package handlers

import (
	"encoding/json"
	"net/http"

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

	"github.com/forgeo/forgebucket/internal/api/middleware"
	"github.com/forgeo/forgebucket/internal/models"
)

type PRSettingsHandler struct{ db *xorm.Engine }

func NewPRSettingsHandler(db *xorm.Engine) *PRSettingsHandler {
	return &PRSettingsHandler{db: db}
}

func (h *PRSettingsHandler) resolveRepo(w http.ResponseWriter, r *http.Request) (*models.Repository, bool) {
	ownerName := chi.URLParam(r, "owner")
	repoName := chi.URLParam(r, "repo")
	var owner models.User
	if found, _ := h.db.Where("username = ?", ownerName).Get(&owner); !found {
		jsonError(w, "repository not found", http.StatusNotFound)
		return nil, false
	}
	var repo models.Repository
	if found, _ := h.db.Where("owner_id = ? AND name = ?", owner.ID, repoName).Get(&repo); !found {
		jsonError(w, "repository not found", http.StatusNotFound)
		return nil, false
	}
	return &repo, true
}

func (h *PRSettingsHandler) canManage(repo *models.Repository, callerID int64) bool {
	if callerID == repo.OwnerID {
		return true
	}
	var m models.RepoMember
	found, _ := h.db.Where("repo_id = ? AND user_id = ? AND permission = 'admin'", repo.ID, callerID).Get(&m)
	return found
}

// ── Default reviewers ─────────────────────────────────────────────────────────

type defaultReviewerInfo struct {
	UserID    int64  `json:"userId"`
	Username  string `json:"username"`
	AvatarURL string `json:"avatarUrl"`
}

func (h *PRSettingsHandler) ListDefaultReviewers(w http.ResponseWriter, r *http.Request) {
	repo, ok := h.resolveRepo(w, r)
	if !ok {
		return
	}
	var rows []models.RepoDefaultReviewer
	h.db.Where("repo_id = ?", repo.ID).Find(&rows)

	result := make([]defaultReviewerInfo, 0, len(rows))
	for _, dr := range rows {
		var u models.User
		if found, _ := h.db.ID(dr.UserID).Get(&u); found {
			result = append(result, defaultReviewerInfo{
				UserID:    u.ID,
				Username:  u.Username,
				AvatarURL: u.AvatarURL,
			})
		}
	}
	jsonOK(w, result)
}

func (h *PRSettingsHandler) AddDefaultReviewer(w http.ResponseWriter, r *http.Request) {
	repo, ok := h.resolveRepo(w, r)
	if !ok {
		return
	}
	callerID, _ := middleware.UserIDFromContext(r.Context())
	if !h.canManage(repo, callerID) {
		jsonError(w, "forbidden", http.StatusForbidden)
		return
	}

	var body struct {
		Username string `json:"username"`
	}
	if err := json.NewDecoder(r.Body).Decode(&body); err != nil || body.Username == "" {
		jsonError(w, "username is required", http.StatusBadRequest)
		return
	}

	var u models.User
	if found, _ := h.db.Where("username = ?", body.Username).Get(&u); !found {
		jsonError(w, "user not found", http.StatusNotFound)
		return
	}

	// Idempotent: don't duplicate
	var existing models.RepoDefaultReviewer
	if found, _ := h.db.Where("repo_id = ? AND user_id = ?", repo.ID, u.ID).Get(&existing); found {
		jsonOK(w, defaultReviewerInfo{UserID: u.ID, Username: u.Username, AvatarURL: u.AvatarURL})
		return
	}

	dr := &models.RepoDefaultReviewer{RepoID: repo.ID, UserID: u.ID}
	if _, err := h.db.Insert(dr); err != nil {
		jsonError(w, "could not add reviewer", http.StatusInternalServerError)
		return
	}
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(http.StatusCreated)
	json.NewEncoder(w).Encode(defaultReviewerInfo{UserID: u.ID, Username: u.Username, AvatarURL: u.AvatarURL})
}

func (h *PRSettingsHandler) RemoveDefaultReviewer(w http.ResponseWriter, r *http.Request) {
	repo, ok := h.resolveRepo(w, r)
	if !ok {
		return
	}
	callerID, _ := middleware.UserIDFromContext(r.Context())
	if !h.canManage(repo, callerID) {
		jsonError(w, "forbidden", http.StatusForbidden)
		return
	}
	username := chi.URLParam(r, "username")
	var u models.User
	if found, _ := h.db.Where("username = ?", username).Get(&u); !found {
		w.WriteHeader(http.StatusNoContent)
		return
	}
	h.db.Where("repo_id = ? AND user_id = ?", repo.ID, u.ID).Delete(&models.RepoDefaultReviewer{})
	w.WriteHeader(http.StatusNoContent)
}

