game/internal/controller/controller.go

@@ -38,6 +38,10 @@ type Repo interface {
 	// SaveBattle stores a new battle protocol and battle meta data for turn t
 	SaveBattle(uint, *report.BattleReport, *game.BattleMeta) error
 
+	// LoadBattle reads battle's protocol for turn t and battle id.
+	// Returns false if battle with such id was never stored at turn t
+	LoadBattle(t uint, id uuid.UUID) (*report.BattleReport, bool, error)
+
 	// SaveBombing stores all prodused bombings for turn t
 	SaveBombings(uint, []*game.Bombing) error
 
@@ -143,6 +147,14 @@ func FetchOrder(configure func(*Param), actor string, turn uint) (order *order.U
 	return ec.fetchOrder(actor, turn)
 }
 
+func FetchBattle(configure func(*Param), turn uint, ID uuid.UUID) (b *report.BattleReport, exists bool, err error) {
+	ec, err := NewRepoController(configure)
+	if err != nil {
+		return nil, false, err
+	}
+	return ec.fetchBattle(turn, ID)
+}
+
 func BanishRace(configure func(*Param), actor string) error {
 	ec, err := NewRepoController(configure)
 	if err != nil {
@@ -261,6 +273,14 @@ func (ec *RepoController) fetchOrder(actor string, turn uint) (order *order.User
 	return
 }
 
+func (ec *RepoController) fetchBattle(turn uint, ID uuid.UUID) (order *report.BattleReport, exists bool, err error) {
+	err = ec.executeSafe(func(t uint, c *Controller) error {
+		order, exists, err = ec.Repo.LoadBattle(turn, ID)
+		return err
+	})
+	return
+}
+
 func (ec *RepoController) loadReport(actor string, turn uint) (r *report.Report, err error) {
 	execErr := ec.executeSafe(func(t uint, c *Controller) (exErr error) {
 		id, exErr := c.RaceID(actor)

game/internal/repo/game.go

@@ -13,6 +13,7 @@ package repo
 import (
 	"encoding/json"
 	"fmt"
+	"slices"
 
 	"galaxy/model/order"
 	"galaxy/model/report"
@@ -117,9 +118,25 @@ func loadMeta(s Storage) (*game.GameMeta, error) {
 	return result, nil
 }
 
-func saveMeta(s Storage, t uint, gm *game.GameMeta) error {
+func loadTurnMeta(s Storage, turn uint) (*game.GameMeta, error) {
+	var result *game.GameMeta = new(game.GameMeta)
+	path := fmt.Sprintf("%s/%s", TurnDir(turn), metaPath)
+	exist, err := s.Exists(path)
+	if err != nil {
+		return nil, NewStorageError(err)
+	}
+	if !exist {
+		return result, nil
+	}
+	if err := s.ReadSafe(path, result); err != nil {
+		return nil, NewStorageError(err)
+	}
+	return result, nil
+}
+
+func saveMeta(s Storage, turn uint, gm *game.GameMeta) error {
 	// save turn's meta
-	path := fmt.Sprintf("%s/%s", TurnDir(t), metaPath)
+	path := fmt.Sprintf("%s/%s", TurnDir(turn), metaPath)
 	if err := s.Write(path, gm); err != nil {
 		return NewStorageError(err)
 	}
@@ -131,27 +148,43 @@ func saveMeta(s Storage, t uint, gm *game.GameMeta) error {
 	return nil
 }
 
-func (r *repo) SaveBattle(t uint, b *report.BattleReport, m *game.BattleMeta) error {
+func (r *repo) LoadBattle(turn uint, id uuid.UUID) (*report.BattleReport, bool, error) {
+	meta, err := loadTurnMeta(r.s, turn)
+	if err != nil {
+		return nil, false, err
+	}
+	i := slices.IndexFunc(meta.Battles, func(m game.BattleMeta) bool { return m.BattleID == id })
+	if i < 0 {
+		return nil, false, nil
+	}
+	result, err := loadBattle(r.s, turn, meta.Battles[i].BattleID)
+	if err != nil {
+		return nil, false, err
+	}
+	return result, true, nil
+}
+
+func (r *repo) SaveBattle(turn uint, b *report.BattleReport, m *game.BattleMeta) error {
 	meta, err := loadMeta(r.s)
 	if err != nil {
 		return err
 	}
-	err = saveBattle(r.s, t, b)
+	err = saveBattle(r.s, turn, b)
 	if err != nil {
 		return err
 	}
 	meta.Battles = append(meta.Battles, *m)
-	return saveMeta(r.s, t, meta)
+	return saveMeta(r.s, turn, meta)
 }
 
