package admin

import (
	"net/http"
	"regexp"
	"strconv"
	"strings"
	"time"

	"gitea.tbdevent.eu/TBD/reforger_crawler_main/initializers"
	"gitea.tbdevent.eu/TBD/reforger_crawler_main/models"
	"github.com/gin-gonic/gin"
	"gorm.io/gorm"
)

var sha512Re = regexp.MustCompile(`^[0-9a-f]{128}$`)

// legacyAddWhitelistedHash keeps the original form-based endpoint working.
func legacyAddWhitelistedHash(c *gin.Context) {
	hash := c.PostForm("hash")
	if hash == "" {
		c.JSON(400, gin.H{"error": "Hash is required"})
		return
	}

	ret := initializers.DB.Find(&models.WhitelistedHash{}, "hash = ?", hash)
	if ret.RowsAffected > 0 {
		c.JSON(400, gin.H{"error": "Hash already whitelisted"})
		return
	}

	if err := initializers.DB.Create(&models.WhitelistedHash{Hash: hash}).Error; err != nil {
		c.JSON(500, gin.H{"error": "Failed to add whitelisted hash"})
		return
	}
	audit(c, "whitelist_add", map[string]any{"added": 1, "legacy": true})
	invalidate("overview")
	c.JSON(200, gin.H{"message": "Whitelisted hash added successfully"})
}

type whitelistRow struct {
	ID         uint      `json:"id"`
	Hash       string    `json:"hash"`
	Note       string    `json:"note"`
	CreatedAt  time.Time `json:"createdAt"`
	Files      int64     `json:"files"`
	Addons     int64     `json:"addons"`
	SamplePath string    `json:"samplePath"`
}

func listWhitelist(c *gin.Context) {
	limit := queryInt(c, "limit", 50, 1, 500)
	offset := queryInt(c, "offset", 0, 0, 1<<30)
	q := initializers.DB.Model(&models.WhitelistedHash{})
	if s := strings.TrimSpace(strings.ToLower(c.Query("q"))); s != "" {
		like := "%" + likeEscape(s) + "%"
		q = q.Where(`hash LIKE ? ESCAPE '\' OR LOWER(note) LIKE ? ESCAPE '\'`, likeEscape(s)+"%", like)
	}
	var total int64
	q.Session(&gorm.Session{}).Count(&total)

	rows := []whitelistRow{}
	if err := q.Select("id, hash, note, created_at").Order("id DESC").Limit(limit).Offset(offset).Scan(&rows).Error; err != nil {
		fail(c, http.StatusInternalServerError, err.Error())
		return
	}
	if len(rows) > 0 {
		hashes := make([]string, len(rows))
		for i, r := range rows {
			hashes[i] = r.Hash
		}
		var usage []struct {
			Hash   string
			Files  int64
			Addons int64
			Sample string
		}
		initializers.DB.Raw(`SELECT hash, COUNT(*) AS files, COUNT(DISTINCT addon_id) AS addons, MIN(path) AS sample
			FROM addon_files WHERE deleted_at IS NULL AND hash IN ? GROUP BY hash`, hashes).Scan(&usage)
		byHash := map[string]int{}
		for i, u := range usage {
			byHash[u.Hash] = i
		}
		for i := range rows {
			if j, ok := byHash[rows[i].Hash]; ok {
				rows[i].Files, rows[i].Addons, rows[i].SamplePath = usage[j].Files, usage[j].Addons, usage[j].Sample
			}
		}
	}
	c.JSON(http.StatusOK, gin.H{"items": rows, "total": total, "limit": limit, "offset": offset})
}

type skipped struct {
	Hash   string `json:"hash"`
	Reason string `json:"reason"`
}

func addWhitelist(c *gin.Context) {
	var body struct {
		Hashes []string `json:"hashes"`
		Text   string   `json:"text"`
		Note   string   `json:"note"`
	}
	if err := c.ShouldBindJSON(&body); err != nil {
		fail(c, http.StatusBadRequest, "invalid JSON")
		return
	}
	candidates := append([]string{}, body.Hashes...)
	candidates = append(candidates, strings.FieldsFunc(body.Text, func(r rune) bool {
		return r == ',' || r == ';' || r == ' ' || r == '\n' || r == '\r' || r == '\t'
	})...)
	if len(candidates) == 0 {
		fail(c, http.StatusBadRequest, "no hashes given")
		return
	}
	if len(candidates) > 5000 {
		fail(c, http.StatusBadRequest, "at most 5000 hashes per request")
		return
	}
	note := body.Note
	if len(note) > 256 {
		note = note[:256]
	}

