package main

import (
	"database/sql"
	"encoding/csv"
	"encoding/json"
	"fmt"
	"net/http"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"time"
)

func registerCompetitionRoutes(mux *http.ServeMux) {
	mux.HandleFunc("GET /api/competitions", requireAuth(handleListCompetitions))
	mux.HandleFunc("POST /api/competitions", requireAdmin(handleCreateCompetition))
	mux.HandleFunc("GET /api/competitions/{id}", requireAuth(handleGetCompetition))
	mux.HandleFunc("PATCH /api/competitions/{id}", requireAuth(handleUpdateCompetition))
	mux.HandleFunc("DELETE /api/competitions/{id}", requireAdmin(handleDeleteCompetition))
	mux.HandleFunc("POST /api/competitions/{id}/close", requireAdmin(handleCloseCompetition))
	mux.HandleFunc("POST /api/competitions/{id}/reopen", requireAdmin(handleReopenCompetition))
	mux.HandleFunc("GET /api/competitions/{id}/members", requireAuth(handleListMembers))
	mux.HandleFunc("POST /api/competitions/{id}/members", requireAuth(handleAddMember))
	mux.HandleFunc("DELETE /api/competitions/{id}/members/{uid}", requireAuth(handleRemoveMember))
}

func userRole(competitionID, userID int64) (string, error) {
	var role string
	err := db.QueryRow("SELECT role FROM competition_users WHERE competition_id=? AND user_id=?", competitionID, userID).Scan(&role)
	if err == sql.ErrNoRows {
		return "", nil
	}
	return role, err
}

func canAccessCompetition(u *User, competitionID int64) (string, bool) {
	if u.IsSystemAdmin {
		return "system_admin", true
	}
	role, err := userRole(competitionID, u.ID)
	if err != nil || role == "" {
		return "", false
	}
	return role, true
}

func handleListCompetitions(w http.ResponseWriter, r *http.Request) {
	u := userFromCtx(r)
	var rows *sql.Rows
	var err error
	if u.IsSystemAdmin {
		rows, err = db.Query("SELECT id,name,allow_any_scorer_edit,rules_language,closed,closed_at,created_at FROM competitions ORDER BY created_at DESC")
	} else {
		rows, err = db.Query(`SELECT c.id,c.name,c.allow_any_scorer_edit,c.rules_language,c.closed,c.closed_at,c.created_at,cu.role
			FROM competitions c JOIN competition_users cu ON cu.competition_id=c.id
			WHERE cu.user_id=? ORDER BY c.created_at DESC`, u.ID)
	}
	if err != nil {
		writeError(w, http.StatusInternalServerError, "db_error")
		return
	}
	defer rows.Close()
	out := []Competition{}
	for rows.Next() {
		var c Competition
		var allow, closed int
		if u.IsSystemAdmin {
			rows.Scan(&c.ID, &c.Name, &allow, &c.RulesLanguage, &closed, &c.ClosedAt, &c.CreatedAt)
			c.Role = "system_admin"
		} else {
			rows.Scan(&c.ID, &c.Name, &allow, &c.RulesLanguage, &closed, &c.ClosedAt, &c.CreatedAt, &c.Role)
		}
		c.AllowAnyScorerEdit = allow == 1
		c.Closed = closed == 1
		out = append(out, c)
	}
	writeJSON(w, http.StatusOK, out)
}

func handleCreateCompetition(w http.ResponseWriter, r *http.Request) {
	var req struct {
		Name               string `json:"name"`
		AllowAnyScorerEdit bool   `json:"allow_any_scorer_edit"`
		RulesLanguage      string `json:"rules_language"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid_body")
		return
	}
	if req.Name == "" {
		writeError(w, http.StatusBadRequest, "missing_name")
		return
	}
	if len(req.Name) > 200 {
		writeError(w, http.StatusBadRequest, "too_long")
		return
	}
	allow := 0
	if req.AllowAnyScorerEdit {
		allow = 1
	}
	lang := normalizeRulesLanguage(req.RulesLanguage)
	res, err := db.Exec("INSERT INTO competitions(name,allow_any_scorer_edit,rules_language) VALUES(?,?,?)", req.Name, allow, lang)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "db_error")
		return
	}
	id, _ := res.LastInsertId()
	c := Competition{ID: id, Name: req.Name, AllowAnyScorerEdit: req.AllowAnyScorerEdit, RulesLanguage: lang}
	writeJSON(w, http.StatusCreated, c)
}