// ── Default description ───────────────────────────────────────────────────────

func (h *PRSettingsHandler) GetDefaultDescription(w http.ResponseWriter, r *http.Request) {
	repo, ok := h.resolveRepo(w, r)
	if !ok {
		return
	}
	var dd models.RepoDefaultDescription
	h.db.Where("repo_id = ?", repo.ID).Get(&dd)
	jsonOK(w, map[string]string{"template": dd.Template})
}

func (h *PRSettingsHandler) UpdateDefaultDescription(w http.ResponseWriter, r *http.Request) {
	repo, ok := h.resolveRepo(w, r)
	if !ok {
		return
	}
	callerID, _ := middleware.UserIDFromContext(r.Context())
	if !h.canManage(repo, callerID) {
		jsonError(w, "forbidden", http.StatusForbidden)
		return
	}

	var body struct {
		Template string `json:"template"`
	}
	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
		jsonError(w, "invalid body", http.StatusBadRequest)
		return
	}

	var dd models.RepoDefaultDescription
	found, _ := h.db.Where("repo_id = ?", repo.ID).Get(&dd)
	dd.RepoID = repo.ID
	dd.Template = body.Template
	if found {
		h.db.ID(dd.ID).Cols("template").Update(&dd)
	} else {
		h.db.Insert(&dd)
	}
	jsonOK(w, map[string]string{"template": dd.Template})
}

// ── Excluded files ────────────────────────────────────────────────────────────

func (h *PRSettingsHandler) GetExcludedFiles(w http.ResponseWriter, r *http.Request) {
	repo, ok := h.resolveRepo(w, r)
	if !ok {
		return
	}
	var ef models.RepoExcludedFiles
	h.db.Where("repo_id = ?", repo.ID).Get(&ef)
	jsonOK(w, map[string]string{"patterns": ef.Patterns})
}

func (h *PRSettingsHandler) UpdateExcludedFiles(w http.ResponseWriter, r *http.Request) {
	repo, ok := h.resolveRepo(w, r)
	if !ok {
		return
	}
	callerID, _ := middleware.UserIDFromContext(r.Context())
	if !h.canManage(repo, callerID) {
		jsonError(w, "forbidden", http.StatusForbidden)
		return
	}

	var body struct {
		Patterns string `json:"patterns"`
	}
	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
		jsonError(w, "invalid body", http.StatusBadRequest)
		return
	}

	var ef models.RepoExcludedFiles
	found, _ := h.db.Where("repo_id = ?", repo.ID).Get(&ef)
	ef.RepoID = repo.ID
	ef.Patterns = body.Patterns
	if found {
		h.db.ID(ef.ID).Cols("patterns").Update(&ef)
	} else {
		h.db.Insert(&ef)
	}
	jsonOK(w, map[string]string{"patterns": ef.Patterns})
}

// ── Helpers used by PR create ─────────────────────────────────────────────────

// AutoAssignReviewers inserts PrReviewer rows for all default reviewers of a repo.
func AutoAssignReviewers(db *xorm.Engine, repoID, prID int64) {
	var defaults []models.RepoDefaultReviewer
	db.Where("repo_id = ?", repoID).Find(&defaults)
	for _, dr := range defaults {
		db.Insert(&models.PrReviewer{PRID: prID, UserID: dr.UserID})
	}
}

// GetDefaultDescriptionTemplate returns the stored PR body template for a repo.
func GetDefaultDescriptionTemplate(db *xorm.Engine, repoID int64) string {
	var dd models.RepoDefaultDescription
	db.Where("repo_id = ?", repoID).Get(&dd)
	return dd.Template
}

// GetPrReviewers returns reviewer details for a PR.
type ReviewerInfo struct {
	UserID    int64  `json:"userId"`
	Username  string `json:"username"`
	AvatarURL string `json:"avatarUrl"`
}

func GetPrReviewers(db *xorm.Engine, prID int64) []ReviewerInfo {
	var rows []models.PrReviewer
	db.Where("pr_id = ?", prID).Find(&rows)
	result := make([]ReviewerInfo, 0, len(rows))
	for _, rv := range rows {
		var u models.User
		if found, _ := db.ID(rv.UserID).Get(&u); found {
			result = append(result, ReviewerInfo{UserID: u.ID, Username: u.Username, AvatarURL: u.AvatarURL})
		}
	}
	return result
}