package handler

import (
	"strconv"

	"github.com/gin-gonic/gin"

	"carrot_bbs/internal/pkg/response"
	"carrot_bbs/internal/service"
)

type ScheduleHandler struct {
	scheduleService service.ScheduleService
}

func NewScheduleHandler(scheduleService service.ScheduleService) *ScheduleHandler {
	return &ScheduleHandler{scheduleService: scheduleService}
}

type createScheduleCourseRequest struct {
	Name         string `json:"name" binding:"required"`
	Teacher      string `json:"teacher"`
	Location     string `json:"location"`
	DayOfWeek    int    `json:"day_of_week" binding:"required"`
	StartSection int    `json:"start_section" binding:"required"`
	EndSection   int    `json:"end_section" binding:"required"`
	Weeks        []int  `json:"weeks" binding:"required,min=1"`
	Color        string `json:"color"`
}

type updateScheduleCourseRequest = createScheduleCourseRequest

func (h *ScheduleHandler) ListCourses(c *gin.Context) {
	userID := c.GetString("user_id")
	if userID == "" {
		response.Unauthorized(c, "")
		return
	}

	week := 0
	if rawWeek := c.Query("week"); rawWeek != "" {
		parsed, err := strconv.Atoi(rawWeek)
		if err != nil {
			response.BadRequest(c, "invalid week")
			return
		}
		week = parsed
	}

	list, err := h.scheduleService.ListCourses(userID, week)
	if err != nil {
		response.HandleError(c, err, "failed to list schedule courses")
		return
	}
	response.Success(c, gin.H{"list": list})
}

func (h *ScheduleHandler) CreateCourse(c *gin.Context) {
	userID := c.GetString("user_id")
	if userID == "" {
		response.Unauthorized(c, "")
		return
	}

	var req createScheduleCourseRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, err.Error())
		return
	}

	created, err := h.scheduleService.CreateCourse(userID, service.CreateScheduleCourseInput{
		Name:         req.Name,
		Teacher:      req.Teacher,
		Location:     req.Location,
		DayOfWeek:    req.DayOfWeek,
		StartSection: req.StartSection,
		EndSection:   req.EndSection,
		Weeks:        req.Weeks,
		Color:        req.Color,
	})
	if err != nil {
		response.HandleError(c, err, "failed to create schedule course")
		return
	}
	response.SuccessWithMessage(c, "course created", gin.H{"course": created})
}

func (h *ScheduleHandler) UpdateCourse(c *gin.Context) {
	userID := c.GetString("user_id")
	if userID == "" {
		response.Unauthorized(c, "")
		return
	}
	courseID := c.Param("id")
	if courseID == "" {
		response.BadRequest(c, "invalid course id")
		return
	}

	var req updateScheduleCourseRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, err.Error())
		return
	}

	updated, err := h.scheduleService.UpdateCourse(userID, courseID, service.CreateScheduleCourseInput{
		Name:         req.Name,
		Teacher:      req.Teacher,
		Location:     req.Location,
		DayOfWeek:    req.DayOfWeek,
		StartSection: req.StartSection,
		EndSection:   req.EndSection,
		Weeks:        req.Weeks,
		Color:        req.Color,
	})
	if err != nil {
		response.HandleError(c, err, "failed to update schedule course")
		return
	}
	response.SuccessWithMessage(c, "course updated", gin.H{"course": updated})
}

func (h *ScheduleHandler) DeleteCourse(c *gin.Context) {
	userID := c.GetString("user_id")
	if userID == "" {
		response.Unauthorized(c, "")
		return
	}
	courseID := c.Param("id")
	if courseID == "" {
		response.BadRequest(c, "invalid course id")
		return
	}

	if err := h.scheduleService.DeleteCourse(userID, courseID); err != nil {
		response.HandleError(c, err, "failed to delete schedule course")
		return
	}
	response.SuccessWithMessage(c, "course deleted", nil)
}