package httpapi

import (
	"database/sql"
	"net/url"
	"strconv"
	"strings"

	hres "form-builder-be-go/internal/hal"
	sq "form-builder-be-go/internal/sqlc"
	"github.com/gin-gonic/gin"
	"github.com/raff/halgo"
)

func RegisterCategoryRoutes(r *gin.Engine, db *sql.DB) {
	// List categories
	r.GET("/categories", func(c *gin.Context) {
		limit := parseIntDefault(c.Query("limit"), 20)
		if limit > 100 {
			limit = 100
		}
		offset := parseIntDefault(c.Query("offset"), 0)
		order := c.Query("order") // currently static ORDER BY in query; keep for link preservation

		q := sq.New(db)
		cats, err := q.ListCategories(c, sq.ListCategoriesParams{Limit: int64(limit), Offset: int64(offset)})
		if err != nil {
			c.JSON(500, gin.H{"error": err.Error()})
			return
		}
		total, err := q.CountCategories(c)
		if err != nil {
			c.JSON(500, gin.H{"error": err.Error()})
			return
		}

		selfURL := buildURL("/categories", limit, offset, order, c.Query("expand"))
		res := hres.New(selfURL)
		res.AddCurie()
		res.AddLink("self", halgo.Link{Href: selfURL})
		if int64(offset+limit) < total {
			nextURL := buildURL("/categories", limit, offset+limit, order, c.Query("expand"))
			res.AddLink("next", halgo.Link{Href: nextURL})
		}
		if offset > 0 {
			prev := offset - limit
			if prev < 0 {
				prev = 0
			}
			prevURL := buildURL("/categories", limit, prev, order, c.Query("expand"))
			res.AddLink("prev", halgo.Link{Href: prevURL})
		}

		var embedded []interface{}
		for _, cat := range cats {
			itemURL := "/categories/" + strconv.FormatInt(cat.CategoryID, 10)
			item := hres.New(itemURL)
			item.SetState(cat)
			item.AddLink("self", halgo.Link{Href: itemURL})
			name := strings.TrimSpace(cat.Name)
			if name != "" {
				qv := url.Values{"category.name": []string{name}}
				item.AddLink("sakila:films", halgo.Link{Href: "/films?" + qv.Encode()})
			}
			embedded = append(embedded, item)
		}
		res.Embed("categories", embedded)
		res.SetState(gin.H{"count": len(cats), "total": total, "limit": limit, "offset": offset})
		c.Header("Content-Type", "application/hal+json")
		c.JSON(200, res)
	})

	// Get category
	r.GET("/categories/:id", func(c *gin.Context) {
		id, err := strconv.ParseInt(c.Param("id"), 10, 64)
		if err != nil {
			c.JSON(400, gin.H{"error": "invalid id"})
			return
		}
		q := sq.New(db)
		cat, err := q.GetCategory(c, id)
		if err != nil {
			if err == sql.ErrNoRows {
				c.JSON(404, gin.H{"error": "not found"})
				return
			}
			c.JSON(500, gin.H{"error": err.Error()})
			return
		}
		self := "/categories/" + strconv.FormatInt(cat.CategoryID, 10)
		res := hres.New(self)
		res.AddCurie()
		res.SetState(cat)
		res.AddLink("self", halgo.Link{Href: self})
		name := strings.TrimSpace(cat.Name)
		if name != "" {
			qv := url.Values{"category.name": []string{name}}
			res.AddLink("sakila:films", halgo.Link{Href: "/films?" + qv.Encode()})
		}
		c.Header("Content-Type", "application/hal+json")
		c.JSON(200, res)
	})
}