-func saveBattle(s Storage, t uint, b *report.BattleReport) error {
-	path := fmt.Sprintf("%s/battle/%s.json", TurnDir(t), b.ID.String())
+func saveBattle(s Storage, turn uint, b *report.BattleReport) error {
+	path := fmt.Sprintf("%s/battle/%s.json", TurnDir(turn), b.ID.String())
 	exist, err := s.Exists(path)
 	if err != nil {
 		return NewStorageError(err)
 	}
 	if exist {
-		return NewStateError(fmt.Sprintf("battle %v for turn %d already has been saved", b.ID, t))
+		return NewStateError(fmt.Sprintf("battle %v for turn %d already has been saved", b.ID, turn))
 	}
 	if err := s.Write(path, b); err != nil {
 		return NewStorageError(err)
@@ -159,7 +192,23 @@ func saveBattle(s Storage, t uint, b *report.BattleReport) error {
 	return nil
 }
 
-func (r *repo) SaveBombings(t uint, b []*game.Bombing) error {
+func loadBattle(s Storage, turn uint, id uuid.UUID) (*report.BattleReport, error) {
+	path := fmt.Sprintf("%s/battle/%s.json", TurnDir(turn), id.String())
+	exist, err := s.Exists(path)
+	if err != nil {
+		return nil, NewStorageError(err)
+	}
+	if !exist {
+		return nil, NewStateError(fmt.Sprintf("battle %v for turn %d never was saved", id, turn))
+	}
+	result := new(report.BattleReport)
+	if err := s.ReadSafe(path, result); err != nil {
+		return nil, NewStorageError(err)
+	}
+	return result, nil
+}
+
+func (r *repo) SaveBombings(turn uint, b []*game.Bombing) error {
 	meta, err := loadMeta(r.s)
 	if err != nil {
 		return err
@@ -167,11 +216,11 @@ func (r *repo) SaveBombings(t uint, b []*game.Bombing) error {
 	for i := range b {
 		meta.Bombings = append(meta.Bombings, *b[i])
 	}
-	return saveMeta(r.s, t, meta)
+	return saveMeta(r.s, turn, meta)
 }
 
-func (r *repo) SaveReport(t uint, rep *report.Report) error {
-	return saveReport(r.s, t, rep)
+func (r *repo) SaveReport(turn uint, rep *report.Report) error {
+	return saveReport(r.s, turn, rep)
 }
 
 func saveReport(s Storage, t uint, v *report.Report) error {
@@ -182,12 +231,12 @@ func saveReport(s Storage, t uint, v *report.Report) error {
 	return nil
 }
 
-func (r *repo) LoadReport(t uint, id uuid.UUID) (*report.Report, error) {
-	return loadReport(r.s, t, id)
+func (r *repo) LoadReport(turn uint, id uuid.UUID) (*report.Report, error) {
+	return loadReport(r.s, turn, id)
 }
 
-func loadReport(s Storage, t uint, id uuid.UUID) (*report.Report, error) {
-	path := ReportDir(t, id)
+func loadReport(s Storage, turn uint, id uuid.UUID) (*report.Report, error) {
+	path := ReportDir(turn, id)
 	result := new(report.Report)
 	exist, err := s.Exists(path)
 	if err != nil {

game/internal/router/handler/battle.go

@@ -0,0 +1,37 @@
+package handler
+
+import (
+	"net/http"
+	"strconv"
+
+	"github.com/gin-gonic/gin"
+	"github.com/google/uuid"
+)
+
+func BattleHandler(c *gin.Context, executor CommandExecutor) {
+	turn := c.Param("turn")
+	t, err := strconv.Atoi(turn)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+	if t < 0 {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "turn number can't be negative"})
+		return
+	}
+	id := c.Param("uuid")
+	battleID, err := uuid.Parse(id)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+	r, exists, err := executor.FetchBattle(uint(t), battleID)
+	if errorResponse(c, err) {
+		return
+	}
+	if !exists {
+		c.JSON(http.StatusNotFound, gin.H{"error": "unknown battle"})
+		return
+	}
+	c.JSON(http.StatusOK, r)
+}

game/internal/router/handler/handler.go

@@ -17,6 +17,7 @@ import (
 
 	"github.com/gin-gonic/gin"
 	"github.com/go-playground/validator/v10"
+	"github.com/google/uuid"
 )
 
 type CommandExecutor interface {
@@ -29,6 +30,7 @@ type CommandExecutor interface {
 	Execute(cmd ...Command) error
 	ValidateOrder(actor string, cmd ...order.DecodableCommand) (*order.UserGamesOrder, error)
 	FetchOrder(actor string, turn uint) (*order.UserGamesOrder, bool, error)
+	FetchBattle(turn uint, ID uuid.UUID) (*report.BattleReport, bool, error)
 }
 
 type Command func(controller.Ctrl) error
@@ -86,6 +88,10 @@ func (e *executor) FetchOrder(actor string, turn uint) (*order.UserGamesOrder, b
 	return controller.FetchOrder(e.cfg, actor, turn)
 }
 
