package handlers

import (
	"archive/zip"
	"encoding/json"
	"io"
	"log"
	"net/http"
	"os"
	"path/filepath"
	"regexp"
	"strings"

	"github.com/gin-gonic/gin"

	"git.gobha.me/xcaliber/chat-switchboard/store"
)

// validPackageID matches lowercase alphanumeric slugs with optional hyphens.
// No leading/trailing hyphens, 2-64 chars.
var validPackageID = regexp.MustCompile(`^[a-z0-9][a-z0-9-]{0,62}[a-z0-9]$`)

// PackageHandler manages unified package lifecycle (admin-only).
// Replaces SurfaceHandler (v0.28.7).
type PackageHandler struct {
	stores      store.Stores
	packagesDir string // e.g. /data/packages — where archives are extracted
}

func NewPackageHandler(s store.Stores, packagesDir ...string) *PackageHandler {
	dir := ""
	if len(packagesDir) > 0 {
		dir = packagesDir[0]
	}
	return &PackageHandler{stores: s, packagesDir: dir}
}

// ListPackages returns all registered packages.
// GET /api/v1/admin/packages
// GET /api/v1/admin/surfaces (alias)
func (h *PackageHandler) ListPackages(c *gin.Context) {
	typeFilter := c.Query("type")

	var pkgs []store.PackageRegistration
	var err error
	if typeFilter != "" {
		pkgs, err = h.stores.Packages.ListByType(c.Request.Context(), typeFilter)
	} else {
		pkgs, err = h.stores.Packages.List(c.Request.Context())
	}
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to list packages"})
		return
	}
	if pkgs == nil {
		pkgs = []store.PackageRegistration{}
	}
	c.JSON(http.StatusOK, gin.H{"data": pkgs})
}

// GetPackage returns a single package by ID.
// GET /api/v1/admin/packages/:id
// GET /api/v1/admin/surfaces/:id (alias)
func (h *PackageHandler) GetPackage(c *gin.Context) {
	id := c.Param("id")
	pkg, err := h.stores.Packages.Get(c.Request.Context(), id)
	if err != nil || pkg == nil {
		c.JSON(http.StatusNotFound, gin.H{"error": "package not found"})
		return
	}
	c.JSON(http.StatusOK, pkg)
}

// EnablePackage enables a package.
// PUT /api/v1/admin/packages/:id/enable
// PUT /api/v1/admin/surfaces/:id/enable (alias)
func (h *PackageHandler) EnablePackage(c *gin.Context) {
	id := c.Param("id")
	if err := h.stores.Packages.SetEnabled(c.Request.Context(), id, true); err != nil {
		c.JSON(http.StatusNotFound, gin.H{"error": "package not found"})
		return
	}
	c.JSON(http.StatusOK, gin.H{"id": id, "enabled": true})
}

// DisablePackage disables a package. Chat and Admin cannot be disabled.
// PUT /api/v1/admin/packages/:id/disable
// PUT /api/v1/admin/surfaces/:id/disable (alias)
func (h *PackageHandler) DisablePackage(c *gin.Context) {
	id := c.Param("id")

	if id == "chat" || id == "admin" {
		c.JSON(http.StatusBadRequest, gin.H{"error": id + " cannot be disabled"})
		return
	}

	if err := h.stores.Packages.SetEnabled(c.Request.Context(), id, false); err != nil {
		c.JSON(http.StatusNotFound, gin.H{"error": "package not found"})
		return
	}
	c.JSON(http.StatusOK, gin.H{"id": id, "enabled": false})
}

// DeletePackage uninstalls a package. Core packages cannot be deleted.
// DELETE /api/v1/admin/packages/:id
// DELETE /api/v1/admin/surfaces/:id (alias)
func (h *PackageHandler) DeletePackage(c *gin.Context) {
	id := c.Param("id")

	pkg, err := h.stores.Packages.Get(c.Request.Context(), id)
	if err != nil || pkg == nil {
		c.JSON(http.StatusNotFound, gin.H{"error": "package not found"})
		return
	}
	if pkg.Source == "core" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "core packages cannot be uninstalled"})
		return
	}

	if err := h.stores.Packages.Delete(c.Request.Context(), id); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to delete package"})
		return
	}

