package controller

import (
	"log/slog"
	"strconv"
	"strings"

	"github.com/gofiber/fiber/v2"

	"xiangj-adapter/internal/apperror"
	"xiangj-adapter/internal/model"
	"xiangj-adapter/internal/service"
)

type DataController struct {
	service *service.DataService
	log     *slog.Logger
}

func NewDataController(service *service.DataService, log *slog.Logger) *DataController {
	return &DataController{service: service, log: log}
}

func (c *DataController) GetData(ctx *fiber.Ctx) error {
	op := strings.ToLower(ctx.Query("op"))
	if op == "" {
		op = "select"
	}
	switch op {
	case "select":
		return c.handleSelect(ctx)
	default:
		return apperror.BadRequest("op not supported")
	}
}

func (c *DataController) handleSelect(ctx *fiber.Ctx) error {
	doid := ctx.Query("doid")
	table := strings.ToLower(lastSegment(doid))
	if table == "" {
		return apperror.BadRequest("doid is required")
	}

	offset, err := parseNonNegativeIntDefault(ctx.Query("offset"), "offset", 0)
	if err != nil {
		return err
	}

	count, err := parsePositiveIntDefault(ctx.Query("count"), "count", 100)
	if err != nil {
		return err
	}

	data, err := c.service.Select(ctx.Context(), table, offset, count)
	if err != nil {
		c.log.Error("select failed", "table", table, "err", err)
		return apperror.Internal("query failed")
	}

	return ctx.JSON(model.APIResponse{Data: data, Error: ""})
}

func lastSegment(input string) string {
	trimmed := strings.Trim(input, "/")
	if trimmed == "" {
		return ""
	}
	parts := strings.Split(trimmed, "/")
	return parts[len(parts)-1]
}

func parseNonNegativeInt(value, field string) (int, error) {
	if value == "" {
		return 0, apperror.BadRequest(field + " is required")
	}
	parsed, err := strconv.Atoi(value)
	if err != nil || parsed < 0 {
		return 0, apperror.BadRequest(field + " must be a non-negative integer")
	}
	return parsed, nil
}

func parsePositiveInt(value, field string) (int, error) {
	if value == "" {
		return 0, apperror.BadRequest(field + " is required")
	}
	parsed, err := strconv.Atoi(value)
	if err != nil || parsed <= 0 {
		return 0, apperror.BadRequest(field + " must be a positive integer")
	}
	return parsed, nil
}

func parseNonNegativeIntDefault(value, field string, defaultValue int) (int, error) {
	if value == "" {
		return defaultValue, nil
	}
	return parseNonNegativeInt(value, field)
}

func parsePositiveIntDefault(value, field string, defaultValue int) (int, error) {
	if value == "" {
		return defaultValue, nil
	}
	return parsePositiveInt(value, field)
}