package services

import (
	"context"
	"encoding/json"
	"fmt"
	"log/slog"
	"strconv"

	"github.com/andyleap/hnh-map/internal/app"
	"github.com/andyleap/hnh-map/internal/app/store"
	"go.etcd.io/bbolt"
	"golang.org/x/crypto/bcrypt"
)

// AdminService handles admin business logic (users, settings, maps, wipe, tile ops).
type AdminService struct {
	st     *store.Store
	mapSvc *MapService
}

// NewAdminService creates an AdminService with the given store and map service.
func NewAdminService(st *store.Store, mapSvc *MapService) *AdminService {
	return &AdminService{st: st, mapSvc: mapSvc}
}

// ListUsers returns all usernames.
func (s *AdminService) ListUsers(ctx context.Context) ([]string, error) {
	var list []string
	err := s.st.View(ctx, func(tx *bbolt.Tx) error {
		return s.st.ForEachUser(tx, func(k, _ []byte) error {
			list = append(list, string(k))
			return nil
		})
	})
	return list, err
}

// GetUser returns a user's permissions by username.
func (s *AdminService) GetUser(ctx context.Context, username string) (auths app.Auths, found bool) {
	s.st.View(ctx, func(tx *bbolt.Tx) error {
		raw := s.st.GetUser(tx, username)
		if raw == nil {
			return nil
		}
		var u app.User
		json.Unmarshal(raw, &u)
		auths = u.Auths
		found = true
		return nil
	})
	return auths, found
}

// CreateOrUpdateUser creates or updates a user.
// Returns (true, nil) when admin user was created fresh (temp admin bootstrap).
func (s *AdminService) CreateOrUpdateUser(ctx context.Context, username string, pass string, auths app.Auths) (adminCreated bool, err error) {
	err = s.st.Update(ctx, func(tx *bbolt.Tx) error {
		existed := s.st.GetUser(tx, username) != nil
		u := app.User{}
		raw := s.st.GetUser(tx, username)
		if raw != nil {
			json.Unmarshal(raw, &u)
		}
		if pass != "" {
			hash, e := bcrypt.GenerateFromPassword([]byte(pass), bcrypt.DefaultCost)
			if e != nil {
				return e
			}
			u.Pass = hash
		}
		u.Auths = auths
		raw, _ = json.Marshal(u)
		if e := s.st.PutUser(tx, username, raw); e != nil {
			return e
		}
		if username == "admin" && !existed {
			adminCreated = true
		}
		return nil
	})
	return adminCreated, err
}

// DeleteUser removes a user and their tokens.
func (s *AdminService) DeleteUser(ctx context.Context, username string) error {
	return s.st.Update(ctx, func(tx *bbolt.Tx) error {
		uRaw := s.st.GetUser(tx, username)
		if uRaw != nil {
			var u app.User
			json.Unmarshal(uRaw, &u)
			for _, tok := range u.Tokens {
				s.st.DeleteToken(tx, tok)
			}
		}
		return s.st.DeleteUser(tx, username)
	})
}

// GetSettings returns the current server settings.
func (s *AdminService) GetSettings(ctx context.Context) (prefix string, defaultHide bool, title string, err error) {
	err = s.st.View(ctx, func(tx *bbolt.Tx) error {
		if v := s.st.GetConfig(tx, "prefix"); v != nil {
			prefix = string(v)
		}
		if v := s.st.GetConfig(tx, "defaultHide"); v != nil {
			defaultHide = true
		}
		if v := s.st.GetConfig(tx, "title"); v != nil {
			title = string(v)
		}
		return nil
	})
	return prefix, defaultHide, title, err
}

// UpdateSettings updates the specified server settings (nil fields are skipped).
func (s *AdminService) UpdateSettings(ctx context.Context, prefix *string, defaultHide *bool, title *string) error {
	return s.st.Update(ctx, func(tx *bbolt.Tx) error {
		if prefix != nil {
			s.st.PutConfig(tx, "prefix", []byte(*prefix))
		}
		if defaultHide != nil {
			if *defaultHide {
				s.st.PutConfig(tx, "defaultHide", []byte("1"))
			} else {
				s.st.DeleteConfig(tx, "defaultHide")
			}
		}
		if title != nil {
			s.st.PutConfig(tx, "title", []byte(*title))
		}
		return nil
	})
}

// ListMaps returns all maps for the admin panel.
func (s *AdminService) ListMaps(ctx context.Context) ([]app.MapInfo, error) {
	var maps []app.MapInfo
	err := s.st.View(ctx, func(tx *bbolt.Tx) error {
		return s.st.ForEachMap(tx, func(k, v []byte) error {
			mi := app.MapInfo{}
			json.Unmarshal(v, &mi)
			if id, err := strconv.Atoi(string(k)); err == nil {
				mi.ID = id
			}
			maps = append(maps, mi)
			return nil
		})
	})
	return maps, err
}

// GetMap returns a map by ID.
func (s *AdminService) GetMap(ctx context.Context, id int) (*app.MapInfo, bool) {
	var mi *app.MapInfo
	s.st.View(ctx, func(tx *bbolt.Tx) error {
		raw := s.st.GetMap(tx, id)
		if raw != nil {
			mi = &app.MapInfo{}
			json.Unmarshal(raw, mi)
			mi.ID = id
		}
		return nil
	})
	return mi, mi != nil
}

// UpdateMap updates a map's name, hidden, and priority fields.
func (s *AdminService) UpdateMap(ctx context.Context, id int, name string, hidden, priority bool) error {
	return s.st.Update(ctx, func(tx *bbolt.Tx) error {
		mi := app.MapInfo{}
		raw := s.st.GetMap(tx, id)
		if raw != nil {
			json.Unmarshal(raw, &mi)
		}
		mi.ID = id
		mi.Name = name
		mi.Hidden = hidden
		mi.Priority = priority
		raw, _ = json.Marshal(mi)
		return s.st.PutMap(tx, id, raw)
	})
}

