = e.Encode(d);
		}
	}
	return
}

/*
func (d *Document) MapConfigurationURI(uri string, block data.Block) {
	d.configUris[uri] = block
}
*/

func (d *Document) MapResourceURI(uri string, declaration data.Declaration) {
	d.uris[uri] = declaration
}

func (d *Document) UnMapResourceURI(uri string) {
	d.uris.Delete(uri)
}

func (d *Document) AddDeclaration(declaration data.Declaration) {
	uri := declaration.URI()
	decl := declaration.(*Declaration)
	if decl.Requires.Check() {

		d.ResourceDeclarations = append(d.ResourceDeclarations, decl)

		d.MapResourceURI(uri, declaration)
		decl.SetDocument(d)
		d.Registry.DeclarationMap[decl] = d
	}
}

func (d *Document) AddResourceDeclaration(resourceType string, resourceDeclaration data.Resource) {
	slog.Info("Document.AddResourceDeclaration()", "type", resourceType, "resource", resourceDeclaration)
	decl := NewDeclarationFromDocument(d)
	decl.Type = TypeName(resourceType)
	if decl.Requires.Check() {
		decl.Attributes = resourceDeclaration
		d.ResourceDeclarations = append(d.ResourceDeclarations, decl)
		d.MapResourceURI(decl.Attributes.URI(), decl)
		decl.SetDocument(d)
		d.Registry.DeclarationMap[decl] = d
	}
}

func (d *Document) NewResource(uri string) (newResource data.Resource, err error) {

	decl := NewDeclarationFromDocument(d)

	if err = decl.NewResource(&uri); err != nil {
		return
	}

	if decl.Attributes == nil {
		err = fmt.Errorf("%w: %s", ErrUnknownResourceType, uri)
		return
	}

	decl.Type = TypeName(decl.Attributes.Type())

	if decl.Requires.Check() {
		slog.Info("Document.NewResource()", "type", decl.Type, "declaration", decl)

		d.ResourceDeclarations = append(d.ResourceDeclarations, decl)
		d.MapResourceURI(decl.Attributes.URI(), decl)
		decl.SetDocument(d)
		d.Registry.DeclarationMap[decl] = d
		newResource = decl.Attributes
	} else {
		err = fmt.Errorf("%w: %s", ErrConstraintFailure, uri)
	}
	return
}

func (d *Document) NewResourceFromURI(uri URI) (newResource data.Resource, err error) {
	return d.NewResourceFromParsedURI(uri.Parse())
}

func (d *Document) NewResourceFromParsedURI(uri data.URIParser) (newResource data.Resource, err error) {
	if uri == nil {
		return nil, fmt.Errorf("%w: %s", ErrUnknownResourceType, uri)
	}

	decl := NewDeclarationFromDocument(d)
	if err = decl.NewResourceFromParsedURI(uri); err != nil {
		return
	}

	if decl.Attributes == nil {
		err = fmt.Errorf("%w: %s", ErrUnknownResourceType, uri)
		return
	}

	decl.Type = TypeName(decl.Attributes.Type())

	if decl.Requires.Check() {
		d.ResourceDeclarations = append(d.ResourceDeclarations, decl)

		d.MapResourceURI(decl.Attributes.URI(), decl)
		decl.SetDocument(d)
		d.Registry.DeclarationMap[decl] = d
		newResource = decl.Attributes
	} else {
		err = fmt.Errorf("%w: %s", ErrConstraintFailure, uri)
	}
	return
}

func (d *Document) AddResource(uri string) error {
	decl := NewDeclarationFromDocument(d)
	if e := decl.SetURI(uri); e != nil {
		return e
	}

	if decl.Requires.Check() {
		d.ResourceDeclarations = append(d.ResourceDeclarations, decl)
		d.MapResourceURI(decl.Attributes.URI(), decl)
		decl.SetDocument(d)
		d.Registry.DeclarationMap[decl] = d
	} else {
		return fmt.Errorf("%w: %s", ErrConstraintFailure, uri)
	}
	return nil
}

func (d *Document) JSON() ([]byte, error) {
	var buf strings.Builder
	err := codec.FormatJson.Serialize(d, &buf)
	return []byte(buf.String()), err
}

func (d *Document) YAML() ([]byte, error) {
	var buf strings.Builder
	err := codec.FormatYaml.Serialize(d, &buf)
	return []byte(buf.String()), err
}

func (d *Document) PB() ([]byte, error) {
	var buf strings.Builder
	err := codec.FormatProtoBuf.Serialize(d, &buf)
	return []byte(buf.String()), err
}

