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

package client

import (
	"decl/internal/data"
	"decl/internal/folio"
_	"decl/internal/fan"
_	"decl/internal/config"
_	"decl/internal/resource"
	"decl/internal/fs"
	"decl/internal/builtin"
	"errors"
	"fmt"
	"context"
	"log/slog"
	"os"
)


var (
	ErrFailedResources error = errors.New("Failed Resources")
	ErrFailedDocuments error = errors.New("Document errors")
)

type App struct {
	Target folio.URI
	ImportedMap map[folio.URI]data.Document
	Documents []data.Document
	emitter data.Converter
	merged data.Document
	Config data.Document
}

func NewClient() *App {
	a := &App{ ImportedMap: make(map[folio.URI]data.Document), Documents: make([]data.Document, 0, 100) }
	return a
}

// Load compiled-in config documents.
func (a *App) BuiltInConfiguration() (err error) {
	var defaultConfigurations []data.Document
	if defaultConfigurations, err = builtin.BuiltInDocuments(); len(defaultConfigurations) > 0 {
		slog.Info("Client.BuiltInConfiguration()", "documents", defaultConfigurations, "error", err)
		a.Config.AppendConfigurations(defaultConfigurations)
	}
	return
}

// Load config documents from default system config path.  Ignore if missing.
func (a *App) SystemConfiguration(configPath string) (err error) {
        var extractor data.Converter
        var sourceResource data.Resource
	if a.Config == nil {
		a.Config = folio.DocumentRegistry.NewDocument("file:///etc/jx/runtimeconfig.jx.yaml")
	}
	if configPath != "" {
		//configURI := folio.URI(configPath)
		var loaded []data.Document
		docFs := fs.NewWalkDir(os.DirFS(configPath), configPath, func(fsys fs.FS, path string, file fs.DirEntry) (loadErr error) {
			u := folio.URI(fmt.Sprintf("file://%s", path))

			if ! file.IsDir() {
				slog.Info("Client.SystemConfiguration()", "uri", u)
				if extractor, loadErr = folio.DocumentRegistry.ConverterTypes.New(string(u)); loadErr == nil {
					if sourceResource, loadErr = u.NewResource(nil); loadErr == nil {
						if loaded, loadErr = extractor.(data.ManyExtractor).ExtractMany(sourceResource, nil); loadErr == nil {
							a.Config.AppendConfigurations(loaded)
						}
					}
				}
			}
			return
		})
		err = docFs.Walk(nil)
	}
	return
}

func (a *App) MergeDocuments() {
	a.merged = folio.DocumentRegistry.NewDocument("file://-")
	for _, d := range a.Documents {
		for _, declaration := range d.(*folio.Document).ResourceDeclarations {
			a.merged.AddDeclaration((data.Declaration)(declaration))
		}
	}
}

func (a *App) SetOutput(uri string) (err error) {
        if uri == "-" {
                uri = "jx://-"
        }
	a.Target = folio.URI(uri)
	if a.emitter, err = folio.DocumentRegistry.ConverterTypes.New(uri); err != nil {
		return fmt.Errorf("Failed opening target: %s, %w", uri, err)
	}
	slog.Info("Client.SetOutput()", "uri", uri, "emitter", a.emitter)
	return
}

// Each document has an `imports` keyword which can be used to load dependencies
func (a *App) LoadDocumentImports() error {
	for i, d := range a.Documents {
		importedDocs := d.ImportedDocuments()
		for _, importedDocument := range importedDocs {
			docURI := folio.URI(importedDocument.GetURI())
			if _, ok := a.ImportedMap[docURI]; !ok {
				a.ImportedMap[docURI] = importedDocument
				a.Documents = append(a.Documents, nil)
				copy(a.Documents[i+1:], a.Documents[i:])
				a.Documents[i] = importedDocument
/*
				if _, outputErr := a.emitter.Emit(importedDocument, nil); outputErr != nil {
					return outputErr
				}
*/
			}
		}
	}
	return nil
}


func (a *App) ImportResource(ctx context.Context, uri string) (err error) {
	if len(a.Documents) < 1 {
		a.Documents = append(a.Documents, folio.DocumentRegistry.NewDocument(""))
	}
	resourceURI := folio.URI(uri)
	u := resourceURI.Parse().URL()
	if u == nil {
		return fmt.Errorf("Failed adding resource: %s", uri)
	}
	if u.Scheme == "" {
		u.Scheme = "file"
	}

	for _, d := range a.Documents {
		if newResource, newResourceErr := d.NewResource(uri); newResourceErr == nil {
			if _, err = newResource.Read(ctx); err != nil {
				return
			}
		} else {
			return newResourceErr
		}
	}
	return
}

func (a *App) ImportSource(uri string) (loadedDocuments []data.Document, err error) {
	if source := folio.URI(uri).Parse().URL(); source != nil {
		if source.Scheme == "" {
			source.Scheme = "file"
		}

		slog.Info("Client.ImportSource()", "uri", uri, "source", source, "error", err)
		if loadedDocuments, err = folio.DocumentRegistry.LoadFromParsedURI(source); err == nil && loadedDocuments != nil {
			a.Documents = append(a.Documents, loadedDocuments...)
		}
	} else {
		err = folio.ErrInvalidURI
	}

	slog.Info("Client.ImportSource()", "uri", uri, "error", err)
	return
}

func (a *App) Import(docs []string) (err error) {
	for _, source := range docs {
		if _, err = a.ImportSource(source); err != nil {
			return
		}
	}
	return
}

func (a *App) Apply(ctx context.Context, deleteResources bool) (err error) {
	var errorsCount int = 0
	for _, d := range a.Documents {
		d.SetConfig(a.Config)

		var overrideState string = ""
		if deleteResources {
			overrideState = "delete"
		}
		d.ResolveIds(ctx)

