package controllers

import (
	"strconv"

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

// SetAddonDependencies replaces all outgoing dependency edges for an addon.
// An empty dependency list is valid and clears the edges.
func SetAddonDependencies(c *gin.Context) {
	var report models.DependencyReport
	if err := c.ShouldBindJSON(&report); err != nil {
		c.JSON(400, gin.H{"error": "Invalid JSON"})
		return
	}

	if report.AddonID == "" {
		c.JSON(400, gin.H{"error": "addonId is required"})
		return
	}

	seen := make(map[string]bool)
	edges := make([]models.AddonDependency, 0, len(report.Dependencies))
	for _, dep := range report.Dependencies {
		if dep.ID == "" || dep.ID == report.AddonID || seen[dep.ID] {
			continue
		}
		seen[dep.ID] = true
		edges = append(edges, models.AddonDependency{
			AddonID:        report.AddonID,
			DependencyID:   dep.ID,
			Version:        dep.Version,
			DependencyName: dep.Name,
		})
	}

	err := initializers.DB.Transaction(func(tx *gorm.DB) error {
		if err := tx.Where("addon_id = ?", report.AddonID).Delete(&models.AddonDependency{}).Error; err != nil {
			return err
		}
		if len(edges) == 0 {
			return nil
		}
		return tx.Clauses(clause.OnConflict{DoNothing: true}).CreateInBatches(&edges, 100).Error
	})
	if err != nil {
		c.JSON(500, gin.H{"error": err.Error()})
		return
	}

	c.JSON(200, gin.H{"status": "success", "stored": len(edges)})
}

// GetDependents returns the addons that depend on the given addon.
func GetDependents(c *gin.Context) {
	addonID := c.Param("id")

	var addon models.Addon
	if err := initializers.DB.Where("id = ?", addonID).First(&addon).Error; err != nil {
		c.JSON(404, gin.H{"error": "Addon not found"})
		return
	}

	limit := parseLimit(c.Query("limit"))
	offset := parseOffset(c.Query("offset"))

	dependents, total, err := queryRelatedAddons(addonID, "ad.addon_id", "ad.dependency_id", limit, offset)
	if err != nil {
		c.JSON(500, gin.H{"error": err.Error()})
		return
	}

	c.JSON(200, models.DependentsResponse{
		AddonID:    addonID,
		Dependents: dependents,
		Total:      total,
		Limit:      limit,
		Offset:     offset,
	})
}

// GetDependencies returns the addons that the given addon depends on.
func GetDependencies(c *gin.Context) {
	addonID := c.Param("id")

	var addon models.Addon
	if err := initializers.DB.Where("id = ?", addonID).First(&addon).Error; err != nil {
		c.JSON(404, gin.H{"error": "Addon not found"})
		return
	}

	limit := parseLimit(c.Query("limit"))
	offset := parseOffset(c.Query("offset"))

	dependencies, total, err := queryRelatedAddons(addonID, "ad.dependency_id", "ad.addon_id", limit, offset)
	if err != nil {
		c.JSON(500, gin.H{"error": err.Error()})
		return
	}

	c.JSON(200, models.DependenciesResponse{
		AddonID:      addonID,
		Dependencies: dependencies,
		Total:        total,
		Limit:        limit,
		Offset:       offset,
	})
}

// queryRelatedAddons returns one page of addons linked to addonID through the
// addon_dependencies edge table, plus the total number of matches.
//
// joinCol is the edge column joined to addons.id; filterCol is the edge column
// matched against addonID. Both are caller-supplied constants, never user input.
//
// The addons.id tiebreaker in the ORDER BY is required: subscriber_count alone
// is not a unique ordering, so without it paging could repeat or skip rows.
func queryRelatedAddons(addonID, joinCol, filterCol string, limit, offset int) ([]models.AddonSearchResult, int, error) {
	base := func() *gorm.DB {
		return initializers.DB.Model(&models.Addon{}).
			Joins("JOIN addon_dependencies ad ON "+joinCol+" = addons.id").
			Where(filterCol+" = ?", addonID)
	}

	var total int64
	if err := base().Count(&total).Error; err != nil {
		return nil, 0, err
	}

	results := []models.AddonSearchResult{}
	err := base().
		Select("addons.id, addons.name, addons.type, addons.summary, addons.preview, addons.subscriber_count, addons.current_version_number, addons.author").
		Order("addons.subscriber_count DESC, addons.id ASC").
		Limit(limit).
		Offset(offset).
		Find(&results).Error
	if err != nil {
		return nil, 0, err
	}

	return results, int(total), nil
}

func parseLimit(raw string) int {
	limit := 100
	if raw != "" {
		if val, err := strconv.Atoi(raw); err == nil && val > 0 {
			limit = val
		}
	}
	if limit > 500 {
		limit = 500
	}
	return limit
}

func parseOffset(raw string) int {
	if raw == "" {
		return 0
	}
	val, err := strconv.Atoi(raw)
	if err != nil || val < 0 {
		return 0
	}
	return val
}