	var skips []skipped
	seen := map[string]bool{}
	valid := []string{}
	for _, raw := range candidates {
		h := strings.ToLower(strings.TrimSpace(raw))
		switch {
		case h == "":
			continue
		case !sha512Re.MatchString(h):
			skips = append(skips, skipped{raw, "not a SHA-512 hex hash"})
		case seen[h]:
			skips = append(skips, skipped{h, "duplicate in request"})
		default:
			seen[h] = true
			valid = append(valid, h)
		}
	}

	added := 0
	err := initializers.DB.Transaction(func(tx *gorm.DB) error {
		existing := map[string]bool{}
		for start := 0; start < len(valid); start += 500 {
			end := min(start+500, len(valid))
			var found []string
			if err := tx.Model(&models.WhitelistedHash{}).Where("hash IN ?", valid[start:end]).Pluck("hash", &found).Error; err != nil {
				return err
			}
			for _, h := range found {
				existing[h] = true
			}
		}
		rows := []models.WhitelistedHash{}
		for _, h := range valid {
			if existing[h] {
				skips = append(skips, skipped{h, "already whitelisted"})
				continue
			}
			rows = append(rows, models.WhitelistedHash{Hash: h, Note: note})
		}
		if len(rows) == 0 {
			return nil
		}
		added = len(rows)
		return tx.CreateInBatches(&rows, 200).Error
	})
	if err != nil {
		fail(c, http.StatusInternalServerError, err.Error())
		return
	}
	if added > 0 {
		audit(c, "whitelist_add", map[string]any{"added": added, "note": note})
		invalidate("overview")
	}
	if skips == nil {
		skips = []skipped{}
	}
	c.JSON(http.StatusOK, gin.H{"added": added, "skipped": skips})
}

func deleteWhitelist(c *gin.Context) {
	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
	if err != nil {
		fail(c, http.StatusBadRequest, "invalid id")
		return
	}
	var row models.WhitelistedHash
	if err := initializers.DB.Unscoped().First(&row, id).Error; err != nil {
		fail(c, http.StatusNotFound, "not found")
		return
	}
	// remove every row of this hash, the table has no unique constraint
	res := initializers.DB.Unscoped().Where("hash = ?", row.Hash).Delete(&models.WhitelistedHash{})
	if res.Error != nil {
		fail(c, http.StatusInternalServerError, res.Error.Error())
		return
	}
	audit(c, "whitelist_remove", map[string]any{"hash": row.Hash})
	invalidate("overview")
	c.JSON(http.StatusOK, gin.H{"deleted": res.RowsAffected})
}

// hashUsage lists the addons that contain a file with the given hash.
func hashUsage(c *gin.Context) {
	hash := strings.ToLower(c.Param("hash"))
	var total int64
	initializers.DB.Model(&models.AddonFile{}).Where("hash = ?", hash).Count(&total)
	items := []struct {
		AddonID string `json:"addonId"`
		Name    string `json:"name"`
		Path    string `json:"path"`
		Version string `json:"version"`
	}{}
	err := initializers.DB.Raw(`SELECT f.addon_id, COALESCE(a.name, '') AS name, f.path, f.version
		FROM addon_files f LEFT JOIN addons a ON a.id = f.addon_id
		WHERE f.hash = ? AND f.deleted_at IS NULL ORDER BY a.subscriber_count DESC LIMIT 200`, hash).Scan(&items).Error
	if err != nil {
		fail(c, http.StatusInternalServerError, err.Error())
		return
	}
	var wl int64
	initializers.DB.Model(&models.WhitelistedHash{}).Where("hash = ?", hash).Count(&wl)
	c.JSON(http.StatusOK, gin.H{"hash": hash, "whitelisted": wl > 0, "total": total, "items": items})
}