+func (e *executor) FetchBattle(turn uint, ID uuid.UUID) (*report.BattleReport, bool, error) {
+	return controller.FetchBattle(e.cfg, turn, ID)
+}
+
 func (e *executor) GenerateGame(races []string) (rest.StateResponse, error) {
 	s, err := controller.GenerateGame(e.cfg, races)
 	if err != nil {

game/internal/router/router.go

@@ -76,6 +76,7 @@ func setupRouter(executor handler.CommandExecutor) *gin.Engine {
 	groupV1.GET("/report", func(ctx *gin.Context) { handler.ReportHandler(ctx, executor) })
 	groupV1.PUT("/order", func(ctx *gin.Context) { handler.PutOrderHandler(ctx, executor) })
 	groupV1.GET("/order", func(ctx *gin.Context) { handler.GetOrderHandler(ctx, executor) })
+	groupV1.GET("/battle/:turn/:uuid", func(ctx *gin.Context) { handler.BattleHandler(ctx, executor) })
 
 	// /command is reserved for future use; any API request for orders should use /order
 	groupV1.PUT("/command", LimitMiddleware(1), func(ctx *gin.Context) { handler.CommandHandler(ctx, executor) })

game/internal/router/router_helper_test.go

@@ -68,6 +68,10 @@ func (e *dummyExecutor) FetchOrder(actor string, turn uint) (*order.UserGamesOrd
 	return e.FetchOrderResult, e.FetchOrderOK, e.FetchOrderErr
 }
 
+func (e *dummyExecutor) FetchBattle(turn uint, ID uuid.UUID) (*report.BattleReport, bool, error) {
+	return nil, false, nil
+}
+
 func (e *dummyExecutor) Execute(command ...handler.Command) error {
 	e.CommandsExecuted = len(command)
 	return nil

pkg/model/report/battle.go

@@ -7,31 +7,53 @@ import (
 )
 
 type BattleReport struct {
-	ID         uuid.UUID                 `json:"id"`
-	Planet     uint                      `json:"planet"`
-	PlanetName string                    `json:"planetName"`
-	Races      map[int]uuid.UUID         `json:"races"`
-	Ships      map[int]BattleReportGroup `json:"ships"`
-	Protocol   []BattleActionReport      `json:"protocol"`
+	// Battle unique ID
+	ID uuid.UUID `json:"id"`
+	// Planet number
+	Planet uint `json:"planet"`
+	// Planet name at battle start
+	PlanetName string `json:"planetName"`
+	// Races participating map: <key:RaceID>
+	Races map[int]uuid.UUID `json:"races"`
+	// Ships Groups participating map: <key:BattleReportGroup>
+	Ships map[int]BattleReportGroup `json:"ships"`
+	// Battle's firing protocol
+	Protocol []BattleActionReport `json:"protocol"`
 }
 
 type BattleReportGroup struct {
-	InBattle     bool             `json:"inBattle"`
-	Number       uint             `json:"num"`
-	NumberLeft   uint             `json:"numLeft"`
-	LoadQuantity Float            `json:"loadQuantity"`
-	Tech         map[string]Float `json:"tech"`
-	Race         string           `json:"race"`
-	ClassName    string           `json:"className"`
-	LoadType     string           `json:"loadType"`
+	// Name of the race
+	Race string `json:"race"`
+	// Name of the Ship Class.
+	// By design, ship's info MUST be present in Game's Repors in 'LocalShipClass' or 'OtherShipClass'
+	ClassName string `json:"className"`
+	// Ship Group's technologies mapping <tech:level>
+	Tech map[string]Float `json:"tech"`
+	// Initial number of ships in this group
+	Number uint `json:"num"`
+	// Number of ships left after battle
+	NumberLeft uint `json:"numLeft"`
+	// Type of cargo loaded
+	LoadType string `json:"loadType"`
+	// Quantity of cargo loaded
+	LoadQuantity Float `json:"loadQuantity"`
+	// A Race with its ships can be in Peace state with all participants,
+	// so no shots will be fired and no damage taken, participating only as viewer
+	// when InBattle=false
+	InBattle bool `json:"inBattle"`
 }
 
 type BattleActionReport struct {
-	Attacker          int  `json:"a"`
-	AttackerShipClass int  `json:"sa"`
-	Defender          int  `json:"d"`
-	DefenderShipClass int  `json:"sd"`
-	Destroyed         bool `json:"x"`
+	// `key` from BattleReport.Races map
+	Attacker int `json:"a"`
+	// `key` from BattleReport.Ships map
+	AttackerShipClass int `json:"sa"`
+	// `key` from BattleReport.Races map
+	Defender int `json:"d"`
+	// `key` from BattleReport.Ships map
+	DefenderShipClass int `json:"sd"`
+	// Was ship destroyed after attack or survived under shields
+	Destroyed bool `json:"x"`
 }
 
 func (b BattleReport) MarshalBinary() (data []byte, err error) {