	// Clean up extracted static assets
	if h.packagesDir != "" {
		assetDir := filepath.Join(h.packagesDir, id)
		if err := os.RemoveAll(assetDir); err != nil {
			log.Printf("⚠️ Failed to clean up package assets at %s: %v", assetDir, err)
		}
	}

	c.JSON(http.StatusOK, gin.H{"id": id, "deleted": true})
}

// InstallPackage uploads and installs a .pkg/.surface archive.
// POST /api/v1/admin/packages/install
// POST /api/v1/admin/surfaces/install (alias)
func (h *PackageHandler) InstallPackage(c *gin.Context) {
	file, header, err := c.Request.FormFile("file")
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "no file uploaded"})
		return
	}
	defer file.Close()

	// Validate extension
	validExt := strings.HasSuffix(header.Filename, ".pkg") ||
		strings.HasSuffix(header.Filename, ".surface") ||
		strings.HasSuffix(header.Filename, ".zip")
	if !validExt {
		c.JSON(http.StatusBadRequest, gin.H{"error": "file must be a .pkg, .surface, or .zip archive"})
		return
	}

	// Size limit: 50MB
	if header.Size > 50*1024*1024 {
		c.JSON(http.StatusBadRequest, gin.H{"error": "archive too large (max 50MB)"})
		return
	}

	// Read into temp file for zip processing
	tmpFile, err := os.CreateTemp("", "package-*.zip")
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to create temp file"})
		return
	}
	tmpPath := tmpFile.Name()
	defer os.Remove(tmpPath)

	if _, err := io.Copy(tmpFile, file); err != nil {
		tmpFile.Close()
		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to read upload"})
		return
	}
	tmpFile.Close()

	// Open as zip
	zr, err := zip.OpenReader(tmpPath)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid zip archive"})
		return
	}
	defer zr.Close()

	// Find and parse manifest.json
	var manifest map[string]any
	for _, f := range zr.File {
		name := filepath.Base(f.Name)
		if name == "manifest.json" && !f.FileInfo().IsDir() {
			rc, err := f.Open()
			if err != nil {
				continue
			}
			data, err := io.ReadAll(rc)
			rc.Close()
			if err != nil {
				continue
			}
			if err := json.Unmarshal(data, &manifest); err != nil {
				c.JSON(http.StatusBadRequest, gin.H{"error": "invalid manifest.json: " + err.Error()})
				return
			}
			break
		}
	}

	if manifest == nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "archive missing manifest.json"})
		return
	}

	// Validate required fields
	pkgID, _ := manifest["id"].(string)
	title, _ := manifest["title"].(string)
	if pkgID == "" || title == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "manifest must have 'id' and 'title'"})
		return
	}

	// Validate package ID is a safe slug
	if !validPackageID.MatchString(pkgID) {
		c.JSON(http.StatusBadRequest, gin.H{"error": "package id must be a lowercase slug (a-z, 0-9, hyphens, 2-64 chars)"})
		return
	}

	// Determine type (default: surface for backward compat)
	pkgType, _ := manifest["type"].(string)
	if pkgType == "" {
		pkgType = "surface"
	}
	if pkgType != "surface" && pkgType != "extension" && pkgType != "full" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "manifest type must be 'surface', 'extension', or 'full'"})
		return
	}

	// Type-specific validation
	hasRoute := manifest["route"] != nil || manifest["routes"] != nil
	hasTools := manifest["tools"] != nil
	hasPipes := manifest["pipes"] != nil
	hasHooks := manifest["hooks"] != nil
	hasExtBehavior := hasTools || hasPipes || hasHooks

	switch pkgType {
	case "surface":
		// route is optional for surfaces (core surfaces don't always have it in manifest)
	case "extension":
		if !hasExtBehavior {
			c.JSON(http.StatusBadRequest, gin.H{"error": "extension packages require at least one of: tools, pipes, hooks"})
			return
		}
		if hasRoute {
			c.JSON(http.StatusBadRequest, gin.H{"error": "extension packages cannot have a route — use type 'full' for both"})
			return
		}
	case "full":
		if !hasRoute {
			c.JSON(http.StatusBadRequest, gin.H{"error": "full packages require a route"})
			return
		}
		if !hasExtBehavior {
			c.JSON(http.StatusBadRequest, gin.H{"error": "full packages require at least one of: tools, pipes, hooks"})
			return
		}
	}

	// Check for conflicts with core packages
	existing, _ := h.stores.Packages.Get(c.Request.Context(), pkgID)
	if existing != nil && existing.Source == "core" {
		c.JSON(http.StatusConflict, gin.H{"error": "cannot overwrite core package: " + pkgID})
		return
	}

