package config

import (
	"fmt"
	"io"
	"io/fs"
	"os"
	"path/filepath"

	"github.com/google/uuid"
	yamlcodec "go.unistack.org/micro-codec-yaml/v3"
	mtime "go.unistack.org/micro/v3/util/time"
)

var Filesytem fs.FS

func init() {
	dir, _ := os.Getwd()
	Filesytem = os.DirFS(dir)
}

type Config struct {
	App   *AppConfig   `json:"app,omitempty" yaml:"app,omitempty"`
	Meter *MeterConfig `json:"meter,omitempty" yaml:"meter,omitempty"`
}

type AppConfig struct {
	ChecksFiles []string       `json:"checks_files,omitempty" yaml:"checks_files,omitempty"`
	Checks      []*CheckConfig `json:"checks,omitempty" yaml:"checks,omitempty"`
	MultiUser   bool           `json:"multi_user,omitempty" yaml:"multi_user,omitempty"`
}

type MeterConfig struct {
	Addr string `json:"addr,omitempty" yaml:"addr,omitempty"`
	Path string `json:"path,omitempty" yaml:"path,omitempty"`
}

type CheckConfig struct {
	Name       string         `json:"name,omitempty" yaml:"name,omitempty"`
	User       string         `json:"user,omitempty" yaml:"user,omitempty"`
	Tasks      []*TaskConfig  `json:"tasks,omitempty" yaml:"tasks,omitempty"`
	TasksFiles []string       `json:"tasks_files,omitempty" yaml:"tasks_files,omitempty"`
	Timeout    mtime.Duration `json:"timeout,omitempty" yaml:"timeout,omitempty"`
	Interval   mtime.Duration `json:"interval,omitempty" yaml:"interval,omitempty"`
	Active     bool           `json:"active,omitempty" yaml:"active,omitempty"`
}

type HTTPConfig struct {
	Metadata map[string]string `json:"metadata,omitempty" yaml:"metadata,omitempty"`
	Endpoint string            `json:"endpoint,omitempty" yaml:"endpoint,omitempty"`
	Data     string            `json:"data,omitempty" yaml:"data,omitempty"`
	Addr     string            `json:"addr,omitempty" yaml:"addr,omitempty"`
	OpenAPI  string            `json:"openapi,omitempty" yaml:"openapi,omitempty"`
	Method   string            `json:"method,omitempty" yaml:"method,omitempty"`
}

type GRPCConfig struct {
	Metadata map[string]string `json:"metadata,omitempty" yaml:"metadata,omitempty"`
	Endpoint string            `json:"endpoint,omitempty" yaml:"endpoint,omitempty"`
	Data     string            `json:"data,omitempty" yaml:"data,omitempty"`
	Addr     string            `json:"addr,omitempty" yaml:"addr,omitempty"`
	Protoset string            `json:"protoset,omitempty" yaml:"protoset,omitempty"`
}

type GraphQLConfig struct {
	Metadata map[string]string `json:"metadata,omitempty" yaml:"metadata,omitempty"`
	Endpoint string            `json:"endpoint,omitempty" yaml:"endpoint,omitempty"`
	Data     string            `json:"data,omitempty" yaml:"data,omitempty"`
	Addr     string            `json:"addr,omitempty" yaml:"addr,omitempty"`
}

type TaskConfig struct {
	HTTP      *HTTPConfig    `json:"http,omitempty" yaml:"http,omitempty"`
	GRPC      *GRPCConfig    `json:"grpc,omitempty" yaml:"grpc,omitempty"`
	GraphQL   *GraphQLConfig `json:"graphql,omitempty" yaml:"graphql"`
	TLSVerify *bool          `json:"tls_verify,omitempty" yaml:"tls_verify,omitempty"`
	Name      string         `json:"name,omitempty" yaml:"name,omitempty"`
	Timeout   mtime.Duration `json:"timeout,omitempty" yaml:"timeout,omitempty"`
	Active    bool           `json:"active,omitempty" yaml:"active,omitempty"`
}

func Load(fileSystem fs.FS, name string, cfg *Config) error {
	if err := load(fileSystem, name, cfg); err != nil {
		return err
	}

	for _, checksPatternFile := range cfg.App.ChecksFiles {
		checkRoot := filepath.Dir(checksPatternFile)
		checksFiles := fsWalkDir(fileSystem, checkRoot, checksPatternFile)
		for _, checkFile := range checksFiles {
			checks := []*CheckConfig{}
			if err := load(fileSystem, checkFile, &checks); err != nil {
				return err
			}
			for ckecksIdx := range checks {
				for _, tasksPatternFile := range checks[ckecksIdx].TasksFiles {
					taskRoot := filepath.Join(filepath.Dir(checksPatternFile), filepath.Dir(tasksPatternFile))
					tasksFiles := fsWalkDir(fileSystem, taskRoot, filepath.Join(filepath.Dir(checksPatternFile), tasksPatternFile))
					for tasksIdx := range tasksFiles {
						tasks := []*TaskConfig{}
						if err := load(fileSystem, tasksFiles[tasksIdx], &tasks); err != nil {
							return err
						}
						checks[ckecksIdx].Tasks = append(checks[ckecksIdx].Tasks, tasks...)
					}
				}
				cfg.App.Checks = append(cfg.App.Checks, checks[ckecksIdx])
			}
		}
	}

	if !cfg.App.MultiUser {
		for _, check := range cfg.App.Checks {
			check.User = uuid.Nil.String()
		}
	}

	return nil
}

func fsWalkDir(fileSystem fs.FS, root string, pattern string) []string {
	var files []string
	fs.WalkDir(fileSystem, root, func(path string, d fs.DirEntry, err error) error {
		if err != nil {
			return err
		}
		if d.IsDir() || !d.Type().IsRegular() {
			return nil
		}
		var ok bool
		if ok, err = filepath.Match(pattern, path); err == nil && ok {
			files = append(files, path)
		} else {
			return err
		}

		return nil
	})
	return files
}

func load(fileSystem fs.FS, name string, cfg interface{}) error {
	f, err := fileSystem.Open(name)
	if err != nil {
		return err
	}

	c := yamlcodec.NewCodec()
	var buf []byte

	if buf, err = io.ReadAll(f); err == nil {
		if err = f.Close(); err == nil {
			err = c.Unmarshal(buf, cfg)
		}
	}

	if err != nil {
		return fmt.Errorf("failed to load config %w", err)
	}

	return nil
}