// ui_account.go — self-service account surface (password change).
//
// Routes (wired in server.go):
//
//	POST /api/account/password  — JSON change-password (mounted in viewer band)
//	GET  /settings/account      — page (lands in Task F4)
//	POST /settings/account      — page submit (lands in Task F4)
package http

import (
	"encoding/json"
	stdhttp "net/http"
	"time"

	"github.com/oklog/ulid/v2"

	"gitea.dcglab.co.uk/steve/restic-manager/internal/auth"
	"gitea.dcglab.co.uk/steve/restic-manager/internal/store"
)

type passwordChangeRequest struct {
	CurrentPassword string `json:"current_password"`
	NewPassword     string `json:"new_password"`
}

func (s *Server) handleAPIAccountPassword(w stdhttp.ResponseWriter, r *stdhttp.Request) {
	u, ok := s.requireUser(r)
	if !ok {
		writeJSONError(w, stdhttp.StatusUnauthorized, "unauthorised", "")
		return
	}
	var req passwordChangeRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeJSONError(w, stdhttp.StatusBadRequest, "invalid_json", err.Error())
		return
	}
	if len(req.NewPassword) < 12 {
		writeJSONError(w, stdhttp.StatusBadRequest, "password_too_short", "min 12 chars")
		return
	}
	// Skip current-password check when must_change_password is set —
	// the user has no current password to know (only matters for the
	// legacy reset-password path; setup-token path doesn't use this).
	if !u.MustChangePassword {
		if err := auth.VerifyPassword(u.PasswordHash, req.CurrentPassword); err != nil {
			writeJSONError(w, stdhttp.StatusUnauthorized, "current_password_wrong", "")
			return
		}
	}
	hash, err := auth.HashPassword(req.NewPassword)
	if err != nil {
		writeJSONError(w, stdhttp.StatusInternalServerError, "internal", err.Error())
		return
	}
	if err := s.deps.Store.SetPasswordHash(r.Context(), u.ID, hash); err != nil {
		writeJSONError(w, stdhttp.StatusInternalServerError, "internal", err.Error())
		return
	}
	_ = s.deps.Store.AppendAudit(r.Context(), store.AuditEntry{
		ID: ulid.Make().String(), UserID: &u.ID, Actor: "user",
		Action:     "user.password_changed",
		TargetKind: ptr("user"), TargetID: &u.ID,
		TS: time.Now().UTC(),
	})
	w.WriteHeader(stdhttp.StatusOK)
}