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

package config

import (
_	"context"
_	"encoding/json"
_	"fmt"
_	"gopkg.in/yaml.v3"
	"net/url"
	"path/filepath"
	"decl/internal/transport"
	"decl/internal/codec"
_	"os"
	"io"
	"errors"
	"log/slog"
)

type ConfigFile struct {
	Path string `yaml:"path" json:"path"`
	Format codec.Format `yaml:"format" json:"format"`
	reader *transport.Reader `yaml:"-" json:"-"`
	writer *transport.Writer `yaml:"-" json:"-"`
	encoder codec.Encoder `yaml:"-" json:"-"`
	decoder codec.Decoder `yaml:"-" json:"-"`
}

func NewConfigFile() *ConfigFile {
	return &ConfigFile{ Format: codec.FormatYaml }
}

func NewConfigFileFromURI(u *url.URL) *ConfigFile {
	t := NewConfigFile()
	if u.Scheme == "file" {
		t.Path,_ = filepath.Abs(filepath.Join(u.Hostname(), u.Path))
	} else {
		t.Path = filepath.Join(u.Hostname(), u.Path)
	}
	return t
}

func NewConfigFileSource(u *url.URL) *ConfigFile {
	t := NewConfigFileFromURI(u)
	t.reader,_ = transport.NewReader(u)
	contentType := codec.Format(t.reader.ContentType())
	if contentType.Validate() == nil {
		if formatErr := t.Format.Set(t.reader.ContentType()); formatErr != nil {
			panic(formatErr)
		}
	}
	t.decoder = codec.NewDecoder(t.reader, t.Format)
	return t
}

func NewConfigFileTarget(u *url.URL) *ConfigFile {
	t := NewConfigFileFromURI(u)
	t.writer,_ = transport.NewWriter(u)
	contentType := codec.Format(t.writer.ContentType())
	if contentType.Validate() == nil {
		if formatErr := t.Format.Set(t.writer.ContentType()); formatErr != nil {
			panic(formatErr)
		}
	}
	t.encoder = codec.NewEncoder(t.writer, t.Format)
	return t
}

func init() {
	ConfigSourceTypes.Register([]string{"file"}, func(u *url.URL) ConfigSource {
		return NewConfigFileSource(u)
	})

	ConfigSourceTypes.Register([]string{"pb","pb.gz","json","json.gz","yaml","yml","yaml.gz","yml.gz"}, func(u *url.URL) ConfigSource {
		return NewConfigFileSource(u)
	})

	ConfigTargetTypes.Register([]string{"file"}, func(u *url.URL) ConfigTarget {
		return NewConfigFileTarget(u)
	})

	ConfigTargetTypes.Register([]string{"pb","pb.gz","json","json.gz","yaml","yml","yaml.gz","yml.gz"}, func(u *url.URL) ConfigTarget {
		return NewConfigFileTarget(u)
	})
}


func (c *ConfigFile) Type() string { return "file" }

func (c *ConfigFile) Extract(filter ConfigurationSelector) ([]*Document, error) {
	documents := make([]*Document, 0, 100)

	defer func() {
		c.reader.Close()
	}()

	slog.Info("Extract()", "documents", documents)  
	index := 0
	for {
		doc := NewDocument()
		e := c.decoder.Decode(doc)
		if errors.Is(e, io.EOF) {
			break
		}
		if e != nil {
			return documents, e
		}
		slog.Info("Extract()", "res", doc.ConfigBlocks[0].Values)  
		if validationErr := doc.Validate(); validationErr != nil {
			return documents, validationErr
		}
		documents = append(documents, doc)
		index++
	}
	return documents, nil
}

func (c *ConfigFile) EmitResources(documents []*Document, filter ConfigurationSelector) (error) {
	defer func() {
		c.encoder.Close()
		c.writer.Close()
	}()

	for _, doc := range documents {
		emitDoc := NewDocument()
		if validationErr := doc.Validate(); validationErr != nil {
			return validationErr
		}
		for _, block := range doc.Filter(filter) {
			emitDoc.ConfigBlocks = append(emitDoc.ConfigBlocks, *block)
		}
		slog.Info("EmitResources", "doctarget", c, "encoder", c.encoder, "emit", emitDoc)
		if documentErr := c.encoder.Encode(emitDoc); documentErr != nil {
			slog.Info("EmitResources", "err", documentErr)
			return documentErr
		}
	}
	return nil
}

func (c *ConfigFile) Close() (error) {
	return nil
}