package handler

import (
	"context"
	"strconv"
	"strings"

	"gcy_hpc_server/internal/model"
	"gcy_hpc_server/internal/server"
	"gcy_hpc_server/internal/service"

	"github.com/gin-gonic/gin"
	"go.uber.org/zap"
)

type folderServiceProvider interface {
	CreateFolder(ctx context.Context, name string, parentID *int64) (*model.FolderResponse, error)
	GetFolder(ctx context.Context, id int64) (*model.FolderResponse, error)
	ListFolders(ctx context.Context, parentID *int64) ([]model.FolderResponse, error)
	DeleteFolder(ctx context.Context, id int64) error
}

type FolderHandler struct {
	svc    folderServiceProvider
	logger *zap.Logger
}

func NewFolderHandler(svc *service.FolderService, logger *zap.Logger) *FolderHandler {
	return &FolderHandler{svc: svc, logger: logger}
}

func (h *FolderHandler) CreateFolder(c *gin.Context) {
	var req model.CreateFolderRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		h.logger.Warn("invalid request body for create folder", zap.Error(err))
		server.BadRequest(c, "invalid request body")
		return
	}
	if req.Name == "" {
		h.logger.Warn("missing folder name")
		server.BadRequest(c, "name is required")
		return
	}

	resp, err := h.svc.CreateFolder(c.Request.Context(), req.Name, req.ParentID)
	if err != nil {
		errStr := err.Error()
		if strings.Contains(errStr, "invalid folder name") || strings.Contains(errStr, "cannot be") {
			h.logger.Warn("invalid folder name", zap.String("name", req.Name), zap.Error(err))
			server.BadRequest(c, errStr)
			return
		}
		h.logger.Error("failed to create folder", zap.Error(err))
		server.InternalError(c, errStr)
		return
	}
	h.logger.Info("folder created", zap.Int64("id", resp.ID))
	server.Created(c, resp)
}

func (h *FolderHandler) GetFolder(c *gin.Context) {
	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
	if err != nil {
		h.logger.Warn("invalid folder id", zap.String("id", c.Param("id")))
		server.BadRequest(c, "invalid id")
		return
	}

	resp, err := h.svc.GetFolder(c.Request.Context(), id)
	if err != nil {
		if strings.Contains(err.Error(), "not found") {
			h.logger.Warn("folder not found", zap.Int64("id", id))
			server.NotFound(c, "folder not found")
			return
		}
		h.logger.Error("failed to get folder", zap.Int64("id", id), zap.Error(err))
		server.InternalError(c, err.Error())
		return
	}
	server.OK(c, resp)
}

func (h *FolderHandler) ListFolders(c *gin.Context) {
	var parentID *int64
	if q := c.Query("parent_id"); q != "" {
		pid, err := strconv.ParseInt(q, 10, 64)
		if err != nil {
			h.logger.Warn("invalid parent_id query param", zap.String("parent_id", q))
			server.BadRequest(c, "invalid parent_id")
			return
		}
		parentID = &pid
	}

	folders, err := h.svc.ListFolders(c.Request.Context(), parentID)
	if err != nil {
		h.logger.Error("failed to list folders", zap.Error(err))
		server.InternalError(c, err.Error())
		return
	}
	if folders == nil {
		folders = []model.FolderResponse{}
	}
	server.OK(c, folders)
}

func (h *FolderHandler) DeleteFolder(c *gin.Context) {
	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
	if err != nil {
		h.logger.Warn("invalid folder id for delete", zap.String("id", c.Param("id")))
		server.BadRequest(c, "invalid id")
		return
	}

	if err := h.svc.DeleteFolder(c.Request.Context(), id); err != nil {
		errStr := err.Error()
		if strings.Contains(errStr, "not empty") {
			h.logger.Warn("cannot delete non-empty folder", zap.Int64("id", id))
			server.BadRequest(c, "folder is not empty")
			return
		}
		if strings.Contains(errStr, "not found") {
			h.logger.Warn("folder not found for delete", zap.Int64("id", id))
			server.NotFound(c, "folder not found")
			return
		}
		h.logger.Error("failed to delete folder", zap.Int64("id", id), zap.Error(err))
		server.InternalError(c, errStr)
		return
	}
	h.logger.Info("folder deleted", zap.Int64("id", id))
	server.OK(c, gin.H{"message": "folder deleted"})
}