func (d *Document) AddConfigurationBlock(configurationName string, configurationType TypeName, configuration data.Configuration) {
	cfg := NewBlock()
	cfg.Name = configurationName
	cfg.Type = configurationType
	cfg.Values = configuration
	d.configNames[cfg.Name] = cfg
	d.Configurations = append(d.Configurations, cfg)
}

func (d *Document) AddConfiguration(uri string) error {
	cfg := NewBlock()
	if e := cfg.SetURI(uri); e != nil {
		return e
	}
	if cfg.Name == "" {
		return data.ErrConfigUndefinedName
	}
	d.configNames[cfg.Name] = cfg
	d.Configurations = append(d.Configurations, cfg)
	return nil
}

func (d *Document) HasConfig(name string) bool {
	_, ok := d.configNames[name]
	return ok
}

func (d *Document) GetConfig(name string) data.Block {
	return d.configNames[name]
}

func (d *Document) AppendConfigurations(docs []data.Document) {
	for _, doc := range docs {
		for _, config := range doc.(*Document).Configurations {
			d.AddConfigurationBlock(config.Name, config.Type, config.Values)
		}
	}
}

// Generate a diff of the loaded document against the current resource state
func (d *Document) DiffState(output io.Writer) (returnOutput string, diffErr error) {
	clone := d.Clone()
	diffErr = clone.Apply("read")
	if diffErr != nil {
		return "", diffErr
	}
	return d.Diff(clone, output)
}

func (d *Document) YamlDiff(with data.Document) (diffs []*yamldiff.YamlDiff, diffErr error) {
	defer func() {
		if r := recover(); r != nil {
			diffErr = fmt.Errorf("%s", r)
		}
	}()

	opts := []yamldiff.DoOptionFunc{}
	ydata, yerr := d.YAML()
	if yerr != nil {
		return nil, yerr
	}
	yamlDiff,yamlDiffErr := yamldiff.Load(string(ydata))
	if yamlDiffErr != nil {
		return nil, yamlDiffErr
	}
	wdata,werr := with.YAML()
	if werr != nil {
		return nil, werr
	}
	withDiff,withDiffErr := yamldiff.Load(string(wdata))
	if withDiffErr != nil {
		return nil, withDiffErr
	}
	
	slog.Info("Document.Diff() ", "document.yaml", ydata, "with.yaml", wdata)
	return yamldiff.Do(yamlDiff, withDiff, opts...), nil
}

func (d *Document) Diff(with data.Document, output io.Writer) (returnOutput string, diffErr error) {
	defer func() {
		if r := recover(); r != nil {
			returnOutput = ""
			diffErr = fmt.Errorf("%s", r)
		}
	}()

	if output == nil {
		output = &strings.Builder{}
	}

	var diffs []*yamldiff.YamlDiff
	diffs, diffErr = d.YamlDiff(with)
	
	for _,docDiffResults := range diffs {
		slog.Info("Diff()", "diff", docDiffResults, "dump", docDiffResults.Dump())
		_,e := output.Write([]byte(docDiffResults.Dump()))
		if e != nil {
			return "", e
		}
	}
	if stringOutput, ok := output.(*strings.Builder); ok {
		return stringOutput.String(), nil
	}
	return "", nil
}

/*
func (d *Document) UnmarshalValue(value *DocumentType) error {
	d.Requires = value.Requires
}
*/

func (d *Document) UnmarshalYAML(value *yaml.Node) (err error) {
	type decodeDocument Document
	t := &DocumentType{}
	if unmarshalDocumentErr := value.Decode(t); unmarshalDocumentErr != nil {
		return unmarshalDocumentErr
	}

	if unmarshalResourcesErr := value.Decode((*decodeDocument)(d)); unmarshalResourcesErr != nil {
		return unmarshalResourcesErr
	}
	err = d.loadImports()
	d.assignConfigurationsDocument()
	d.assignResourcesDocument()
	return 
}

func (d *Document) UnmarshalJSON(data []byte) (err error) {
	type decodeDocument Document
	t := (*decodeDocument)(d)
	if unmarshalDocumentErr := json.Unmarshal(data, t); unmarshalDocumentErr != nil {
		return unmarshalDocumentErr
	}
	err = d.loadImports()
	d.assignConfigurationsDocument()
	d.assignResourcesDocument()
	return 
}

func (d *Document) AddError(e error) {
	d.Errors = append(d.Errors, e.Error())
}