		_ = d.Apply("stat")

		if ! d.CheckConstraints() {
			slog.Info("Client.Apply() document constraints failed", "requires", d)
			d.AddError(fmt.Errorf("%w: %s", folio.ErrConstraintFailure, d.GetURI()))
			errorsCount++
			continue
		}

		slog.Info("Client.Apply()", "uri", d.GetURI(), "document", d, "state", overrideState, "error", err)
		if e := d.(*folio.Document).Apply(overrideState); e != nil {
			slog.Info("Client.Apply() error", "error", e)
			return e
		}
		if d.Failures() > 0 {
			d.AddError(fmt.Errorf("%w: %d, %w", ErrFailedResources, d.Failures(), err))
			errorsCount++
		}
	}

	if errorsCount > 0 {
		return fmt.Errorf("%w: %d", ErrFailedDocuments, errorsCount)
	}
	return
}

func (a *App) ImportCmd(ctx context.Context, docs []string, resourceURI string, quiet bool, merge bool) (err error) {
	defer a.Close()
	if err = a.Import(docs); err != nil {
		return
	}

	if err = a.LoadDocumentImports(); err != nil {
		return
	}

	if len(resourceURI) > 0 {
		if err = a.ImportResource(ctx, resourceURI); err != nil {
			return
		}
	}

	if quiet {
		err = a.Quiet()
	} else {
		if merge {
			a.MergeDocuments()
		}
		err = a.Emit()
		if err != nil {
			return
		}
	}
	return
}

func (a *App) ApplyCmd(ctx context.Context, docs []string, quiet bool, deleteResources bool) (err error) {
	defer a.Close()
	var failedResources error
	if err = a.Import(docs); err != nil {
		return
	}

	if err = a.LoadDocumentImports(); err != nil {
		return
	}

	if failedResources = a.Apply(ctx, deleteResources); failedResources != nil {
		slog.Info("Client.ApplyCmd()", "client", a, "error", failedResources)
		if ! errors.Is(failedResources, ErrFailedResources) && ! errors.Is(failedResources, ErrFailedDocuments) {
			return failedResources
		}
	}

	if quiet {
		err = a.Quiet()
	} else {
		err = a.Emit()
	}

	if failedResources != nil {
		if err != nil {
			return fmt.Errorf("%w %w", failedResources, err)
		} else {
			return failedResources
		}
	}

	return
}

func (a *App) Diff(left []data.Document, right []data.Document) (err error) {
	output := os.Stdout
	slog.Info("jx diff ", "right", right, "left", left)
        index := 0
        for {
                if index >= len(right) && index >= len(left) {
                        break
                }
                if index >= len(right) {
                        if _, err = left[index].Diff(folio.DocumentRegistry.NewDocument(""), output); err != nil {
                                return
                        }
                        index++
                        continue
                }
                if index >= len(left) {
                        if _, err = folio.DocumentRegistry.NewDocument("").Diff(right[index], output); err != nil {
                                return
                        }
                        index++
                        continue
                }
                if _, err = left[index].Diff(right[index], output); err != nil {
                        return
                }
                index++
        }
	return
}

func (a *App) DiffCmd(docs []string) (err error) {
	output := os.Stdout

	var leftDocuments, rightDocuments []data.Document
	var rightSource folio.URI

	//leftSource := folio.URI(docs[0])
	if len(docs) > 1 {
		rightSource = folio.URI(docs[1])
	}

	if leftDocuments, err = a.ImportSource(docs[0]); err == nil {
		if rightSource.IsEmpty() {
			for _, doc := range leftDocuments {
				_, err = doc.DiffState(output)
			}
		} else {
			if rightDocuments, err = a.ImportSource(docs[1]); err == nil {
				err = a.Diff(leftDocuments, rightDocuments)
			}
		}
	}
        return err
}

func (a *App) ConfigCmd(docs []string, includeSystemConfig bool) (err error) {
	defer a.Close()
	if err = a.BuiltInConfiguration(); err != nil {
		slog.Warn("BuiltInConfiguration()", "error", err)
	}

	if err = a.Import(docs); err != nil {
		return
	}

	if err = a.LoadDocumentImports(); err != nil {
		return
	}

	if includeSystemConfig {
		if _, err = a.emitter.Emit(a.Config, nil); err != nil {
			return
		}
	}
	_, err = a.emitter.(data.ManyEmitter).EmitMany(a.Documents, nil)
	return
}

func (a *App) Quiet() (err error) {
	output := os.Stdout
	for _, d := range a.Documents {
		for _, dr := range d.Declarations() {
			if _, err = output.Write([]byte(fmt.Sprintf("%s\n", dr.Resource().URI()))); err != nil {
				return
			}
		}
	}
	return
}

func (a *App) Emit() (err error) {
	if a.merged == nil {
		for _, d := range a.Documents {
			slog.Info("Client.Emit() document", "document", d) 
			if _, err = a.emitter.Emit(d, nil); err != nil {
				return
			}
		}
	} else {
		if _, err = a.emitter.Emit(a.merged, nil); err != nil {
			return
		}
	}
	return
}

func (a *App) Close() (err error) {
	if a.emitter != nil {
		slog.Info("Client.Close() emitter", "emitter", a.emitter)
		return a.emitter.Close()
	}
	return
}