package app

import (
	"encoding/json"
	"io"
	"log"
	"net/http"
	"strconv"
	"time"

	"github.com/andyleap/hnh-map/internal/app/store"
	"go.etcd.io/bbolt"
)

func (a *App) updatePositions(rw http.ResponseWriter, req *http.Request) {
	defer req.Body.Close()
	craws := map[string]struct {
		Name   string
		GridID string
		Coords struct {
			X, Y int
		}
		Type string
	}{}
	buf, err := io.ReadAll(req.Body)
	if err != nil {
		log.Println("Error reading position update json: ", err)
		return
	}
	err = json.Unmarshal(buf, &craws)
	if err != nil {
		log.Println("Error decoding position update json: ", err)
		log.Println("Original json: ", string(buf))
		return
	}
	// Read grid data first (inside db.View), then update characters (with chmu only).
	// Avoid holding db.View and chmu simultaneously to prevent deadlock.
	gridDataByID := make(map[string]GridData)
	a.db.View(func(tx *bbolt.Tx) error {
		grids := tx.Bucket(store.BucketGrids)
		if grids == nil {
			return nil
		}
		for _, craw := range craws {
			grid := grids.Get([]byte(craw.GridID))
			if grid != nil {
				var gd GridData
				if json.Unmarshal(grid, &gd) == nil {
					gridDataByID[craw.GridID] = gd
				}
			}
		}
		return nil
	})

	a.chmu.Lock()
	defer a.chmu.Unlock()
	for id, craw := range craws {
		gd, ok := gridDataByID[craw.GridID]
		if !ok {
			continue
		}
		idnum, _ := strconv.Atoi(id)
		c := Character{
			Name: craw.Name,
			ID:   idnum,
			Map:  gd.Map,
			Position: Position{
				X: craw.Coords.X + (gd.Coord.X * 100),
				Y: craw.Coords.Y + (gd.Coord.Y * 100),
			},
			Type:    craw.Type,
			updated: time.Now(),
		}
		old, ok := a.characters[id]
		if !ok {
			a.characters[id] = c
		} else {
			if old.Type == "player" {
				if c.Type == "player" {
					a.characters[id] = c
				} else {
					old.Position = c.Position
					a.characters[id] = old
				}
			} else if old.Type != "unknown" {
				if c.Type != "unknown" {
					a.characters[id] = c
				} else {
					old.Position = c.Position
					a.characters[id] = old
				}
			} else {
				a.characters[id] = c
			}
		}
	}
}