package handler

import (
	"bugulma/backend/internal/service"
	"net/http"
	"strconv"
	"time"

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

// PublicTransportHandler handles endpoints for public transport data
type PublicTransportHandler struct {
	service  *service.PublicTransportService
	schedule *service.ScheduleService
}

// NewPublicTransportHandler creates a new handler
func NewPublicTransportHandler(svc *service.PublicTransportService, schedule *service.ScheduleService) *PublicTransportHandler {
	return &PublicTransportHandler{service: svc, schedule: schedule}
}

// GetMetadata returns general metadata about the public transport dataset
func (h *PublicTransportHandler) GetMetadata(c *gin.Context) {
	c.JSON(http.StatusOK, h.service.GetMetadata())
}

// ListStops returns a list of common stops
func (h *PublicTransportHandler) ListStops(c *gin.Context) {
	stops := h.service.ListStops()
	c.JSON(http.StatusOK, gin.H{"stops": stops})
}

// GetStop returns a single stop by key
func (h *PublicTransportHandler) GetStop(c *gin.Context) {
	id := c.Param("id")
	if st, ok := h.service.GetStop(id); ok {
		c.JSON(http.StatusOK, st)
		return
	}
	c.JSON(http.StatusNotFound, gin.H{"error": "stop not found"})
}

// SearchStops searches stops by name
func (h *PublicTransportHandler) SearchStops(c *gin.Context) {
	q := c.Query("q")
	res := h.service.SearchStops(q)
	c.JSON(http.StatusOK, gin.H{"results": res})
}

// GetGTFSFile returns a raw GTFS file from the export directory
func (h *PublicTransportHandler) GetGTFSFile(c *gin.Context) {
	filename := c.Param("filename")
	content, err := h.service.ReadGTFSFile(filename)
	if err != nil {
		c.JSON(http.StatusNotFound, gin.H{"error": "file not found"})
		return
	}
	c.Data(http.StatusOK, "text/plain; charset=utf-8", []byte(content))
}

// GetNextDepartures returns upcoming departures for a stop
func (h *PublicTransportHandler) GetNextDepartures(c *gin.Context) {
	if h.schedule == nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "schedule service not available"})
		return
	}

	stopID := c.Param("id")
	fromStr := c.DefaultQuery("from", "")
	limitStr := c.DefaultQuery("limit", "10")

	var from time.Time
	var err error
	if fromStr == "" {
		from = time.Now().UTC()
	} else {
		from, err = time.Parse(time.RFC3339, fromStr)
		if err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": "invalid from time, expected RFC3339"})
			return
		}
	}

	limit, err := strconv.Atoi(limitStr)
	if err != nil || limit <= 0 {
		limit = 10
	}

	deps, err := h.schedule.GetNextDepartures(c.Request.Context(), stopID, from, limit)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"departures": deps})
}