func normalizeRulesLanguage(lang string) string {
	if lang == "" {
		return "en"
	}
	rulesMu.RLock()
	_, ok := rules[lang]
	rulesMu.RUnlock()
	if !ok {
		return "en"
	}
	return lang
}

func handleGetCompetition(w http.ResponseWriter, r *http.Request) {
	id, err := strconv.ParseInt(r.PathValue("id"), 10, 64)
	if err != nil {
		writeError(w, http.StatusBadRequest, "invalid_id")
		return
	}
	u := userFromCtx(r)
	role, ok := canAccessCompetition(u, id)
	if !ok {
		writeError(w, http.StatusForbidden, "forbidden")
		return
	}
	var c Competition
	var allow, closed int
	err = db.QueryRow("SELECT id,name,allow_any_scorer_edit,rules_language,closed,closed_at,created_at FROM competitions WHERE id=?", id).
		Scan(&c.ID, &c.Name, &allow, &c.RulesLanguage, &closed, &c.ClosedAt, &c.CreatedAt)
	if err != nil {
		writeError(w, http.StatusNotFound, "not_found")
		return
	}
	c.AllowAnyScorerEdit = allow == 1
	c.Closed = closed == 1
	c.Role = role
	writeJSON(w, http.StatusOK, c)
}

func handleUpdateCompetition(w http.ResponseWriter, r *http.Request) {
	id, err := strconv.ParseInt(r.PathValue("id"), 10, 64)
	if err != nil {
		writeError(w, http.StatusBadRequest, "invalid_id")
		return
	}
	u := userFromCtx(r)
	role, ok := canAccessCompetition(u, id)
	if !ok || (role != "system_admin" && role != "chief_scorer") {
		writeError(w, http.StatusForbidden, "forbidden")
		return
	}
	if closed, _ := isCompetitionClosed(id); closed && role != "system_admin" {
		writeError(w, http.StatusConflict, "competition_closed")
		return
	}
	var req struct {
		Name               *string `json:"name"`
		AllowAnyScorerEdit *bool   `json:"allow_any_scorer_edit"`
		RulesLanguage      *string `json:"rules_language"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid_body")
		return
	}
	if req.Name != nil {
		db.Exec("UPDATE competitions SET name=? WHERE id=?", *req.Name, id)
	}
	if req.AllowAnyScorerEdit != nil {
		v := 0
		if *req.AllowAnyScorerEdit {
			v = 1
		}
		db.Exec("UPDATE competitions SET allow_any_scorer_edit=? WHERE id=?", v, id)
	}
	if req.RulesLanguage != nil {
		db.Exec("UPDATE competitions SET rules_language=? WHERE id=?", normalizeRulesLanguage(*req.RulesLanguage), id)
	}
	hub.broadcast(id, "competition_updated", nil)
	w.WriteHeader(http.StatusNoContent)
}

func handleDeleteCompetition(w http.ResponseWriter, r *http.Request) {
	id, err := strconv.ParseInt(r.PathValue("id"), 10, 64)
	if err != nil {
		writeError(w, http.StatusBadRequest, "invalid_id")
		return
	}
	db.Exec("DELETE FROM competitions WHERE id=?", id)
	w.WriteHeader(http.StatusNoContent)
}

func isCompetitionClosed(id int64) (bool, error) {
	var closed int
	err := db.QueryRow("SELECT closed FROM competitions WHERE id=?", id).Scan(&closed)
	if err != nil {
		return false, err
	}
	return closed == 1, nil
}

