package handlers

import (
	"Yimaru-Backend/internal/domain"
	"Yimaru-Backend/internal/services/courses"
	"Yimaru-Backend/internal/services/modules"
	"context"
	"errors"
	"strconv"

	"github.com/gofiber/fiber/v2"
)

// CreateModule godoc
// @Summary Create module
// @Description Create a module under a course; parent program is taken from the course.
// @Tags modules
// @Accept json
// @Produce json
// @Param courseId path int true "Course ID"
// @Param body body domain.CreateModuleInput true "Module"
// @Success 201 {object} domain.Response
// @Failure 400 {object} domain.ErrorResponse
// @Router /api/v1/courses/{courseId}/modules [post]
func (h *Handler) CreateModule(c *fiber.Ctx) error {
	courseID, err := strconv.ParseInt(c.Params("courseId"), 10, 64)
	if err != nil {
		return c.Status(fiber.StatusBadRequest).JSON(domain.ErrorResponse{
			Message: "Invalid course id",
			Error:   err.Error(),
		})
	}
	var req domain.CreateModuleInput
	if err := c.BodyParser(&req); err != nil {
		return c.Status(fiber.StatusBadRequest).JSON(domain.ErrorResponse{
			Message: "Invalid request body",
			Error:   err.Error(),
		})
	}
	if valErrs, ok := h.validator.Validate(c, req); !ok {
		return c.Status(fiber.StatusBadRequest).JSON(domain.ErrorResponse{
			Message: "Validation failed",
			Error:   firstValidationError(valErrs),
		})
	}
	mod, err := h.moduleSvc.Create(c.Context(), courseID, req)
	if err != nil {
		if errors.Is(err, courses.ErrCourseNotFound) {
			return c.Status(fiber.StatusNotFound).JSON(domain.ErrorResponse{
				Message: "Course not found",
				Error:   err.Error(),
			})
		}
		return c.Status(fiber.StatusInternalServerError).JSON(domain.ErrorResponse{
			Message: "Failed to create module",
			Error:   err.Error(),
		})
	}
	actorID := c.Locals("user_id").(int64)
	actorRole := string(c.Locals("role").(domain.Role))
	ip := c.IP()
	ua := c.Get("User-Agent")
	rid := mod.ID
	go h.activityLogSvc.RecordAction(context.Background(), &actorID, &actorRole, domain.ActionModuleCreated, domain.ResourceModule, &rid, "Created module: "+mod.Name, nil, &ip, &ua)

	return c.Status(fiber.StatusCreated).JSON(domain.Response{
		Message:    "Module created successfully",
		Data:       mod,
		Success:    true,
		StatusCode: fiber.StatusCreated,
	})
}

// ListModulesByCourse godoc
// @Summary List modules for a course
// @Tags modules
// @Produce json
// @Param courseId path int true "Course ID"
// @Param limit query int false "Page size" default(20)
// @Param offset query int false "Offset" default(0)
// @Success 200 {object} domain.Response
// @Router /api/v1/courses/{courseId}/modules [get]
func (h *Handler) ListModulesByCourse(c *fiber.Ctx) error {
	courseID, err := strconv.ParseInt(c.Params("courseId"), 10, 64)
	if err != nil {
		return c.Status(fiber.StatusBadRequest).JSON(domain.ErrorResponse{
			Message: "Invalid course id",
			Error:   err.Error(),
		})
	}
	limit, _ := strconv.Atoi(c.Query("limit", "20"))
	offset, _ := strconv.Atoi(c.Query("offset", "0"))
	items, total, err := h.moduleSvc.ListByCourse(c.Context(), courseID, int32(limit), int32(offset))
	if err != nil {
		if errors.Is(err, courses.ErrCourseNotFound) {
			return c.Status(fiber.StatusNotFound).JSON(domain.ErrorResponse{
				Message: "Course not found",
				Error:   err.Error(),
			})
		}
		return c.Status(fiber.StatusInternalServerError).JSON(domain.ErrorResponse{
			Message: "Failed to list modules",
			Error:   err.Error(),
		})
	}
	return c.JSON(domain.Response{
		Message: "Modules retrieved successfully",
		Data: fiber.Map{
			"modules":     items,
			"total_count": total,
			"limit":       limit,
			"offset":      offset,
		},
		Success:    true,
		StatusCode: fiber.StatusOK,
	})
}

