// Package httpapi 提供 REST 接口、静态资源托管与统一响应结构。
package httpapi

import (
	"database/sql"
	"io/fs"
	"log/slog"
	"net/http"
	"strings"
	"time"

	"git.yeij.top/AskaEth/Scoreboard/server/internal/auth"
	"git.yeij.top/AskaEth/Scoreboard/server/internal/middleware"
	"git.yeij.top/AskaEth/Scoreboard/server/internal/webui"
)

// DisplaySender 把大屏控制命令推给实时层；未接入时命令只记审计、不影响接口可用性。
type DisplaySender interface {
	SendDisplayCommand(action string, payload any) error
}

// Options 是构建路由所需的依赖。
type Options struct {
	Logger  *slog.Logger
	Version string
	// System 是系统库连接（users/sessions）。
	System *sql.DB
	// Event 是赛事库连接（teams/events/results/ledger/audit…）。
	Event *sql.DB
	// Auth 可选；为空时用 System 自动构建。
	Auth *auth.Service
	// DataDir 用于备份目录 data/backups。
	DataDir string
	// Display 可选，实时层接入后传入。
	Display DisplaySender
	// WS 可选，实时层的 WebSocket 处理器，挂到 /ws。
	WS http.Handler
	// WebFS 可选，默认使用内嵌前端资源。
	WebFS fs.FS
}

type server struct {
	logger  *slog.Logger
	version string
	sys     *sql.DB
	ev      *sql.DB
	auth    *auth.Service
	dataDir string
	display DisplaySender
	idem    *idempotencyStore
}

// New 组装并返回服务端的 HTTP 处理器。
func New(opts Options) http.Handler {
	logger := opts.Logger
	if logger == nil {
		logger = slog.Default()
	}
	svc := opts.Auth
	if svc == nil {
		svc = auth.New(opts.System, auth.Options{Logger: logger})
	}

	s := &server{
		logger:  logger,
		version: opts.Version,
		sys:     opts.System,
		ev:      opts.Event,
		auth:    svc,
		dataDir: opts.DataDir,
		display: opts.Display,
		idem:    newIdempotencyStore(10 * time.Minute),
	}

	mux := http.NewServeMux()
	s.routes(mux)
	s.exportRoutes(mux)
	s.rulesRoutes(mux)
	if opts.WS != nil {
		mux.Handle("/ws", opts.WS)
	}

	assets := opts.WebFS
	if assets == nil {
		var err error
		assets, err = webui.FS()
		if err != nil {
			logger.Error("前端资源不可用", "err", err)
		}
	}
	if assets != nil {
		mux.Handle("/", staticHandler(assets))
	}

	var h http.Handler = mux
	h = middleware.NewAuditor(opts.Event, logger).Middleware(h)
	h = middleware.RateLimitWrite(svc)(h)
	h = middleware.CSRF(h)
	h = middleware.Authenticate(svc)(h)
	h = middleware.Log(logger)(h)
	h = middleware.Recover(logger)(h)
	h = middleware.RequestID(h)
	return h
}

func middlewareUserID(r *http.Request) int64 {
	u := middleware.User(r.Context())
	if u.Role == auth.RoleGuest {
		return 0
	}
	return u.ID
}

// public 注册公开接口（guest 可读）。
func (s *server) public(fn handler) http.HandlerFunc { return s.handle(fn) }

// read 注册「guest 也不可读」的接口，权限不足一律 403。
func (s *server) read(role auth.Role, fn handler) http.HandlerFunc {
	return middleware.RequireRole(role)(s.handle(fn)).ServeHTTP
}

// write 注册写接口：未登录 401，角色不足 403；成功后按 X-Request-Id 支持幂等回放。
func (s *server) write(role auth.Role, fn handler) http.HandlerFunc {
	return middleware.RequireWrite(role)(s.cached(s.handle(fn))).ServeHTTP
}