// ToggleMapHidden toggles the hidden flag of a map and returns the updated map.
func (s *AdminService) ToggleMapHidden(ctx context.Context, id int) (*app.MapInfo, error) {
	var mi *app.MapInfo
	err := s.st.Update(ctx, func(tx *bbolt.Tx) error {
		raw := s.st.GetMap(tx, id)
		mi = &app.MapInfo{}
		if raw != nil {
			json.Unmarshal(raw, mi)
		}
		mi.ID = id
		mi.Hidden = !mi.Hidden
		raw, _ = json.Marshal(mi)
		return s.st.PutMap(tx, id, raw)
	})
	return mi, err
}

// Wipe deletes all grids, markers, tiles, and maps from the database.
func (s *AdminService) Wipe(ctx context.Context) error {
	return s.st.Update(ctx, func(tx *bbolt.Tx) error {
		for _, b := range [][]byte{
			store.BucketGrids,
			store.BucketMarkers,
			store.BucketTiles,
			store.BucketMaps,
		} {
			if s.st.BucketExists(tx, b) {
				if err := s.st.DeleteBucket(tx, b); err != nil {
					return err
				}
			}
		}
		return nil
	})
}

// WipeTile removes a tile at the given coordinates and rebuilds zoom levels.
func (s *AdminService) WipeTile(ctx context.Context, mapid, x, y int) error {
	c := app.Coord{X: x, Y: y}
	if err := s.st.Update(ctx, func(tx *bbolt.Tx) error {
		grids := tx.Bucket(store.BucketGrids)
		if grids == nil {
			return nil
		}
		var ids [][]byte
		err := grids.ForEach(func(k, v []byte) error {
			g := app.GridData{}
			if err := json.Unmarshal(v, &g); err != nil {
				return err
			}
			if g.Coord == c && g.Map == mapid {
				ids = append(ids, k)
			}
			return nil
		})
		if err != nil {
			return err
		}
		for _, id := range ids {
			grids.Delete(id)
		}
		return nil
	}); err != nil {
		return err
	}

	s.mapSvc.SaveTile(ctx, mapid, c, 0, "", -1)
	zc := c
	for z := 1; z <= app.MaxZoomLevel; z++ {
		zc = zc.Parent()
		s.mapSvc.UpdateZoomLevel(ctx, mapid, zc, z)
	}
	return nil
}

// SetCoords shifts all grid and tile coordinates by a delta.
func (s *AdminService) SetCoords(ctx context.Context, mapid, fx, fy, tx2, ty int) error {
	fc := app.Coord{X: fx, Y: fy}
	tc := app.Coord{X: tx2, Y: ty}
	diff := app.Coord{X: tc.X - fc.X, Y: tc.Y - fc.Y}

	var tds []*app.TileData
	if err := s.st.Update(ctx, func(tx *bbolt.Tx) error {
		grids := tx.Bucket(store.BucketGrids)
		if grids == nil {
			return nil
		}
		tiles := tx.Bucket(store.BucketTiles)
		if tiles == nil {
			return nil
		}
		mapZooms := tiles.Bucket([]byte(strconv.Itoa(mapid)))
		if mapZooms == nil {
			return nil
		}
		mapTiles := mapZooms.Bucket([]byte("0"))
		if err := grids.ForEach(func(k, v []byte) error {
			g := app.GridData{}
			if err := json.Unmarshal(v, &g); err != nil {
				return err
			}
			if g.Map == mapid {
				g.Coord.X += diff.X
				g.Coord.Y += diff.Y
				raw, _ := json.Marshal(g)
				grids.Put(k, raw)
			}
			return nil
		}); err != nil {
			return err
		}
		if err := mapTiles.ForEach(func(k, v []byte) error {
			td := &app.TileData{}
			if err := json.Unmarshal(v, td); err != nil {
				return err
			}
			td.Coord.X += diff.X
			td.Coord.Y += diff.Y
			tds = append(tds, td)
			return nil
		}); err != nil {
			return err
		}
		return tiles.DeleteBucket([]byte(strconv.Itoa(mapid)))
	}); err != nil {
		return err
	}

	ops := make([]TileOp, len(tds))
	for i, td := range tds {
		ops[i] = TileOp{MapID: td.MapID, X: td.Coord.X, Y: td.Coord.Y, File: td.File}
	}
	s.mapSvc.ProcessZoomLevels(ctx, ops)
	return nil
}

// HideMarker marks a marker as hidden.
func (s *AdminService) HideMarker(ctx context.Context, markerID string) error {
	return s.st.Update(ctx, func(tx *bbolt.Tx) error {
		_, idB, err := s.st.CreateMarkersBuckets(tx)
		if err != nil {
			return err
		}
		grid := s.st.GetMarkersGridBucket(tx)
		if grid == nil {
			return fmt.Errorf("markers grid bucket not found")
		}
		key := idB.Get([]byte(markerID))
		if key == nil {
			slog.Warn("marker not found", "id", markerID)
			return nil
		}
		raw := grid.Get(key)
		if raw == nil {
			return nil
		}
		m := app.Marker{}
		json.Unmarshal(raw, &m)
		m.Hidden = true
		raw, _ = json.Marshal(m)
		grid.Put(key, raw)
		return nil
	})
}

// RebuildZooms delegates to MapService.
func (s *AdminService) RebuildZooms(ctx context.Context) {
	s.mapSvc.RebuildZooms(ctx)
}