func handleCloseCompetition(w http.ResponseWriter, r *http.Request) {
	id, err := strconv.ParseInt(r.PathValue("id"), 10, 64)
	if err != nil {
		writeError(w, http.StatusBadRequest, "invalid_id")
		return
	}
	var name, rulesLang string
	if err := db.QueryRow("SELECT name,rules_language FROM competitions WHERE id=?", id).Scan(&name, &rulesLang); err != nil {
		writeError(w, http.StatusNotFound, "not_found")
		return
	}
	path, err := writeCompetitionBackup(id, name, rulesLang)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "backup_error")
		return
	}
	now := time.Now().UTC().Format(time.RFC3339)
	if _, err := db.Exec("UPDATE competitions SET closed=1, closed_at=? WHERE id=?", now, id); err != nil {
		writeError(w, http.StatusInternalServerError, "db_error")
		return
	}
	hub.broadcast(id, "competition_updated", nil)
	writeJSON(w, http.StatusOK, map[string]string{"backup": filepath.Base(path)})
}

func handleReopenCompetition(w http.ResponseWriter, r *http.Request) {
	id, err := strconv.ParseInt(r.PathValue("id"), 10, 64)
	if err != nil {
		writeError(w, http.StatusBadRequest, "invalid_id")
		return
	}
	if _, err := db.Exec("UPDATE competitions SET closed=0, closed_at='' WHERE id=?", id); err != nil {
		writeError(w, http.StatusInternalServerError, "db_error")
		return
	}
	hub.broadcast(id, "competition_updated", nil)
	w.WriteHeader(http.StatusNoContent)
}

// sanitizeFilename returns a safe filesystem fragment derived from name.
func sanitizeFilename(s string) string {
	s = strings.TrimSpace(s)
	var b strings.Builder
	for _, r := range s {
		switch {
		case r >= 'a' && r <= 'z', r >= 'A' && r <= 'Z', r >= '0' && r <= '9':
			b.WriteRune(r)
		case r == '-' || r == '_':
			b.WriteRune(r)
		case r == ' ':
			b.WriteRune('_')
		}
	}
	out := b.String()
	if len(out) > 60 {
		out = out[:60]
	}
	if out == "" {
		out = "competition"
	}
	return out
}

// writeCompetitionBackup writes a CSV snapshot of all penalties (joined with
// pilot and current rule text) into the backup directory and returns the path.
func writeCompetitionBackup(id int64, name, rulesLang string) (string, error) {
	dir := backupDir
	if dir == "" {
		dir = "backup"
	}
	if err := os.MkdirAll(dir, 0o755); err != nil {
		return "", err
	}
	rulesMu.RLock()
	ruleMap := rules[rulesLang]
	if ruleMap == nil {
		ruleMap = rules["en"]
	}
	rulesMu.RUnlock()

	rows, err := db.Query(`SELECT p.id,p.flight,p.date,p.pilot_number,
		COALESCE(pl.last_name || ', ' || pl.first_name, ''),
		p.rule_number,p.task,p.penalties_text,p.description,
		COALESCE(u.display_name, u.username),p.transferred,p.created_at,p.updated_at
		FROM penalties p
		LEFT JOIN pilots pl ON pl.competition_id=p.competition_id AND pl.number=p.pilot_number
		LEFT JOIN users u ON u.id=p.created_by
		WHERE p.competition_id=? ORDER BY p.id`, id)
	if err != nil {
		return "", err
	}
	defer rows.Close()

	ts := time.Now().UTC().Format("20060102T150405Z")
	fname := fmt.Sprintf("competition_%d_%s_%s.csv", id, sanitizeFilename(name), ts)
	path := filepath.Join(dir, fname)
	f, err := os.Create(path)
	if err != nil {
		return "", err
	}
	defer f.Close()
	cw := csv.NewWriter(f)
	defer cw.Flush()

