package artefact

import (
	"crypto/sha256"
	"errors"
	"fmt"
	"io"
	"net/http"
	"os"
	"path/filepath"
	"strconv"

	"github.com/gin-gonic/gin"
	"gorm.io/gorm"

	"onixbyte.com/pipely/internal/database"
	"onixbyte.com/pipely/internal/model"
)

type Handler struct {
	db          *gorm.DB
	artefactDir string
}

func NewHandler(db *gorm.DB, artefactDir string) *Handler {
	return &Handler{db: db, artefactDir: artefactDir}
}

func (h *Handler) Upload(c *gin.Context) {
	version := c.PostForm("version")
	if version == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "version is required"})
		return
	}

	deltaRef := c.PostForm("deltaRef")
	metadata := c.PostForm("metadata")
	if metadata == "" {
		metadata = "{}"
	}

	file, header, err := c.Request.FormFile("file")
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "file is required: " + err.Error()})
		return
	}
	defer file.Close()

	destDir := filepath.Join(h.artefactDir, version)
	if err := os.MkdirAll(destDir, 0755); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to create directory"})
		return
	}

	destPath := filepath.Join(destDir, header.Filename)
	out, err := os.Create(destPath)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to create file"})
		return
	}
	defer out.Close()

	hasher := sha256.New()
	writer := io.MultiWriter(out, hasher)

	size, err := io.Copy(writer, file)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to write file"})
		return
	}

	sha256Hash := fmt.Sprintf("%x", hasher.Sum(nil))

	artefact := &model.Artefact{
		Version:    version,
		FileName:   header.Filename,
		FilePath:   destPath,
		FileSize:   size,
		SHA256Hash: sha256Hash,
		DeltaRef:   deltaRef,
		IsDelta:    deltaRef != "",
		Metadata:   metadata,
	}

	if err := database.CreateArtefact(h.db, artefact); err != nil {
		os.Remove(destPath)
		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to save artefact: " + err.Error()})
		return
	}

	c.JSON(http.StatusCreated, artefact)
}

func (h *Handler) List(c *gin.Context) {
	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
	pageSize, _ := strconv.Atoi(c.DefaultQuery("pageSize", "20"))

	if page < 1 {
		page = 1
	}
	if pageSize < 1 || pageSize > 100 {
		pageSize = 20
	}

	artefacts, total, err := database.ListArtefacts(h.db, page, pageSize)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	c.JSON(http.StatusOK, model.PaginatedResponse{
		Data:     artefacts,
		Total:    total,
		Page:     page,
		PageSize: pageSize,
	})
}

func (h *Handler) Get(c *gin.Context) {
	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid id"})
		return
	}

	artefact, err := database.GetArtefactByID(h.db, id)
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			c.JSON(http.StatusNotFound, gin.H{"error": "Artefact not found"})
			return
		}
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	c.JSON(http.StatusOK, artefact)
}