	// Extract static assets (js/, css/, assets/) to packagesDir/{id}/
	if h.packagesDir != "" {
		destDir := filepath.Join(h.packagesDir, pkgID)
		os.MkdirAll(destDir, 0755)

		for _, f := range zr.File {
			if f.FileInfo().IsDir() {
				continue
			}

			relPath := extractableRelPath(f.Name)
			if relPath == "" {
				continue
			}

			destPath := filepath.Join(destDir, relPath)

			// Security: prevent path traversal
			if !strings.HasPrefix(filepath.Clean(destPath), filepath.Clean(destDir)) {
				continue
			}

			os.MkdirAll(filepath.Dir(destPath), 0755)

			rc, err := f.Open()
			if err != nil {
				continue
			}
			out, err := os.Create(destPath)
			if err != nil {
				rc.Close()
				continue
			}
			io.Copy(out, rc)
			out.Close()
			rc.Close()
		}

		log.Printf("[packages] Extracted %s to %s", pkgID, destDir)
	}

	// Extract manifest fields for DB columns
	version, _ := manifest["version"].(string)
	if version == "" {
		version = "0.0.0"
	}
	description, _ := manifest["description"].(string)
	author, _ := manifest["author"].(string)
	tier, _ := manifest["tier"].(string)
	if tier == "" {
		tier = "browser"
	}

	userID := c.GetString("user_id")

	// Register in database via Seed (upsert — handles re-install)
	if err := h.stores.Packages.Seed(c.Request.Context(), pkgID, title, "extension", manifest); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to register package"})
		return
	}

	// Read back to get the preserved enabled state (Seed doesn't override it)
	existing, _ = h.stores.Packages.Get(c.Request.Context(), pkgID)
	preservedEnabled := true
	if existing != nil {
		preservedEnabled = existing.Enabled
	}

	// Update fields that Seed doesn't set (type, version, author, etc.)
	pkg := &store.PackageRegistration{
		Title:       title,
		Type:        pkgType,
		Version:     version,
		Description: description,
		Author:      author,
		Tier:        tier,
		IsSystem:    false,
		Enabled:     preservedEnabled,
		Manifest:    manifest,
	}
	if userID != "" {
		pkg.InstalledBy = &userID
	}
	if err := h.stores.Packages.Update(c.Request.Context(), pkgID, pkg); err != nil {
		log.Printf("[packages] Failed to update package metadata for %s: %v", pkgID, err)
	}

	c.JSON(http.StatusOK, gin.H{
		"id":      pkgID,
		"title":   title,
		"type":    pkgType,
		"version": version,
		"source":  "extension",
		"enabled": preservedEnabled,
	})
}

// extractableRelPath returns the relative path for a zip entry if it
// belongs to an extractable static directory (js/, css/, assets/).
// Returns "" if the file should be skipped.
func extractableRelPath(name string) string {
	staticPrefixes := []string{"js/", "css/", "assets/"}

	for _, p := range staticPrefixes {
		if strings.HasPrefix(name, p) {
			return name
		}
	}

	idx := strings.Index(name, "/")
	if idx <= 0 {
		return ""
	}

	rest := name[idx+1:]
	for _, p := range staticPrefixes {
		if strings.HasPrefix(rest, p) {
			return rest
		}
	}

	return ""
}

// ListEnabledSurfaces returns enabled surface/full packages for nav rendering.
// GET /api/v1/surfaces
func (h *PackageHandler) ListEnabledSurfaces(c *gin.Context) {
	pkgs, err := h.stores.Packages.List(c.Request.Context())
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to list surfaces"})
		return
	}

	type navSurface struct {
		ID    string `json:"id"`
		Title string `json:"title"`
		Route string `json:"route"`
	}

	var enabled []navSurface
	for _, p := range pkgs {
		if !p.Enabled {
			continue
		}
		// Only surface and full types have routes
		if p.Type != "surface" && p.Type != "full" {
			continue
		}
		route, _ := p.Manifest["route"].(string)
		enabled = append(enabled, navSurface{
			ID:    p.ID,
			Title: p.Title,
			Route: route,
		})
	}
	if enabled == nil {
		enabled = []navSurface{}
	}
	c.JSON(http.StatusOK, gin.H{"data": enabled})
}