	if err := cw.Write([]string{
		"id", "flight", "date", "pilot_number", "pilot_name", "rule_number",
		"rule_text", "suggested_penalty", "task", "penalties", "description",
		"created_by", "transferred", "created_at", "updated_at",
	}); err != nil {
		return "", err
	}
	for rows.Next() {
		var idv int64
		var flight, date, pnum, pname, rnum, task, pens, desc, creator, createdAt, updatedAt string
		var transferred int
		if err := rows.Scan(&idv, &flight, &date, &pnum, &pname, &rnum, &task, &pens, &desc, &creator, &transferred, &createdAt, &updatedAt); err != nil {
			return "", err
		}
		ruleText, suggested := "", ""
		if ru, ok := ruleMap[rnum]; ok {
			ruleText = ru.Text
			suggested = ru.SuggestedPenalty
		}
		t := "0"
		if transferred == 1 {
			t = "1"
		}
		if err := cw.Write([]string{
			strconv.FormatInt(idv, 10),
			csvSafe(flight), csvSafe(date), csvSafe(pnum), csvSafe(pname),
			csvSafe(rnum), csvSafe(ruleText), csvSafe(suggested),
			csvSafe(task), csvSafe(pens), csvSafe(desc),
			csvSafe(creator), t, createdAt, updatedAt,
		}); err != nil {
			return "", err
		}
	}
	return path, nil
}

func handleListMembers(w http.ResponseWriter, r *http.Request) {
	id, err := strconv.ParseInt(r.PathValue("id"), 10, 64)
	if err != nil {
		writeError(w, http.StatusBadRequest, "invalid_id")
		return
	}
	u := userFromCtx(r)
	if _, ok := canAccessCompetition(u, id); !ok {
		writeError(w, http.StatusForbidden, "forbidden")
		return
	}
	rows, err := db.Query(`SELECT u.id,u.username,u.display_name,cu.role
		FROM competition_users cu JOIN users u ON u.id=cu.user_id
		WHERE cu.competition_id=? ORDER BY cu.role,u.username`, id)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "db_error")
		return
	}
	defer rows.Close()
	out := []CompetitionUser{}
	for rows.Next() {
		var m CompetitionUser
		rows.Scan(&m.UserID, &m.Username, &m.DisplayName, &m.Role)
		out = append(out, m)
	}
	writeJSON(w, http.StatusOK, out)
}

func handleAddMember(w http.ResponseWriter, r *http.Request) {
	id, err := strconv.ParseInt(r.PathValue("id"), 10, 64)
	if err != nil {
		writeError(w, http.StatusBadRequest, "invalid_id")
		return
	}
	u := userFromCtx(r)
	role, ok := canAccessCompetition(u, id)
	if !ok || (role != "system_admin" && role != "chief_scorer") {
		writeError(w, http.StatusForbidden, "forbidden")
		return
	}
	var req struct {
		UserID int64  `json:"user_id"`
		Role   string `json:"role"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid_body")
		return
	}
	if req.Role != "chief_scorer" && req.Role != "scorer" {
		writeError(w, http.StatusBadRequest, "invalid_role")
		return
	}
	_, err = db.Exec("INSERT OR REPLACE INTO competition_users(competition_id,user_id,role) VALUES(?,?,?)", id, req.UserID, req.Role)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "db_error")
		return
	}
	w.WriteHeader(http.StatusNoContent)
}

func handleRemoveMember(w http.ResponseWriter, r *http.Request) {
	id, err := strconv.ParseInt(r.PathValue("id"), 10, 64)
	if err != nil {
		writeError(w, http.StatusBadRequest, "invalid_id")
		return
	}
	uid, err := strconv.ParseInt(r.PathValue("uid"), 10, 64)
	if err != nil {
		writeError(w, http.StatusBadRequest, "invalid_id")
		return
	}
	u := userFromCtx(r)
	role, ok := canAccessCompetition(u, id)
	if !ok || (role != "system_admin" && role != "chief_scorer") {
		writeError(w, http.StatusForbidden, "forbidden")
		return
	}
	db.Exec("DELETE FROM competition_users WHERE competition_id=? AND user_id=?", id, uid)
	w.WriteHeader(http.StatusNoContent)
}