package app

import (
	"fmt"
	"os"
	"path"

	"go.balki.me/tss/parser"
	"gopkg.in/yaml.v3"
)

type FeedLimit int

const NoLimit FeedLimit = -1

type FeedURL []string

type FeedCfg struct {
	// Unique identifier for the feed. Used as filename, so keep it simple
	Name string `yaml:"name" jsonschema:"required"`

	// Telegram channel name in the form "@foobar" or "-1004242442" (private)
	Channel string `yaml:"channel" jsonschema:"required"`

	// Telegram instant view rhash id, see https://instantview.telegram.org/#publishing-templates
	Rhash string `yaml:"rhash" jsonschema:"default="`

	// Feed URL, string or array of strings
	// If array, all entries are merged, e.g ["https://example.com/blog/tag/foo/feed", "https://example.com/blog/tag/bar/feed" ]
	URL FeedURL `yaml:"url" jsonschema:"required,oneof_type=string;array"`

	// Cron expression, see https://pkg.go.dev/github.com/robfig/cron#hdr-CRON_Expression_Format
	Cron string `yaml:"cron" jsonschema:"required"`

	// Proxy for this feed if different from global
	Proxy string `yaml:"proxy" jsonschema:"default=<global proxy>"`

	// Rss or Atom feed
	Type parser.FeedType `yaml:"type" jsonschema:"required,enum=rss,enum=atom"`

	// Text of the link sent to telegram,
	Title string `yaml:"title" jsonschema:"default=Link"`

	// Number of entries to process when the feed is seen for the first time
	FTL *int `yaml:"first_time_limit" jsonschema:"default=<global value>"`

	FirstTimeLimit FeedLimit `yaml:"-"`
}

type Config struct {
	// default proxy url that http.Client can understand
	// or socks5://unix/path/to/sock for socks proxy over unix socket
	// empty for no proxy
	Proxy string `yaml:"proxy" jsonschema:"default=,example=socks5://unix/run/tor/socks,example=*myvpsproxy"`

	// proxy for telegram if different from default
	// NONE to not use global default
	TelegramProxy string `yaml:"telegram_proxy" jsonschema:"default=<global proxy>"`

	// Auth token for telegram in the form of 424242424:AB02132skdcjlisjkjflewjlfkjslkfHHXX
	TelegramAuthToken string `yaml:"telegram_auth_token" jsonschema:"required"` //TODO: read from credential file

	// Base directory to write feed data and schedule file
	DataDir string `yaml:"data_dir" jsonschema:"default=./"`

	// Path to the file where last success time for each feed is saved
	LastSuccessPath string `yaml:"last_loaded_path" jsonschema:"default=<datadir>/last_success.yml"`

	// Path to the directory where feed content is saved
	DbDir string `yaml:"db_dir" jsonschema:"default=<datadir>/feed_data"`

	// Number of entries to process when the feed is seen for the first time
	// -1 means no limit
	FTL *int `yaml:"first_time_limit" jsonschema:"default=-1"`

	// Feed config
	Feeds []FeedCfg `yaml:"feeds" jsonschema:"required"`
}

func ParseConfig(configPath string) (*Config, error) {

	cfg, err := os.ReadFile(configPath)
	if err != nil {
		return nil, err
	}

	c := Config{}
	err = yaml.Unmarshal(cfg, &c)

	if err != nil {
		return nil, err
	}

	if c.DataDir == "" {
		c.DataDir = "."
	}

	if c.LastSuccessPath == "" {
		c.LastSuccessPath = path.Join(c.DataDir, "last_success.yml")
	}

	if c.DbDir == "" {
		c.DbDir = path.Join(c.DataDir, "feed_data")
	}

	err = os.MkdirAll(c.DbDir, 0755)

	if err != nil {
		return nil, err
	}

	err = os.MkdirAll(c.DataDir, 0755)
	if err != nil {
		return nil, err
	}

	if c.Proxy != "" {
		if c.TelegramProxy == "" {
			c.TelegramProxy = c.Proxy
		}
		for i := range c.Feeds {
			feedCfg := &c.Feeds[i]
			if feedCfg.Proxy == "" {
				feedCfg.Proxy = c.Proxy
			}
		}
	}

	if c.TelegramProxy == "NONE" {
		c.TelegramProxy = ""
	}

	for i := range c.Feeds {
		feedCfg := &c.Feeds[i]
		if feedCfg.Proxy == "NONE" {
			feedCfg.Proxy = ""
		}
		if feedCfg.FTL != nil {
			feedCfg.FirstTimeLimit = FeedLimit(*feedCfg.FTL)
		} else if c.FTL != nil {
			feedCfg.FirstTimeLimit = FeedLimit(*c.FTL)
		} else {
			feedCfg.FirstTimeLimit = NoLimit
		}
	}

	return &c, nil
}

func (fu *FeedURL) UnmarshalYAML(node *yaml.Node) error {
	switch node.Kind {
	case yaml.SequenceNode:
		return node.Decode((*[]string)(fu))
	case yaml.ScalarNode:
		*fu = []string{""}
		return node.Decode(&(*fu)[0])
	}
	return fmt.Errorf("unexpected node type: %s, at %d:%d", node.ShortTag(), node.Line, node.Column)
}