package processor

import (
	"encoding/json"
	"fmt"
	"spider/internal/model"
)

// SourceInfo describes where a merchant was discovered.
type SourceInfo struct {
	SourceType string `json:"source_type"`
	SourceName string `json:"source_name"`
	SourceURL  string `json:"source_url"`
}

// DedupResult holds keepers and duplicates after deduplication.
type DedupResult struct {
	Keepers    []MergedMerchant
	Duplicates []model.MerchantRaw
}

// MergedMerchant is the best raw record plus merged source info.
type MergedMerchant struct {
	Best        model.MerchantRaw
	AllSources  []SourceInfo
	SourceCount int
}

// Deduplicate groups by tg_username, keeps the richest record, merges sources.
func Deduplicate(raws []model.MerchantRaw) DedupResult {
	groups := map[string][]model.MerchantRaw{}
	for _, raw := range raws {
		key := raw.TgUsername
		if key == "" {
			key = raw.Website
		}
		if key == "" {
			key = raw.Email
		}
		if key == "" {
			key = fmt.Sprintf("_id_%d", raw.ID)
		}
		groups[key] = append(groups[key], raw)
	}

	var result DedupResult
	for _, group := range groups {
		// Collect all sources
		var sources []SourceInfo
		for _, r := range group {
			sources = append(sources, SourceInfo{
				SourceType: r.SourceType,
				SourceName: r.SourceName,
				SourceURL:  r.SourceURL,
			})
		}

		if len(group) == 1 {
			result.Keepers = append(result.Keepers, MergedMerchant{
				Best:        group[0],
				AllSources:  sources,
				SourceCount: 1,
			})
			continue
		}

		// Find richest record
		bestIdx := 0
		bestScore := richness(group[0])
		for i := 1; i < len(group); i++ {
			s := richness(group[i])
			if s > bestScore {
				bestIdx = i
				bestScore = s
			}
		}

		// Mark all others as duplicate
		for i, r := range group {
			if i != bestIdx {
				result.Duplicates = append(result.Duplicates, r)
			}
		}

		result.Keepers = append(result.Keepers, MergedMerchant{
			Best:        group[bestIdx],
			AllSources:  sources,
			SourceCount: len(group),
		})
	}

	return result
}

func richness(r model.MerchantRaw) int {
	score := 0
	if r.TgUsername != "" {
		score++
	}
	if r.Website != "" {
		score++
	}
	if r.Email != "" {
		score++
	}
	if r.Phone != "" {
		score++
	}
	if r.MerchantName != "" {
		score++
	}
	return score
}

// MarshalSources converts source list to JSON bytes.
func MarshalSources(sources []SourceInfo) []byte {
	b, _ := json.Marshal(sources)
	return b
}