// writeVoid 注册无返回体的写接口。
func (s *server) writeVoid(role auth.Role, fn func(w http.ResponseWriter, r *http.Request) error) http.HandlerFunc {
	return middleware.RequireWrite(role)(s.cached(s.handleVoid(fn))).ServeHTTP
}

func (s *server) routes(mux *http.ServeMux) {
	// 健康检查不走 {ok,data} 包装（05 第 7 节）。
	mux.HandleFunc("GET /api/health", func(w http.ResponseWriter, r *http.Request) {
		writeJSON(w, http.StatusOK, map[string]any{"ok": true, "version": s.version})
	})

	// 认证
	mux.HandleFunc("POST /api/auth/login", s.handle(s.login))
	mux.HandleFunc("POST /api/auth/logout", s.handle(s.logout))
	mux.HandleFunc("GET /api/auth/me", s.handle(s.me))

	// 系统配置（guest 一律 403）
	mux.HandleFunc("GET /api/settings", s.read(auth.RoleAdmin, s.getSettingsHandler))
	mux.HandleFunc("PUT /api/settings", s.write(auth.RoleAdmin, s.updateSettingsHandler))

	// 基础配置
	mux.HandleFunc("GET /api/teams", s.public(s.listTeamsHandler))
	mux.HandleFunc("POST /api/teams", s.write(auth.RoleRecorder, s.createTeamHandler))
	mux.HandleFunc("GET /api/teams/{id}", s.public(s.getTeamHandler))
	mux.HandleFunc("PUT /api/teams/{id}", s.write(auth.RoleRecorder, s.updateTeamHandler))
	mux.HandleFunc("DELETE /api/teams/{id}", s.writeVoid(auth.RoleRecorder, s.deleteTeamHandler))

	mux.HandleFunc("GET /api/sports", s.public(s.listSportsHandler))
	mux.HandleFunc("POST /api/sports", s.write(auth.RoleRecorder, s.createSportHandler))
	mux.HandleFunc("GET /api/sports/{id}", s.public(s.getSportHandler))
	mux.HandleFunc("PUT /api/sports/{id}", s.write(auth.RoleRecorder, s.updateSportHandler))
	mux.HandleFunc("DELETE /api/sports/{id}", s.writeVoid(auth.RoleRecorder, s.deleteSportHandler))

	mux.HandleFunc("GET /api/events", s.public(s.listEventsHandler))
	mux.HandleFunc("POST /api/events", s.write(auth.RoleRecorder, s.createEventHandler))
	mux.HandleFunc("GET /api/events/{id}", s.public(s.getEventHandler))
	mux.HandleFunc("PUT /api/events/{id}", s.write(auth.RoleRecorder, s.updateEventHandler))
	mux.HandleFunc("DELETE /api/events/{id}", s.writeVoid(auth.RoleRecorder, s.deleteEventHandler))
	mux.HandleFunc("GET /api/events/{id}/entries", s.public(s.listEntriesHandler))
	mux.HandleFunc("GET /api/events/{id}/categories", s.public(s.listCategoriesHandler))
	mux.HandleFunc("PUT /api/events/{id}/categories", s.write(auth.RoleRecorder, s.replaceCategoriesHandler))
	mux.HandleFunc("GET /api/events/{id}/channels", s.public(s.listChannelsHandler))
	mux.HandleFunc("PUT /api/events/{id}/channels", s.write(auth.RoleRecorder, s.replaceChannelsHandler))

	mux.HandleFunc("GET /api/scoring-profiles", s.public(s.listProfilesHandler))
	mux.HandleFunc("POST /api/scoring-profiles", s.write(auth.RoleRecorder, s.createProfileHandler))
	mux.HandleFunc("GET /api/scoring-profiles/{id}", s.public(s.getProfileHandler))
	mux.HandleFunc("PUT /api/scoring-profiles/{id}", s.write(auth.RoleRecorder, s.updateProfileHandler))

	mux.HandleFunc("GET /api/athletes", s.public(s.listAthletesHandler))
	mux.HandleFunc("POST /api/athletes", s.write(auth.RoleRecorder, s.createAthleteHandler))
	mux.HandleFunc("GET /api/athletes/{id}", s.public(s.getAthleteHandler))
	mux.HandleFunc("PUT /api/athletes/{id}", s.write(auth.RoleRecorder, s.updateAthleteHandler))
	mux.HandleFunc("DELETE /api/athletes/{id}", s.writeVoid(auth.RoleRecorder, s.deleteAthleteHandler))

	mux.HandleFunc("POST /api/entries/import", s.write(auth.RoleRecorder, s.importEntriesHandler))

