package config

import (
	"encoding/json"
	"errors"
	"fmt"
	"live-streamer/utils"
	"log"
	"os"
	"path/filepath"
	"strings"
)

type OutputConfig struct {
	RTMPServer string `json:"rtmp_server"`
	StreamKey  string `json:"stream_key"`
}

type InputItem struct {
	Path     string `json:"path"`
	Start    string `json:"start"`
	End      string `json:"end"`
	ItemType string `json:"-"`
}

type LogConfig struct {
	PlayState bool `json:"play_state"`
}

type ServerConfig struct {
	Addr  string `json:"addr"`
	Token string `json:"token"`
}

type Config struct {
	Input      []any          `json:"input"`
	InputItems []InputItem    `json:"-"` // contains video file or dir
	VideoList  []InputItem    `json:"-"` // only contains video file
	Play       map[string]any `json:"play"`
	Output     OutputConfig   `json:"output"`
	Log        LogConfig      `json:"log"`
	Server     ServerConfig   `json:"server"`
}

var GlobalConfig Config

func init() {
	GlobalConfig = Config{}
	err := readConfig("config.json")
	if len(GlobalConfig.Input) == 0 {
		log.Fatal("No input video found")
	}
	if err != nil {
		if os.IsNotExist(err) {
			log.Fatal("Config not exists")
		} else {
			log.Fatal(err)
		}
	}
}

func readConfig(configPath string) error {
	stat, err := os.Stat(configPath)
	if err != nil {
		return fmt.Errorf("config read failed: %v", err)
	}
	if stat.IsDir() {
		return os.ErrNotExist
	}
	databytes, err := os.ReadFile(configPath)
	if err != nil {
		return fmt.Errorf("Config read failed: %v", err)
	}
	if err = json.Unmarshal(databytes, &GlobalConfig); err != nil {
		return fmt.Errorf("config unmarshal failed: %v", err)
	}
	err = validateConfig()
	if err != nil {
		return fmt.Errorf("config validate failed: %v", err)
	}
	return nil
}

func validateConfig() error {
	if err := validateInputConfig(); err != nil {
		return err
	}
	if err := validateOutputConfig(); err != nil {
		return err
	}
	if err := validateServerConfig(); err != nil {
		return err
	}
	return nil
}

func validateInputConfig() error {
	if GlobalConfig.Input == nil {
		return errors.New("video_path is nil")
	}

	GlobalConfig.InputItems = make([]InputItem, 0, len(GlobalConfig.Input))
	GlobalConfig.VideoList = []InputItem{}

	for i, item := range GlobalConfig.Input {
		var inputItem InputItem

		switch v := item.(type) {
		case string:
			inputItem = InputItem{Path: v}
		case map[string]any:
			data, err := json.Marshal(v)
			if err != nil {
				return fmt.Errorf("failed to marshal input item[%d]: %v", i, err)
			}
			if err := json.Unmarshal(data, &inputItem); err != nil {
				return fmt.Errorf("failed to unmarshal input item[%d]: %v", i, err)
			}
			// more efficient, but coupled
			// if path, ok := v["path"].(string); ok {
			// 	inputItem.Path = path
			// }
			// if start, ok := v["start"].(string); ok {
			// 	inputItem.Start = start
			// }
			// if end, ok := v["end"].(string); ok {
			// 	inputItem.End = end
			// }
		default:
			return fmt.Errorf("invalid input type for item[%d]: %T", i, item)
		}

		if inputItem.Path == "" {
			return fmt.Errorf("video_path[%d] is empty", i)
		}

		stat, err := os.Stat(inputItem.Path)
		if err != nil {
			return fmt.Errorf("video_path[%d] stat failed: %v", i, err)
		}

		if stat.IsDir() {
			inputItem.ItemType = "dir"
			videos, err := getAllVideos(inputItem.Path)
			if err != nil {
				return fmt.Errorf("video_path[%d] get videos error: %v", i, err)
			}
			GlobalConfig.VideoList = append(GlobalConfig.VideoList, videos...)
		} else {
			inputItem.ItemType = "file"
			if !utils.IsSupportedVideo(inputItem.Path) {
				return fmt.Errorf("video_path[%d] is not supported", i)
			}
			GlobalConfig.VideoList = append(GlobalConfig.VideoList, inputItem)
		}

		GlobalConfig.InputItems = append(GlobalConfig.InputItems, inputItem)
	}

	return nil
}

func validateOutputConfig() error {
	if GlobalConfig.Output.RTMPServer == "" {
		return errors.New("rtmp_server is empty")
	} else if !strings.HasPrefix(GlobalConfig.Output.RTMPServer, "rtmp://") &&
		!strings.HasPrefix(GlobalConfig.Output.RTMPServer, "rtmps://") {
		return errors.New("rtmp_server is not a valid rtmp server")
	} else {
		GlobalConfig.Output.RTMPServer = strings.TrimSuffix(GlobalConfig.Output.RTMPServer, "/")
	}
	if GlobalConfig.Output.StreamKey == "" {
		return errors.New("stream_key is empty")
	} else {
		GlobalConfig.Output.StreamKey = strings.TrimPrefix(GlobalConfig.Output.StreamKey, "/")
	}
	return nil
}

func validateServerConfig() error {
	if GlobalConfig.Server.Addr == "" {
		GlobalConfig.Server.Addr = ":8080"
	}
	return nil
}

func getAllVideos(dirPath string) ([]InputItem, error) {
	res := []InputItem{}
	err := filepath.Walk(dirPath, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}
		if !info.IsDir() && utils.IsSupportedVideo(path) {
			res = append(res, InputItem{Path: path})
		}
		return nil
	})
	if err != nil {
		return nil, err
	}
	return res, nil
}