package httpapi

import (
	"errors"
	"net/http"
	"strconv"
	"time"

	"watch-party-backend/internal/repo"
	"watch-party-backend/internal/service"

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

func NewRouter(svc service.EpisodeService) *gin.Engine {
	r := gin.New()
	r.Use(gin.Logger(), gin.Recovery())

	r.GET("healthz", healthzHandler)

	api := r.Group("/api")
	v1 := api.Group("/v1")

	v1.GET("/time", timeHandler)
	v1.GET("/current", getCurrentHandler(svc))
	v1.POST("/current", setCurrentHandler(svc))
	v1.POST("/archive", moveToArchiveHandler(svc))
	v1.GET("/shows", listShowsHandler(svc))
	v1.DELETE("/shows", deleteShowsHandler(svc))

	return r
}

// GET /healthz
func healthzHandler(c *gin.Context) {
	c.JSON(http.StatusOK, gin.H{"status": "ok"})
}

// GET /v1/time
func timeHandler(c *gin.Context) {
	now := time.Now().UTC().UnixMilli()
	c.Header("Cache-Control", "no-store, max-age=0, must-revalidate")
	c.JSON(http.StatusOK, gin.H{
		"now": now,
	})
}

// getCurrentHandler godoc
// @Summary      Get current show
// @Description  Returns the current row from `current` table.
// @Tags         current
// @Produce      json
// @Success      200 {object} CurrentResponse
// @Failure      404 {object} HTTPError "no current row found"
// @Failure      500 {object} HTTPError "query failed"
// @Router       /api/v1/current [get]
func getCurrentHandler(svc service.EpisodeService) gin.HandlerFunc {
	return func(c *gin.Context) {
		cur, err := svc.GetCurrent(c.Request.Context())
		if err != nil {
			if err == repo.ErrNotFound {
				c.JSON(http.StatusNotFound, gin.H{"error": "no current row found"})
				return
			}
			c.JSON(http.StatusInternalServerError, gin.H{"error": "query failed"})
			return
		}
		c.JSON(http.StatusOK, cur)
	}
}

// setCurrentHandler godoc
// @Summary      Set current show
// @Description  Set the current show ID and start time.
// @Tags         current
// @Accept       json
// @Produce      json
// @Param        body  body      SetCurrentReq  true  "Current show payload"
// @Success      200   {object}  CurrentResponse
// @Failure      400   {object}  HTTPError "invalid payload or invalid time"
// @Failure      404   {object}  HTTPError "id not found"
// @Failure      500   {object}  HTTPError "update failed"
// @Router       /api/v1/current [post]
func setCurrentHandler(svc service.EpisodeService) gin.HandlerFunc {
	return func(c *gin.Context) {
		var req SetCurrentReq
		if err := c.ShouldBindJSON(&req); err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": "invalid payload"})
			return
		}
		cur, err := svc.SetCurrent(c.Request.Context(), req.ID, req.StartTime)
		if err != nil {
			switch err {
			case service.ErrInvalidTime:
				c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
				return
			case repo.ErrNotFound:
				c.JSON(http.StatusNotFound, gin.H{"error": "id not found"})
				return
			default:
				c.JSON(http.StatusInternalServerError, gin.H{"error": "update failed"})
				return
			}
		}
		c.JSON(http.StatusOK, cur)
	}
}

// moveToArchiveHandler godoc
// @Summary      Move shows to archive
// @Description  Move one or many IDs from `current` to `current_archive`.
// @Tags         archive
// @Accept       json
// @Produce      json
// @Param        body  body      MoveReq  true  "IDs to move"
// @Success      200   {object}  MoveRes
// @Failure      400   {object}  HTTPError "empty ids"
// @Failure      500   {object}  HTTPError "move failed"
// @Router       /api/v1/archive [post]
func moveToArchiveHandler(svc service.EpisodeService) gin.HandlerFunc {
	return func(c *gin.Context) {
		var req MoveReq
		if err := c.ShouldBindJSON(&req); err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": "invalid payload"})
			return
		}
		ids := make([]int64, 0, len(req.IDs)+1)
		if req.ID != nil {
			ids = append(ids, *req.ID)
		}
		ids = append(ids, req.IDs...)

		res, err := svc.MoveToArchive(c.Request.Context(), ids)
		if err != nil {
			if err == service.ErrEmptyIDs {
				c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
				return
			}
			c.JSON(http.StatusInternalServerError, gin.H{"error": "move failed"})
			return
		}
		c.JSON(http.StatusOK, gin.H{
			"moved_ids":   res.MovedIDs,
			"deleted_ids": res.DeletedIDs,
			"skipped_ids": res.SkippedIDs,
			"inserted":    len(res.MovedIDs),
			"deleted":     len(res.DeletedIDs),
			"skipped":     len(res.SkippedIDs),
		})
	}
}

// listShowsHandler godoc
// @Summary      List current shows
// @Description  List all rows from `current` table.
// @Tags         shows
// @Produce      json
// @Success      200 {array} CurrentResponse
// @Failure      500 {object} HTTPError "list failed"
// @Router       /api/v1/shows [get]
func listShowsHandler(svc service.EpisodeService) gin.HandlerFunc {
	return func(c *gin.Context) {
		items, err := svc.ListAll(c.Request.Context())
		if err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": "list failed"})
			return
		}
		c.JSON(http.StatusOK, items)
	}
}

// deleteShowHandler godoc
// @Summary      Delete show
// @Description  Delete a row from `current` by ID.
// @Tags         shows
// @Produce      json
// @Param        id  query     int64  true  "Show ID"
// @Success      204 "No Content"
// @Failure      400 {object}  HTTPError "invalid id"
// @Failure      404 {object}  HTTPError "id not found"
// @Failure      500 {object}  HTTPError "delete failed"
// @Router       /api/v1/shows [delete]
func deleteShowsHandler(svc service.EpisodeService) gin.HandlerFunc {
	return func(c *gin.Context) {
		idStr := c.Query("id")
		id, err := strconv.ParseInt(idStr, 10, 64)
		if err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": "invalid id"})
			return
		}
		err = svc.Delete(c.Request.Context(), id)
		if err != nil {
			if errors.Is(err, repo.ErrNotFound) {
				c.JSON(http.StatusNotFound, gin.H{"error": "id not found"})
				return
			}
			c.JSON(http.StatusInternalServerError, gin.H{"error": "delete failed"})
			return
		}
		c.Status(http.StatusNoContent)
	}
}