	// 成绩
	mux.HandleFunc("GET /api/results", s.public(s.listResultsHandler))
	mux.HandleFunc("PUT /api/results/draft", s.write(auth.RoleRecorder, s.saveDraftHandler))
	mux.HandleFunc("POST /api/results/publish", s.write(auth.RoleRecorder, s.publishHandler))
	mux.HandleFunc("POST /api/results/unpublish", s.write(auth.RoleRecorder, s.unpublishHandler))
	mux.HandleFunc("POST /api/results/{id}/void", s.write(auth.RoleRecorder, s.voidResultHandler))

	// 积分与排名
	mux.HandleFunc("GET /api/standings", s.public(s.standingsHandler))
	mux.HandleFunc("GET /api/standings/athletes", s.public(s.athleteStandingsHandler))
	mux.HandleFunc("GET /api/standings/teams/{id}/breakdown", s.public(s.breakdownHandler))
	mux.HandleFunc("GET /api/adjustments", s.public(s.listAdjustmentsHandler))
	mux.HandleFunc("POST /api/adjustments", s.write(auth.RoleRecorder, s.createAdjustmentHandler))
	mux.HandleFunc("POST /api/adjustments/{id}/void", s.write(auth.RoleRecorder, s.voidAdjustmentHandler))

	// 纪录
	mux.HandleFunc("GET /api/records", s.public(s.listRecordsHandler))
	mux.HandleFunc("POST /api/record-breaks", s.write(auth.RoleRecorder, s.createRecordBreakHandler))
	mux.HandleFunc("POST /api/record-breaks/{id}/approve", s.write(auth.RoleRecorder, s.approveRecordBreakHandler))

	// 大屏控制与运维
	mux.HandleFunc("POST /api/display/command", s.write(auth.RoleRecorder, s.displayCommandHandler))
	mux.HandleFunc("GET /api/audit-logs", s.read(auth.RoleAdmin, s.listAuditLogsHandler))
	mux.HandleFunc("POST /api/backup", s.write(auth.RoleAdmin, s.backupHandler))

	// 由其他模块负责的接口：先占位，避免落到静态资源处理器。
	mux.HandleFunc("/api/export/", s.notWired("导出"))
	mux.HandleFunc("/api/rules/", s.notWired("规则导入导出"))
	mux.HandleFunc("/api/", func(w http.ResponseWriter, r *http.Request) {
		writeAPIError(w, s.logger, notFound("接口不存在"))
	})
}

// notWired 为待接线的接口返回 501，避免请求被静态资源兜底成 HTML。
func (s *server) notWired(name string) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		writeAPIError(w, s.logger, notImplemented(name+"接口尚未接入"))
	}
}

// staticHandler 把 URL 映射到多页面前端产物。
//
//	/            → index.html
//	/display     → display.html
//	/admin       → admin.html
//	/其他         → 按文件路径查找
func staticHandler(assets fs.FS) http.Handler {
	files := http.FileServerFS(assets)

	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		p := strings.TrimPrefix(r.URL.Path, "/")

		switch p {
		case "", "index.html":
			http.ServeFileFS(w, r, assets, "index.html")
		case "display", "display/":
			http.ServeFileFS(w, r, assets, "display.html")
		case "admin", "admin/":
			http.ServeFileFS(w, r, assets, "admin.html")
		default:
			if _, err := fs.Stat(assets, p); err != nil {
				http.NotFound(w, r)
				return
			}
			files.ServeHTTP(w, r)
		}
	})
}