// Package threatbook logic
package threatbook

import (
	"context"
	"fmt"
	"strconv"
	"time"

	jsoniter "github.com/json-iterator/go"

	"github.com/projectdiscovery/subfinder/v2/pkg/subscraping"
)

type threatBookResponse struct {
	ResponseCode int64  `json:"response_code"`
	VerboseMsg   string `json:"verbose_msg"`
	Data         struct {
		Domain     string `json:"domain"`
		SubDomains struct {
			Total string   `json:"total"`
			Data  []string `json:"data"`
		} `json:"sub_domains"`
	} `json:"data"`
}

// Source is the passive scraping agent
type Source struct {
	apiKeys   []string
	timeTaken time.Duration
	errors    int
	results   int
	requests  int
	skipped   bool
}

// Run function returns all subdomains found with the service
func (s *Source) Run(ctx context.Context, domain string, session *subscraping.Session) <-chan subscraping.Result {
	results := make(chan subscraping.Result)
	s.errors = 0
	s.results = 0
	s.requests = 0

	go func() {
		defer func(startTime time.Time) {
			s.timeTaken = time.Since(startTime)
			close(results)
		}(time.Now())

		randomApiKey := subscraping.PickRandom(s.apiKeys, s.Name())
		if randomApiKey == "" {
			s.skipped = true
			return
		}

		s.requests++
		resp, err := session.SimpleGet(ctx, fmt.Sprintf("https://api.threatbook.cn/v3/domain/sub_domains?apikey=%s&resource=%s", randomApiKey, domain))
		if err != nil && resp == nil {
			results <- subscraping.Result{Source: s.Name(), Type: subscraping.Error, Error: err}
			s.errors++
			session.DiscardHTTPResponse(resp)
			return
		}

		var response threatBookResponse
		err = jsoniter.NewDecoder(resp.Body).Decode(&response)
		if err != nil {
			results <- subscraping.Result{Source: s.Name(), Type: subscraping.Error, Error: err}
			s.errors++
			session.DiscardHTTPResponse(resp)
			return
		}
		session.DiscardHTTPResponse(resp)

		if response.ResponseCode != 0 {
			results <- subscraping.Result{
				Source: s.Name(), Type: subscraping.Error,
				Error: fmt.Errorf("code %d, %s", response.ResponseCode, response.VerboseMsg),
			}
			s.errors++
			return
		}

		total, err := strconv.ParseInt(response.Data.SubDomains.Total, 10, 64)
		if err != nil {
			results <- subscraping.Result{Source: s.Name(), Type: subscraping.Error, Error: err}
			s.errors++
			return
		}

		if total > 0 {
			for _, subdomain := range response.Data.SubDomains.Data {
				select {
				case <-ctx.Done():
					return
				case results <- subscraping.Result{Source: s.Name(), Type: subscraping.Subdomain, Value: subdomain}:
					s.results++
				}
			}
		}
	}()

	return results
}

// Name returns the name of the source
func (s *Source) Name() string {
	return "threatbook"
}

func (s *Source) IsDefault() bool {
	return false
}

func (s *Source) HasRecursiveSupport() bool {
	return false
}

func (s *Source) KeyRequirement() subscraping.KeyRequirement {
	return subscraping.RequiredKey
}

func (s *Source) NeedsKey() bool {
	return s.KeyRequirement() == subscraping.RequiredKey
}

func (s *Source) AddApiKeys(keys []string) {
	s.apiKeys = keys
}

func (s *Source) Statistics() subscraping.Statistics {
	return subscraping.Statistics{
		Errors:    s.errors,
		Results:   s.results,
		TimeTaken: s.timeTaken,
		Skipped:   s.skipped,
		Requests:  s.requests,
	}
}
