package handlers

import (
	"encoding/json"
	"net/http"
	"path/filepath"
	"strconv"

	"github.com/go-chi/chi/v5"
	"xorm.io/xorm"

	"github.com/forgeo/forgebucket/internal/api/middleware"
	"github.com/forgeo/forgebucket/internal/config"
	gitdomain "github.com/forgeo/forgebucket/internal/domain/git"
	"github.com/forgeo/forgebucket/internal/models"
)

type RepoHandler struct {
	db  *xorm.Engine
	cfg *config.Config
}

func NewRepoHandler(db *xorm.Engine, cfg *config.Config) *RepoHandler {
	return &RepoHandler{db: db, cfg: cfg}
}

func (h *RepoHandler) List(w http.ResponseWriter, r *http.Request) {
	userID, _ := middleware.UserIDFromContext(r.Context())

	var repos []models.Repository
	if err := h.db.Where("owner_id = ?", userID).Find(&repos); err != nil {
		jsonError(w, "could not list repositories", http.StatusInternalServerError)
		return
	}
	if repos == nil {
		repos = []models.Repository{}
	}
	jsonOK(w, repos)
}

func (h *RepoHandler) Create(w http.ResponseWriter, r *http.Request) {
	userID, _ := middleware.UserIDFromContext(r.Context())

	var body struct {
		Name        string `json:"name"`
		Description string `json:"description"`
		IsPrivate   bool   `json:"isPrivate"`
	}
	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
		jsonError(w, "invalid request body", http.StatusBadRequest)
		return
	}
	if body.Name == "" {
		jsonError(w, "name is required", http.StatusBadRequest)
		return
	}

	diskPath := filepath.Join(h.cfg.RepoRoot, strconv.FormatInt(userID, 10), body.Name+".git")

	repo := &models.Repository{
		OwnerID:       userID,
		Name:          body.Name,
		Description:   body.Description,
		IsPrivate:     body.IsPrivate,
		DefaultBranch: "main",
		DiskPath:      diskPath,
	}

	// Initialise bare repo on disk before inserting to DB
	gitdomain.SetRepoRoot(h.cfg.RepoRoot)
	if err := gitdomain.Init(diskPath); err != nil {
		jsonError(w, "could not initialise git repository", http.StatusInternalServerError)
		return
	}

	if _, err := h.db.Insert(repo); err != nil {
		jsonError(w, "repository name already taken", http.StatusConflict)
		return
	}

	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(http.StatusCreated)
	json.NewEncoder(w).Encode(repo)
}

func (h *RepoHandler) Get(w http.ResponseWriter, r *http.Request) {
	repo, ok := h.lookupRepo(w, r)
	if !ok {
		return
	}
	jsonOK(w, repo)
}

func (h *RepoHandler) Tree(w http.ResponseWriter, r *http.Request) {
	repo, ok := h.lookupRepo(w, r)
	if !ok {
		return
	}

	ref := r.URL.Query().Get("ref")
	if ref == "" {
		ref = repo.DefaultBranch
	}
	subPath := r.URL.Query().Get("path")

	gitdomain.SetRepoRoot(h.cfg.RepoRoot)
	entries, err := gitdomain.TreeLS(repo.DiskPath, ref, subPath)
	if err != nil {
		jsonError(w, "could not read tree", http.StatusInternalServerError)
		return
	}
	if entries == nil {
		entries = []gitdomain.TreeEntry{}
	}
	jsonOK(w, entries)
}

func (h *RepoHandler) Blob(w http.ResponseWriter, r *http.Request) {
	repo, ok := h.lookupRepo(w, r)
	if !ok {
		return
	}

	ref := r.URL.Query().Get("ref")
	if ref == "" {
		ref = repo.DefaultBranch
	}
	path := r.URL.Query().Get("path")
	if path == "" {
		jsonError(w, "path is required", http.StatusBadRequest)
		return
	}

	gitdomain.SetRepoRoot(h.cfg.RepoRoot)
	content, err := gitdomain.BlobCat(repo.DiskPath, ref, path)
	if err != nil {
		jsonError(w, "file not found", http.StatusNotFound)
		return
	}
	jsonOK(w, map[string]string{"content": string(content), "path": path, "ref": ref})
}

func (h *RepoHandler) Commits(w http.ResponseWriter, r *http.Request) {
	repo, ok := h.lookupRepo(w, r)
	if !ok {
		return
	}

	ref := r.URL.Query().Get("ref")
	if ref == "" {
		ref = repo.DefaultBranch
	}
	limit := 30
	if l := r.URL.Query().Get("limit"); l != "" {
		if n, err := strconv.Atoi(l); err == nil && n > 0 && n <= 100 {
			limit = n
		}
	}

	gitdomain.SetRepoRoot(h.cfg.RepoRoot)
	commits, err := gitdomain.Log(repo.DiskPath, ref, limit)
	if err != nil {
		jsonError(w, "could not read commits", http.StatusInternalServerError)
		return
	}
	if commits == nil {
		commits = []gitdomain.Commit{}
	}
	jsonOK(w, commits)
}

// lookupRepo resolves {owner}/{repo} URL params to a DB row, enforcing access.
func (h *RepoHandler) lookupRepo(w http.ResponseWriter, r *http.Request) (*models.Repository, bool) {
	ownerName := chi.URLParam(r, "owner")
	repoName := chi.URLParam(r, "repo")

	var owner models.User
	found, err := h.db.Where("username = ?", ownerName).Get(&owner)
	if err != nil || !found {
		jsonError(w, "repository not found", http.StatusNotFound)
		return nil, false
	}

	var repo models.Repository
	found, err = h.db.Where("owner_id = ? AND name = ?", owner.ID, repoName).Get(&repo)
	if err != nil || !found {
		jsonError(w, "repository not found", http.StatusNotFound)
		return nil, false
	}

	// Private repo: only the owner may access (RBAC will be expanded in Phase 3)
	if repo.IsPrivate {
		callerID, _ := middleware.UserIDFromContext(r.Context())
		if callerID != repo.OwnerID {
			jsonError(w, "repository not found", http.StatusNotFound)
			return nil, false
		}
	}

	return &repo, true
}