// GetModule godoc
// @Tags modules
// @Param id path int true "Module ID"
// @Success 200 {object} domain.Response
// @Router /api/v1/modules/{id} [get]
func (h *Handler) GetModule(c *fiber.Ctx) error {
	id, err := strconv.ParseInt(c.Params("id"), 10, 64)
	if err != nil {
		return c.Status(fiber.StatusBadRequest).JSON(domain.ErrorResponse{
			Message: "Invalid module id",
			Error:   err.Error(),
		})
	}
	mod, err := h.moduleSvc.GetByID(c.Context(), id)
	if err != nil {
		if errors.Is(err, modules.ErrModuleNotFound) {
			return c.Status(fiber.StatusNotFound).JSON(domain.ErrorResponse{
				Message: "Module not found",
				Error:   err.Error(),
			})
		}
		return c.Status(fiber.StatusInternalServerError).JSON(domain.ErrorResponse{
			Message: "Failed to load module",
			Error:   err.Error(),
		})
	}
	return c.JSON(domain.Response{
		Message:    "Module retrieved successfully",
		Data:       mod,
		Success:    true,
		StatusCode: fiber.StatusOK,
	})
}

// UpdateModule godoc
// @Tags modules
// @Param id path int true "Module ID"
// @Param body body domain.UpdateModuleInput true "Fields to update"
// @Router /api/v1/modules/{id} [put]
func (h *Handler) UpdateModule(c *fiber.Ctx) error {
	id, err := strconv.ParseInt(c.Params("id"), 10, 64)
	if err != nil {
		return c.Status(fiber.StatusBadRequest).JSON(domain.ErrorResponse{
			Message: "Invalid module id",
			Error:   err.Error(),
		})
	}
	var req domain.UpdateModuleInput
	if err := c.BodyParser(&req); err != nil {
		return c.Status(fiber.StatusBadRequest).JSON(domain.ErrorResponse{
			Message: "Invalid request body",
			Error:   err.Error(),
		})
	}
	mod, err := h.moduleSvc.Update(c.Context(), id, req)
	if err != nil {
		if errors.Is(err, modules.ErrModuleNotFound) {
			return c.Status(fiber.StatusNotFound).JSON(domain.ErrorResponse{
				Message: "Module not found",
				Error:   err.Error(),
			})
		}
		return c.Status(fiber.StatusInternalServerError).JSON(domain.ErrorResponse{
			Message: "Failed to update module",
			Error:   err.Error(),
		})
	}
	actorID := c.Locals("user_id").(int64)
	actorRole := string(c.Locals("role").(domain.Role))
	ip := c.IP()
	ua := c.Get("User-Agent")
	rid := mod.ID
	go h.activityLogSvc.RecordAction(context.Background(), &actorID, &actorRole, domain.ActionModuleUpdated, domain.ResourceModule, &rid, "Updated module: "+mod.Name, nil, &ip, &ua)

	return c.JSON(domain.Response{
		Message:    "Module updated successfully",
		Data:       mod,
		Success:    true,
		StatusCode: fiber.StatusOK,
	})
}

// DeleteModule godoc
// @Tags modules
// @Param id path int true "Module ID"
// @Router /api/v1/modules/{id} [delete]
func (h *Handler) DeleteModule(c *fiber.Ctx) error {
	id, err := strconv.ParseInt(c.Params("id"), 10, 64)
	if err != nil {
		return c.Status(fiber.StatusBadRequest).JSON(domain.ErrorResponse{
			Message: "Invalid module id",
			Error:   err.Error(),
		})
	}
	if err := h.moduleSvc.Delete(c.Context(), id); err != nil {
		if errors.Is(err, modules.ErrModuleNotFound) {
			return c.Status(fiber.StatusNotFound).JSON(domain.ErrorResponse{
				Message: "Module not found",
				Error:   err.Error(),
			})
		}
		return c.Status(fiber.StatusInternalServerError).JSON(domain.ErrorResponse{
			Message: "Failed to delete module",
			Error:   err.Error(),
		})
	}
	actorID := c.Locals("user_id").(int64)
	actorRole := string(c.Locals("role").(domain.Role))
	ip := c.IP()
	ua := c.Get("User-Agent")
	go h.activityLogSvc.RecordAction(context.Background(), &actorID, &actorRole, domain.ActionModuleDeleted, domain.ResourceModule, &id, "Deleted module", nil, &ip, &ua)

	return c.JSON(domain.Response{
		Message:    "Module deleted successfully",
		Success:    true,
		StatusCode: fiber.StatusOK,
	})
}