package main

import (
	"log"
	"net/http"
	"strconv"

	"github.com/gin-gonic/gin"
)

// MovieList 电影列表
func MovieList(c *gin.Context) {
	response := gin.H{
		"code":    http.StatusInternalServerError,
		"message": "An unexpected error occurred.", // Default error message
		"data":    gin.H{"items": []Movie{}, "total": 0},
	}

	categoryName := c.Query("category") // Expects category name like "15min", "30min", etc.

	var moviesToPaginate []Movie

	// Filter movies by category if a categoryName is provided
	if categoryName != "" {
		for _, m := range movies { // 'movies' is the global slice from initMovie()
			if m.TimeCategory == categoryName {
				moviesToPaginate = append(moviesToPaginate, m)
			}
		}
	} else {
		// If no category is specified, use all movies
		// The global 'movies' slice is already sorted by category, then duration.
		// So, if no category is given, pagination will occur over this pre-sorted list.
		moviesToPaginate = movies
	}

	// Pagination logic
	page := 0 // Default to page 1 (0-indexed internally)
	spage := c.Query("page")
	if spage != "" {
		p, err := strconv.Atoi(spage)
		if err != nil || p < 1 { // Page numbers should be 1 or greater
			log.Println("Invalid page number:", spage, err)
			response["code"] = http.StatusBadRequest
			response["message"] = "Invalid page number. Must be a positive integer."
			c.JSON(http.StatusBadRequest, response) // Send response immediately for bad input
			return
		}
		page = p - 1 // Convert to 0-indexed
	}

	limit := 12 // Default limit
	slimit := c.Query("limit")
	if slimit != "" {
		l, err := strconv.Atoi(slimit)
		if err != nil || l < 1 { // Limit should be positive
			log.Println("Invalid limit number:", slimit, err)
			response["code"] = http.StatusBadRequest
			response["message"] = "Invalid limit number. Must be a positive integer."
			c.JSON(http.StatusBadRequest, response) // Send response immediately
			return
		}
		limit = l
	}

	// Calculate start and end for slicing
	start := page * limit
	end := start + limit

	// Handle cases where the requested page is out of bounds
	if start >= len(moviesToPaginate) {
		// Requested page is beyond the available data, return empty list for items
		response["data"] = gin.H{
			"items": []Movie{},
			"total": len(moviesToPaginate),
		}
		response["code"] = http.StatusOK
		response["message"] = "Success"
		c.JSON(http.StatusOK, response)
		return
	}

	if end > len(moviesToPaginate) {
		end = len(moviesToPaginate)
	}

	// Prepare successful response data
	responseData := gin.H{
		"items": moviesToPaginate[start:end],
		"total": len(moviesToPaginate),
	}

	response["code"] = http.StatusOK
	response["message"] = "Success"
	response["data"] = responseData
	c.JSON(http.StatusOK, response)
}